Sample records for solder repair automobile

  1. Contact Dermatitis In Automobile Repair workers

    Joshi M P


    Full Text Available Automobile repair workers are at risk of developing skin morbidity including occupational dermatoses because of their exposure to mineral oils, petroleum products and its derivatives and lubricating oil. This cross- sectional study was carried out at Maharashtra State Road Transport Corporation workshops in Nagpur city to investigate prevalence of skin morbidity including contact dermatitis in automobile repair workers. The study included 288 (49.9% automobile repair workers 180 (31.3% workshop office staff and 109 (18.8% divisional office employees. Dermatitis was the commonest skin morbidity in all the study subjects and it was significantly more prevalent in automobile repair workers. Folliculitis was detected in 13.2% of auto â€" repair workers and was not seen in the other two groups. Increasing trend of skin morbidity was correlated with the length of service of employees. Proper protective measures along with suitable washing facilities should be provided

  2. Pulmonary function in automobile repair workers

    Chattopadhyay O


    Full Text Available Background : Automobile repair shop is a place where workers are exposed to harmful chemicals and toxic substances. Objective : To study the occurrence of obstructive and restrictive pulmonary impairment among automobile garage workers. Methods : A cross sectional study involving 151 automobile garage workers from 14 randomly selected garages of urban Kolkata. The study variables were Forced Expiratory Volume in 1 second (FEV 1 , Forced Vital Capacity (FVC, Peak Expiratory Flow Rate (PE FR, age, smoking habit, duration of work, type of work, and respiratory symptoms. The study was analysed using Regression equations, and Chi-square test. Results : All the workers were male. Obstructive impairment was seen in 25.83% of the workers whereas restrictive impairment was seen in 21.19% of the workers. Mixed obstructive and restrictive impairment was seen in 10.6% of the workers. The frequency of obstructive impairment was higher in older workers. In the age group of less than 20 years, 13.6% of the workers had obstructive impairment while 42.86% of workers above 40 years of age had obstructive impairment. Obstructive impairment was more frequently observed in battery repair workers (58.33% and spray painters (37.5% while 16.67% of the body repair workers and 30.19% of the engine mechanics had obstructive impairment. Obstructive impairment was more frequently observed in smokers (53.1 % as compared to ex-smokers (33.3% and non-smokers (6.4%. Obstructive impairment was more frequently observed in workers who had been working for a longer duration. Conclusion: Nearly 36.4% of the automobile garage workers had some form of pulmonary function impairment; obstructive and/or restrictive. The use of personal protective equipment, worker education, and discontinuation of the use of paints containing toxic pigments are recommended.

  3. Occupational injuries in automobile repair workers.

    Vyas, Heer; Das, Subir; Mehta, Shashank


    Mechanics are exposed to varied work stressors such as hot noisy environments, strenuous postures, improperly designed tools and machinery and poor psycho-social environments which may exert an influence on their health and safety. The study aimed to examine the occupational injury patterns and identify work stressors associated with injury amongst automobile mechanics. A descriptive ergonomic checklist and questionnaire on general health and psycho-social issues were administered to male workers (N=153). The relative risk factors and correlation statistics were used to identify the work stressors associated with occupational injury. 63% of the workers reported injuries. Cuts were the chief injuries being reported. Poor work environment, machinery and tool characteristics, suffering from poor health and psycho-social stressors were associated with injury occurrence amongst automobile repair workers.

  4. Evaluation of nephrotoxic effect of lead exposure among automobile repairers in Nnewi Metropolis

    Ubuo K. Amah


    Full Text Available Background: Lead toxicity is one of the most common occupational hazards that affect several organs of the body, kidney inclusive. Auto repairers are exposed to lead in petrol, radiator, leaded battery, lead soldering wire, and spray paints, thus this study was designed to evaluate lead-induced nephrotoxic effect among automobile repairers. Methods: A total of 80 male subjects within the age range of 20 and 65 years were recruited for this study. 50 subjects were occupationally exposed automobile repairers, of which 15 were electricians, 21 mechanics and 14 panel beaters/spray painters, whereas 30 were non-exposed students and staff from Nnamdi Azikiwe University, Nnewi campus. Blood sample was collected from these individuals and their blood lead levels were determined alongside creatinine, urea, uric acid, sodium, potassium, chloride and bicarbonate. Results: The results showed that the mean levels of blood lead is significantly higher in automobile repairers than in control group (P 0.05. The evaluation of the renal function markers show that, there were significant increases in the mean serum concentration of creatinine, urea, and uric acid in the study group compare to the control subjects (P 0.05. Conclusion: Findings from this study show that blood lead level is high among automobile repairers above CDC recommended level for adults. This high blood lead level among automobile repairers may be responsible for raised levels of renal markers which may eventually lead to their renal damage. [Int J Res Med Sci 2014; 2(3.000: 1107-1111

  5. Laser solder repair technique for nerve anastomosis: temperatures required for optimal tensile strength

    McNally-Heintzelman, Karen M.; Dawes, Judith M.; Lauto, Antonio; Parker, Anthony E.; Owen, Earl R.; Piper, James A.


    Laser-assisted repair of nerves is often unsatisfactory and has a high failure rate. Two disadvantages of laser assisted procedures are low initial strength of the resulting anastomosis and thermal damage of tissue by laser heating. Temporary or permanent stay sutures are used and fluid solders have been proposed to increase the strength of the repair. These techniques, however, have their own disadvantages including foreign body reaction and difficulty of application. To address these problems solid protein solder strips have been developed for use in conjunction with a diode laser for nerve anastomosis. The protein helps to supplement the bond, especially in the acute healing phase up to five days post- operative. Indocyanine green dye is added to the protein solder to absorb a laser wavelength (approximately 800 nm) that is poorly absorbed by water and other bodily tissues. This reduces the collateral thermal damage typically associated with other laser techniques. An investigation of the feasibility of the laser-solder repair technique in terms of required laser irradiance, tensile strength of the repair, and solder and tissue temperature is reported here. The tensile strength of repaired nerves rose steadily with laser irradiance reaching a maximum of 105 plus or minus 10 at 12.7 When higher laser irradiances were used the tensile strength of the resulting bonds dropped. Histopathological analysis of the laser- soldered nerves, conducted immediately after surgery, showed the solder to have adhered well to the perineurial membrane, with minimal damage to the inner axons of the nerve. The maximum temperature reached at the solder surface and at the solder/nerve interface, measured using a non-contact fiber optic radiometer and thermocouple respectively, also rose steadily with laser irradiance. At 12.7, the temperatures reached at the surface and at the interface were 85 plus or minus 4 and 68 plus or minus 4 degrees Celsius respectively

  6. Solid protein solder-doped biodegradable polymer membranes for laser-assisted tissue repair

    Hodges, Diane E.; McNally-Heintzelman, Karen M.; Welch, Ashley J.


    Solid protein solder-doped polymer membranes have been developed for laser-assisted tissue repair. Biodegradable polymer films of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) using a solvent-casting and particulate-leaching technique. The films provided a porous scaffold that readily absorbed the traditional protein solder mix composed of bovine serum albumin (BSA) and indocyanine green (ICG) dye. In vitro investigations were conducted to assess the influence of various processing parameters on the strength of tissue repairs formed using the new membranes. These parameters included the PLGA copolymer and PLGA/PEG blend ratio, the salt particle size, the initial bovine serum albumin (BSA) weight fraction, and the laser irradiance used to denature the solder. Altering the PLGA copolymer ratio had little effect on repair strength, however, it influenced the membrane degradation rate. Repair strength increased with increased membrane pore size and BSA concentration. The addition of PEG during the film casting stage increased the flexibility of the membranes but not necessarily the repair strength. The repair strength increased with increasing irradiance from 12 W/cm2 to 15 W/cm2. The new solder-doped polymer membranes provide all of the benefits associated with solid protein solders including high repair strength and improved edge coaptation. In addition, the flexible and moldable nature of the new membranes offer the capability of tailoring the membranes to a wide range of tissue geometries, and consequently, improved clinical applicability of laser- assisted tissue repair.




    Full Text Available This research work applied a simulation model in determining the optimal number of artisans to employ to carry out routine checks on vehicles on a waiting line. The waiting line under consideration is that of an automobile repair and maintenance workshop in South- Western Nigeria. The data collection was based on arrival pattern of vehicles and service pattern of artisans in the maintenance workshop. A discrete distribution was assumed for both the inter–arrival and service time patterns. An optimal number of 7 servers serving one queue were obtained as against 4 servers and 1 queue in the system in use. There was also a savings in cost of N2.45 Million per month when compared to the system in use. The results of this research work will be significant and important for decision making.

  8. Liver repair and hemorrhage control using laser soldering of liquid albumin in a porcine model

    Wadia, Yasmin; Xie, Hua; Kajitani, Michio; Gregory, Kenton W.; Prahl, Scott A.


    The purpose of this study was to evaluate laser soldering using liquid albumin for welding liver lacerations and sealing raw surfaces created by segmental resection of a lobe. Major liver trauma has a high mortality due to immediate exsanguination and a delayed morbidity and mortality from septicemia, peritonitis, biliary fistulae and delayed secondary hemorrhage. Eight laceration injuries (6 cm long X 2 cm deep) and eight non-anatomical resection injuries (raw surface 6 cm X 2 cm) were repaired. An 805 nm laser was used to weld 53% liquid albumin-ICG solder to the liver surface, reinforcing it with a free autologous omental scaffold. The animals were heparinized to simulate coagulation failure and hepatic inflow occlusion was used for vascular control. For both laceration and resection injuries, eight soldering repairs each were evaluated at three hours. A single suture repair of each type was evaluated at three hours. All 16 laser mediated liver repairs were accompanied by minimal blood loss as compared to the suture controls. No dehiscence, hemorrhage or bile leakage was seen in any of the laser repairs after three hours. In conclusion laser fusion repair of the liver is a quick and reliable technique to gain hemostasis on the cut surface as well as weld lacerations.

  9. The Relationship of Academic Courses to Skills Required of Automobile Repair Technicians

    Freund, Stephen H.


    The primary objective was to show the important need of academic skills, specifically general education coursework, to the effectiveness of the technician's expertise in the field of automobile repair. Additionally, I emphasized that one of the keys to the quality of the technician's education is the method of instruction analyzed through…

  10. The Relationship of Academic Courses to Skills Required of Automobile Repair Technicians

    Freund, Stephen H.


    The primary objective was to show the important need of academic skills, specifically general education coursework, to the effectiveness of the technician's expertise in the field of automobile repair. Additionally, I emphasized that one of the keys to the quality of the technician's education is the method of instruction analyzed…

  11. Soldering handbook

    Vianco, Paul T


    Contains information related to soldering processes, and solder joint performance and reliability. Covers soldering fundamentals, technology, materials, substrate materials, fluxes, pastes, assembly processes, inspection, and environment. Covers today's advanced joining applications and emphasizes new materials, including higher strength alloys; predictive performance; computer modeling; advanced inspection techniques; new processing concepts, including laser heating; and the resurgence in ultrasonic soldering.

  12. A study on morbidity among automobile service and repair workers in an urban area of South India.

    Philip, Mathew; Alex, Reginald G; Sunny, Soumya S; Alwan, Anand; Guzzula, Deepak; Srinivasan, Rajan


    Service sector in Indian industrial growth has obtained significant numbers. Automobile service industry is one of the largest in the world with a majority of the workers in unorganized sector of the industry. This study was carried out among auto service industry workers in Vellore urban area to assess possible occupation related morbidity. A cross-sectional observation study was carried out among 106 automobile repair shop workers. Half (47%) suffered work related stress, 32 (30.2%) reported exposure to dust, 81 (76%) to heat, and 50 (17%) to hazardous chemicals and heavy metals. More than 90% reported over exposure to petroleum products. A third reported cough for more than 2 weeks, more than a quarter reported gastrointestinal symptoms associated with work. Half of them reported musculoskeletal complaints associated with work with a quarter reporting un-intentional work place injuries. A tenth of them were found to have reduced pulmonary function on testing and nearly half had impaired sensory functions in peripheries. Reduced pulmonary function was found to be significantly associated with heavy metal exposure (P = 0.001). Peripheral neuropathy was significantly associated with years of occupation (P = 0.001), exposure to petroleum products (P = 0.03) and exposure to heavy metals (P = 0.018). Half of the workers were unaware of health problems associated with their occupational exposures and thereby the use of personal protection is abysmally low. A very high proportion of workers had symptoms of cough, breathlessness, abdominal pain, abdominal discomfort and muscle aches. Almost a quarter of the workers had un-intentional occupational injuries in the last 6 months. Though they work in a high-risk environment with chances of fire hazard, falls and chemical exposures, none of the workshops had fire-extinguishers, first aid kits or any such safety devices.

  13. A study on morbidity among automobile service and repair workers in an urban area of South India

    Mathew Philip


    Full Text Available Introduction: Service sector in Indian industrial growth has obtained significant numbers. Automobile service industry is one of the largest in the world with a majority of the workers in unorganized sector of the industry. This study was carried out among auto service industry workers in Vellore urban area to assess possible occupation related morbidity. Materials and Methods: A cross-sectional observation study was carried out among 106 automobile repair shop workers. Results: Half (47% suffered work related stress, 32 (30.2% reported exposure to dust, 81 (76% to heat, and 50 (17% to hazardous chemicals and heavy metals. More than 90% reported over exposure to petroleum products. A third reported cough for more than 2 weeks, more than a quarter reported gastrointestinal symptoms associated with work. Half of them reported musculoskeletal complaints associated with work with a quarter reporting un-intentional work place injuries. A tenth of them were found to have reduced pulmonary function on testing and nearly half had impaired sensory functions in peripheries. Reduced pulmonary function was found to be significantly associated with heavy metal exposure (P = 0.001. Peripheral neuropathy was significantly associated with years of occupation (P = 0.001, exposure to petroleum products (P = 0.03 and exposure to heavy metals (P = 0.018. Discussion: Half of the workers were unaware of health problems associated with their occupational exposures and thereby the use of personal protection is abysmally low. A very high proportion of workers had symptoms of cough, breathlessness, abdominal pain, abdominal discomfort and muscle aches. Almost a quarter of the workers had un-intentional occupational injuries in the last 6 months. Though they work in a high-risk environment with chances of fire hazard, falls and chemical exposures, none of the workshops had fire-extinguishers, first aid kits or any such safety devices.

  14. Cumulative asbestos exposure for US automobile mechanics involved in brake repair (circa 1950s-2000).

    Finley, Brent L; Richter, Richard O; Mowat, Fionna S; Mlynarek, Steve; Paustenbach, Dennis J; Warmerdam, John M; Sheehan, Patrick J


    We analyzed cumulative lifetime exposure to chrysotile asbestos experienced by brake mechanics in the US during the period 1950-2000. Using Monte Carlo methods, cumulative exposures were calculated using the distribution of 8-h time-weighted average exposure concentrations for brake mechanics and the distribution of job tenure data for automobile mechanics. The median estimated cumulative exposures for these mechanics, as predicted by three probabilistic models, ranged from 0.16 to 0.41 fibers per cubic centimeter (f/cm(3)) year for facilities with no dust-control procedures (1970s), and from 0.010 to 0.012 f/cm(3) year for those employing engineering controls (1980s). Upper-bound (95%) estimates for the 1970s and 1980s were 1.96 to 2.79 and 0.07-0.10 f/cm(3) year, respectively. These estimates for US brake mechanics are consistent with, but generally slightly lower than, those reported for European mechanics. The values are all substantially lower than the cumulative exposure of 4.5 f/cm(3) year associated with occupational exposure to 0.1 f/cm(3) of asbestos for 45 years that is currently permitted under the current occupational exposure limits in the US. Cumulative exposures were usually about 100- to 1,000-fold less than those of other occupational groups with asbestos exposure for similar time periods. The cumulative lifetime exposure estimates presented here, combined with the negative epidemiology data for brake mechanics, could be used to refine the risk assessments for chrysotile-exposed populations.

  15. Wave soldering with Pb-free solders

    Artaki, I.; Finley, D.W.; Jackson, A.M.; Ray, U. [AT and T Bell Labs., Princeton, NJ (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)


    The manufacturing feasibility and attachment reliability of a series of newly developed lead-free solders were investigated for wave soldering applications. Some of the key assembly aspects addressed included: wettability as a function of board surface finish, flux activation and surface tension of the molten solder, solder joint fillet quality and optimization of soldering thermal profiles. Generally, all new solder formulations exhibited adequate wave soldering performance and can be considered as possible alternatives to eutectic SnPb for wave soldering applications. Further process optimization and flux development is necessary to achieve the defect levels associated with the conventional SnPb process.

  16. Soldering in electronics assembly

    Judd, Mike


    Soldering in Electronics Assembly discusses several concerns in soldering of electronic assemblies. The book is comprised of nine chapters that tackle different areas in electronic assembly soldering. Chapter 1 discusses the soldering process itself, while Chapter 2 covers the electronic assemblies. Chapter 3 talks about solders and Chapter 4 deals with flux. The text also tackles the CS and SC soldering process. The cleaning of soldered assemblies, solder quality, and standards and specifications are also discussed. The book will be of great use to professionals who deal with electronic assem

  17. Bioaccumulation and cancer risk of polycyclic aromatic hydrocarbons in leafy vegetables grown in soils within automobile repair complex and environ in Uyo, Nigeria.

    Inam, Edu; Ibanga, Felicia; Essien, Joseph


    Using gas chromatography-mass spectrometry and an incremental lifetime cancer risks (ILCRs) assessment model, the bioaccumulation and cancer risk of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in leafy vegetables (Vernonia amygdalina and Lasianthera africanum) grown in soils within an automobile repair complex environment in Uyo, Nigeria was studied. The total PAHs concentrations recorded for soils ranged from 0.02 to 1.77 mg/kg. The highest level of 1.77 mg/kg was recorded for soils from the main automobile repair complex (site 1). Low molecular weight (LMW) PAHs were predominant although some high molecular weight (HMW) PAHs suites (0.04 mg/kg of chrysene and 0.04 of benzo[k]fluoranthene) were also found in site 1. The leafy vegetables accumulated PAHs were mostly LMW. Accumulation levels were similar but the extent of PAH uptake in vegetables was species dependent as V. amygdalina accumulated more (0.81 mg/kg). The bioaccumulation factors (BaFs) calculated ranged from 0.22 to 0.63 for L. africanum, and 0.18 to 0.55 for V. amygdalina in site 1 where high PAH levels were recorded in soil. Pearson correlation coefficient analysis revealed a strong positive relation between the PAH content of soil and the amount accumulated by L. africanum (r = 0.5) and V. amygdalina (r = 0.8) at p = 0.05. The vegetable's potential to bioaccumulate PAHs is indicative of their use as good bioindicators for PAH contamination in soil. Only two of the USEPA possible human carcinogenic PAHs were detected, and carcinogenic risk assessment based on occupational exposures to soil particles by adults revealed that the total risk level (7.17 × 10(-5)) contribution from incidental soil ingestion, dermal contact, and soil particle dust inhalation slightly exceed the USEPA acceptable limits (automobile repair complexes across Nigeria.

  18. How vulnerable are automobile repair workers to HIV/AIDS? A quantitative and qualitative assessment in a slum of Kolkata,India

    Mukherjee Shuvankar


    Full Text Available Background: Automobile repair workers may run high risk of acquiring HIV/AIDS infection owing to their socio cultural background. A cross- sectional study was conducted among them in Chetla, Kolkata to assess knowledge, attitude and practices related to HIV/AIDS and to find out difference in knowledge status based on different socio-demographic variables. Materials and Methods: Both qualitative and quantitative methods were adopted. A total of 114 male workers were interviewed from randomly selected 12 automobile garages using pre-designed, pre-tested schedule. A uniform scoring system for knowledge was adopted. Chi-square test was applied to find out difference in knowledge score based on different socio-demographic variables. Qualitative analysis was performed after conducting in-depth interview with 24 participants. Results: About 84% belonged to 15-35 years age group with mean age 26.3(+ 2.7 years. Overall, 63.2% had poor knowledge score. Higher difference in knowledge score was obtained with higher literacy status and age (p<0.05. About 29 % of the respondents opined that People Living with HIV/AIDS (PLHAs should not continue their work and 47.4% commented that PLHAs should not reveal their HIV status. One of the three participants who had commercial sex in last 12 months did not use condom. Two participants complained about symptom of genital discharge in last 12 months and none underwent any treatment. Qualitative analysis revealed low awareness level and discriminatory attitude towards PLHAs.Conclusions: Poor level of knowledge and unfavourable attitude of the participants were observed from both quantitative and qualitative analyses though they could not be considered high risk group. Appropriate communication for behavioural change both by group approach and by interpersonal communication was required.

  19. Optimal Allocation of Repair Shops in the Automobile Recall%缺陷汽车召回所需安排的最优维修店数目

    熊中楷; 刘学勇; 郭年


    讨论了缺陷汽车产品制造商在汽车召回事件中如何安排最优维修店数目.假设汽车制造商在召回期限内维修几乎全部召回汽车,车主逗留时间和维修时间都服从指数分布,并且假设维修人员会根据库存水平(车位)调整维修速度.选取制造商安排组织的维修店数目为决策变量,利用有限源排队理论建立了成本控制模型.搜索算法确定了最优的维修店数目,使得期望总成本最小.%Toyota Motor Corporation has recalled more than 8.5 million defective vehicles since March 2010 according to a Reuters report. The State Administration of Quality Supervision Defective Product Management Center ( AQSIQ) is formed by nearly 60 domestic and foreign automobile manufacturers. An AQSIQ report shows that there had been 212 active recall, and recall of 321 thousand units of vehicles from 2004 to 2009.In 2009 China had 57 auto recalls, and involved 1, 364, 820 vehicles and 33 companies. The number of auto recalls in 2009 is 1. 5 times more than that in 2008. Twenty nine recalls involve 1, 283 , 400 domestic cars. The number of recalls is higher than that of imported cars. The average recall completion rate of enterprises is more than 85. 5% . Regardless the number of recalls, the number of auto recall in China reached the in the history of a new high record, according to the AQSIQ. Car market in 2009 and 2010, a significant change in the recall is voluntarily recalling its own brand awareness began to increase. As a corporate strategic decision, the subtle optimization on product recall decision leads to fruitful academic contributions and managerial insights.When launching product recall, the motor manufacturer must organize repairers to recover defective vehicles as well as bear the repair fees and necessary logistical costs. Then, the optimal number of repairers is an important managerial issue. If too few repairers are organized, the great number of defective vehicles that wait

  20. 汽车发动机的维修与保养分析%Repair and maintenance of automobile engine



    With the continued growth of the national economy, people's living standards improve, the automotive in-dustry significantly increased the pace of development. Car engine is a core part of automotive parts, but also to start the car the only member which is not only to ensure quality performance guarantee safe driving cars, but also extend vehicle life. Therefore, to do routine maintenance and repair car engine work is very important. Articles will be corporate engine repair and maintenance work to discuss, to understand the basic principles of automotive engine, and its routine mainte-nance and repair to propose effective countermeasures.%随着国民经济持续增长,人们生活水平不断提高,汽车工业的发展速度显著提高。汽车发动机是汽车零部件的核心部分,也是启动汽车的唯一部件,其质量性能保障不仅保证汽车安全驾驶,还延长汽车使用寿命。因此,做好汽车发动机日常维修与保养工作十分重要。文章将对企业发动机的维修与保养工作展开讨论,了解汽车发动机的基本原理,并对其日常保养与维修提出有效的对策。

  1. An Exploration into The Application of Multi-media Teaching in Automobile Maintenance and Repair Major%多媒体网络教学在汽车维修中的应用探索



    校园网上实现多媒体教学,是每个学校致力开发一个项目。汽车产业作为国民支柱的重要领头项目,其中汽车维修起着举足轻重地位,有着得天独厚的优势。多媒体网络教学的应用和发展有利于提高汽车维修教学改革水平,扩展教学改革思路。通过我校多媒体教学的尝试,探索多媒体网络教学在现代职业教育层面上的作用,特别是在汽车维修中应用的几点体会,为机电一体化教学改革提出新的思路,有利于我国汽车维修事业的蓬勃发展。%To achieve teaching through multi-media in campus network is a program that each school is engaged in,automobile industry is an important national leading pillar program,and automobile maintenance and repair plays an important role and it has special advantages,the application and development of teaching through multi-media network helps to improve the teaching and reform level of automobile maintenance and repair and extend the thought on teaching reform.Attempts to teaching through multi-media network in our school,exploration into the effect of teaching through multi-media network on modern vocational education and the experience about the application in automobile maintenance and repair provide new ideas for the reform of the teaching of integration of mechatronics,it would be conducive to the flourishing development of automobile maintenance and repair business.

  2. Solderability test system

    Yost, Fred (Cedar Crest, NM); Hosking, Floyd M. (Albuquerque, NM); Jellison, James L. (Albuquerque, NM); Short, Bruce (Beverly, MA); Giversen, Terri (Beverly, MA); Reed, Jimmy R. (Austin, TX)


    A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time.

  3. Solderability test system

    Yost, F.; Hosking, F.M.; Jellison, J.L.; Short, B.; Giversen, T.; Reed, J.R.


    A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time. 11 figs.

  4. Reduced oxide soldering activation (ROSA) PWB solderability testing

    Hernandez, C.L.; Hosking, F.M. [Sandia National Labs., Albuquerque, NM (United States). Physical and Joining Metallurgy Dept.; Reed, J. [Texas Instruments, Austin, TX (United States); Tench, D.M.; White, J. [Rockwell Science Center, Thousand Oaks, CA (United States)


    The effect of ROSA pretreatment on the solderability of environmentally stressed PWB test coupons was investigated. The PWB surface finish was an electroplated, reflowed solder. Test results demonstrated the ability to recover plated-through-hole fill of steam aged samples with solder after ROSA processing. ROSA offers an alternative method for restoring the solderability of aged PWB surfaces.

  5. Lead-free solder

    Anderson, Iver E. (Ames, IA); Terpstra, Robert L. (Ames, IA)


    A Sn--Ag--Cu eutectic alloy is modified with one or more low level and low cost alloy additions to enhance high temperature microstructural stability and thermal-mechanical fatigue strength without decreasing solderability. Purposeful fourth or fifth element additions in the collective amount not exceeding about 1 weight % (wt. %) are added to Sn--Ag--Cu eutectic solder alloy based on the ternary eutectic Sn--4.7%Ag--1.7%Cu (wt. %) and are selected from the group consisting essentially of Ni, Fe, and like-acting elements as modifiers of the intermetallic interface between the solder and substrate to improve high temperature solder joint microstructural stability and solder joint thermal-mechanical fatigue strength.

  6. Removing Dross From Molten Solder

    Webb, Winston S.


    Automatic device helps to assure good solder connections. Machine wipes dross away from area on surface of molten solder in pot. Sweeps across surface of molten solder somewhat in manner of windshield wiper. Each cycle of operation triggered by pulse from external robot. Equipment used wherever precise, automated soldering must be done to military specifications.

  7. Imaging and Analysis of Void-defects in Solder Joints Formed in Reduced Gravity using High-Resolution Computed Tomography

    Easton, John W.; Struk, Peter M.; Rotella, Anthony


    As a part of efforts to develop an electronics repair capability for long duration space missions, techniques and materials for soldering components on a circuit board in reduced gravity must be developed. This paper presents results from testing solder joint formation in low gravity on a NASA Reduced Gravity Research Aircraft. The results presented include joints formed using eutectic tin-lead solder and one of the following fluxes: (1) a no-clean flux core, (2) a rosin flux core, and (3) a solid solder wire with external liquid no-clean flux. The solder joints are analyzed with a computed tomography (CT) technique which imaged the interior of the entire solder joint. This replaced an earlier technique that required the solder joint to be destructively ground down revealing a single plane which was subsequently analyzed. The CT analysis technique is described and results presented with implications for future testing as well as implications for the overall electronics repair effort discussed.

  8. Albumin-genipin solder for laser tissue welding

    Lauto, Antonio; Foster, John; Avolio, Albert; Poole-Warren, Laura


    Background. Laser tissue soldering (LTS) is an alternative technique to suturing for tissue repair. One of the major drawbacks of LTS is the weak tensile strength of the solder welds when compared to sutures. In this study, the possibility was investigated for a low cytotoxic crosslinker, acting on amino groups, to enhance the bond strength of albumin solders. Materials and Methods. Solder strips were welded onto rectangular sections of sheep small intestine by a diode laser. The laser delivered in continuous mode mode a power of 170 +/- 10 mW at λ=808 nm, through a multimode optical fiber (core size = 200 μm) to achieve a dose of 10.8 +/- 0.5 J/mg. The solder thickness and surface area were kept constant throughout the experiment (thickness = 0.15 +/- 1 mm, area = 12 +/- 1.2 mm2). The solder incorporated 62% bovine serum albumin, 0.38% genipin, 0.25% indocyanin green dye (IG) and water. Tissue welding was also performed with a similar solder, which did not incorporate genipin, as a control group. The repaired tissue was tested for tensile strength by a calibrated tensiometer. Results. The tensile strength of the "genipin" solder was twice as high as the strength of the BSA solder (0.21 +/- 0.04 N and 0.11 +/- 0.04 N respectively; p~10-15 unpaired t-test, N=30). Discussion. Addition of a chemical crosslinking agent, such as genipin, significantly increased the tensile strength of adhesive-tissue bonds. A proposed mechanism for this enhanced bond strength is the synergistic action of mechanical adhesion with chemical crosslinking by genipin.

  9. Solder dross removal apparatus

    Webb, Winston S. (Inventor)


    An automatic dross removal apparatus (10) is disclosed for removing dross from the surface of a solder bath (22) in an automated electric component handling system. A rotatable wiper blade (14) is positioned adjacent the solder bath (22) which skims the dross off of the surface prior to the dipping of a robot conveyed component into the bath. An electronic control circuit (34) causes a motor (32) to rotate the wiper arm (14) one full rotational cycle each time a pulse is received from a robot controller (44) as a component approaches the solder bath (22).

  10. An Analysis on Working-learning Integrated Teaching Mode or Automobile Maintenance & Repair Major%汽车维修专业"工学一体化"教学模式分析



    With the reform of teaching,working-learning integrated teaching mode has become critical point to the reform of teaching in automobile maintenance and repair major in vocational colleges,it is playing an important role.and can meet the demand on competent personnel specialized in automobile maintenance and repair in social market,it also conform to the objective law of social economic as to push the modernization of vocational education in our country onto a new way.%在教学改革中,"工学一体化"教学模式已成为当前职业院校汽车维修专业教学改革的关键点,扮演着重要的角色,能够满足社会市场对汽车维修专业高素质人才的需求,也是对社会经济发展客观规律的顺应. 以此,不断推动我国现代化职业教育走上全新的发展道路.

  11. Tissue soldering with biodegradable polymer films: in-vitro investigation of hydration effects on weld strength

    Sorg, Brian S.; Welch, Ashley J.


    Previous work demonstrated increased breaking strengths of tissue repaired with liquid albumin solder reinforced with a biodegradable polymer film compared to unreinforced control specimens. It was hypothesized that the breaking strength increase was due to reinforcement of the liquid solder cohesive strength. Immersion in a moist environment can decrease the adhesion of solder to tissue and negate any strength benefits gained from reinforcement. The purpose of this study was to determine if hydrated specimens repaired with reinforced solder would still be stronger than unreinforced controls. A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green dye was used to repair an incision in bovine aorta. The solder was coagulated with 806-nm diode laser light. A poly(DL-lactic- co-glycolic acid) film was used to reinforce the solder (the controls had no reinforcement). The repaired tissues were immersed in phosphate buffered saline for time periods of 1 and 2 days. The breaking strengths of all of the hydrated specimens decreased compared to the acute breaking strengths. However, the reinforced specimens still had larger breaking strengths than the unreinforced controls. These results indicate that reinforcement of a liquid albumin solder may have the potential to improve the breaking strength in a clinical setting.

  12. Low temperature aluminum soldering analysis

    Peterkort, W.G.


    The investigation of low temperature aluminum soldering included the collection of spread factor and dihedral angle data for several solder alloys and a study of flux effects on aluminum. Selected solders were subjected to environmental tests and evaluated on the basis of tensile strength, joint resistance, visual appearance, and metallurgical analysis. A production line method for determining adequate flux removal was developed.

  13. Microwave Tissue Soldering for Immediate Wound Closure

    Arndt, G. Dickey; Ngo, Phong H.; Phan, Chau T.; Byerly, Diane; Dusl, John; Sognier, Marguerite A.; Carl, James


    A novel approach for the immediate sealing of traumatic wounds is under development. A portable microwave generator and handheld antenna are used to seal wounds, binding the edges of the wound together using a biodegradable protein sealant or solder. This method could be used for repairing wounds in emergency settings by restoring the wound surface to its original strength within minutes. This technique could also be utilized for surgical purposes involving solid visceral organs (i.e., liver, spleen, and kidney) that currently do not respond well to ordinary surgical procedures. A miniaturized microwave generator and a handheld antenna are used to deliver microwave energy to the protein solder, which is applied to the wound. The antenna can be of several alternative designs optimized for placement either in contact with or in proximity to the protein solder covering the wound. In either case, optimization of the design includes the matching of impedances to maximize the energy delivered to the protein solder and wound at a chosen frequency. For certain applications, an antenna could be designed that would emit power only when it is in direct contact with the wound. The optimum frequency or frequencies for a specific application would depend on the required depth of penetration of the microwave energy. In fact, a computational simulation for each specific application could be performed, which would then match the characteristics of the antenna with the protein solder and tissue to best effect wound closure. An additional area of interest with potential benefit that remains to be validated is whether microwave energy can effectively kill bacteria in and around the wound. Thus, this may be an efficient method for simultaneously sterilizing and closing wounds.

  14. 汽车底盘的保养与维修方法探讨%Discussion on maintenance and repair methods of automobile chassis



    The chassis is an important part of the car,car driven mainly by the subject,strengthen the daily maintenance of the chassis and maintenance is to extend the service life of automobile is an important way,is also promoting China's automobile production and application to achieve further technology high quality development in an effective way,realize the modern means of science and technology in the automobile industry in the development of application and innovation and development.%汽车底盘是汽车车中的重要组成部分,是汽车驱动下主要受重主体,加强对汽车底盘的日常保养和维护是延长汽车寿命的重要途径,同时也是促进我国汽车生产、应用进一步实现技术高质量发展的有效途径,实现现代科学技术手段在汽车事业发展中的应用与创新发展。

  15. Laser Soldering of Rat Skin Using a Controlled Feedback System

    Mohammad Sadegh Nourbakhsh


    Full Text Available Introduction: Laser tissue soldering using albumin and indocyanine green dye (ICG is an effective technique utilized in various surgical procedures. The purpose of this study was to perform laser soldering of rat skin under a feedback control system and compare the results with those obtained using standard sutures. Material and Methods: Skin incisions were made over eight rats’ dorsa, which were subsequently closed using different wound closure interventions in two groups: (a using a temperature controlled infrared detector or (b by suture. Tensile strengths were measured at 2, 5, 7 and 10 days post-incision. Histological examination was performed at the time of sacrifice. Results: Tensile strength results showed that during the initial days following the incisions, the tensile strengths of the sutured samples were greater than the laser samples. However, 10 days after the incisions, the tensile strengths of the laser soldered incisions were higher than the sutured cuts. Histopathological examination showed a preferred wound healing response in the soldered skin compared with the control samples. The healing indices of the laser soldered repairs (426 were significantly better than the control samples (340.5. Conclusion: Tissue feedback control of temperature and optical changes in laser soldering of skin leads to a higher tensile strength and better histological results and hence this method may be considered as an alternative to standard suturing.

  16. Low-temperature solder for laser tissue welding

    Lauto, Antonio; Stewart, Robert B.; Felsen, D.; Foster, John; Poole-Warren, Laura; Poppas, Dix P.


    In this study, a two layer (TL) solid solder was developed with a fixed thickness to minimize the difference in temperature across the solder (ΔT) and to weld at low temperature. Solder strips comprising two layers (65% albumin, 35% water) were welded onto rectangular sections of dog small intestine by a diode laser (λ = 808 nm). The laser delivered a power of 170 +/- 10 mW through an optical fiber (spot size approximately 1 mm) for 100 seconds. A solder layer incorporated also a dye (carbon black, 0.25%) to absorb the laser radiation. A thermocouple and an infrared thermometer system recorded the temperatures at the tissue interface and at the external solder surface, during welding. The repaired tissue was tested for tensile strength by a calibrated tensiometer. The TL strips were able to minimize ΔT (12 +/- 4°C) and control the temperature at tissue-interface. The strips fused on tissue at 55=70°C for tissue repair, which cause more irreversible thermal damage.

  17. Mechanical properties of QFP micro-joints soldered with lead-free solders using diode laser soldering technology

    HAN Zong-jie; XUE Song-bai; WANG Jian-xin; ZHANG Xin; ZHANG Liang; YU Sheng-lin; WANG Hui


    Soldering experiments of quad flat package(QFP) devices were carried out by means of diode laser soldering system with Sn-Ag-Cu and Sn-Cu-Ni lead-free solders, and competitive experiments were also carried out not only with Sn-Pb eutectic solders but also with infrared reflow soldering method. The results indicate that under the conditions of laser continuous scanning mode as well as the fixed laser soldering time, an optimal power exists, while the optimal mechanical properties of QFP micro-joints are gained. Mechanical properties of QFP micro-joints soldered with laser soldering system are better than those of QFP micro-joints soldered with IR reflow soldering method. Fracture morphologies of QFP micro-joints soldered with laser soldering system exhibit the characteristic of tough fracture, and homogeneous and fine dimples appear under the optimal laser output power.

  18. Soldering of Nanotubes onto Microelectrodes

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina


    Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing solder...... bonds were formed at the intersection of the nanotube and the electrodes. Current-voltage curves indicated metallic conduction of the nanotubes, with resistances in the range of 9-29 kOmega. Bridges made entirely of the soldering material exhibited resistances on the order of 100 Omega, and the solder...... bonds were consistently found to be mechanically stronger than the carbon nanotubes....

  19. Capillary flow solder wettability test

    Vianco, P.T.; Rejent, J.A.


    A test procedure was developed to assess the capillary flow wettability of solders inside of a confined geometry. The test geometry was comprised of two parallel plates with a controlled gap of constant thickness (0.008 cm, 0.018 cm, 0.025 cm, and 0.038 cm). Capillary flow was assessed by: (1) the meniscus or capillary rise of the solder within the gap, (2) the extent of void formation in the gap, and (3) the time-dependence of the risen solder film. Tests were performed with the lead-free solders.

  20. Dural reconstruction by fascia using a temperature-controlled CO2 laser soldering system

    Forer, Boaz; Vasilyev, Tamar; Brosh, Tamar; Kariv, Naam; Gil, Ziv; Fliss, Dan M.; Katzir, Abraham


    Conventional methods for dura repair are normally based on sutures or stitches. These methods have several disadvantages: (1) The dura is often brittle, and the standard procedures are difficult and time consuming. (2) The seal is leaky. (3) The introduction of a foreign body (e.g. sutures) may cause an inflammatory response. In order to overcome these difficulties we used a temperature controlled fiber optic based CO2 laser soldering system. In a set of in vitro experiments we generated a hole of diameter 10 mm in the dura of a pig corpse, covered the hole with a segment of fascia, and soldered the fascia to the edges of the hole, using 47% bovine albumin as a solder. The soldering was carried out spot by spot, and each spot was heated to 65° C for 3-6 seconds. The soldered dura was removed and the burst pressure of the soldered patch was measured. The average value for microscopic muscular side soldering was 194 mm Hg. This is much higher than the maximal physiological pressure of the CSF fluid in the brain, which is 15 mm Hg. In a set of in vivo experiments, fascia patches were soldered on holes in five farm pigs. The long term results of these experiments were very promising. In conclusion, we have developed an advanced technique for dural reconstruction, which will find important clinical applications.

  1. Enhanced laser tissue soldering using indocyanine green chromophore and gold nanoshells combination.

    Khosroshahi, Mohammad E; Nourbakhsh, Mohammad S


    Gold nanoshells (GNs) are new materials that have an optical response dictated by the plasmon resonance. The wavelength at which the resonance occurs depends on the core and shell sizes. The purposes of this study were to use the combination of indocyanine green (ICG) and different concentration of gold nanoshells for skin tissue soldering and also to examine the effect of laser soldering parameters on the properties of repaired skin. Two mixtures of albumin solder and different combinations of ICG and gold nanoshells were prepared. A full thickness incision of 2 × 20 mm(2) was made on the surface and after addition of mixtures it was irradiated by an 810 nm diode laser at different power densities. The changes of tensile strength (σ(t)) due to temperature rise, number of scan (Ns), and scan velocity (Vs) were investigated. The results showed at constant laser power density (I), σ(t) of repaired incisions increases by increasing the concentration of gold nanoshells in solder, Ns, and decreasing Vs. It was demonstrated that laser soldering using combination of ICG + GNs could be practical provided the optothermal properties of the tissue are carefully optimized. Also, the tensile strength of soldered skin is higher than skins that soldered with only ICG or GNs. In our case, this corresponds to σ(t) = 1800 g cm(-2) at I ∼ 47 Wcm(-2), T ∼ 85 [ordinal indicator, masculine]C, Ns = 10, and Vs = 0.3 mms(-1).

  2. Analysis on the Current Situation of“Dual-Qualification”Teachers in the Teaching of “Automobile Repair and Maintenance”Major%“双师型”教师在“汽修”专业教学中的现状分析



    In recent years, with the rapid development of automo-bile industry, more and more automobile related occupations ap-peared, and the demand for professional automobile talents is ris-ing. Therefore, secondary vocational schools and higher vocation-al colleges all over the country have successively opened related majors such as automobile repair and maintenance, automobile manufacture and assembling, automobile marketing, etc., in order to train application-oriented automobile talents with certain technical ability. However, vocational education is faced with many problems, such as poor basic knowledge of students, insuf-ficient funds, backward equipment, and even the gap between the basic conditions of running a vocational school and national re-quirements, especially the big problems of teaching staff, etc. This paper detailed and analyzed the current situation of“dual-qualifi-cation”teachers in the teaching of automobile repair and mainte-nance major.%近年来,随着汽车产业的快速发展,与汽车相关的职业岗位越来越多,对汽车专业人才的需求也随之高涨。因此,在全国各地市中等职业学校和高等职业院校相继开设汽车检测与维修、汽车制造与装配、汽车营销等相关专业,以培养具有一定技术能力水平的汽车专业应用型人才十分必要。但是,职业教育面临着很多问题,比如学生入学成绩和知识基础差,学校资金不足,设备落后,甚至办学基本条件都达不到国家要求,尤其是在师资力量方面存在很大的问题。本文就“双师型”教师在汽车检测与维修专业教学中的现状做具体阐述分析。

  3. SnAg-alloy coating for connectors and soldering applications; Alliages SnAg pour revetements de connecteurs et brasage

    Buresch, I. [Wieland-Werke AG, Ulm (Germany)


    The announced ban of lead in electronic products (WEEE-Waste Electrical and Electronic Equipment from 2006 onwards) is one chance to implement better alternatives. It is a challenge for researcher to develop one alternative which fulfills the different requirements for conditions in use for connectors and production like soldering. The system SnAgCu gives us.good opportunities for soldering applications and as a coating material for connectors. The tin-silver-copper alloy SnTOP meets the engine compartment requirements in automobiles in terms of temperature exposure while simultaneously provide low insertion forces using it as a functional coating on connectors combined with good solderability using it as a solder. (authors)

  4. 游戏化汽车维修学习软件的开发研究%Research and development of automobile repair game-based learning software



    The common automotive repair knowledge is selected as the main content in this study. The car owners and car major students are taken as the target population to develop games-based learning software by means of Flash game engine. The game-based learning software has transcended the old onefold teaching method which only adopts the introductory content such as characters,images,etc. It use Flash technology to make a virtual auto repair factory in which learners can learn vehicle main-tenance knowledge intuitively. Meanwhile the enjoyment of the game makes learners more actively to achieve better learning out-come.%该研究选取常见的汽车维修知识为主要内容,以有车一族和汽车专业学习者为目标人群,利用Flash游戏引擎开发游戏化学习软件。在该游戏化学习软件中,突破了以往仅仅是文字、图片等介绍性为主的单一教学方式,通过Flash技术让现实中的汽车修理厂再现,让学习者能够在创设的虚拟情景中直观地学习汽车维修知识。同时游戏的趣味性能够让学习者在学习中更加主动,取得较好的学习效果。

  5. Soldering Formalism Theory and Applications

    Wotzasek, C


    The soldering mechanism is a new technique to work with distinct manifestations of dualities that incorporates interference effects, leading to new physical results that includes quantum contributions. This approach was used to investigate the cases of electromagnetic dualities, and $D\\geq 2$ bosonization. In the former context this technique is applied for the quantum mechanical harmonic oscillator, the scalar field theory in two dimensions and the Maxwell theory in four dimensions. The soldered actions in any dimension leads to a master action which is duality invariant under a much bigger set of symmetries. The effects of coupling to gravity are also elaborated. In the later context, a technique is developed that solders the dual aspects of some symmetry following from the bosonisation of two distinct fermionic models, leading to new results which cannot be otherwise obtained. Exploiting this technique, the two dimensional chiral determinants with opposite chirality are soldered to reproduce either the usu...

  6. Solar Energy Automobile

    He, Jianhua


    The thesis was to design a solar energy automobile, which is using solar power as energy re-source. At the moment, Finland was chosen as an example place. It was necessary to calculate the related data, which are the solar angle and the day length when designing the solar energy automobile. Also the seats and dashboard to improve the performance. Actually, in Finland it is possible to use solar energy automobile in summer. But in winter, the day length is so short and the solar constant i...

  7. Solar Energy Automobile

    He, Jianhua


    The thesis was to design a solar energy automobile, which is using solar power as energy re-source. At the moment, Finland was chosen as an example place. It was necessary to calculate the related data, which are the solar angle and the day length when designing the solar energy automobile. Also the seats and dashboard to improve the performance. Actually, in Finland it is possible to use solar energy automobile in summer. But in winter, the day length is so short and the solar constant i...

  8. Modeling of high temperature- and diffusion-controlled die soldering in aluminum high pressure die casting

    Domkin, Konstantin; Hattel, Jesper Henri; Thorborg, Jesper


    Soldering of cast alloys to the dies has been a continuing source of die surface damage in the aluminum die-casting industry. To reduce the repair and maintenance costs, an approach to modeling the damage and predicting the die lifetime is required. The aim of the present study is the estimation...... of the die lifetime based on a quantitative analysis of die soldering in the framework of the numerical simulations of the die-casting process. Full 3D simulations of the process, including the filling. solidification, and the die cooling, are carried out using the casting simulation software MAGMAsoft....... The resulting transient temperature fields on the die surface and in the casting are then post-processed to estimate the die soldering. The present work deals only with the metallurgical/chemical kind of soldering which occurs at high temperatures and involves formation and growth of intermetallic layers...

  9. In-vitro Investigations of Skin Closure using Diode Laser and Protein Solder Containing Gold Nanoshells

    Mohammad Sadegh Nourbakhsh


    Full Text Available Introduction: Laser tissue soldering is a new technique for repair of various tissues including the skin, liver, articular cartilage and nerves and is a promising alternative to suture. To overcome the problems of thermal damage to surrounding tissues and low laser penetration depth, some exogenous chromophores such as gold nanoshells, a new class of nanoparticles consisting of a dielectric core surrounded by a thin metal shell, are used. The aims of this study were to use two different concentrations of gold nanoshells as the exogenous material for skin tissue soldering and also to examine the effects of laser soldering parameters on the properties of the repaired skin. Material and Methods: Two mixtures of albumin solder and different concentrations of gold nanoshells were prepared. A full thickness incision of 2×20 mm2 was made on the surface and after placing 50 μl of the solder mixture on the incision, an 810 nm diode laser was used to irradiate it at different power densities. The changes of tensile strength, σt, due to temperature rise, number of scan (Ns, and scan velocity (Vs were investigated. Results: The results showed that the tensile strength of the repaired skin increased with increasing irradiance for both gold nanoshell concentrations. In addition, at constant laser irradiance (I, the tensile strength of the repaired incision increased with increasing Ns and decreasing Vs. In our case, this corresponded to st = 1610 g/cm2 at I ~ 60 Wcm-2, T ~ 65ºC, Ns = 10 and Vs = 0.2 mms-1. Discussion and Conclusion: Gold nanoshells can be used as an indocyanine green dye (ICG alterative for laser tissue soldering.  Although by increasing the laser power density, the tensile strength of the repaired skin increases, an optimum power density must be considered due to the resulting increase in tissue temperature.

  10. Solder joint technology materials, properties, and reliability

    Tu, King-Ning


    Solder joints are ubiquitous in electronic consumer products. The European Union has a directive to ban the use of Pb-based solders in these products on July 1st, 2006. There is an urgent need for an increase in the research and development of Pb-free solders in electronic manufacturing. For example, spontaneous Sn whisker growth and electromigration induced failure in solder joints are serious issues. These reliability issues are quite complicated due to the combined effect of electrical, mechanical, chemical, and thermal forces on solder joints. To improve solder joint reliability, the science of solder joint behavior under various driving forces must be understood. In this book, the advanced materials reliability issues related to copper-tin reaction and electromigration in solder joints are emphasized and methods to prevent these reliability problems are discussed.

  11. Wetting behavior of alternative solder alloys

    Hosking, F.M.; Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.


    Recent economic and environmental issues have stimulated interest in solder alloys other than the traditional Sn-Pb eutectic or near eutectic composition. Preliminary evaluations suggest that several of these alloys approach the baseline properties (wetting, mechanical, thermal, and electrical) of the Sn-Pb solders. Final alloy acceptance will require major revisions to existing industrial and military soldering specifications. Bulk alloy and solder joint properties are consequently being investigated to validate their producibility and reliability. The work reported in this paper examines the wetting behavior of several of the more promising commercial alloys on copper substrates. Solder wettability was determined by the meniscometer and wetting balance techniques. The wetting results suggest that several of the alternative solders would satisfy pretinning and surface mount soldering applications. Their use on plated through hole technology might be more difficult since the alloys generally did not spread or flow as well as the 60Sn-40Pb solder.

  12. Biodegradable polymer thin film for enhancement of laser-assisted incision closure with an indocyanine-green-doped liquid albumin solder

    Sorg, Brian S.; McNally-Heintzelman, Karen M.; Welch, Ashley J.


    The purpose of this study was to determine if solid material reinforcement of a liquid albumin solder coagulum could improve the cohesive strength of the solder and thus the ultimate breaking strength of the incision repair in vitro. A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green (ICG) dye was used to repair an incision in bovine aorta. The solder was coagulated with an 806 nm CW diode laser. A 50 micrometer thick poly(DL-lactic-co-glycolic acid) film was used to reinforce the solder (the controls had no reinforcement). Acute breaking strengths were measured and the data were analyzed by one-way ANOVA (P less than 0.05). Multiple comparisons of means were performed using the Newman- Keuls test. Observations of the failure modes indicated cohesive strength reinforcement of the test specimens versus the controls. At the higher laser powers used in this study (400 and 450 mW), the reinforced solder was consistently stronger than the controls. Reinforcement of liquid albumin solders in laser-assisted incision repair may have mechanical advantages in terms of acute breaking strength over conventional methods that do not reinforce the cohesive strength of the solder.

  13. Solder Joint Health Monitoring Testbed

    Delaney, Michael M.; Flynn, James G.; Browder, Mark E.


    A method of monitoring the health of selected solder joints, called SJ-BIST, has been developed by Ridgetop Group Inc. under a Small Business Innovative Research (SBIR) contract. The primary goal of this research program is to test and validate this method in a flight environment using realistically seeded faults in selected solder joints. An additional objective is to gather environmental data for future development of physics-based and data-driven prognostics algorithms. A test board is being designed using a Xilinx FPGA. These boards will be tested both in flight and on the ground using a shaker table and an altitude chamber.

  14. Handbook of machine soldering SMT and TH

    Woodgate, Ralph W


    A shop-floor guide to the machine soldering of electronics Sound electrical connections are the operational backbone of every piece of electronic equipment-and the key to success in electronics manufacturing. The Handbook of Machine Soldering is dedicated to excellence in the machine soldering of electrical connections. Self-contained, comprehensive, and down-to-earth, it cuts through jargon, peels away outdated notions, and presents all the information needed to select, install, and operate machine soldering equipment. This fully updated and revised volume covers all of the new technologies and processes that have emerged in recent years, most notably the use of surface mount technology (SMT). Supplemented with 200 illustrations, this thoroughly accessible text Describes reflow and wave soldering in detail, including reflow soldering of SMT boards and the use of nitrogen blankets * Explains the setup, operation, and maintenance of a variety of soldering machines * Discusses theory, selection, and control met...

  15. On the automobile lightweight

    Ma Mingtu; Yi Hongliang; Lu Hongzhou; Wan Xinming


    The significance, description parameters, evaluation method, implement way and design for lightweight of au- tomobile are comprehensively reviewed. The relationship among the performances of auto parts & components, the prop- erties of materials and application of advanced technologies is also elaborated. According to recently related progress of lightweight and authors' research and developing work, lightweight of automobile is comprehensively and systematically overviewed.

  16. Hydrogen storage for automobiles

    Strickland, G.


    Results of an analysis of hydrogen-fueled automobiles are presented as a part of a continuing study conducted by Lawrence Livermore Laboratory (LLL) on Energy Storage Systems for Automobile Propulsion. The hydrogen is stored either as a metal hydride at moderate pressure in TiFe/sub 0/ /sub 9/Mn/sub 0/ /sub 1/H/sub x/ and at low pressure in MgH/sub x/ catalyzed with 10 wt % Ni, or it is stored in hollow glass microspheres at pressures up to about 400 atm. Improved projections are given for the two hydrides, which are used in combination to take advantage of their complementary properties. In the dual-hydride case and in the microsphere case where Ti-based hydride is used for initial operation, hydrogen is consumed in an internal-combustion engine; whereas in the third case, hydrogen from Ti-based hydride is used with air in an alkaline fuel cell/Ni-Zn battery combination which powers an electric vehicle. Each system is briefly described; and the results of the vehicle analysis are compared with those for the conventional automobile and with electric vehicles powered by Pb-acid or Ni-Zn batteries. Comparisons are made on the basis of automobile weight, initial user cost, and life-cycle cost. In this report, the results are limited to those for the 5-passenger vehicle in the period 1985-1990, and are provided as probable and optimistic values.

  17. Manual Soldering Process Technology (continued)%手工软钎焊工艺技术(待续)

    史建卫; 檀正东; 周璇; 苏立军; 杜彬


    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。

  18. Manual Soldering Process Technology (continued)%手工软钎焊工艺技术(续三)

    史建卫; 檀正东; 周璇; 苏立军; 杜彬


    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。

  19. Manual Soldering Process Technology (continued)%手工软钎焊工艺技术(续二)

    史建卫; 檀正东; 周璇; 苏立军; 杜彬


    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。

  20. 手工软钎焊工艺技术(续完)%Manual Soldering Process Technology ( continued )

    史建卫; 檀正东; 周璇; 苏立军; 杜彬


    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一.主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据.

  1. Lead free solder mechanics and reliability

    Pang, John Hock Lye


    Lead-free solders are used extensively as interconnection materials in electronic assemblies and play a critical role in the global semiconductor packaging and electronics manufacturing industry. Electronic products such as smart phones, notebooks and high performance computers rely on lead-free solder joints to connect IC chip components to printed circuit boards. Lead Free Solder: Mechanics and Reliability provides in-depth design knowledge on lead-free solder elastic-plastic-creep and strain-rate dependent deformation behavior and its application in failure assessment of solder joint reliability. It includes coverage of advanced mechanics of materials theory and experiments, mechanical properties of solder and solder joint specimens, constitutive models for solder deformation behavior; numerical modeling and simulation of solder joint failure subject to thermal cycling, mechanical bending fatigue, vibration fatigue and board-level drop impact tests. This book also: Discusses the mechanical prope...

  2. Die Soldering in Aluminium Die Casting

    Han, Q.; Kenik, E.A.; Viswanathan, S.


    Two types of tests, dipping tests and dip-coating tests were carried out on small steel cylinders using pure aluminum and 380 alloy to investigate the mechanism of die soldering during aluminum die casting. Optical and scanning electron microscopy were used to study the morphology and composition of the phases formed during soldering. A soldering mechanism is postulated based on experimental observations. A soldering critical temperature is postulated at which iron begins to react with aluminum to form an aluminum-rich liquid phase and solid intermetallic compounds. When the temperature at the die surface is higher than this critical temperature, the aluminum-rich phase is liquid and joins the die with the casting during the subsequent solidification. The paper discusses the mechanism of soldering for the case of pure aluminum and 380 alloy casting in a steel mold, the factors that promote soldering, and the strength of the bond formed when soldering occurs. conditions, an aluminum-rich soldering layer may also form over the intermetallic layer. Although a significant amount of research has been conducted on the nature of these intermetallics, little is known about the conditions under which soldering occurs.

  3. Environmentally Benign Automobiles

    Sperling, Daniel; Schipper, Lee; Deluchi, Mark; Wang, Quanlu


    His dream has come true. There's now more than one vehicle for every licensed driver in the United States, and other developed countries are not far behind. But has the car's success created the conditions for its own demise? Conventional wisdom of market researchers, consultants, and other experts is that the automobile and its petroleum-powered internal combustion engine will be with us for a long time and that any energy and environmental problems can be readily solved. T...

  4. Soldering in a Reduced Gravity Environment (SoRGE)

    Easton, John W.; Struk, Peter M.


    Future long-duration human exploration missions will be challenged by constraints on mass and volume allocations available for spare parts. Addressing this challenge will be critical to the success of these missions. As a result, it is necessary to consider new approaches to spacecraft maintenance and repair that reduce the need for large replacement components. Currently, crew members on the International Space Station (ISS) recover from faults by removing and replacing, using backup systems, or living without the function of Orbital Replacement Units (ORUs). These ORUs are returned to a depot where the root cause of the failure is determined and the ORU is repaired. The crew has some limited repair capability with the Modulation/DeModulation (MDM) ORU, where circuit cards are removed and replace in faulty units. The next step to reducing the size of the items being replaced would be to implement component-level repair. This mode of repair has been implemented by the U.S. Navy in an operational environment and is now part of their standard approach for maintenance. It is appropriate to consider whether this approach can be adapted for future spaceflight operations. To this end, the Soldering in a Reduced Gravity Environment (SoRGE) experiment studied the effect of gravity on the formation of solder joints on electronic circuit boards. This document describes the SoRGE experiment, the analysis methods, and results to date. This document will also contain comments from the crew regarding their experience conducting the SoRGE experiment as well as recommendations for future improvements. Finally, this document will discuss the plans for the SoRGE samples which remain on ISS.

  5. 49 CFR 523.4 - Passenger automobile.


    ... 49 Transportation 6 2010-10-01 2010-10-01 false Passenger automobile. 523.4 Section 523.4... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.4 Passenger automobile. A passenger automobile is any automobile (other than an automobile capable of off-highway operation)...

  6. Study on laser and hot air reflow soldering of PBGA solder ball

    田艳红; 王春青


    Laser and hot air reflow soldering of PBGA solder ball was investigated. Experimental results showed that surface quality and shear strength of solder bump reflowed by laser was superior than the solder bump by hot air, and the microstructure within the solder bump reflowed by laser was much finer. Analysis on interfacial reaction showed that eutectic solder reacted with Au/Ni/Cu pad shortly after the solder was melted. Interface of solder bump reflowed by laser consists of a continuous AuSn4 layer and remnant Au element. Needle-like AuSn4 grew sidewise from interface, and then spread out to the entire interface region. A thin layer of Ni3Sn4 intermetallic compound was found at the interface of solder bump reflowed by hot air, and AuSn4 particles distributed within the whole solder bump randomly. The combination effect of the continuous AuSn4 layer and finer eutectic microstructure contributes to the higher shear strength of solder bump reflowed by laser.

  7. Okoliš i automobil

    Nada Štrumberger


    Full Text Available Constant increase of the number of automobiles causes demand for individual materials to get on the rise, thus giving an impulse to the development of recycling logistics. Used automobiles get disassembled and individual parts which can be used as raw materials or additives get recycled. Automobile tires can be reclaimed or vulcanized. In July 1978 the environmental-friendly "Blauer Engel" or "Blue Angel" symbol was first introduced for reclaimed tires. Later, emblems were introduced for other recycled automobile pans. The awarding of the emblem is being controlled and approved by authorized institutes, because the emblem rightfully designates traffic safety.



    Mar 1, 2012 ... Based on this, a wettability test using copper grid was conducted on the solder alloys produced. The result shows that wetting time varied from 4 seconds to 5 seconds for the lead-free solders ... at the interfaces [4]. This study ...

  9. Nano-soldering to single atomic layer

    Girit, Caglar O.; Zettl, Alexander K.


    A simple technique to solder submicron sized, ohmic contacts to nanostructures has been disclosed. The technique has several advantages over standard electron beam lithography methods, which are complex, costly, and can contaminate samples. To demonstrate the soldering technique graphene, a single atomic layer of carbon, has been contacted, and low- and high-field electronic transport properties have been measured.

  10. Automobile Starting and Lighting System Maintenance Training ...

    Automobile Starting and Lighting System Maintenance Training Manual for Effective Learning ... Journal Home > Vol 10, No 2 (2015) > ... College Minna and Automobile Supervisors in automobile companies in Minna to establish its reliability.

  11. The automobile after tomorrow

    Guzzella, L. [Swiss Federal Inst. of Technology (ETH), Zurich (Switzerland)


    This talk discusses the technical options available for automobiles within the next 5 to 10 years. With the objective to reduce consumption and pollution, several alternative approaches are presented and analyzed using simplified but realistic calculations. Main emphasis is laid on CO{sub 2} emission of the complete energy transformation path from the primary energy carrier to the energy dissipated in test cycles. It is shown that no single optimal solution exist but that a trade-off between consumption, pollution and cost must be made for each specific situation. (author) 17 figs., 2 tabs.

  12. Low cycle fatigue of lead free solder joints

    Schemmann, Lars; Wedi, Andre; Baither, Dietmar; Schmitz, Guido [Institut fuer Materialphysik, Westf. Wilhelms-Universitaet, Muenster (Germany)


    Presently solders containing lead are banned from consumer electronics. Important alternatives are the Sn-Ag-Cu (SAC) solders and solders containing antimony. This work studies the isothermal low cycle fatigue properties of SAC solders and the SnSb(8) solder. For the experiments, model solder joints were produced and used. They consist of two pure copper plates joined together by a circular disk of solder. Low cycle fatigue experiments were done under displacement control. Furthermore hardness was tested by a micro indenter. In order to find an explanation for the different lifetimes of the solders, several micro structural investigations were performed. For this we used transmission and scanning electron microscopy as well as optical microscopy. The measured data showed a strong relation between lifetime and hardness of the solder alloy. We also found, that the type of solder influences the crack propagation.

  13. Automobile Club CERN

    Automobile Club CERN


     L’Assemblée Générale Ordinaire de «L’Automobile Club du CERN» s’est tenue le mercredi 12 janvier 2010. Le Président, J. Pierlot, souhaite la bienvenue aux membres présents, annonce l’agenda et résume les activités et événements du club pour l’année 2009. Le Club compte environ 600 membres, une petite diminution par rapport aux précédentes années dû surtout aux départs anticipés à la retraite. La cotisation reste inchangée : 50 CHF. Notre trésorier, E. Squadrani, présente de façon détaillée la situation du compte d’exploitation pour 2009 ainsi que le bilan de l’Automobile Club. Les comptes sont équilibrés, la situation de la trés...

  14. Integrated Electrical Wire Insulation Repair System

    Williams, Martha; Jolley, Scott; Gibson, Tracy; Parks, Steven


    An integrated system tool will allow a technician to easily and quickly repair damaged high-performance electrical wire insulation in the field. Low-melt polyimides have been developed that can be processed into thin films that work well in the repair of damaged polyimide or fluoropolymer insulated electrical wiring. Such thin films can be used in wire insulation repairs by affixing a film of this low-melt polyimide to the damaged wire, and heating the film to effect melting, flow, and cure of the film. The resulting repair is robust, lightweight, and small in volume. The heating of this repair film is accomplished with the use of a common electrical soldering tool that has been modified with a special head or tip that can accommodate the size of wire being repaired. This repair method can furthermore be simplified for the repair technician by providing replaceable or disposable soldering tool heads that have repair film already "loaded" and ready for use. The soldering tool heating device can also be equipped with a battery power supply that will allow its use in areas where plug-in current is not available

  15. Thermomechanical Behavior of Monolithic SN-AG-CU Solder and Copper Fiber Reinforced Solders


    controlled fatigue life, likely because of increased void -nucleation via creep-fatigue interactions. Since the solder is largely under plastically deform the solder in order to break the oxide layers and eliminate some minor voids around the NiTi particles. Figure 32... Underfill Constraint Effects during Thermomechanical Cycling of Flip Chip Solder Joints,” Journal of Electronic Materials, Vol. 31, No. 4, 2002

  16. Lead Ingestion Hazard in Hand Soldering Environments.



  17. Alternative propulsion for automobiles

    Stan, Cornel


    The book presents – based on the most recent research and development results worldwide - the perspectives of new propulsion concepts such as electric cars with batteries and fuel cells, and furthermore plug in hybrids with conventional and alternative fuels. The propulsion concepts are evaluated based on specific power, torque characteristic, acceleration behaviour, specific fuel consumption and pollutant emissions. The alternative fuels are discussed in terms of availability, production, technical complexity of the storage on board, costs, safety and infrastructure. The book presents summarized data about vehicles with electric and hybrid propulsion. The propulsion of future cars will be marked by diversity – from compact electric city cars and range extender vehicles for suburban and rural areas up to hybrid or plug in SUV´s, Pick up´s and luxury class automobiles.

  18. 49 CFR 523.3 - Automobile.


    ... 49 Transportation 6 2010-10-01 2010-10-01 false Automobile. 523.3 Section 523.3 Transportation..., DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.3 Automobile. (a) An automobile is any 4-wheeled... pounds and less than 10,000 pounds gross vehicle weight are determined to be automobiles: (1)...

  19. 19 CFR 148.39 - Rented automobiles.


    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Rented automobiles. 148.39 Section 148.39 Customs... automobiles. (a) Importation for temporary period. An automobile rented by a resident of the United States... (HTSUS) (19 U.S.C. 1202), without payment of duty. The automobile shall be used for the transportation...

  20. Modeling the diffusion of solid copper into liquid solder alloys

    Rizvi, M.J. [School of Computing and Mathematical Sciences, University of Greenwich, 30 Park Row, London, SE10 9LS (United Kingdom)], E-mail:; Lu, H.; Bailey, C. [School of Computing and Mathematical Sciences, University of Greenwich, 30 Park Row, London, SE10 9LS (United Kingdom)


    During the soldering process, the copper atoms diffuse into liquid solders. The diffusion process determines integrity and the reworking possibility of a solder joint. In order to capture the diffusion scenarios of solid copper into liquid Sn-Pb and Sn-Cu solders, a computer modeling has been performed for 10 s. An analytical model has also been proposed for calculating the diffusion coefficient of copper into liquid solders. It is found that the diffusion coefficient for Sn-Pb solder is 2.74 x 10{sup -10} m{sup 2}/s and for Sn-Cu solder is 6.44 x 10{sup -9} m{sup 2}/s. The modeling results reveal that the diffusion coefficient is one of the major factors that govern the rate at which solid Cu dissolve in the molten solder. The predicted dissolved amounts of copper into solders have been validated with the help of scanning electron microscopic analysis.

  1. Organic solderability preservation evaluation. Topical report

    Becka, G.A.; McHenry, M.R.; Slanina, J.T.


    An evaluation was conducted to determine the possible replacement of the hot air solder leveling (HASL) process used in the Allied Signal Federal Manufacturing & Technologies (FM&T) Printed Wiring Board Facility with an organic solderability preservative (OSP). The drivers for replacing HASL include (1) Eliminating lead from PWB fabrication processes; (2) Potential legislation restricting use of lead, (3) Less expensive processing utilizing OSP rather than HASL processing; (4) Avoiding solder dross disposal inherent with HASL processing, (5) OSP provides flat, planar surface required for surface mount technology product, and (6) Trend to thinner PWB designs. A reduction in the cost of nonconformance (CONC) due to HASL defects (exposed copper, solderability, dewetting and non-wetting) would be realized with the incorporation of the OSP process. Several supplier HASL replacement candidates were initially evaluated. One supplier chemistry was chosen for potential use in the FM&T PWB and assembly areas.

  2. Soldering Chiralities; 2, Non-Abelian Case

    Wotzasek, C


    We study the non-abelian extension of the soldering process of two chiral WZW models of opposite chiralities, resulting in a (non-chiral) WZW model living in a 2D space-time with non trivial Riemanian curvature.

  3. The Linguistic Features of English Automobile Advertisements



    Household cars are largely demanded today, stimulating the economic development throughout the automobile industry. To enlarge market, all automobile producers pay great efforts to advertisements which result in a large quantity of automobile advertisements. Due to the rare analysis on the linguistic features of automobile advertisements, this essay makes a specific study on this. Analysis will be done through the perspectives of the lexical level, the syntactic level and the rhetoric level. Hence, valid references could be offered to future automobile advertisers.

  4. Shrink-Fit Solderable Inserts Seal Hermetically

    Croucher, William C.


    Shrink-fit stainless-steel insert in aluminum equipment housing allows electrical connectors to be replaced by soldering, without degrading hermeticity of housing or connector. Welding could destroy electrostatic-sensitive components and harm housing and internal cables. Steel insert avoids problems because connector soldered directly to it rather than welded to housing. Seals between flange and housing, and between connector and flange resistant to leaks, even after mechanical overloading and thermal shocking.

  5. Comfort model for automobile seat.

    da Silva, Lizandra da; Bortolotti, Silvana Ligia Vincenzi; Campos, Izabel Carolina Martins; Merino, Eugenio Andrés Díaz


    Comfort on automobile seats is lived daily by thousands of drivers. Epistemologically, comfort can be understood under the theory of complexity, since it emerges from a chain of interrelationships between man and several elements of the system. This interaction process can engender extreme comfort associated to the feeling of pleasure and wellbeing or, on the other hand, lead to discomfort, normally followed by pain. This article has for purpose the development of a theoretical model that favours the comfort feature on automobile seats through the identification of its facets and indicators. For such, a theoretical study is resorted to, allowing the mapping of elements that constitute the model. The results present a comfort model on automobile seats that contemplates the (physical, psychological, object, context and environment) facets. This model is expected to contribute with the automobile industry for the development of improvements of the ergonomic project of seats to increase the comfort noticed by the users.

  6. Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes

    Takahashi, Junichi; Nakahara, Sumio; Hisada, Shigeyoshi; Fujita, Takeyoshi


    It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry, typical alloys have narrowed down to Sn-Ag-Cu and Sn-Zn lead-free solder. In this study, solderability of Pb-free solder that are Sn-Ag-Cu and Sn-Zn-Bi alloy was studied on soldering using YAG (yttrium aluminum garnet) laser and diode laser. Experiments were peformed in order to determine the range of soldering parameters for obtaining an appropriate wettability based on a visual inspection. Joining strength of surface mounting chip components soldered on PCB (printed circuit board) was tested on application thickness of solder paste (0.2, 0.3, and 0.4 mm). In addition, joining strength characteristics of eutectic Sn-Pb alloy and under different power density were examined. As a result, solderability of Sn-Ag-Cu (Pb-free) solder paste are equivalent to that of coventional Sn-Pb solder paste, and are superior to that of Sn-Zn-Bi solder paste in the laser soldering method.

  7. Temperature versus time curves for manual and automated soldering processes

    Trent, M.A.


    Temperature-versus-time curves were recorded for various electronic components during pre-tinning, hand soldering, and drag soldering operations to determine the temperature ranges encountered. The component types investigated included a wide range of electronic assemblies. The data collected has been arranged by process and will help engineers to: (1) predetermine the thermal profile to which various components are subjected during the soldering operation; (2) decide--on the basis of component heat sensitivity and the need for thermal relief--where hand soldering would be more feasible than drag soldering; and (3) determine the optimum drag solder control parameters.

  8. Integrated environmentally compatible soldering technologies. Final report

    Hosking, F.M.; Frear, D.R.; Iman, R.L.; Keicher, D.M.; Lopez, E.P.; Peebles, H.C.; Sorensen, N.R.; Vianco, P.T.


    Chemical fluxes are typically used during conventional electronic soldering to enhance solder wettability. Most fluxes contain very reactive, hazardous constituents that require special storage and handling. Corrosive flux residues that remain on soldered parts can severely degrade product reliability. The residues are removed with chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), or other hazardous solvents that contribute to ozone depletion, release volatile organic compounds into the atmosphere, or add to the solvent waste stream. Alternative materials and processes that offer the potential for the reduction or elimination of cleaning are being developed to address these environmental issues. Timing of the effort is critical, since the targeted chemicals will soon be heavily taxed or banned. DOE`s Office of Environmental Restoration and Waste Management (DOE/EM) has supported Sandia National Laboratories` Environmentally Conscious Manufacturing Integrated Demonstration (ECMID). Part of the ECM program involves the integration of several environmentally compatible soldering technologies for assembling electronics devices. Fluxless or {open_quotes}low-residue/no clean{close_quotes} soldering technologies (conventional and ablative laser processing, controlled atmospheres, ultrasonic tinning, protective coatings, and environmentally compatible fluxes) have been demonstrated at Sandia (SNL/NM), the University of California at Berkeley, and Allied Signal Aerospace-Kansas City Division (AS-KCD). The university demonstrations were directed under the guidance of Sandia staff. Results of the FY93 Soldering ID are presented in this report.

  9. SNL initiatives in electronic fluxless soldering

    Hosking, F. M.; Frear, D. R.; Vianco, P. T.; Keicher, D. M.

    Conventional soldering of electronic components generally requires the application of a chemical flux to promote solder wetting and flow. Chlorofluorocarbons (CFC) and halogenated solvents are normally used to remove the resulting flux residues. While such practice has been routinely accepted throughout the electronics industry, the environmental impact of hazardous solvents on ozone depletion will eventually limit or prevent their use. Solvent substitution or alternative technologies must be developed to meet these goals. Sandia National Laboratories (SNL), Albuquerque has a comprehensive environmentally conscious electronics manufacturing program underway that is funded by the DOE Office of Technology Development. Primary elements of the integrated task are the characterization and development of alternative fluxless soldering technologies that would eliminate circuit board cleaning associated with flux residue removal. Storage and handling of hazardous solvents and mixed solvent-flux waste would be consequently reduced during electronics soldering. This paper will report on the progress of the SNL fluxless soldering initiative. Emphasis is placed on the use of controlled atmospheres, laser heating, and ultrasonic soldering.

  10. PWB solder wettability after simulated storage

    Hernandez, C.L.; Hosking, F.M.


    A new solderability test method has been developed at Sandia National Laboratories that simulates the capillary flow physics of solders on circuit board surfaces. The solderability test geometry was incorporated on a circuit board prototype that was developed for a National Center for Manufacturing Sciences (NCMS) program. The work was conducted under a cooperative research and development agreement between Sandia National Laboratories, NCMS, and several PWB fabricators (AT&T, IBM, Texas Instruments, United Technologies/Hamilton Standard and Hughes Aircraft) to advance PWB interconnect technology. The test was used to investigate the effects of environmental prestressing on the solderability of printed wiring board (PWB) copper finishes. Aging was performed in a controlled chamber representing a typical indoor industrial environment. Solderability testing on as-fabricated and exposed copper samples was performed with the Sn-Pb eutectic solder at four different reflow temperatures (215, 230, 245 and 260{degrees}C). Rosin mildly activated (RMA), low solids (LS), and citric acid-based (CA) fluxes were included in the evaluation. Under baseline conditions, capillary flow was minimal at the lowest temperatures with all fluxes. Wetting increased with temperature at both baseline and prestressing conditions. Poor wetting, however, was observed at all temperatures with the LS flux. Capillary flow is effectively restored with the CA flux.

  11. Manual Soldering Process Technology (continued)%手工软钎焊工艺技术(续一)实用电子组装技术

    史建卫; 檀正东; 周璇; 苏立军; 杜彬


    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。

  12. Use of organic solderability preservatives on solderability retention of copper after accelerated aging

    Hernandez, C.L.; Sorensen, N.R.; Lucero, S.J.


    Organic solderability preservatives (OSP`s) have been used by the electronics industry for some time to maintain the solderability of circuit boards and components. Since solderability affects both manufacturing efficiency and product reliability, there is significant interest in maintaining good solder wettability. There is often a considerable time interval between the initial fabrication of a circuit board or component and its use at the assembly level. Parts are often stored under a variety of conditions, in many cases not well controlled. Solder wettability can deteriorate during storage, especially in harsh environments. This paper describes the ongoing efforts at Sandia National Laboratories to quantify solder watability on bare and aged copper surfaces. Benzotriazole and imidazole were applied to electronic grade copper to retard aging effects on solderability. The coupons were introduced into Sandia`s Facility for Atmospheric Corrosion Testing (FACT) to simulate aging in a typical indoor industrial environment. H{sub 2}S, NO{sub 2} and Cl{sub 2} mixed gas was introduced into the test cell and maintained at 35{degrees}C and 70% relative humidity for test periods of one day to two weeks. The OSP`s generally performed better than bare Cu, although solderability diminished with increasing exposure times.

  13. Corrosion resistance of the soldering joint of post-soldering of palladium-based metal-ceramic alloys.

    Kawada, E; Sakurai, Y; Oda, Y


    To evaluate the corrosion resistance of post soldering of metal-ceramic alloys, four commercially available palladium-system metal-ceramic alloys (Pd-Cu, Pd-Ni, Pd-Ag, and Pd-Sb systems) and two types of solder (12 k gold solder and 16 k gold solder) with different compositions and melting points were used. The corrosion resistance of the soldered joint was evaluated by anodic polarization. The electrochemical characteristics of soldered surface were measured using electrochemical equipment. Declines in corrosion resistance were not detectable with Pd-Cu, Pd-Ag and Pd-Sb types, but break down at low potential occurred with Pd-Ni type.

  14. Age-aware solder performance models : level 2 milestone completion.

    Neilsen, Michael K.; Vianco, Paul Thomas; Neidigk, Matthew Aaron; Holm, Elizabeth Ann


    Legislated requirements and industry standards are replacing eutectic lead-tin (Pb-Sn) solders with lead-free (Pb-free) solders in future component designs and in replacements and retrofits. Since Pb-free solders have not yet seen service for long periods, their long-term behavior is poorly characterized. Because understanding the reliability of Pb-free solders is critical to supporting the next generation of circuit board designs, it is imperative that we develop, validate and exercise a solder lifetime model that can capture the thermomechanical response of Pb-free solder joints in stockpile components. To this end, an ASC Level 2 milestone was identified for fiscal year 2010: Milestone 3605: Utilize experimentally validated constitutive model for lead-free solder to simulate aging and reliability of solder joints in stockpile components. This report documents the completion of this milestone, including evidence that the milestone completion criteria were met and a summary of the milestone Program Review.

  15. Computer simulation of solder joint failure

    Burchett, S.N.; Frear, D.R. [Sandia National Lab., Albuquerque, NM (United States); Rashid, M.M. [Univ. of California, Davis, CA (United States)


    The thermomechanical fatigue failure of solder joints is increasingly becoming an important reliability issue for electronic packages. The purpose of this Laboratory Directed Research and Development (LDRD) project was to develop computational tools for simulating the behavior of solder joints under strain and temperature cycling, taking into account the microstructural heterogeneities that exist in as-solidified near eutectic Sn-Pb joints, as well as subsequent microstructural evolution. The authors present two computational constitutive models, a two-phase model and a single-phase model, that were developed to predict the behavior of near eutectic Sn-Pb solder joints under fatigue conditions. Unique metallurgical tests provide the fundamental input for the constitutive relations. The two-phase model mathematically predicts the heterogeneous coarsening behavior of near eutectic Sn-Pb solder. The finite element simulations with this model agree qualitatively with experimental thermomechanical fatigue tests. The simulations show that the presence of an initial heterogeneity in the solder microstructure could significantly degrade the fatigue lifetime. The single-phase model was developed to predict solder joint behavior using materials data for constitutive relation constants that could be determined through straightforward metallurgical experiments. Special thermomechanical fatigue tests were developed to give fundamental materials input to the models, and an in situ SEM thermomechanical fatigue test system was developed to characterize microstructural evolution and the mechanical behavior of solder joints during the test. A shear/torsion test sample was developed to impose strain in two different orientations. Materials constants were derived from these tests. The simulation results from the two-phase model showed good fit to the experimental test results.

  16. Evaluation technology of lead-free solders; Namari free handa zairyo ni okeru hyoka gijutsu

    Yamashita, M.; Shiokawa, K. [Fuji Electric Co. Ltd., Tokyo (Japan); Ueda, A. [Fuji Electric Corporate Research and Development,Ltd., Kanagawa (Japan)


    Solders mainly composed of tin and lead are currently in widespread use in semiconductor devices. However, in view of lead influences on the human body and environmental problems, lead-free solders have been in urgent demand. In this study, aiming to improve the solderability and reliability of a tin-silver solder, one of most promising lead-free solder materials, we have investigated elements to be added. Focusing on typical lead-free tin-silver solders and tin-lead eutectic solders, this paper describes the result of investigations into the mechanical properties solderability, micro structures of the solder materials and gas analysis in soldering. (author)

  17. Automobile Driver Fingerprinting

    Enev Miro


    Full Text Available Today’s automobiles leverage powerful sensors and embedded computers to optimize efficiency, safety, and driver engagement. However the complexity of possible inferences using in-car sensor data is not well understood. While we do not know of attempts by automotive manufacturers or makers of after-market components (like insurance dongles to violate privacy, a key question we ask is: could they (or their collection and later accidental leaks of data violate a driver’s privacy? In the present study, we experimentally investigate the potential to identify individuals using sensor data snippets of their natural driving behavior. More specifically we record the in-vehicle sensor data on the controllerarea- network (CAN of a typical modern vehicle (popular 2009 sedan as each of 15 participants (a performed a series of maneuvers in an isolated parking lot, and (b drove the vehicle in traffic along a defined ~ 50 mile loop through the Seattle metropolitan area. We then split the data into training and testing sets, train an ensemble of classifiers, and evaluate identification accuracy of test data queries by looking at the highest voted candidate when considering all possible one-vs-one comparisons. Our results indicate that, at least among small sets, drivers are indeed distinguishable using only incar sensors. In particular, we find that it is possible to differentiate our 15 drivers with 100% accuracy when training with all of the available sensors using 90% of driving data from each person. Furthermore, it is possible to reach high identification rates using less than 8 minutes of training data. When more training data is available it is possible to reach very high identification using only a single sensor (e.g., the brake pedal. As an extension, we also demonstrate the feasibility of performing driver identification across multiple days of data collection

  18. Effect of Solder Flux Residues on Corrosion of Electronics

    Hansen, Kirsten Stentoft; Jellesen, Morten Stendahl; Møller, Per


    Flux from ‘No Clean’ solder processes can cause reliability problems in the field due to aggressive residues, which may be electrical conducting or corrosive in humid environments. The solder temperature during a wave solder process is of great importance to the amount of residues left on a PCBA[...

  19. Efforts to Develop a 300°C Solder

    Norann, Randy A [Perma Works LLC


    This paper covers the efforts made to find a 300°C electrical solder solution for geothermal well monitoring and logging tools by Perma Works LLC. This paper covers: why a high temperature solder is needed, what makes for a good solder, testing flux, testing conductive epoxy and testing intermetallic bonds. Future areas of research are suggested.

  20. Microstructural evolution of eutectic Au-Sn solder joints

    Song, Ho Geon


    Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

  1. Microstructural evolution of eutectic Au-Sn solder joints

    Song, Ho Geon [Univ. of California, Berkeley, CA (United States)


    Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

  2. Testing of printed circuit board solder joints by optical correlation

    Espy, P. N.


    An optical correlation technique for the nondestructive evaluation of printed circuit board solder joints was evaluated. Reliable indications of induced stress levels in solder joint lead wires are achievable. Definite relations between the inherent strength of a solder joint, with its associated ability to survive stress, are demonstrable.

  3. Thermal decomposition of solder flux activators under simulated wave soldering conditions

    Piotrowska, Kamila; Jellesen, Morten Stendahl; Ambat, Rajan


    Purpose:The aim of this work is to investigate the decomposition behaviour of the activator species commonly used in the wave solder no-clean flux systems and to estimate the residue amount left after subjecting the samples to simulated wave soldering conditions. Design/methodology/approach: Chan......Purpose:The aim of this work is to investigate the decomposition behaviour of the activator species commonly used in the wave solder no-clean flux systems and to estimate the residue amount left after subjecting the samples to simulated wave soldering conditions. Design....../methodology/approach: Changes in the chemical structure of the activators were studied using Fourier transform infrared spectroscopy technique and were correlated to the exposure temperatures within the range of wave soldering process. The amount of residue left on the surface was estimated using standardized acid......-malic). The decomposition patterns of solder flux activators depend on their chemical nature, time of heat exposure and substrate materials. Evaporation of the residue from the surface of different materials (laminate with solder mask, copper surface or glass surface) was found to be more pronounced for succinic...

  4. A Study of the Interface of Soldered Joints of SnInAgTi Active Solder with Ito Ceramics

    M. Provazník; R. Koleňák


    This paper presents an analysis of the solderability ITO ceramics (In2O3/SnO2). The soft active solder SnInAgeTi was used for the experiments. The solder was activated by power ultrasound in air without flux. An analysis of the interface of the phases between the solder and the ceramic was carried out in order to discover the ultrasonic impacts on the active metal and to identify the mechanism of the joint on the ceramic side.

  5. A novel method for direct solder bump pull testing using lead-free solders

    Turner, Gregory Alan

    This thesis focuses on the design, fabrication, and evaluation of a new method for testing the adhesion strength of lead-free solders, named the Isotraction Bump Pull method (IBP). In order to develop a direct solder joint-strength testing method that did not require customization for different solder types, bump sizes, specific equipment, or trial-and-error, a combination of two widely used and accepted standards was created. First, solder bumps were made from three types of lead free solder were generated on untreated copper PCB substrates using an in-house fabricated solder bump-on-demand generator, Following this, the newly developed method made use of a polymer epoxy to encapsulate the solder bumps that could then be tested under tension using a high precision universal vertical load machine. The tests produced repeatable and predictable results for each of the three alloys tested that were in agreement with the relative behavior of the same alloys using other testing methods in the literature. The median peak stress at failure for the three solders tested were 2020.52 psi, 940.57 psi, and 2781.0 psi, and were within one standard deviation of the of all data collected for each solder. The assumptions in this work that brittle fracture occurred through the Intermetallic Compound layer (IMC) were validated with the use of Energy-Dispersive X-Ray Spectrometry and high magnification of the fractured surface of both newly exposed sides of the test specimens. Following this, an examination of the process to apply the results from the tensile tests into standard material science equations for the fracture of the systems was performed..

  6. Manual Method of Removing and Soldering for QFP%手工拆焊QFP器件的方法



    在电子装联中,手工焊接始终是不可缺少的操作方法,特别是在产品以多品种和小批量为主的各大研究所内.以QFP封装器件为例,介绍QFP器件的封装类型和其发展趋势,从手工焊接方面论述焊接的条件、焊接温度、焊接技巧、焊接工具和相关焊接辅料的选择等.结合返修实践,分析手工返修QFP的相关过程控制要点和手工拆除QFP的方法.%Manual soldering is always an indispensable operational approach in electronic assembly, especially in institutes whose products are mainly in multi-varieties and small batch. Take QFP encapsulation device as an example, encapsulation kinds of QFP device and their development trends are introduced. The soldering conditions, temperature, techniques, tools, as well as selection of relevant soldering materials are discussed from the aspect of manual soldering. Combination of repair practice, key points for process control relating to manual repairing of QFP and method for mannul removing of QFP are analyzed.

  7. Intense generation of respirable metal nanoparticles from a low-power soldering unit

    Gómez, Virginia [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Irusta, Silvia [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain); Balas, Francisco [Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain); Instituto de Carboquímica – Consejo Superior de Investigaciones Científicas (ICB-CSIC), 50018 Zaragoza (Spain); Santamaria, Jesus, E-mail: [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain)


    Highlights: • Intense generation of nanoparticles in the breathing range from a flux-soldering unit is detected. • Coagulation in the aerosol phase leads to 200-nm respirable nanoparticles up to 30 min after operation. • Nanoparticle concentration in the working environment depends on the presence of ambient air. • Metal-containing nanoparticles are collected in TEM grids and filters in the hundreds of nanometer range. -- Abstract: Evidence of intense nanoparticle generation from a low power (45 W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 10{sup 6} particles/cm{sup 3}) within the breathing range of the operator, with initial size distributions centered at 35–60 nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals.

  8. Capillary wave formation on excited solder jet and fabrication of lead-free solder ball

    ZHANG Shu-guang; HE Li-jun; ZHU Xue-xin; ZHANG Shao-ming; SHI Li-kai; XU Jun


    A survey of solder ball production processes especially focusing on disturbed molten metal jet breakup process was made. Then the formation of capillary wave on tin melt jet in the way of rapid solidification was studied. A semi-empirical formula, which can be written as λ = Cvib (σ/ρ)1/3f-2/3 to predict the relationship between wavelength of capillary wave and frequency of imposed vibration was obtained. Sn-4.0Ag-0.5Cu lead free solder ball was successfully produced with tight distribution and good sphericity. The excited jet breakup process is promising for cost effectively producing solder ball.

  9. Solder Joint Health Monitoring Testbed System

    Delaney, Michael M.


    The density and pin count for Field Programmable Gate Arrays (FPGAs) has been increasing, and has exceeded current methods of solder joint inspection, making early detection of failures more problematic. These failures are a concern for both flight safety and maintenance in commercial aviation. Ridgetop Group, Inc. has developed a method for detecting solder joint failures in real time. The NASA Dryden Flight Research Center is developing a set of boards to test this method in ground environmental and accelerated testing as well as flight test on a Dryden F-15 or F-18 research aircraft. In addition to detecting intermittent and total solder joint failures, environmental data on the boards, such as temperature and vibration, will be collected and time-correlated to aircraft state data. This paper details the technical approach involved in the detection process, and describes the design process and products to date for Dryden s FPGA failure detection boards.

  10. Pb-Free Soldering Iron Temperature Controller

    Hamane, Hiroto; Wajima, Kenji; Hayashi, Yoichi; Komiyama, Eiichi; Tachibana, Toshiaki; Miyazaki, Kazuyoshi

    Recently, much importance has been attached to the environmental problem. The content of two directives to better control the management of waste electronic equipment was approved. The two directives are the Waste from Electrical and Electronic Equipment (WEEE) and the Restriction of Hazardous Substances (RoHS). These set phase-out dates for the use of lead materials contained in electronic products. Increasingly, attention is focusing on the potential use of Pb-free soldering in electronics manufacturing. It should be noted that many of the current solding irons are not suitable for Pb-free technology, due to the inferior wetting ability of Pb-free alloys compared with SnPb solder pastes. This paper presents a Pb-free soldering iron temperature controller using an embedded micro-processor with a low memory capacity.

  11. Nanocopper Based Solder-Free Electronic Assembly

    Schnabl, K.; Wentlent, L.; Mootoo, K.; Khasawneh, S.; Zinn, A. A.; Beddow, J.; Hauptfleisch, E.; Blass, D.; Borgesen, P.


    CuantumFuse nano copper material has been used to assemble functional LED test boards and a small camera board with a 48 pad CMOS sensor quad-flat no-lead chip and a 10 in flexible electronics demo. Drop-in replacement of solder, by use of stencil printing and standard surface mount technology equipment, has been demonstrated. Applications in space and commercial systems are currently under consideration. The stable copper-nanoparticle paste has been examined and characterized by scanning electron microscopy and high-resolution transmission electron microscopy; this has shown that the joints are nanocrystalline but with substantial porosity. Assessment of reliability is expected to be complicated by this and by the effects of thermal and strain-enhanced coarsening of pores. Strength, creep, and fatigue properties were measured and results are discussed with reference to our understanding of solder reliability to assess the potential of this nano-copper based solder alternative.

  12. 40 CFR 600.315-82 - Classes of comparable automobiles.


    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Classes of comparable automobiles. 600... 1977 and Later Model Year Automobiles-Labeling § 600.315-82 Classes of comparable automobiles. (a) The Secretary will classify automobiles as passenger automobiles or light trucks (nonpassenger automobiles)...

  13. Moisture and aging effects of solder wettability of copper surfaces

    Hernandez, C.L.; Sorensen, N.R.; Lucero, S.J.


    Solderability is a critical property of electronic assembly that affects both manufacturing efficiency and product reliability. There is often a considerable time interval between initial fabrication of a circuit board or component and its use at the assembly level. Parts are often stored under a variety of conditions, usually not controlled. Solder wettability can soon deteriorate during storage, especially in extreme environments. This paper describes ongoing efforts at Sandia to quantify solder wettability on bare and aged Cu surfaces. In addition, organic solderability preservatives (OSPs) were applied to the bare Cu to retard solderability loss due to aging. The OSPs generally performed well, although wetting did decrease with exposure time.

  14. Parametric study on the solderability of etched PWB copper

    Hosking, F.M.; Stevenson, J.O.; Hernandez, C.L.


    The rapid advancement of interconnect technology has resulted in a more engineered approach to designing and fabricating printed wiring board (PWB) surface features. Recent research at Sandia National Laboratories has demonstrated the importance of surface roughness on solder flow. This paper describes how chemical etching was used to enhance the solderability of surfaces that were normally difficult to wet. The effects of circuit geometry, etch concentration, and etching time on solder flow are discussed. Surface roughness and solder flow data are presented. The results clearly demonstrate the importance of surface roughness on the solderability of fine PWB surface mount features.

  15. The Hybrid Automobile and the Atkinson Cycle

    Feldman, Bernard J.


    The hybrid automobile is a strikingly new automobile technology with a number of new technological features that dramatically improve energy efficiency. This paper will briefly describe how hybrid automobiles work; what are these new technological features; why the Toyota Prius hybrid internal combustion engine operates on the Atkinson cycle…

  16. The Hybrid Automobile and the Atkinson Cycle

    Feldman, Bernard J.


    The hybrid automobile is a strikingly new automobile technology with a number of new technological features that dramatically improve energy efficiency. This paper will briefly describe how hybrid automobiles work; what are these new technological features; why the Toyota Prius hybrid internal combustion engine operates on the Atkinson cycle…

  17. Lead (Pb)-Free Solder Applications



    Legislative and marketing forces both abroad and in the US are causing the electronics industry to consider the use of Pb-free solders in place of traditional Sn-Pb alloys. Previous case studies have demonstrated the satisfactory manufacturability and reliability of several Pb-free compositions for printed circuit board applications. Those data, together with the results of fundamental studies on Pb-free solder materials, have indicated the general feasibility of their use in the broader range of present-day, electrical and electronic components.

  18. Effects of PCB thickness on adjustable fountain wave soldering

    M S Abdul Aziz; M Z Abdullah; C Y Khor; A Jalar; M A Bakar; W Y W Yusoff; F Che Ani; Nobe Yan; M Zhou; C Cheok


    This study investigates the effects of printed circuit board (PCB) thickness on adjustable fountain and conventional wave soldering. The pin-through-hole (PTH) vertical fill is examined with three PCBs of different thicknesses (i.e., 1.6, 3.1, and 6.0 mm) soldered through adjustable fountain and conventional wave soldering at conveyor angles of 0° and 6°. The vertical fill of each PCB is the focus. The PTH solder profile is inspected with a non-destructive X-ray computed tomography scanning machine. The percentages of the PTH vertical fill of both soldering processes are also estimated and compared. The aspect ratio of the PCB is also investigated. Experimental results reveal that adjustable fountain wave soldering yields better vertical fill than conventional wave soldering. The vertical fill level of adjustable fountain wave soldering is 100%, 90%, and 50% for the 1.6, 3.1, and 6.0 mm PCB thickness, respectively. FLUENT simulation is conducted for the vertical fill of the solder profile. Simulation and experimental results show that the PTH solder profiles of the two soldering processes are almost identical. The effect of PCB thickness on PTH voiding is also discussed.

  19. Solder flow over fine line PWB surface finishes

    Hosking, F.M.; Hernandez, C.L.


    The rapid advancement of interconnect technology has stimulated the development of alternative printed wiring board (PWB) surface finishes to enhance the solderability of standard copper and solder-coated surfaces. These new finishes are based on either metallic or organic chemistries. As part of an ongoing solderability study, Sandia National Laboratories has investigated the solder flow behavior of two azole-based organic solderability preservations, immersion Au, immersion Ag, electroless Pd, and electroless Pd/Ni on fine line copper features. The coated substrates were solder tested in the as-fabricated and environmentally-stressed conditions. Samples were processed through an inerted reflow machine. The azole-based coatings generally provided the most effective protection after aging. Thin Pd over Cu yielded the best wetting results of the metallic coatings, with complete dissolution of the Pd overcoat and wetting of the underlying Cu by the flowing solder. Limited wetting was measured on the thicker Pd and Pd over Ni finishes, which were not completely dissolved by the molten solder. The immersion Au and Ag finishes yielded the lowest wetted lengths, respectively. These general differences in solderability were directly attributed to the type of surface finish which the solder came in contact with. The effects of circuit geometry, surface finish, stressing, and solder processing conditions are discussed.

  20. Prototype circuit boards assembled with non-lead bearing solders

    Vianco, P.T.; Rejent, J.A.


    The 91.84Sn-3.33Ag-4.83Bi and 96.5Sn-3.5Ag Pb-free solders were evaluated for surface mount circuit board interconnects. The 63Sn-37Pb solder provided the baseline data. All three solders exhibited suitable manufacturability per a defect analyses of circuit board test vehicles. Thermal cycling had no significant effect on the 91.84Sn-3.33Ag-4.83Bi solder joints. Some degradation in the form of grain boundary sliding was observed in 96.5Sn-3.5Ag and 63Sn-37Pb solder joints. The quality of the solder joint microstructures showed a slight degree of degradation under thermal shock exposure for all of the solders tested. Trends in the solder joint shear strengths could be traced to the presence of Pd in the solder, the source of which was the Pd/Ni finish on the circuit board conductor features. The higher, intrinsic strengths of the Pb-free solders encouraged the failure path to be located in proximity to the solder/substrate interface where Pd combined with Sn to form brittle PdSn{sub 4} particles, resulting in reduced shear strengths.

  1. Capillary flow of solder on chemically roughened PWB surfaces

    Hosking, F.M.; Stevenson, J.O.; Yost, F.G.


    The Center for Solder Science and Technology at Sandia National Laboratories has developed a solderability test for evaluating fundamental solder flow over PWB (printed wiring boards) surface finishes. The work supports a cooperative research and development agreement between Sandia, the National Center for Manufacturing Sciences (NCMS), and several industrial partners. An important facet of the effort involved the ``engineering`` of copper surfaces through mechanical and chemical roughening. The roughened topography enhances solder flow, especially over very fine features. In this paper, we describe how etching with different chemical solutions can affect solder flow on a specially designed ball grid array test vehicle (BGATV). The effects of circuit geometry, solution concentration, and etching time are discussed. Surface roughness and solder flow data are presented to support the roughening premise. Noticeable improvements in solder wettability were observed on uniformly etched surfaces having relatively steep peak-to-valley slopes.

  2. Automatic computer-aided system of simulating solder joint formation

    Zhao, Xiujuan; Wang, Chunqing; Zheng, Guanqun; Wang, Gouzhong; Yang, Shiqin


    One critical aspect in electronic packaging is the fatigue/creep-induced failure in solder interconnections, which is found to be highly dependent on the shape of solder joints. Thus predicting and analyzing the solder joint shape is warranted. In this paper, an automatic computer-aided system is developed to simulate the formation of solder joint and analyze the influence of the different process parameters on the solder joint shape. The developed system is capable of visually designing the process parameters and calculating the solder joint shape automatically without any intervention from the user. The automation achieved will enable fast shape estimation with the variation of process parameters without time consuming experiments, and the simulating system provides the design and manufacturing engineers an efficient software tools to design soldering process in design environment. Moreover, a program developed from the system can serve as the preprocessor for subsequent finite element joint analysis program.

  3. A multi-wavelength fiber-optic temperature-controlled laser soldering system for upper aerodigestive tract reconstruction: an animal model.

    Abergel, Avraham; Gabay, Ilan; Fliss, Dan M; Katzir, Abraham; Gil, Ziv


    Laser soldering of a thick multilayer organ using conventional CO(2) lasers is ineffective. The purpose of this work was to develop a method for bonding the multilayer tissue of the upper aerodigestive tracts (UADT) without the need of sutures or stapling. Animal model. Academic research laboratory. The authors developed a multi-wavelength laser system, based on 2 fiber-optic lasers applied simultaneously. A highly absorbable CO(2) laser interacts with the muscular layer, and a nonabsorbable GaAs laser interacts with indocyanine-green solid albumin, placed between the mucosa and the muscular layer. The authors used an ex vivo porcine model to examine the capability of this system to effectively correct esophageal tears. The soldered esophagi burst pressure was >175 cm H(2)O (98% success rate) in 88 of the 90 experiments. A conventional CO(2) laser soldering resulted in insufficient bonding (mean burst pressure of 40 ± 7 cm H(2)O, n = 5), while the multi-wavelength laser system provided an ~9-fold tighter seal (359 ± 75.4 cm H(2)O, P system. Bonding of the UADT mucosa using a multi-wavelength, temperature-controlled laser soldering system can support significantly higher pressures then conventional CO(2) laser soldering and suture repair. The mean bonding pressure was 3.5-fold higher than the maximal swallowing pressure. Our findings provide a basis for implementation of new surgical tools for repair of esophageal perforations.

  4. Repairing sealing surfaces on aluminum castings

    Hanna, T. L.


    Approach using stylus nickel plating instead of copper and cadmium plating has simplified repair procedure. Damaged sealing surfaces are stylus nickelplated in one step. Superficial scratches and porous areas are removed more easily from repaired surface by simply lapping sealing areas to required finish. Although method is aimed for aerospace components, it may be easily incorporated into conventional aluminumcasting technology. One-step repair can be considered for cast-aluminum automobile and aircraft engines to reduce time and costs.

  5. Microstructural Evolution of Lead-Free Solder Joints in Ultrasonic-Assisted Soldering

    Ji, Hongjun; Wang, Qiang; Li, Mingyu


    Solder joint reliability greatly depends on the microstructure of the solder matrix and the morphology of intermetallic compounds (IMCs) in the joints. Addition of strengthening phases such as carbon nanotubes and ceramic particles to solder joints to improve their properties has been widely studied. In this work, ultrasonic vibration (USV) of casting ingots was applied to considerably improve their microstructure and properties, and the resulting influence on fluxless soldering of Cu/Sn-3.0Ag-0.5Cu/Cu joints and their microstructural evolution was investigated. It was demonstrated that USV application during reflow of Sn-based solder had favorable effects on β-Sn grain size refinement as well as the growth and distribution of various IMC phases within the joints. The β-Sn grain size was significantly refined as the ultrasound power was increased, with a reduction of almost 90% from more than 100 μm to below 10 μm. Long and large Cu6Sn5 tubes in the solder matrix of the joints were broken into tiny ones. Needle-shaped Ag3Sn was transformed into flake-shaped. These IMCs were mainly precipitated along β-Sn phase boundaries. High-temperature storage tests indicated that the growth rate of interfacial IMCs in joints formed with USV was slower than in conventional reflow joints. The mechanisms of grain refinement and IMC fragmentation are discussed and related to the ultrasonic effects.

  6. Bundled automobile insurance coverage and accidents.

    Li, Chu-Shiu; Liu, Chwen-Chi; Peng, Sheng-Chang


    This paper investigates the characteristics of automobile accidents by taking into account two types of automobile insurance coverage: comprehensive vehicle physical damage insurance and voluntary third-party liability insurance. By using a unique data set in the Taiwanese automobile insurance market, we explore the bundled automobile insurance coverage and the occurrence of claims. It is shown that vehicle physical damage insurance is the major automobile coverage and affects the decision to purchase voluntary liability insurance coverage as a complement. Moreover, policyholders with high vehicle physical damage insurance coverage have a significantly higher probability of filing vehicle damage claims, and if they additionally purchase low voluntary liability insurance coverage, their accident claims probability is higher than those who purchase high voluntary liability insurance coverage. Our empirical results reveal that additional automobile insurance coverage information can capture more driver characteristics and driving behaviors to provide useful information for insurers' underwriting policies and to help analyze the occurrence of automobile accidents.

  7. Multilead, Vaporization-Cooled Soldering Heat Sink

    Rice, John


    Vaporization-cooled heat sink proposed for use during soldering of multiple electrical leads of packaged electronic devices to circuit boards. Heat sink includes compliant wicks held in grooves on edges of metal fixture. Wicks saturated with water. Prevents excessive increases in temperature at entrances of leads into package.

  8. Soldering and Mass Generation in Four Dimensions

    Banerjee, R; Banerjee, Rabin; Wotzasek, Clovis


    We propose bosonised expressions for the chiral Schwinger models in four dimensions. Then, in complete analogy with the two dimensional case, we show the soldering of two bosonised chiral Schwinger models with opposite chiralities to yield the bosonised Schwinger model in four dimensions. The implications of the Schwinger model or its chiral version, as known for two dimensions, thereby get extended to four dimensions.

  9. Solderability test development. Final report. [Meniscograph tests

    Jarboe, D.M.


    Operating procedures and data reduction techniques applicable to the Meniscograph (General Electric Company, Limited) were developed. Using force-time traces from tests involving various sample materials and configurations, flux types, and test temperatures, the wetting rate and contact angle were obtained through statistical treatment of the data. This information provides a means of directly correlating solderability with the physical phenomenon of wetting.


    Victor NORDIN


    Full Text Available The transport industry development in the Russian Federation makes urgent the problem of transportation security, rendering qualitative services in the goods (passengers transportation field, checkup and repairing motor transport vehicle and etc. Certification is the basic mechanism the work of which should be directed not only at the conformity of service assessment at automobile transport to the specified requirements but also be a regulator of preventing negative developments due to implementing services quality and security improvement. Particularities and stages of conformity assessment are considered in the article also it is offered to differentiate transportation services in levels according to the value of their complex quality level.

  11. Energy autonomous sensors in the automobile; Energieautarke Sensorik im Automobil

    Kuehne, Ingo [Hochschule Heilbronn (Germany). Studiengang Energieoekologie; Schreiter, Matthias [Siemens AG, Muenchen (Germany); Li, Xiaoming [Daimler AG, Sindelfingen (Germany); Hehn, Thorsten [Hahn-Schickard-Gesellschaft fuer angewandte Forschung e.V., Freiburg (Germany). HSG-IMIT, Inst. fuer Mikro- und Informationstechnik; Thewes, Marcell; Scholl, Gerd [Helmut-Schmidt-Univ., Univ. der Bundeswehr, Hamburg (Germany); Wagner, Dieter [Continental Automotive GmbH, Regensburg (Germany); Manoli, Yiannos [Univ. Freiburg (Germany). IMTEK; Frey, Alexander [Hochschule Augsburg (Germany). Fakultaet Elektrotechnik


    A brief outline of energy autonomous sensors in the automobile is given. For this purpose the variety of sensors in today's automotive vehicles is reported. The rationale for the deployment of energy autonomous sensors is given. In addition the potential of using environmental energy and the possibilities of their energy conversion are presented. As part of the funded project ASYMOF, two pioneer applications - a tire pressure monitoring and an anti-theft alarm system - are studied and discussed.

  12. Preparation of solder pads by selective laser scanning

    Wenqing Shi; Yongqiang Yang; Yanlu Huang; Guoqiang Wei; Wei Guo


    We propose a new laser preparation technique to solder Sn-Ag3.5-Cu0.7 on a copper clad laminate (CCL). The experiment is conducted by selective laser heating and melting the thin solder layer and then preprint-ing it on CCL in order to form the matrix with solder pads. Through the analysis of macro morphology of the matrix with solder pads and microstructure of single pads, this technique is proved to be suitable for preparing solder pads and that the solder pads are of good mechanical properties. The results also reveal that high frequency laser pulse is beneficial to the formation of better solder pad, and that the 12-W fiber laser with a beam diameter of 0.030 mm can solder Sn-Ag3.5-Cu0.7 successfully on CCL at 500-kHz pulse frequency. The optimized parameters of laser soldering on CCL are as follows: the laser power is 12 W, the scanning speed is 1.0 mm/s, the beam diameter is 0.030 mm, the lead-free solder is Sn-Ag3.5-Cu0.7, and the laser pulse frequency is 500 kHz.

  13. Automobile accessories: Assessment and improvement

    Jackson, M. [Univ. of Nevada, Las Vegas, NV (United States)


    With mandates and regulatory policies to meet both the California Air Resources Board (CARB) and the Partnership for a New Generation of Vehicles (PNGV), designing vehicles of the future will become a difficult task. As we look into the use of electric and hybrid vehicles, reduction of the required power demand by influential automobile components is necessary in order to obtain performance and range goals. Among those automobile components are accessories. Accessories have a profound impact on the range and mileage of future vehicles with limited amounts of energy or without power generating capabilities such as conventional vehicles. Careful assessment of major power consuming accessories helps us focus on those that need improvement and contributes to attainment of mileage and range goals for electric and hybrid vehicles.

  14. Effects of AlN Nanoparticles on the Microstructure, Solderability, and Mechanical Properties of Sn-Ag-Cu Solder

    Jung, Do-Hyun; Sharma, Ashutosh; Lim, Dong-Uk; Yun, Jong-Hyun; Jung, Jae-Pil


    The addition of nanosized AlN particles to Sn-3.0 wt pctAg-0.5 wt pctCu (SAC305) lead-free solder alloy has been investigated. The various weight fractions of AlN (0, 0.03, 0.12, 0.21, 0.60 wt pct) have been dispersed in SAC305 solder matrix by a mechanical mixing and melting route. The influences of AlN nanosized particles on the microstructure, mechanical properties, and solderability ( e.g., spreadability and wettability) have been carried out. The structural and morphological features of the nanocomposite solder were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscope (TEM). The experimental results show that the best combination of solderability and mechanical properties is obtained at 0.21 wt pct AlN in the solder matrix. The reinforced composite solder with 0.21 wt pct AlN nanoparticles shows ≈25 pct improvement in ultimate tensile strength (UTS), and ≈4 pct increase in the spreadability. In addition, the results of microstructural analyses of composite solders indicate that the nanocomposite solder, especially reinforced with 0.21 wt pct of AlN nanoparticles, exhibits better microstructure and improved elongation percentage, compared with the monolithic SAC305 solder.

  15. Sn-Ag-Cu Nanosolders: Solder Joints Integrity and Strength

    Roshanghias, Ali; Khatibi, Golta; Yakymovych, Andriy; Bernardi, Johannes; Ipser, Herbert


    Although considerable research has been dedicated to the synthesis and characterization of lead-free nanoparticle solder alloys, only very little has been reported on the reliability of the respective joints. In fact, the merit of nanoparticle solders with depressed melting temperatures close to the Sn-Pb eutectic temperature has always been challenged when compared with conventional solder joints, especially in terms of inferior solderability due to the oxide shell commonly present on the nanoparticles, as well as due to compatibility problems with common fluxing agents. Correspondingly, in the current study, Sn-Ag-Cu (SAC) nanoparticle alloys were combined with a proper fluxing vehicle to produce prototype nanosolder pastes. The reliability of the solder joints was successively investigated by means of electron microscopy and mechanical tests. As a result, the optimized condition for employing nanoparticles as a competent nanopaste and a novel procedure for surface treatment of the SAC nanoparticles to diminish the oxide shell prior to soldering are being proposed.

  16. Investigation of Solder Cracking Problems on Printed Circuit Boards

    Berkebile, M. J.


    A Solder Committee designated to investigate a solder cracking phenomena occurring on the SATURN electrical/electronic hardware found the cause to be induced stress in the soldered connections rather than faulty soldering techniques. The design of the printed circuit (PC) board assemblies did not allow for thermal expansion of the boards that occurred during normal operation. The difference between the thermal expansion properties of the boards and component lead materials caused stress and cracking in the soldered connections. The failure mechanism and various PC boards component mounting configurations are examined in this report. Effective rework techniques using flanged tubelets, copper tubelets, and soft copper wiring are detailed. Future design considerations to provide adequate strain relief in mounting configurations are included to ensure successful solder terminations.

  17. Assessment of potential solder candidates for high temperature applications

    Multi-Chip module (MCM) technology is a specialized electronic packaging technology recently gaining momentum due to the miniaturization drive in the microelectronics industry. The step soldering approach is being employed in the MCM technology. This method is used to solder various levels...... of the package with different solders of different melting temperatures. High Pb containing alloys where the lead levels can be above 85% by weight, is one of the solders currently being used in this technology. Responding to market pressure i.e. need for green electronic products there is now an increasing...... criterion, phases predicted in the bulk solder and the thermodynamic stability of chlorides. These promising solder candidates were precisely produced using the hot stage microscope and its respective anodic and cathodic polarization curves were investigated using a micro-electrochemical set up...

  18. 49 CFR 523.5 - Non-passenger automobile.


    ... 49 Transportation 6 2010-10-01 2010-10-01 false Non-passenger automobile. 523.5 Section 523.5... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.5 Non-passenger automobile. A non-passenger automobile means an automobile that is not a passenger automobile or a work truck and...

  19. Anomalous creep in Sn-rich solder joints

    Song, Ho Geon; Morris Jr., John W.; Hua, Fay


    This paper discusses the creep behavior of example Sn-rich solders that have become candidates for use in Pb-free solder joints. The specific solders discussed are Sn-3.5Ag, Sn-3Ag-0.5Cu, Sn-0.7Cu and Sn-10In-3.1Ag, used in thin joints between Cu and Ni-Au metallized pads.



    In order to study the mechanism of vacuum fluxless soldering on the conditions of laser heating, the method of measuring temperature by the thermocouple is used to analyze the spreading and wetting process of boh fluxless SnPb solder in the vacuum surroundings and flux SnPb solder on Cu pad. Solder spreading and wetting affected by the soldering thermal process is also discussed according to the thermodynamics principle. Results show that vacuum fluxless soldering demands higher temperature, and the fall of the solder su rface tension is the important factor achieving fluxless laser soldering.

  1. Roadway Automobile Stability. A Numerical Study

    Nikolov, Svetoslav; Nedev, Valentin; Bachvarov, Stefan


    A mathematical model of the roadway automobile motion is numerically analyzed. This model is intended to describe the roadway automobile stability. A previous paper [6] described the model in detail and the general method of qualitative analysis. In the present paper, we continue the discussion of stability by numerical simulations and the specific question we attempted to answer is: which parameter(s) of automobile geometry and quality of the roadway can serve as a reliable predictor(s) for ...

  2. Solderability preservation through the use of organic inhibitors

    Sorensen, N.R.; Hosking, F.M.


    Organic inhibitors can be used to prevent corrosion of metals and have application in the electronics industry as solderability preservatives. We have developed a model to describe the action of two inhibitors (benzotriazole and imidazole) during the environmental aging and soldering process. The inhibitors bond with the metal surface and form a barrier that prevents or retards oxidation. At soldering temperatures, the metal-organic complex breaks down leaving an oxide-free metal surface that allows excellent wetting by molten solder. The presence of the inhibitor retards the wetting rate relative to clean copper, but provides a vast improvement relative to oxidized copper.

  3. Aging, stressing and solderability of electroplated and electroless copper

    Sorensen, N.R.; Hosking, F.M.


    Organic inhibitors can be used to prevent corrosion of metals have application in the electronics industry as solderability preservatives. We have developed a model to describe the action of two inhibitors (benzotriazole and imidazole) during the environmental aging and soldering process. The inhibitors bond with the metal surface and form a barrier that prevents or retards oxidation. At soldering temperatures, the metal-organic complex breaks down leaving an oxide-free metal surface that allows excellent wetting by the molten solder. The presence of the inhibitor retards the wetting rate relative to clean copper but provides a vast improvement relative to oxidized copper.

  4. High temperature solder alloys for underhood applications: Final report

    Kern, J.A. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mechanical Engineering; Drewien, C.A.; Yost, F.G.; Sackinger, S. [Sandia National Laboratories, Albuquerque, NM (United States); Weiser, M.W. [Johnson-Mathey Electronics Corp., Spokane, WA (United States)


    In this continued study, the microstructural evolution and peel strength as a function of thermal aging were evaluated for four Sn-Ag solders deposited on double layered Ag-Pt metallization. Additionally, activation energies for intermetallic growth over the temperature range of 134 to 190{degrees}C were obtained through thickness measurements of the Ag-Sn intermetallic that formed at the solder-metallization interface. It was found that Bi-containing solders yielded higher activation energies for the intermetallic growth, leading to thicker intermetallic layers at 175 and 190{degrees}C for times of 542 and 20.5 hrs, respectively, than the solders free of Bi. Complete reaction of the solder with the metallization occurred and lower peel strengths were measured on the Bi-containing solders. In all solder systems, a Ag-Sn intermetallic thickness of greater than {approximately}7 {mu}m contributed to lower peel strength values. The Ag-Sn binary eutectic composition and the Ag-Sn-Cu ternary eutectic composition solders yielded lower activation energies for intermetallic formation, less microstructural change with time, and higher peel strengths; these solder systems were resilient to the effects of temperatures up to 175{degrees}C. Accelerated isothermal aging studies provide useful criteria for recommendation of materials systems. The Sn-Ag and Sn-Ag-Cu eutectic compositions should be considered for future service life and reliability studies based upon their performance in this study.

  5. Recent Research Trend in Laser-Soldering Process

    Kim, Hwan Tae; Kil, Sang Cheol [Korea Institute of Science and Technology Information, Seoul (Korea, Republic of); Hwang, Woon Suk [Inha University, Incheon (Korea, Republic of)


    The trend of the microjoining technology by the laser-soldering process has been reviewed. Among the production technologies, joining technology plays an important role in the fabrication of electronic components. This has led to an increasing attention towards the use of modem microjoining technology such as micro-resistance spot joining micro-soldering, micro-friction stir joining and laser-soldering, etc. This review covers the recent technical trends of laser-soldering collected from the COMPENDEX DB analysis of published papers, research subject and research institutes.

  6. The construction of a Danish automobile culture

    Wagner, Michael

    The aim of this article is to discuss the way the automobile was introduced and promoted as a vehicle for modern leisure life in Denmark 1900-1970., and to demonstrate how automobilism was constructed around an ideology of consumption for leisure and recreation.......The aim of this article is to discuss the way the automobile was introduced and promoted as a vehicle for modern leisure life in Denmark 1900-1970., and to demonstrate how automobilism was constructed around an ideology of consumption for leisure and recreation....

  7. Reliability Study of Solder Paste Alloy for the Improvement of Solder Joint at Surface Mount Fine-Pitch Components

    Mohd Nizam Ab. Rahman


    Full Text Available The significant increase in metal costs has forced the electronics industry to provide new materials and methods to reduce costs, while maintaining customers’ high-quality expectations. This paper considers the problem of most electronic industries in reducing costly materials, by introducing a solder paste with alloy composition tin 98.3%, silver 0.3%, and copper 0.7%, used for the construction of the surface mount fine-pitch component on a Printing Wiring Board (PWB. The reliability of the solder joint between electronic components and PWB is evaluated through the dynamic characteristic test, thermal shock test, and Taguchi method after the printing process. After experimenting with the dynamic characteristic test and thermal shock test with 20 boards, the solder paste was still able to provide a high-quality solder joint. In particular, the Taguchi method is used to determine the optimal control parameters and noise factors of the Solder Printer (SP machine, that affects solder volume and solder height. The control parameters include table separation distance, squeegee speed, squeegee pressure, and table speed of the SP machine. The result shows that the most significant parameter for the solder volume is squeegee pressure (2.0 mm, and the solder height is the table speed of the SP machine (2.5 mm/s.

  8. Effects of rare earth element Ce on solderabilities of micron-powdered Sn-Ag-Cu solder

    XUE Song-bai; YU Sheng-lin; WANG Xu-yan; LIU lin; HU Yong-fang; YAO Li-hua


    Several important properties of the micron-powdered Sn-Ag-Cu-Ce solder, including the spreadability, spreading ratio, wetting time, and melting point, were investigated for verifying the effects of rare earth element Ce on solderabilities of micron-powdered Sn-Ag-Cu solder. The solidus and the liquidus of the micron-powdered Sn-Ag-Cu-Ce solder are 193.6℃ and 218.4℃, respectively, about 28℃ and 3℃ lower than the melting point of the block Sn-Ag-Cu solder, which reminds the existence of the surface effect of the micron-powdered solder. By adding Ce into Sn-Ag-Cu alloy, its wetting time on pure copper can be obviously decreased. For the Sn-Ag-Cu-0.03%Ce, the soldering temperature is 250℃, and the wetting time on pure copper is close to 1s, with the soldering temperature approaching to 260℃, the wetting time is dropped to 0.8s, which is close to the wetting time, 0.68s, of Sn-Pb solder at 235℃.

  9. A Study of the Interface of Soldered Joints of SnInAgTi Active Solder with Ito Ceramics

    M. Provazník


    Full Text Available This paper presents an analysis of the solderability ITO ceramics (In2O3/SnO2. The soft active solder SnInAgeTi was used for the experiments. The solder was activated by power ultrasound in air without flux. An analysis of the interface of the phases between the solder and the ceramic was carried out in order to discover the ultrasonic impacts on the active metal and to identify the mechanism of the joint on the ceramic side.

  10. Anhui Jianghuai Automobile Group Co., Ltd.


      Anhui Jianghuai Automobile Group Co., Ltd (hereafter referred to as "Jiangqi Group"),established on May 18, 1997 with approval of Anhui provincial government, is one of 12 key provincial owned enterprises. Its predecessor was Hefei Jianghuai Automobile Factory built in 1964.……

  11. Anhui Jianghuai Automobile Group Co., Ltd.


    @@ Anhui Jianghuai Automobile Group Co., Ltd (hereafter referred to as "Jiangqi Group"),established on May 18, 1997 with approval of Anhui provincial government, is one of 12 key provincial owned enterprises. Its predecessor was Hefei Jianghuai Automobile Factory built in 1964.



    To develop cruise control system of an automobile with the metal pushing V-belt type CVT, the dynamic model of automobile travelling longitudinally is established, and the fuzzy controller of control system is designed. Considering uncertainty system parameter and exterior resistance disturbances, the stability of controller is investigated by simulating. The results of its simulation show that the fuzzy controller designed has practicability.

  13. Surface tension and reactive wetting in solder connections

    Wedi, Andre; Schmitz, Guido [Institut fuer Materialphysik, Westf. Wilhelms-Universitaet, Wilhelm-Klemm-Strasse 10, 48149 Muenster (Germany)


    Wetting is an important pre-requisite of a reliable solder connection. However, it is only an indirect measure for the important specific energy of the reactive interface between solder and base metallization. In order to quantify this energy, we measured wetting angles of solder drops as well as surface tension of SnPb solders under systematic variation of composition and gaseous flux at different reflow temperatures. For the latter, we used the sessile drop method placing a solder drop on a glas substrate. From the two independent data sets, the important energy of the reactive interface is evaluated based on Young's equation. Remarkably, although both, the tension between the solder and flux and the wetting angle, reveal significant dependence on solder composition. So the adhesion energy reveals distinguished plateaus which are related to different reaction products in contact to the solder. TEM analysis and calculations of phase stabilities show that there is no Cu6Sn5 for high lead concentrations. The experiments confirm a model of reactive wetting by Eustathopoulos.

  14. Assessment of potential solder candidates for high temperature applications

    of the package with different solders of different melting temperatures. High Pb containing alloys where the lead levels can be above 85% by weight, is one of the solders currently being used in this technology. Responding to market pressure i.e. need for green electronic products there is now an increasing...

  15. Cost comparison modeling between current solder sphere attachment technology and solder jetting technology

    Davidson, R.N.


    By predicting the total life-cycle cost of owning and operating production equipment, it becomes possible for processors to make accurate and intelligent decisions regarding major capitol equipment investments as well as determining the most cost effective manufacturing processes and environments. Cost of Ownership (COO) is a decision making technique based on inputting the total costs of acquiring, operating and maintaining production equipment. All quantitative economic and production data can be modeled and processed using COO software programs such as the Cost of Ownership Luminator program TWO COOL{trademark}. This report investigated the Cost of Ownership differences between the current state-of-the-art solder ball attachment process and a prototype solder jetting process developed by Sandia National Laboratories. The prototype jetting process is a novel and unique approach to address the anticipated high rate ball grid array (BGA) production requirements currently forecasted for the next decade. The jetting process, which is both economically and environmentally attractive eliminates the solder sphere fabrication step, the solder flux application step as well as the furnace reflow and post cleaning operations.

  16. A Study of Solder Alloy Ductility for Cryogenic Applications

    Lupinacci, A.; Shapiro, A. A.; Suh, J-O.; Minor, A. M.


    For aerospace applications it is important to understand the mechanical performance of components at the extreme temperature conditions seen in service. For solder alloys used in microelectronics, cryogenic temperatures can prove problematic. At low temperatures Sn-based solders undergo a ductile to brittle transition that leads to brittle cracks, which can result in catastrophic failure of electronic components, assemblies and spacecraft payloads. As industrial processes begin to move away from Pb-Sn solder, it is even more critical to characterize the behavior of alternative Sn-based solders. Here we report on initial investigations using a modified Charpy test apparatus to characterize the ductile to brittle transformation temperature of nine different solder systems.

  17. Hybrid microcircuit board assembly with lead-free solders

    Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.


    An assessment was made of the manufacturability of hybrid microcircuit test vehicles assembled using three Pb-free solder compositions 96.5Sn--3.5Ag (wt.%), 91.84Sn--3.33Ag--4.83Bi, and 86.85Sn--3.15Ag--5.0Bi--5.0Au. The test vehicle substrate was 96% alumina; the thick film conductor composition was 76Au--21Pt--3Pd. Excellent registration between the LCCC or chip capacitor packages and the thick film solder pads was observed. Reduced wetting of bare (Au-coated) LCCC castellations was eliminated by hot solder dipping the I/Os prior to assembly of the circuit card. The Pb-free solders were slightly more susceptible to void formation, but not to a degree that would significantly impact joint functionality. Microstructural damage, while noted in the Sn-Pb solder joints, was not observed in the Pb-free interconnects.

  18. Current Status of Lead-Free Soldering and Conductive Adhesives



    Lead-free soldering technology took offin the Japanese market during the year 2000, and as the year 2001-03 ushered in the 21 st century, a large number of products with lead-free soldering were already appearing on store shelves. Elsewhere, EU deliberation on the draft of the WEEE/RoHS directive finalized in February 2003 and be in force in July 2006. The course had been set for adopting lead-free solder for mounting processes of parts as well, bringing the possibility of lead-free solder mounting very close to achievement. This review will provide a view of the current state of technological progress in lead-free soldering, both in Japan and abroad, and will discuss future prospects.

  19. Development of lead-free solders for hybrid microcircuits

    Hosking, F.M.; Vianco, P.T.; Frear, D.R.; Robinson, D.G.


    Extensive work has been conducted by industry to develop lead-free solders for electronics applications. The driving force behind this effort is pressure to ban or tax the use of lead-bearing solders. There has been further interest to reduce the use of hazardous chemical cleaners. Lead-free soldering and low-residue, ``no clean`` assembly processing are being considered as solutions to these environmental issues. Most of the work has been directed toward commercial and military printed wiring board (PWB) technology, although similar problems confront the hybrid microcircuit (HMC) industry, where the development of lead-free HMC solders is generally lagging. Sandia National Laboratories is responsible for designing a variety of critical, high reliability hybrid components for radars. Sandia has consequently initiated a project, as part of its Environmentally Conscious Manufacturing program, to develop low-residue, lead-free soldering for HMCs. This paper discusses the progress of that work.

  20. Duality Symmetry and Soldering in Different Dimensions

    Banerjee, R


    We develop a systematic method of obtaining duality symmetric actions in different dimensions. This technique is applied for the quantum mechanical harmonic oscillator, the scalar field theory in two dimensions and the Maxwell theory in four dimensions. In all cases there are two such distinct actions. Furthermore, by soldering these distinct actions in any dimension a master action is obtained which is duality invariant under a much bigger set of symmetries than is usually envisaged. The concept of swapping duality is introduced and its implications are discussed. The effects of coupling to gravity are also elaborated. Finally, the extension of the analysis for arbitrary dimensions is indicated.


    Viorel Pop


    Full Text Available This paper is a brief overview of the evolution of the global automotive industry during the 20th century, with reference to the main manufacturers, oil crises of 1970-1980, and also the global financial and economic crisis that began in 2008. The analyzed period covers the rise of the Asian Continent, beginning with Japan, then South Korea and more recently the emerging countries: China and India. What was predicted 20-25 years ago, became reality: Asia becomes the economic centre of the world, surpassing unexpectedly fast even the Euro-Atlantic area. Regarding Romania, the revival delay of the automobiles industry, led to the loss of the trucks and bus industry, and after a much awaited rehabilitation of car production, this has stuck now at an unsatisfactory level.

  2. Repairable chip bonding/interconnect process

    Bernhardt, Anthony F.; Contolini, Robert J.; Malba, Vincent; Riddle, Robert A.


    A repairable, chip-to-board interconnect process which addresses cost and testability issues in the multi-chip modules. This process can be carried out using a chip-on-sacrificial-substrate technique, involving laser processing. This process avoids the curing/solvent evolution problems encountered in prior approaches, as well is resolving prior plating problems and the requirements for fillets. For repairable high speed chip-to-board connection, transmission lines can be formed on the sides of the chip from chip bond pads, ending in a gull wing at the bottom of the chip for subsequent solder.

  3. 10 CFR 611.207 - Small automobile and component manufacturers.


    ... 10 Energy 4 2010-01-01 2010-01-01 false Small automobile and component manufacturers. 611.207... VEHICLES MANUFACTURER ASSISTANCE PROGRAM Facility/Funding Awards § 611.207 Small automobile and component... individuals; and (2) Manufactures automobiles or components of automobiles. (b) Set Aside—Of the amount...

  4. 20 CFR 416.1218 - Exclusion of the automobile.


    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Exclusion of the automobile. 416.1218 Section..., BLIND, AND DISABLED Resources and Exclusions § 416.1218 Exclusion of the automobile. (a) Automobile; defined. As used in this section, the term automobile includes, in addition to passenger cars,...

  5. 49 CFR 529.4 - Requirements for incomplete automobile manufacturers.


    ... 49 Transportation 6 2010-10-01 2010-10-01 false Requirements for incomplete automobile... AUTOMOBILES § 529.4 Requirements for incomplete automobile manufacturers. (a) Except as provided in paragraph (c) of this section, §§ 529.5 and 529.6, each incomplete automobile manufacturer is considered,...

  6. Lessons from China’s automobile industry



    Two controversies have emerged in the development of China’s automobile industry.The first is the role of government approval in economy of scale,industrial concentration and redundant construction.Second is the role of foreign-funded companies in the growth of China’s automobile industry.Correct understanding of these matters offers a unique"intellectual asset"for approaching the institutional and policy matters of China’s automobile industry and other sectors.It also serves as guidance in the selection of growth patterns.

  7. Random torsional vibration in automobile transmissions


    The action of a road profile to the torsional vibrations in automobile transmissions is studied. The model to calculate the random torsional vibrations in the transmissions is proposed and the values of the model parameters are determined by both computation and experiment. Furthermore, the dynamic characteristics and the responses of automobile transmissions to the random excitation of road profile are calculated. The results of road experiment demonstrate that the theoretic analyses and the calculation are correct, which imply that the low frequency torsional vibrations in automobile transmissions are caused by the random excitation of a road profile.

  8. Electromigration of composite Sn-Ag-Cu solder bumps

    Sharma, Ashutosh; Xu, Di Erick; Chow, Jasper; Mayer, Michael; Sohn, Heung-Rak; Jung, Jae Pil


    This study investigates the electromigration (EM) behavior of lead free Sn-Ag-Cu (SAC) solder alloys that were reinforced with different types of nanoparticles [Copper-coated carbon nanotubes (Cu/CNT), La2O3, Graphene, SiC, and ZrO2]. The composite solders were bumped on a Cu substrate at 220°C, and the resistance of the bumped solders was measured using a four wire setup. Current aging was carried out for 4 hours at a temperature of 160°C, and an increase in resistance was noted during this time. Of all the composite solders that were studied, La2O3 and SiC reinforced SAC solders exhibited the smallest resistances after current aging. However, the rate of change in the resistance at room temperature was lower for the SiC-reinforced SAC solder. The SAC and Graphene reinforced SAC solder bumps completely failed within 15 - 20 min of these tests. The SiC nanoparticles were reported to possibly entrap the SAC atoms better than other nanoparticles with a lower rate of EM. [Figure not available: see fulltext.

  9. Environmentally compatible solder materials for thick film hybrid assemblies

    Hosking, F.M.; Vianco, P.T.; Rejent, J.A.; Hernandez, C.L. [Sandia National Labs., Albuquerque, NM (United States). Materials and Process Sciences Center


    New soldering materials and processes have been developed over the last several years to address a variety of environmental issues. One of the primary efforts by the electronics industry has involved the development of alternative solders to replace the traditional lead-containing alloys. Sandia National Laboratories is developing such alternative solder materials for printed circuit board and hybrid microcircuit (HMC) applications. This paper describes the work associated with low residue, lead-free soldering of thick film HMC`s. The response of the different materials to wetting, aging, and mechanical test conditions was investigated. Hybrid test vehicles were designed and fabricated with a variety of chip capacitors and leadless ceramic chip carriers to conduct thermal, electrical continuity, and mechanical evaluations of prototype joints. Microstructural development along the solder and thick film interface, after isothermal solid state aging over a range of elevated temperatures and times, was quantified using microanalytical techniques. Flux residues on soldered samples were stressed (temperature-humidity aged) to identify potential corrosion problems. Mechanical tests also supported the development of a solder joint lifetime prediction model. Progress of this effort is summarized.

  10. Simulation of thermomechanical fatigue in solder joints

    Fang, H.E.; Porter, V.L.; Fye, R.M.; Holm, E.A. [Sandia National Labs., Albuquerque, NM (United States)


    Thermomechanical fatigue (TMF) is a very complex phenomenon in electronic component systems and has been identified as one prominent degradation mechanism for surface mount solder joints in the stockpile. In order to precisely predict the TMF-related effects on the reliability of electronic components in weapons, a multi-level simulation methodology is being developed at Sandia National Laboratories. This methodology links simulation codes of continuum mechanics (JAS3D), microstructural mechanics (GLAD), and microstructural evolution (PARGRAIN) to treat the disparate length scales that exist between the macroscopic response of the component and the microstructural changes occurring in its constituent materials. JAS3D is used to predict strain/temperature distributions in the component due to environmental variable fluctuations. GLAD identifies damage initiation and accumulation in detail based on the spatial information provided by JAS3D. PARGRAIN simulates the changes of material microstructure, such as the heterogeneous coarsening in Sn-Pb solder, when the component`s service environment varies.


    Pradeep P.


    Full Text Available BACKGROUND: The global automotive repair and maintenance service industries are expected to be worth almost $306 billion by 2015. The automotive service sectors currently are having employees an estimated 787 , 77702 and increasing at rate of 12% per annum. AIMS & OBJECTIVES: ( 1 To assess the prevalence morbidities among automobile workers (2 To increase the awareness about safety (PPE at work place (3 To motivate about social security schemes coverage. MATERIAL & METHODS: A cross - sectional study was carried out in the territory area of IMSR M edical C ollage of Satara districts. The total no of 117 participants were included for the study. A pretested , predesigned Prof o rma was used to collect the Information’s under supervisi on & analyzed & interpreted with help of percentages & chi square test. RESULT: About 32.76% were only having less than 10 years of service. 68.41% of subjects have dropped their study before high school. Only 25.74% have their own garage , along with 29.25 % of subjects were having specialized training. PPE was available with 29.25% of subjects. Stress , Muscle/bony pain & dyspepsia along with bowl disorders were significant morbidities observed. CONCLUSION: P revalence of morbidities is significant in this st udy & need more medical attention towards automobile workers.

  12. Mechanical Reliability of Aged Lead-­Free Solders

    Lewin, Susanne


    The usage of lead-­free solder joints in electronic packaging is of greatest concern to the electronic industry due to the health and environmental hazards arising with the use of lead. As a consequence, lead is legally prohibited in the European Union and the industry is aiming to produce lead-free products.            The reliability of solder joints is an important issue as the failure could destroy the whole function of a product. SnAgCu is a commonly used alloy for lead-­free solders. Co...

  13. Solder technology in the manufacturing of electronic products

    Vianco, P.T.


    The electronics industry has relied heavily upon the use of soldering for both package construction and circuit assembly. The solder attachment of devices onto printed circuit boards and ceramic microcircuits has supported the high volume manufacturing processes responsible for low cost, high quality consumer products and military hardware. Defects incurred during the manufacturing process are minimized by the proper selection of solder alloys, substrate materials and process parameters. Prototyping efforts are then used to evaluate the manufacturability of the chosen material systems. Once manufacturing feasibility has been established, service reliability of the final product is evaluated through accelerated testing procedures.

  14. Topology Explains Why Automobile Sunshades Fold Oddly

    Feist, Curtis; Naimi, Ramin


    Automobile sunshades always fold into an "odd" number of loops. The explanation why involves elementary topology (braid theory and linking number, both explained in detail here with definitions and examples), and an elementary fact from algebra about symmetric group.

  15. Information searches by consumers of miniature automobiles

    CHEN Dao-ping; LIU Wei


    We studied the information search behaviors of Chinese consumers of miniature automobiles. First, we identified the main sources where consumers acquire or seek information about miniature automobiles and discussed their extent of information search. Then, based on logistic regression and optimal scaling regression of statistics, we studied the influences of characteristics of consumers of miniature automobiles on the extent of information search and on Internet usage. The results indicate that consumers often utilize four sources to obtain information about miniature automobiles. The dominant information source for consumers is their friends/family, followed by dealers, newspapers, and TV. Age, occupation, education and income significantly affect the extent of information search, but gender and city of residence do not have significant impacts. Age, city of residence, occupation, education and income produce significant influences on Internet usage. Gender has an insignificant influence on whether a consumer uses the Internet to search for information.

  16. Solderability and intermetallic compounds formation of Sn-9Zn-xAg lead-free solders wetted on Cu substrate

    CHEN Wenxue; XUE Songbai; WANG Hui; WANG Jianxin; HAN Zongjie


    The eutectie Sn-9Zn alloy was doped with Ag (0 wt.%-1 wt.%) to form Sn-9Zn-xAg lead-free solder alloys. The effect of the addition of Ag on the microstructure and solderability of this alloy was investigated and intermetallic compounds (IMCs) formed at the solder/Cu interface were also examined in this study. The results show that, due to the addition of Ag, the microstructure of the solder changes. When the quan-tity of Ag is lower than 0.3 wt.%, the needle-like Zn-rich phase decreases gradually. However, when the quantity of Ag is 0.5 wt.%-1 wt.%, Ag-Zn intermetallic compounds appear in the solder. In particular, adding 0.3 wt.% Ag improves the wetting behavior due to the better oxi-dation resistance of the Sn-9Zn solder. The addition of an excessive amount of Ag will deteriorate the wetting property because the gluti-nosity and fluidity of Sn-9Zn-(0.5, 1)Ag solder decrease. The results also indicate that the addition of Ag to the Sn-Zn solder leads to the pre-cipitation of ε-AgZn_3 from the liquid solder on preformed interracial intermetallics (Cu_5Zn_8). The peripheral AgZn_3, nodular on the Cu_5Zn_8 IMCs layer, is likely to be generated by a peritectic reaction L+γ-Ag_5Zn8→ε-AgZn_3 and the following crystallization of AgZn_3.

  17. China's Automobile:Walk into Africa


    @@ The press conference and flag presentation ceremony of the 6th China Auto International fAlgeria & Egypt)Exhibition Tour was held on November 3,2008 at China Council for the Promotion of International Trade (CCPIT),Beijing.An international exhibition automobile team,which is composed of China's independent brands and represents the independent research,development and manufacturing level of Chinese automobile industry,is ready to set out for Africa.

  18. Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

    Liu Mei Lee


    Full Text Available This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also discussed. Sn-Ag-Cu lead-free solder alloys are the most promising candidate for the replacement of Sn-Pb solders in modern microelectronic technology. Sn-Ag-Cu solders could possibly be considered and adapted in miniaturization technologies. Therefore, this paper should be of great interest to a large selection of electronics interconnect materials, reliability, processes, and assembly community.

  19. High temperature solder alloys for underhood applications. Progress report

    Drewien, C.A.; Yost, F.G.; Sackinger, S. [Sandia National Labs., Albuquerque, NM (United States); Kern, J.; Weiser, M.W. [Univ. of New Mexico (United States). Dept. of Mechanical Engineering


    Under a cooperative research and development agreement with General Motors Corporation, lead-free solder systems including the flux, metallization, and solder are being developed for high temperature, underhood applications. Six tin-rich solders, five silver-rich metallizations, and four fluxes were screened using an experimental matrix whereby every combination was used to make sessile drops via hot plate or Heller oven processing. The contact angle, sessile drop appearance, and in some instances the microstructure was evaluated to determine combinations that would yield contact angles of less than 30{degrees}, well-formed sessile drops, and fine, uniform microstructures. Four solders, one metallization, and one flux were selected and will be used for further aging and mechanical property studies.

  20. Development of gold based solder candidates for flip chip assembly

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri


    Flip chip technology is now rapidly replacing the traditional wire bonding interconnection technology in the first level packaging applications due to the miniaturization drive in the microelectronics industry. Flip chip assembly currently involves the use of high lead containing solders for inte......Flip chip technology is now rapidly replacing the traditional wire bonding interconnection technology in the first level packaging applications due to the miniaturization drive in the microelectronics industry. Flip chip assembly currently involves the use of high lead containing solders...

  1. Method of defence of solder surface from oxidization

    Kurmashev Sh. D.


    Full Text Available Compositions are developed for defence of fusion solder from oxidization on the basis of mixture of glycerin, urea and powders of refractory oxides, carbides (Al2O3, TiO2, SIC, graphite. The offered compositions can be used for defence of fusion of solder from oxidization in the process of soludering and tinning of explorers, and also electric conclusions of elements of radio electronic apparatus by the method of immersion in stationary baths.

  2. Critical evaluations of lead-free solder alloys and performance comparisons

    Hitch, T.T.; Palit, K.; Prabhu, A.N. [David Sarnoff Research Center, Princeton, NJ (United States)


    This paper discusses the methodology for solder alloy selection, solder preparation processes, test selection, results, and conclusions. The conclusions from this phase of study were that: (1). Solders containing significant amounts of bismuth exhibit poor fatigue life. (2). The Sn-Ag-Cu alloy was the best solder we studied for use as a replacement for Sn-Pb eutectic. A second phase of the work involved detailed study of the Sn-Ag-Cu system with other additions to determine the optimum lead-free solder compositions in terms of melting point, solderability, and mechanical properties.

  3. Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

    Liu Mei Lee; Ahmad Azmin Mohamad


    This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also disc...

  4. Microsurgical anastomosis of sperm duct by laser tissue soldering

    Wehner, Martin M.; Teutu-Kengne, Alain-Fleury; Brkovic, Drasko; Henning, Thomas; Klee, Doris; Poprawe, Reinhart; Jakse, Gerhard


    Connection of small vessels is usually done by suturing which is very cumbersome. Laser tissue soldering can circumvent that obstacle if a handy procedure can be defined. Our principle approach consists of a bioresorbable hollow stent with an expected degradation time of 3 weeks in combination with laser soldering. The stent is to be fed into the vessel to stabilize both ends and should allow percolation immediately after joining. The stents are made of Poly(D,L-lactid-co-glycolid) and solder is prepared from bovine serum albumin (BSA) doped with Indocyanine green (ICG) as chromophore to increase the absorption of laser light. After insertion, solder is applied onto the outer surface of the vessel and coagulated by laser radiation. The wavelength of 810 nm of a diode laser fits favorably to absorption properties of tissue and solder such that heating up of tissue is limited to prevent from necrosis and wound healing complications. In our study the preparation of stents, the consistency and doping of solder, a beam delivery instrument and the irradiation conditions are worked out. In-vitro tests are carried out on sperm ducts of Sprague-Dowlae (SD) rats. Different irradiation conditions are investigated and a micro-optical system consisting of a lens and a reflecting prism to ensure simultaneous irradiation of front and back side of the vessels tested. Under these conditions, the short-term rupture strength of laser anastomosis revealed as high as those achieved by suturing.

  5. Creep properties of Pb-free solder joints

    Song, H.G.; Morris Jr., J.W.; Hua, F.


    Describes the creep behavior of three Sn-rich solders that have become candidates for use in Pb-free solder joints: Sn-3.5Ag, Sn-3Ag-0.5Cu and Sn-0.7Cu. The three solders show the same general behavior when tested in thin joints between Cu and Ni/Au metallized pads at temperatures between 60 and 130 C. Their steady-state creep rates are separated into two regimes with different stress exponents(n). The low-stress exponents range from {approx}3-6, while the high-stress exponents are anomalously high (7-12). Strikingly, the high-stress exponent has a strong temperature dependence near room temperature, increasing significantly as the temperature drops from 95 to 60 C. The anomalous creep behavior of the solders appears to be due to the dominant Sn constituent. Joints of pure Sn have stress exponents, n, that change with stress and temperature almost exactly like those of the Sn-rich solder joints. Research on creep in bulk samples of pure Sn suggests that the anomalous temperature dependence of the stress exponent may show a change in the dominant mechanism of creep. Whatever its source, it has the consequence that conventional constitutive relations for steady-state creep must be used with caution in treating Sn-rich solder joints, and qualification tests that are intended to verify performance should be carefully designed.

  6. Solderability perservative coatings: Electroless tin vs. organic azoles

    Artaki, I.; Ray, U.; Jackson, A.M.; Gordon, H.M. [AT and T Bell Labs., Princeton, NJ (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)


    This paper compares the solderability performance and corrosions ion protection effectiveness of electroless tin coatings versus organic azole films after exposure to a series of humidity and thermal (lead-free solders) cycling conditions. The solderability of immersion tin is directly related to the tin oxide growth on the surface and is not affected by the formation of Sn-Cu intermetallic phases as long as the intermetallic phase is protected by a Sn layer. For a nominal tin thickness of 60{mu}inches, the typical thermal excursions associated with assembly are not sufficient to cause the intermetallic phase to consume the entire tin layer. Exposure to humidity at moderate to elevated temperatures promotes heavy tin oxide formation which leads to solderability loss. In contrast, thin azole films are more robust to humidity exposure; however upon heating in the presence of oxygen, they decompose and lead to severe solderability degradation. Evaluations of lead-free solder pastes for surface mount assembly applications indicate that immersion tin significantly improves the spreading of Sn:Ag and Sn:Bi alloys as compared to azole surface finishes.

  7. Soldering in prosthodontics--an overview, part I.

    Byrne, Gerard


    The fit of fixed multiunit dental prostheses (FDP), traditionally termed fixed partial dentures (FPDs), is an ongoing problem. Poorly fitting restorations may hasten mechanical failure, due to abutment caries or screw failure. Soldering and welding play an important role in trying to overcome misfit of fixed multiunit prostheses. The term FPD will be used to denote multiunit fixed dental prostheses in this review. This is the first of a series of articles that review the state of the art and science of soldering and welding in relation to the fit of cemented or screw-retained multiunit prostheses. A comprehensive archive of background information and scientific findings is presented. Texts in dental materials and prosthodontics were reviewed. Scientific data were drawn from the numerous laboratory studies up to and including 2009. The background, theory, terminology, and working principles, along with the applied research, are presented. This first article focuses on soldering principles and dimensional accuracy in soldering. There is some discussion and suggestions for future research and development. Soldering may improve dimensional accuracy or reduce the distortion of multiunit fixed prostheses. Many variables can affect the outcome in soldering technique. Research science has developed some helpful guidelines. Research projects are disconnected and limited in scope. © 2011 by The American College of Prosthodontists.

  8. Soldering of Thin Film-Metallized Glass Substrates

    Hosking, F.M.; Hernandez, C.L.; Glass, S.J.


    The ability to produce reliable electrical and structural interconnections between glass and metals by soldering was investigated. Soldering generally requires premetallization of the glass. As a solderable surface finish over soda-lime-silicate glass, two thin films coatings, Cr-Pd-Au and NiCr-Sn, were evaluated. Solder nettability and joint strengths were determined. Test samples were processed with Sn60-Pb40 solder alloy at a reflow temperature of 210 C. Glass-to-cold rolled steel single lap samples yielded an average shear strength of 12 MPa. Solder fill was good. Control of the Au thickness was critical in minimizing the formation of AuSn{sub 4} intermetallic in the joint, with a resulting joint shear strength of 15 MPa. Similar glass-to-glass specimens with the Cr-Pd-Au finish failed at 16.5 MPa. The NiCr-Sn thin film gave even higher shear strengths of 20-22.5 MPa, with failures primarily in the glass.

  9. Lead-free solder technology transfer from ASE Americas



    To safeguard the environmental friendliness of photovoltaics, the PV industry follows a proactive, long-term environmental strategy involving a life-of-cycle approach to prevent environmental damage by its processes and products from cradle to grave. Part of this strategy is to examine substituting lead-based solder on PV modules with other solder alloys. Lead is a toxic metal that, if ingested, can damage the brain, nervous system, liver and kidneys. Lead from solder in electronic products has been found to leach out from municipal waste landfills and municipal incinerator ash was found to be high in lead also because of disposed consumer electronics and batteries. Consequently, there is a movement in Europe and Japan to ban lead altogether from use in electronic products and to restrict the movement across geographical boundaries of waste containing lead. Photovoltaic modules may contain small amounts of regulated materials, which vary from one technology to another. Environmental regulations impact the cost and complexity of dealing with end-of-life PV modules. If they were classified as hazardous according to Federal or State criteria, then special requirements for material handling, disposal, record-keeping and reporting would escalate the cost of decommissioning the modules. Fthenakis showed that several of today's x-Si modules failed the US-EPA Toxicity Characteristic Leaching Procedure (TCLP) for potential leaching of Pb in landfills and also California's standard on Total Threshold Limit Concentration (TTLC) for Pb. Consequently, such modules may be classified as hazardous waste. He highlighted potential legislation in Europe and Japan which could ban or restrict the use of lead and the efforts of the printed-circuit industries in developing Pb-free solder technologies in response to such expected legislation. Japanese firms already have introduced electronic products with Pb-free solder, and one PV manufacturer in the US, ASE Americas has used a

  10. Characterization of Low-Melting-Point Sn-Bi-In Lead-Free Solders

    Li, Qin; Ma, Ninshu; Lei, YongPing; Lin, Jian; Fu, HanGuang; Gu, Jian


    Development of lead-free solders with low melting temperature is important for substitution of Pb-based solders to reduce direct risks to human health and the environment. In the present work, Sn-Bi-In solders were studied for different ratios of Bi and Sn to obtain solders with low melting temperature. The microstructure, thermal properties, wettability, mechanical properties, and reliability of joints with Cu have been investigated. The results show that the microstructures of the Sn-Bi-In solders were composed of β-Sn, Bi, and InBi phases. The intermetallic compound (IMC) layer was mainly composed of Cu6Sn5, and its thickness increased slightly as the Bi content was increased. The melting temperature of the solders was around 100°C to 104°C. However, when the Sn content exceeded 50 wt.%, the melting range became larger and the wettability became worse. The tensile strength of the solder alloys and solder joints declined with increasing Bi content. Two fracture modes (IMC layer fracture and solder/IMC mixed fracture) were found in solder joints. The fracture mechanism of solder joints was brittle fracture. In addition, cleavage steps on the fracture surface and coarse grains in the fracture structure were comparatively apparent for higher Bi content, resulting in decreased elongation for both solder alloys and solder joints.

  11. Influences of fine pitch solder joint shape parameters on fatigue life under thermal cycle

    HUANG Chun-yue; WU Zhao-hua; HUANG Hong-yan; ZHOU De-jian


    The solder joint reliability of a 0. 5 mm lead pitch, 240-pin quad flat package(QFP) was studied by nonlinear finite element analysis(FEA). The stress/strain distributions within the solder joints and the maximum plastic strain range of the solder joints were determined. Based on the calculated maximum plastic strain range the thermal fatigue life of the solder joints was calculated using Coffin-Manson equation. The influences of shape parameters including volume of solder joint, pad size and stand-off on the thermal fatigue life of the solder joints were also studied. The results show that the stress and strain distribution in the solder joint are not uniform; the interface between the lead and the solder joint is the high stress and strain region; the maximum stress and stain occur at the topmost point where the solder joint intersects with the inner side of the lead. The solder joint cracks should occur firstly at this point and propagate along the interface between the solder and the lead. The solder joint with the pad size of 1.25 mm× 0.35 mm, the stand-off of 0.02 mm and the solder volume of 0. 026 mm3 has longer fatigue life than that of any others. These optimal parameters have been applied in practice to assemble the 240-pin, 0.5 mm pitch QFP.

  12. Solderability of Sn-9Zn-0.5Ag-1In lead-free solder on Cu substrate

    Chang, T.-C. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Wang, J.-W. [Department of Environmental and Safety Engineering, Chung Hwa College of Medical Technology, 89 Wen-Hwa 1st Street, Jen-Te, Tainan 71703, Taiwan (China); Wang, M.-C. [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China)]. E-mail:; Hon, M.-H. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Da-Yeh University, 112 Shan Jean Road, Da-tsuen, Chang-hua, Taiwan (China)


    The thermal properties, microstructure corrosion and oxidation resistance of the Sn-9Zn-0.5Ag-1In lead-free solder have been investigated by differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, energy dispersive spectrometry, potentiostat and thermogravimetry. The Sn-9Zn-0.5Ag-1In solder alloy has a near-eutectic composition, it melts at 187.6 deg. C and the heat of fusion is determined as 71.3 J/g. The Sn-9Zn-0.5Ag-1In solder alloy with a corrosion potential of -1.09 V{sub SCE} and a current density of 9.90 x 10{sup -2} A/cm{sup 2}, shows a better corrosion resistance than that of the Sn-9Zn solder alloy. From the thermogravimetry analysis, the weight gain ratio of the Sn-9Zn solder alloy appears a parabolic relationship at 150 deg. C. The initial oxidation behavior of the Sn-9Zn-0.5Ag and Sn-9Zn-0.5Ag-1In solder alloys also shows a parabolic relationship but the weight gain ratio of them appears a negative linear one after aging at 150 deg. C for 2.5 and 5 h, respectively.

  13. Solder wetting behavior enhancement via laser-textured surface microcosmic topography

    Chen, Haiyan; Peng, Jianke; Fu, Li; Wang, Xincheng; Xie, Yan


    In order to reduce or even replace the use of Sn-Pb solder in electronics industry, the laser-textured surface microstructures were used to enhance the wetting behavior of lead free solder during soldering. According to wetting theory and Sn-Ag-Cu lead free solder performance, we calculated and designed four microcosmic structures with the similar shape and different sizes to control the wetting behavior of lead free solder. The micro-structured surfaces with different dimensions were processed on copper plates by fiber femtosecond laser, and the effect of microstructures on wetting behavior was verified experimentally. The results showed that the wetting angle of Sn-Ag-Cu solder on the copper plate with microstructures decreased effectively compared with that on the smooth copper plate. The wetting angles had a sound fit with the theoretical values calculated by wetting model. The novel method provided a feasible route for adjusting the wetting behavior of solders and optimizing solders system.

  14. Interaction Kinetics between Sn-Pb Solder Droplet and Au/Ni/Cu Pad

    Fuquan LI; Chunqing WANG; Yanhong TIAN


    The interfacial phenomena of the Sn-Pb solder droplet on Au/Ni/Cu pad are investigated. A continuous AuSn2and needle-like AuSn4 are formed at the interface after the liquid state reaction (soldering). The interfacial reaction between the solder and Au layer continues during solid state aging with AuSn4 breaking off from the interface and felling into the solder. The kinetics of Au layer dissolution and diffusion into the solder during soldering and aging is analyzed to elucidate intermetallic formation mechanism at the solder/Au pad interface.The concentration of Au near the solder/pad interface is identified to increase and reach the solubility limit during the period of liquid state reaction. During solid state reaction, the thickening of Au-Sn compound is mainly controlled by element diffusion.

  15. Development of a new Pb-free solder: Sn-Ag-Cu

    Miller, C.M.


    With the ever increasing awareness of the toxicity of Pb, significant pressure has been put on the electronics industry to get the Pb out of solder. This work pertains to the development and characterization of an alloy which is Pb-free, yet retains the proven positive qualities of current Sn-Pb solders while enhancing the shortcomings of Sn-Pb solder. The solder studied is the Sn-4.7Ag-1.7Cu wt% alloy. By utilizing a variety of experimental techniques the alloy was characterized. The alloy has a melting temperature of 217{degrees}C and exhibits eutectic melting behavior. The solder was examined by subjecting to different annealing schedules and examining the microstructural stability. The effect of cooling rate on the microstructure of the solder was also examined. Overall, this solder alloy shows great promise as a viable alternative to Pb-bearing solders and, as such, an application for a patent has been filed.

  16. A critical review of constitutive models for solders in electronic packaging

    Chen, Gang; Zhao, Xiaochen; Wu, Hao


    .... Because the failure of the whole electronic packaging is often induced by the failure of solders, modeling and simulation of solder joint performance are quite important in ensuring the quality...

  17. Microbial leaching of waste solder for recovery of metal.

    Hocheng, H; Hong, T; Jadhav, U


    This study proposes an environment-friendly bioleaching process for recovery of metals from solders. Tin-copper (Sn-Cu), tin-copper-silver (Sn-Cu-Ag), and tin-lead (Sn-Pb) solders were used in the current study. The culture supernatant of Aspergillus niger removed metals faster than the culture supernatant of Acidithiobacillus ferrooxidans. Also, the metal removal by A. niger culture supernatant is faster for Sn-Cu-Ag solder as compared to other solder types. The effect of various process parameters such as shaking speed, temperature, volume of culture supernatant, and increased solder weight on bioleaching of metals was studied. About 99 (±1.75) % metal dissolution was achieved in 60 h, at 200-rpm shaking speed, 30 °C temperature, and by using 100-ml A. niger culture supernatant. An optimum solder weight for bioleaching was found to be 5 g/l. Addition of sodium hydroxide (NaOH) and sodium chloride (NaCl) in the bioleached solution from Sn-Cu-Ag precipitated tin (85 ± 0.35 %) and silver (80 ± 0.08 %), respectively. Passing of hydrogen sulfide (H2S) gas at pH 8.1 selectively precipitated lead (57.18 ± 0.13 %) from the Sn-Pb bioleached solution. The proposed innovative bioleaching process provides an alternative technology for recycling waste solders to conserve resources and protect environment.

  18. Future possibilities for energy-storage automobiles

    O' Connell, L.G.


    Because of the potential threat of a future petroleum shortage, there is increased interest in developing alternative propulsion systems for automobiles, systems that will allow the nation to reduce its demand for petroleum by this part of the transportation sector. A four-year study which assessed the future of energy storage devices for use in automobile propulsion systems has been completed. Results of the energy storage device evaluation are presented. This includes projections of future device characteristics. In addition, the results of the propulsion system analysis are given. Future energy storage automobiles were conceptually designed and they are compared to each other and the baseline internal combustion engine vehicle for several levels of performance.

  19. Consumption values and consumer attitude towards automobile purchase

    Syed Naveed Altaf; Selvan Perumal; Zolkifli Hussin


    .... A survey of 200 automobile consumers from Islamabad, Pakistan, selected via convenience sampling, was used to draw results on how consumers' consumption values affected their attitude towards automobile purchase...

  20. Analysis of solderability test methods: predicition model generation for through-hole components

    Woods, Bobby


    peer-reviewed In order to achieve a reduction in solderability related defects on electronic components and Printed Circuit Board???s (PCB???s) in electronics manufacturing, preventive controls such as ???Dip & Look??? and ???Wetting Balance??? solderability testing need to be fully optimised to screen out all poor soldering components and PCB???s. Components and PCB???s that pass these tests should solder correctly in volume production. This thesis initially investigates the variations...

  1. Methylene blue solder re-absorption in microvascular anastomoses

    Birch, Jeremy F.; Hepplewhite, J.; Frier, Malcolm; Bell, Peter R. F.


    Soldered vascular anastomoses have been reported using several chromophores but little is known of the optimal conditions for microvascular anastomosis. There are some indications of the optimal protein contents of a solder, and the effects of methylene blue on anastomotic strength. The effects of varying laser power density in vivo have also been described, showing a high rate of thrombosis with laser power over 22.9Wcm-2. However no evidence exists to describe how long the solder remains at the site of the anastomosis. Oz et al reported that the fibrin used in their study had been almost completely removed by 90 days but without objective evidence of solder removal. In order to address the issue of solder re-absorption from the site of an anastomosis we used radio-labelled albumin (I-125) incorporated into methylene blue based solder. This was investigated in both the situation of the patent and thrombosed anastomosis with anastomoses formed at high and low power. Iodine-125 (half life: 60.2 days) was covalently bonded to porcine albumin and mixed with the solder solution. Radio-iodine has been used over many years to determine protein turnover using either I-125 or I-131. Iodine-125 labelled human albumin is regularly used as a radiopharmaceutical tool for the determination of plasma volume. Radio-iodine has the advantages of not affecting protein metabolism and the label is rapidly excreted after metabolic breakdown. Labelling with chromium (Cr-51) causes protein denaturation and is lost from the protein with time. Labelled albumin has been reported in human studies over a 21-day period, with similar results reported by Matthews. Most significantly McFarlane reported a different rate of catabolism of I-131 and I-125 over a 22-day period. The conclusion from this is that the rate of iodine clearance is a good indicator of protein catabolism. In parallel with the surgery a series of blank standards were prepared with a known mass of solder to correct for isotope

  2. Reliability of lead-free solders in electronic packaging technology

    Choi, Woojin

    The electromigration of flip chip solder bump (eutetic SnPb) has been studied at temperatures of 100, 125 and 150°C and current densities of 1.9 to 2.75 x 104 A/cm2. The under-bump-metallization on the chip side is thin film Al/Ni(V)/Cu and on the board side is thick Cu. By simulation, we found that current crowding occurs at the corner on the chip side where the electrons enter the solder ball. We are able to match this simulation to the real electromigration damage in the sample. The experimental result showed that voids initiated from the position of current crowding and propagated across the interface between UBM and the solder ball. The Cu-Sn intermetallic compounds formed during the reflow is known to adhere well to the thin film UBM, but they detached from the UBM after current stressing. Therefore, the UBM itself becomes part of the reliability problem of the flip chip solder joint under electromigration. Currently there is a renewed interest in Sn whisker growth owing to the introduction of Pb-free solder in electronic manufacturing. The leadframe is electroplated or finished with a layer of Pb-free solder. The solder is typically pure Sn or eutectic SnCu (0.7 atomic % Cu). It is a serious reliability concern in the use of the eutectic SnCu solder as leadframe surface finish due to the growth of long whiskers on it. The origin of the driving force of compressive stress can be mechanical, thermal, and chemical. Among them, the chemical force is the most important contribution to the whisker growth and its origin is due to the reaction between Sn and Cu to form intermetallic compound (IMC) at room temperature. For whisker or hillock growth, the surface cannot be free of oxide and it must be covered with oxide and the oxide must be a protective one so that it removes effectively all the vacancy sources and sinks on the surface. Hence, only those metals, which grow protective oxides such as Al and Sn, are known to have hillock growth or whisker growth. We

  3. A Corrosion Investigation of Solder Candidates for High-Temperature Applications

    Chidambaram, Vivek; Hald, John; Ambat, Rajan;


    The step soldering approach is being employed in the Multi-Chip module (MCM) technology. High lead containing alloys is one of the solders currently being used in this approach. Au-Sn and Au-Ge based candidate alloys have been proposed as alternative solders for this application. In this work, co...

  4. 30 CFR 77.1916 - Welding, cutting, and soldering; fire protection.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, and soldering; fire... OF UNDERGROUND COAL MINES Slope and Shaft Sinking § 77.1916 Welding, cutting, and soldering; fire protection. (a) One portable fire extinguisher shall be provided where welding, cutting, or soldering...

  5. 30 CFR 77.1112 - Welding, cutting, or soldering with arc or flame; safeguards.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, or soldering with arc or... WORK AREAS OF UNDERGROUND COAL MINES Fire Protection § 77.1112 Welding, cutting, or soldering with arc or flame; safeguards. (a) When welding, cutting, or soldering with arc or flame near...

  6. Photonic flash soldering of thin chips and SMD components on foils for flexible electronics

    Ende, D.A. van den; Hendriks, R.; Cauchois, R.; Kusters, R.H.L.; Cauwe, M.; Groen, W.A.; Brand, J. van den


    Ultrathin bare die chips and small-size surface mount device components were successfully soldered using a novel roll-to-roll compatible soldering technology. A high-power xenon light flash was used to successfully solder the components to copper tracks on polyimide (PI) and polyethylene terephthala

  7. Investigation Of Intermetallic Compounds In Sn-Cu-Ni Lead-Free Solders

    Nagy E.


    Full Text Available Interfacial intermetallic compounds (IMC play an important role in Sn-Cu lead-free soldering. The size and morphology of the intermetallic compounds formed between the lead-free solder and the Cu substrate have a significant effect on the mechanical strength of the solder joint.

  8. 38 CFR 17.156 - Eligibility for automobile adaptive equipment.


    ... automobile adaptive equipment. 17.156 Section 17.156 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS MEDICAL Automotive Equipment and Driver Training § 17.156 Eligibility for automobile adaptive equipment. Automobile adaptive equipment may be authorized if the Under Secretary for Health...

  9. 38 CFR 3.808 - Automobiles or other conveyances; certification.


    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Automobiles or other....808 Automobiles or other conveyances; certification. (a) Entitlement. A certificate of eligibility for financial assistance in the purchase of one automobile or other conveyance in an amount not exceeding...

  10. Experimental Methods in Reduced-gravity Soldering Research

    Pettegrew, Richard D.; Struk, Peter M.; Watson, John K.; Haylett, Daniel R.


    The National Center for Microgravity Research, NASA Glenn Research Center, and NASA Johnson Space Center are conducting an experimental program to explore the influence of reduced gravity environments on the soldering process. An improved understanding of the effects of the acceleration environment is important to application of soldering during current and future human space missions. Solder joint characteristics that are being considered include solder fillet geometry, porosity, and microstructural features. Both through-hole and surface mounted devices are being investigated. This paper focuses on the experimental methodology employed in this project and the results of macroscopic sample examination. The specific soldering process, sample configurations, materials, and equipment were selected to be consistent with those currently on-orbit. Other apparatus was incorporated to meet requirements imposed by operation onboard NASA's KC-135 research aircraft and instrumentation was provided to monitor both the atmospheric and acceleration environments. The contingent of test operators was selected to include both highly skilled technicians and less skilled individuals to provide a population cross-section that would be representative of the skill mix that might be encountered in space mission crews.

  11. Creep characterization of solder bumps using nanoindentation

    Du, Yingjie; Liu, Xiao Hu; Fu, Boshen; Shaw, Thomas M.; Lu, Minhua; Wassick, Thomas A.; Bonilla, Griselda; Lu, Hongbing


    Current nanoindentation techniques for the measurement of creep properties are applicable to viscoplastic materials with negligible elastic deformations. A new technique for characterization of creep behavior is needed for situations where the elastic deformation plays a significant role. In this paper, the effect of elastic deformation on the determination of creep parameters using nanoindentation with a self-similar nanoindenter tip is evaluated using finite element analysis (FEA). It is found that the creep exponent measured from nanoindentation without taking into account of the contribution of elastic deformation tends to be higher than the actual value. An effective correction method is developed to consider the elastic deformation in the calculation of creep parameters. FEA shows that this method provides accurate creep exponent. The creep parameters, namely the creep exponent and activation energy, were measured for three types of reflowed solder bumps using the nanoindentation method. The measured parameters were verified using FEA. The results show that the new correction approach allows extraction of creep parameters with precision from nanoindentation data.

  12. Repair of Electronics for Long Duration Spaceflight

    Pettegrew, Richard D.; Easton, John; Struk, Peter


    To reduce mission risk, long duration spaceflight and exploration activities will require greater degrees of self-sufficiency with regards to repair capability than have ever been employed before in space exploration. The current repair paradigm of replacing Orbital Replacement Units (ORUs) of malfunctioning avionics and electronic hardware will be impractical, since carrying all of the spares that could possibly be needed for a long duration mission would require upmass and volume at unprecedented and unacceptable levels. A strategy of component-level repair for electronics, however, could significantly reduce the mass and volume necessary for spares and enhance mission safety via a generic contingency capability. This approach is already used to varying degrees by the U.S. Navy, where vessels at sea experience some similar constraints such as the need for self sufficiency for moderately long time periods, and restrictions on volume of repair spares and infrastructure. The concept of conducting component-level repairs of electronics in spacecraft requires the development of design guidelines for future avionics (to enable repair), development of diagnostic techniques to allow an astronaut to pinpoint the faulty component aboard a vastly complex vehicle, and development of tools and methodologies for dealing with the physical processes of replacing the component. This physical process includes tasks such as conformal coating removal and replacement, component removal, replacement, and alignment--all in the difficulty of a reduced gravity environment. Further, the gravitational effects on the soldering process must be characterized and accounted for to ensure reliability of the newly repaired components. The Component-Level Electronics-Assembly Repair (CLEAR) project under the NASA Supportability program was established to develop and demonstrate the practicality of this repair approach. CLEAR involves collaborative efforts between NASA s Glenn Research Center

  13. Motor Vehicle and Machinery Repairers. Reprinted from the Occupational Outlook Handbook, 1978-79 Edition.

    Bureau of Labor Statistics (DOL), Washington, DC.

    Focusing on motor vehicle and machinery repairers, this document is one in a series of forty-one reprints from the Occupational Outlook Handbook providing current information and employment projections for individual occupations and industries through 1985. The specific occupations covered in this document include automobile body repairers,…

  14. 32 CFR 220.11 - Special rules for automobile liability insurance and no-fault automobile insurance.


    ... 32 National Defense 2 2010-07-01 2010-07-01 false Special rules for automobile liability insurance and no-fault automobile insurance. 220.11 Section 220.11 National Defense Department of Defense... OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.11 Special rules for automobile...

  15. American Automobile and Light Truck Statistics Update

    Feldman, Bernard J.


    Given that transportation is an essential topic in any Physics and Society or Energy course, it is necessary to have useful statistics on transportation in order to have a reasoned discussion on this topic. And a major component of the transportation picture is the automobile. This paper presents updated transportation statistics for American…

  16. American Automobile and Light Truck Statistics Update

    Feldman, Bernard J.


    Given that transportation is an essential topic in any Physics and Society or Energy course, it is necessary to have useful statistics on transportation in order to have a reasoned discussion on this topic. And a major component of the transportation picture is the automobile. This paper presents updated transportation statistics for American…

  17. Active Engine Mount Technology for Automobiles

    Rahman, Z.; Spanos, J.


    We present a narrow-band tracking control using a variant of the Least Mean Square (LMS) algorithm [1,2,3] for supressing automobile engine/drive-train vibration disturbances. The algorithm presented here has a simple structure and may be implemented in a low cost micro controller.

  18. Bottom-up nanoarchitecture of semiconductor nano-building blocks by controllable in situ SEM-FIB thermal soldering method

    Zhang, Xuan


    Here we demonstrate that the building blocks of semiconductor WO3 nanowires can be controllably soldered together by a novel nano-soldering technique of in situ SEM-FIB thermal soldering, in which the soldering temperature can precisely remain in an optimal range to avoid a strong thermal diffusion.

  19. Effects of Solder Temperature on Pin Through-Hole during Wave Soldering: Thermal-Fluid Structure Interaction Analysis

    Abdul Aziz, M. S.; Abdullah, M. Z.; Khor, C. Y.


    An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin through-hole connector mounted on a printed circuit board (PCB) was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183°C) analysis. In addition, an experiment was conducted to measure the temperature difference (ΔT) between the top and the bottom of the pin. Analysis results showed that an increase in temperature increased the structural displacement and the von Mises stress. Filling time exhibited a quadratic relationship to the increment of temperature. The deformation of pin showed a linear correlation to the temperature. The ΔT obtained from the simulation and the experimental method were validated. This study elucidates and clearly illustrates wave soldering for engineers in the PCB assembly industry. PMID:25225638

  20. An Overview of Surface Finishes and Their Role in Printed Circuit Board Solderability and Solder Joint Performance

    Vianco, P.T.


    A overview has been presented on the topic of alternative surface finishes for package I/Os and circuit board features. Aspects of processability and solder joint reliability were described for the following coatings: baseline hot-dipped, plated, and plated-and-fused 100Sn and Sn-Pb coatings; Ni/Au; Pd, Ni/Pd, and Ni/Pd/Au finishes; and the recently marketed immersion Ag coatings. The Ni/Au coatings appear to provide the all-around best option in terms of solderability protection and wire bondability. Nickel/Pal ftishes offer a slightly reduced level of performance in these areas that is most likely due to variable Pd surface conditions. It is necessmy to minimize dissolved Au or Pd contents in the solder material to prevent solder joint embrittlement. Ancillary aspects that included thickness measurement techniques; the importance of finish compatibility with conformal coatings and conductive adhesives; and the need for alternative finishes for the processing of non-Pb bearing solders were discussed.

  1. Horizon Shells and BMS-like Soldering Transformations

    Blau, Matthias


    We revisit the theory of null shells in general relativity, with a particular emphasis on null shells placed at horizons of black holes. We study in detail the considerable freedom that is available in the case that one solders two metrics together across null hypersurfaces (such as Killing horizons) for which the induced metric is invariant under translations along the null generators. In this case the group of soldering transformations turns out to be infinite dimensional, and these solderings create non-trivial horizon shells containing both massless matter and impulsive gravitational wave components. We also rephrase this result in the language of Carrollian symmetry groups. To illustrate this phenomenon we discuss in detail the example of shells on the horizon of the Schwarzschild black hole (with equal interior and exterior mass), uncovering a rich classical structure at the horizon and deriving an explicit expression for the general horizon shell energy-momentum tensor. In the special case of BMS-like ...

  2. Development of alternatives to lead-bearing solders

    Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)


    Soldering technology, using tin-lead alloys has had a significant role in the packaging of highly functional, low cost electronic devices. The elimination of lead from all manufactured products, whether through legislation or tax incentives, will impact the electronics community which uses lead-containing solders. In response to these proposed measures, the National Center for Manufacturing Sciences has established a multi-year program involving participants from industry, academia, and the national laboratories with the objective to identify potential replacements for lead-bearing solders. Selection of candidate alloys is based upon the analysis of materials properties, manufacturability, modeling codes for reliability prediction, as well as toxicological properties and resource availability, data developed in the program.

  3. Bosonisation and Duality Symmetry in the Soldering Formalism

    Banerjee, R


    We develop a technique that solders the dual aspects of some symmetry. Using this technique it is possible to combine two theories with such symmetries to yield a new effective theory. Some applications in two and three dimensional bosonisation are discussed. In particular, it is shown that two apparently independent three dimensional massive Thirring models with same coupling but opposite mass signatures, in the long wavelegth limit, combine by the process of bosonisation and soldering to yield an effective massive Maxwell theory. Similar features also hold for quantum electrodynamics in three dimensions. We also provide a systematic derivation of duality symmetric actions and show that the soldering mechanism leads to a master action which is duality invariant under a bigger set of symmetries than is usually envisaged. The concept of duality swapping is introduced and its implications are analysed. The example of electromagnetic duality is discussed in details.

  4. Corrosion Issues in Solder Joint Design and Service



    Corrosion is an important consideration in the design of a solder joint. It must be addressed with respect to the service environment or, as in the case of soldered conduit, as the nature of the medium being transported within piping or tubing. Galvanic-assisted corrosion is of particular concern, given the fact that solder joints are comprised of different metals or alloy compositions that are in contact with one-another. The (thermodynamic) potential for corrosion to take place in a particular environment requires the availability of the galvanic series for those conditions and which includes the metals or alloys in question. However, the corrosion kinetics, which actually determine the rate of material loss under the specified service conditions, are only available through laboratory evaluations or field data that are found in the existing literature or must be obtained by in-house testing.

  5. Materials chemistry. Composition-matched molecular "solders" for semiconductors.

    Dolzhnikov, Dmitriy S; Zhang, Hao; Jang, Jaeyoung; Son, Jae Sung; Panthani, Matthew G; Shibata, Tomohiro; Chattopadhyay, Soma; Talapin, Dmitri V


    We propose a general strategy to synthesize largely unexplored soluble chalcogenidometallates of cadmium, lead, and bismuth. These compounds can be used as "solders" for semiconductors widely used in photovoltaics and thermoelectrics. The addition of solder helped to bond crystal surfaces and link nano- or mesoscale particles together. For example, CdSe nanocrystals with Na2Cd2Se3 solder was used as a soluble precursor for CdSe films with electron mobilities exceeding 300 square centimeters per volt-second. CdTe, PbTe, and Bi2Te3 powders were molded into various shapes in the presence of a small additive of composition-matched chalcogenidometallate or chalcogel, thus opening new design spaces for semiconductor technologies.


    R. B. Ivut


    Full Text Available Investment volume is considered as an important factor in regional development under current conditions. Logistical infrastructure which ensures a complex transport, distributive, information and other services exerts a significant influence on regional investment attractiveness. Lack of clear vision on development and execution of development strategy for logistics infrastructure from the side of regional authorities results in unwillingness of large federal and transnational companies to provide investments in infrastructure projects. Network of automotive transport terminals is one of the main elements in logistics infrastructure. The network allows to optimize a flow of material goods from the point of their origin to the point of their consumption with the lowest possible costs and the required level of service. Automobile transport is one of the main objects of transport infrastructure and it is characterized by rather high flexibility in comparison with other types of transport facilities that preconditions its widespread application. Network of automobile fleets (terminals has been formed for redistribution of goods traffic within the concerned regions. The purpose of the present research is to develop a mathematical model for formation of transport infrastructure on the territory of regions. The paper proposes an approach for formation of automobile fleet (terminal network on the territory of a large region with due account of the established network of distribution and sorting-out warehouse facilities. A model has been developed for solving the problem pertaining to minimization of aggregate costs related to maintenance of automobile fleets, delivery of goods to and from distribution and sorting-out warehouse facilities to consumers, ferry of empty trucks and goods handling. The model makes it possible to determine optimal number and location area of automobile fleets (terminals while accounting for their possible locations, capacity

  7. Process characterization and control of hand-soldered printed wiring assemblies

    Cheray, D.L.; Mandl, R.G.


    A designed experiment was conducted to characterize the hand soldering process parameters for manufacturing printed wiring assemblies (PWAs). Component tinning was identified as the most important parameter in hand soldering. After tinning, the soldering iron tip temperature of 700{degrees}F and the choice of operators influence solder joint quality more than any other parameters. Cleaning and flux/flux core have little impact on the quality of the solder joint. The need for component cleaning prior to assembly must be evaluated for each component.

  8. The impact of process parameters on gold elimination from soldered connector assemblies



    Minimizing the likelihood of solder joint embrittlement in connectors is realized by reducing or eliminating retained Au plating and/or Au-Sn intermetallic compound formation from the assemblies. Gold removal is performed most effectively by using a double wicking process. When only a single wicking procedure can be used, a higher soldering temperature improves the process of Au removal from the connector surfaces and to a nominal extent, removal of Au-contaminated solder from the joint. A longer soldering time did not appear to offer any appreciable improvement toward removing the Au-contaminated solder from the joint. Because the wicking procedure was a manual process, it was operator dependent.

  9. A new active solder for joining electronic components



    Electronic components and micro-sensors utilize ceramic substrates, copper and aluminum interconnect and silicon. The joining of these combinations require pre-metallization such that solders with fluxes can wet such combinations of metals and ceramics. The paper will present a new solder alloy that can bond metals, ceramics and composites. The alloy directly wets and bonds in air without the use flux or premetallized layers. The paper will present typical processing steps and joint microstructures in copper, aluminum, aluminum oxide, aluminum nitride, and silicon joints.

  10. Lead Free Solder Joint Thermal Condition in Semiconductor Packaging

    M. N. Harif


    Full Text Available Problem statement: Solder joints are responsible for both electrical and mechanical connections. Solder does not have adequate ductility to ensure the repeated relative displacements due to the mismatch between expansion coefficients of the chip carrier and the circuit board. Solder material plays a crucial role to provide the necessary electrical and mechanical interconnections in an electronic assembly. Finding a technique to increase the service life of future connections is not the total solution. A method must be developed for predicting the remaining service life of many joints already in use. Approach: The effect of High Temperature Storage (HTS on lead free solder joint material for ball grid array application using pull test method is studied in this study. Some statistical analysis base on the pull test data also discussed. Three samples of different lead free solder joint material were selected in this experiment namely Sn3.8Ag0.7Cu (SAC387, Sn2.3Ag0.08Ni0.01Co (SANC and Sn3.5Ag. After the thermal condition test, all the lead free solder joint material samples were tested using Dage 4000 pull test machine. Each pull test will be 5 units and each unit contains 8 balls. Results: The mean pull strength for high temperature storage is 2847.66, 2628.20 and 2613.79 g for Sn3.5Ag, SANC and SAC387, respectively. Thus, Sn3.5Ag shows a significantly better solder joint performance in terms of joint strength compare to SANC and SAC387. Hence, Intermetallic Compound (IMC thicknesses were measured after cross-sectioning. Sample size for cross-sectioning was 3 units per read point, 2 balls per unit and 3 maximum IMC peaks per ball and the measurement using high power scope of 100x and Image Analyzer software to measure the IMC thickness. For high temperature storage, result show that the mean IMC thicknesses for SAC387, SANC and Sn3.5Ag are 3.9139, 2.3111 and 2.3931 µm. Conclusion/Recommendations: It was found that IMC thickness for SANC and Sn3

  11. Recent trends in automobile recycling: An energy and economic assessment

    Curlee, T.R.; Das, S.; Rizy, C.G. [Oak Ridge National Lab., TN (United States); Schexanyder, S.M. [Tennessee Univ., Knoxville, TN (United States). Dept. of Biochemistry


    Recent and anticipated trends in the material composition of domestic and imported automobiles and the increasing cost of landfilling the non-recyclable portion of automobiles (automobile shredder residue or ASR) pose questions about the future of automobile recycling. This report documents the findings of a study sponsored by the US Department of Energy`s Office of Environmental Analysis to examine the impacts of these and other relevant trends on the life-cycle energy consumption of automobiles and on the economic viability of the domestic automobile recycling industry. More specifically, the study (1) reviewed the status of the automobile recycling industry in the United States, including the current technologies used to process scrapped automobiles and the challenges facing the automobile recycling industry; (2) examined the current status and future trends of automobile recycling in Europe and Japan, with the objectives of identifying ``lessons learned`` and pinpointing differences between those areas and the United States; (3) developed estimates of the energy system impacts of the recycling status quo and projections of the probable energy impacts of alternative technical and institutional approaches to recycling; and (4) identified the key policy questions that will determine the future economic viability of automobile shredder facilities in the United States.

  12. Studies on in situ particulate reinforced tin-silver composite solders relevant to thermomechanical fatigue issues

    Choi, Sunglak


    Global pressure based on environmental and health concerns regarding the use of Pb-bearing solder has forced the electronics industry to develop Pb-free alternative solders. Eutectic Sn-Ag solder has received much attention as a potential Pb-free candidate to replace Sn-Pb solder. Since introduction of surface mount technology, packaging density increased and the electronic devices became smaller. As a result, solders in electronic modules are forced to function as a mechanical connection as well as electrical contact. Solders are also exposed to very harsh service conditions such as automotive under-the-hood and aerospace applications. Solder joints experience thermomechanical fatigue, i.e. interaction of fatigue and creep, during thermal cycling due to temperature fluctuation in service conditions. Microstructural study on thermomechanical fatigue of the actual eutectic Sn-Ag and Sn-4Ag-0.5Cu solder joints was performed to better understand deformation and damage accumulation occurring during service. Incorporation of reinforcements has been pursued to improve the mechanical and particularly thermomechanical behavior of solders, and their service temperature capability. In-situ Sn-Ag composite solders were developed by incorporating Cu 6Sn5, Ni3Sn4, and FeSn2 particulate reinforcements in the eutectic Sn-Ag solder in an effort to enhance thermomechanical fatigue resistance. In-situ composite solders were investigated on the growth of interfacial intermetallic layer between solder and Cu substrate growth and creep properties. Solder joints exhibited significant deformation and damage on free surface and interior regions during thermomechanical fatigue. Cracks initiated on the free surface of the solder joints and propagated toward interior regions near the substrate of the solder joint. Crack grew along Sn grain boundaries by grain boundary sliding. There was significant residual stress within the solder joint causing more damage. Presence of small amount of Cu

  13. High-temperature lead-free solder alternatives

    Nachiappan, Vivek Chidambaram; Hattel, Jesper Henri; Hald, John


    For lead-free solders in the high-temperature regime, unfortunately, a limited number of alloying systems are available. These are Bi based alloys, gold involving alloys and Zn–Al based alloys. Based on these systems, possible candidate alloys were designed to have a melting range between 270°C a...

  14. Thermomechanical fatigue damage evolution in SAC solder joints

    Matin, M. A.; Vellinga, W. P.; D Geers, M. G.


    Thermornechanical fatigue in lab-type Sn-Ag-Cu solder interconnections between two copper plates has been investigated under cyclic thermal loading within a number of temperature ranges. Fatigue mechanisms have been studied using optical and scanning electron microscopy. Among the various fatigue me

  15. Porosity in collapsible Ball Grid Array solder joints

    Gonzalez, C.A. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley National Lab., Berkeley, CA (United States). Materials Science Div.


    Ball Grid Array (BGA) technology has taken off in recent years due to the increased need for high interconnect density. Opposite to all the advantages BGA packages offer, porosity in collapsible BGA solder joints is often a major concern in the reliability of such packages. The effect of pores on the strength of collapsible BGA solder-joints was studied by manufacturing samples with different degrees of porosity and testing them under a shear load. It was found that the shear strength of the solder joints decreased in a linear fashion with increasing porosity. Failure occurred by internal necking of the interpore matrix. It was confirmed that entrapment of flux residues leads to porosity by manufacturing fluxless samples in a specially made furnace, and comparing them with samples assembled using flux. Also, contamination of Au electrodeposits (in substrate metallization) was determined to cause significant porosity. It was found that hard-Au (Co hardened Au) electrodeposits produce high degrees of porosity even in the absence of flux. Finally, increasing the time the solder spends in the molten state was proven to successfully decrease porosity.

  16. Fundamentals of wetting and spreading with emphasis on soldering

    Yost, F.G.


    Soldering is often referred to as a mature technology whose fundamentals were established long ago. Yet a multitude of soldering problems persist, not the least of which are related to the wetting and spreading of solder. The Buff-Goodrich approach to thermodynamics of capillarity is utilized in a review of basic wetting principles. These thermodynamics allow a very compact formulation of capillary phenomena which is used to calculate various meniscus shapes and wetting forces. These shapes and forces lend themselves to experimental techniques, such as the sessile drop and the Wilhelmy plate, for measuring useful surface and interfacial energies. The familiar equations of Young, Wilhelmy, and Neumann are all derived with this approach. The force-energy duality of surface energy is discussed and the force method is developed and used to derive the Herring relations for anisotropic surfaces. The importance of contact angle hysteresis which results from surface roughness and chemical inhomogeneity is presented and Young's equation is modified to reflect these ever present effects. Finally, an analysis of wetting with simultaneous metallurigical reaction is given and used to discuss solder wetting phenomena. 60 refs., 13 figs.

  17. Horizon shells and BMS-like soldering transformations

    Blau, Matthias; O'Loughlin, Martin


    We revisit the theory of null shells in general relativity, with a particular emphasis on null shells placed at horizons of black holes. We study in detail the considerable freedom that is available in the case that one solders two metrics together across null hypersurfaces (such as Killing horizons) for which the induced metric is invariant under translations along the null generators. In this case the group of soldering transformations turns out to be infinite dimensional, and these solderings create non-trivial horizon shells containing both massless matter and impulsive gravitational wave components. We also rephrase this result in the language of Carrollian symmetry groups. To illustrate this phenomenon we discuss in detail the example of shells on the horizon of the Schwarzschild black hole (with equal interior and exterior mass), uncovering a rich classical structure at the horizon and deriving an explicit expression for the general horizon shell energy-momentum tensor. In the special case of BMS-like soldering supertranslations we find a conserved shell-energy that is strikingly similar to the standard expression for asymptotic BMS supertranslation charges, suggesting a direct relation between the physical properties of these horizon shells and the recently proposed BMS supertranslation hair of a black hole.

  18. Thermomechanical fatigue damage evolution in SAC solder joints

    Matin, M. A.; Vellinga, W. P.; D Geers, M. G.


    Thermornechanical fatigue in lab-type Sn-Ag-Cu solder interconnections between two copper plates has been investigated under cyclic thermal loading within a number of temperature ranges. Fatigue mechanisms have been studied using optical and scanning electron microscopy. Among the various fatigue me

  19. Printed-Circuit-Board Soldering Training for Group IV Personnel.

    Hooprich, E. A.; Matlock, E. W.

    As part of a larger program to determine which Navy skills can be learned by lower aptitude personnel, and which methods and techniques would be most effective, an experimental course in printed circuit board soldering was given to 186 Group IV students in 13 classes. Two different training approaches--one stressing instructor guidance and the…

  20. Horizon shells and BMS-like soldering transformations

    Blau, Matthias [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); O’Loughlin, Martin [University of Nova Gorica,Vipavska 13, 5000 Nova Gorica (Slovenia)


    We revisit the theory of null shells in general relativity, with a particular emphasis on null shells placed at horizons of black holes. We study in detail the considerable freedom that is available in the case that one solders two metrics together across null hypersurfaces (such as Killing horizons) for which the induced metric is invariant under translations along the null generators. In this case the group of soldering transformations turns out to be infinite dimensional, and these solderings create non-trivial horizon shells containing both massless matter and impulsive gravitational wave components. We also rephrase this result in the language of Carrollian symmetry groups. To illustrate this phenomenon we discuss in detail the example of shells on the horizon of the Schwarzschild black hole (with equal interior and exterior mass), uncovering a rich classical structure at the horizon and deriving an explicit expression for the general horizon shell energy-momentum tensor. In the special case of BMS-like soldering supertranslations we find a conserved shell-energy that is strikingly similar to the standard expression for asymptotic BMS supertranslation charges, suggesting a direct relation between the physical properties of these horizon shells and the recently proposed BMS supertranslation hair of a black hole.

  1. Recycling of lead solder dross, Generated from PCB manufacturing

    Lucheva, Biserka; Tsonev, Tsonio; Iliev, Peter


    The main purpose of this work is to analyze lead solder dross, a waste product from manufacturing of printed circuit boards by wave soldering, and to develop an effective and environmentally sound technology for its recycling. A methodology for determination of the content and chemical composition of the metal and oxide phases of the dross is developed. Two methods for recycling of lead solder dross were examined—carbothermal reduction and recycling using boron-containing substances. The influence of various factors on the metal yield was studied and the optimal parameters of the recycling process are defined. The comparison between them under the same parameters-temperature and retention time, showed that recycling of dross with a mixture of borax and boric acid in a 1:2 ratio provides higher metal yield (93%). The recycling of this hazardous waste under developed technology gets glassy slag and solder, which after correction of the chemical composition can be used again for production of PCB.

  2. Application of Wireless Sensor Networks to Automobiles

    Tavares, Jorge; Velez, Fernando J.; Ferro, João M.


    Some applications of Wireless Sensor Networks (WSNs) to the automobile are identified, and the use of Crossbow MICAz motes operating at 2.4 GHz is considered together with TinyOS support. These WSNs are conceived in order to measure, process and supply to the user diverse types of information during an automobile journey. Examples are acceleration and fuel consumption, identification of incorrect tire pressure, verification of illumination, and evaluation of the vital signals of the driver. A brief survey on WSNs concepts is presented, as well as the way the wireless sensor network itself was developed. Calibration curves were produced which allowed for obtaining luminous intensity and temperature values in the appropriate units. Aspects of the definition of the architecture and the choice/implementation of the protocols are identified. Security aspects are also addressed.

  3. Automobile active suspension system with fuzzy control

    刘少军; 黄中华; 陈毅章


    A quarter-automobile active suspension model was proposed. High speed on/off solenoid valves were used as control valves and fuzzy control was chosen as control method . Based on force analyses of system parts, a mathematical model of the active suspension system was established and simplified by linearization method. Simulation study was conducted with Matlab and three scale coefficients of fuzzy controller (ke, kec, ku) were acquired. And an experimental device was designed and produced. The results indicate that the active suspension system can achieve better vibration isolation performance than passive suspension system, the displacement amplitude of automobile body can be reduced to 55%. Fuzzy control is an effective control method for active suspension system.

  4. Roles of interfacial reaction on mechanical properties of solder interfaces

    Liu, Pilin

    This study investigated roles of interfacial reaction in fracture and fatigue of solder interconnects. The interfacial reaction phases in the as-reflowed and after aging were examined by cross-sectional transmission electron microscopy (TEM) while interfacial mechanical properties were determined from a flexural peel fracture mechanics technique. Because of their widespread uses in microelectronic packaging, SnPb solder interfaces, and Bi-containing Pb-free solder interfaces were chosen as the subjects of this study. In the interfacial reaction study, we observed a complicated micro structural evolution during solid-state aging of electroless-Ni(P)/SnPb solder interconnects. In as-reflowed condition, the interfacial reaction produced Ni3Sn 4 and P-rich layers. Following overaging, the interfacial microstructure degenerated into a complex multilayer structure consisting of multiple layers of Ni-Sn compounds and transformed Ni-P phases. In SnPb solder interfacial system, fatigue study showed that the overaging of the high P electroless Ni-P/SnPb interconnects resulted in a sharp reduction in the fatigue resistance of the interface in the high crack growth rate regime. Fracture mechanism analysis indicated that the sharp drop in fatigue resistance was triggered by the brittle fracture of the Ni3Sn2 intermetallic phase developed at the overaged interface. The fatigue behavior was strongly dependent on P concentration in electroless Ni. Kirkendall voids were found in the interfacial region after aging, but they did not cause premature fracture of the solder interfaces. In Bi-containing solder interfacial system, we found that Bi segregated to the Cu-intermetallic interface during aging in SnBi/Cu interconnect. This caused serious embrittlement of Sn-Bi/Cu interface. Further aging induced numerous voids along the Cu3Sn/Cu interface. These interfacial voids were different from Kirkendall voids. Their formation was explained on basis of vacancy condensation at the

  5. UNICEF and automobile CO2 negotiation

    Woo, Seok Hun [Korea Energy Management Corporation, Yongin (Korea)


    The EU automobile negotiation was very suggestive since it was the first international trade negotiation related with UNFCCC. It generated considerable reactions in association with {sup v}oluntary negotiation{sup i}n semiconductor sector. Most of all, such a new car negotiation shows well that it is hard to free from global environmental responsibilities even for a company in a developing country in UNFCCC.


    Y.H.Tian; C.Q.Wang


    Interactions between 63Sn37Pb solder and PBGA metallization(Au/Ni/Cu)during laser and infrared reflow soldering were studied.During laser refow soldering process,a thin layer of AuSn4 was observed at the interface of the solder bumps,its morphology was strongly dependent on the laser reflow power and heating time.The solder bumps formed by the first laser reflow was refowed again to form the solder joints.The AuSn4 compounds formed in the first laser reflow process dissolved into the bulk solder after the secondary infrared reflow process.The needle-like AuSn4 changed into rodlike,and distributed inside the solder near the solder/pad interface.

  7. Tendon repair

    Repair of tendon ... Tendon repair can be performed using: Local anesthesia (the immediate area of the surgery is pain-free) ... a cut on the skin over the injured tendon. The damaged or torn ends of the tendon ...

  8. Electromigration Behaviors of Cu Reinforced Sn-3.5Ag Composite Solder Joints

    Wang, Yan; Han, Jing; Ma, Limin; Zuo, Yong; Guo, Fu


    The composite approach, by incorporating small amounts of reinforcement particles in the solder matrix, has proven to be one of the effective ways to improve the reliability of solder joints. The effects of Cu addition on electromigration were investigated in this study by incorporating 2% volume fraction Cu particles into Sn-3.5Ag eutectic solder paste by the in situ process. The one-dimensional solder joints, designed to prevent the current crowding effect, were stressed under a constant current density of 104 A/cm2 at room temperature, and the temperature of the sample could reach 105 ± 5°C due to the Joule heating effect. Doping 2 vol.% Cu was found to retard the electromigration phenomenon effectively. After electric current stressing for 528 h, the growth rate of an interfacial intermetallic compound (IMC) layer at the anode decreased 73% in contrast to that of Sn-3.5Ag solder joints, and the IMC layer at the cathode was almost unchanged. The polarization effect of Cu reinforced composite solder joints was also apparently mitigated. In addition, the surface damage of the composite solder joints was relieved by incorporating 2 vol.% Cu particles. Compared to Sn-3.5Ag solder joints, which had protruded Cu6Sn5 and wrinkles of Sn-solder matrix on the surface, the solder joints with Cu addition had a more even surface.

  9. Electromigration Behaviors of Cu Reinforced Sn-3.5Ag Composite Solder Joints

    Wang, Yan; Han, Jing; Ma, Limin; Zuo, Yong; Guo, Fu


    The composite approach, by incorporating small amounts of reinforcement particles in the solder matrix, has proven to be one of the effective ways to improve the reliability of solder joints. The effects of Cu addition on electromigration were investigated in this study by incorporating 2% volume fraction Cu particles into Sn-3.5Ag eutectic solder paste by the in situ process. The one-dimensional solder joints, designed to prevent the current crowding effect, were stressed under a constant current density of 104 A/cm2 at room temperature, and the temperature of the sample could reach 105 ± 5°C due to the Joule heating effect. Doping 2 vol.% Cu was found to retard the electromigration phenomenon effectively. After electric current stressing for 528 h, the growth rate of an interfacial intermetallic compound (IMC) layer at the anode decreased 73% in contrast to that of Sn-3.5Ag solder joints, and the IMC layer at the cathode was almost unchanged. The polarization effect of Cu reinforced composite solder joints was also apparently mitigated. In addition, the surface damage of the composite solder joints was relieved by incorporating 2 vol.% Cu particles. Compared to Sn-3.5Ag solder joints, which had protruded Cu6Sn5 and wrinkles of Sn-solder matrix on the surface, the solder joints with Cu addition had a more even surface.

  10. Automobile technology in a CO{sub 2}-constrained world

    Kypreos, S.; Barreto Gomez, L.; Dietrich, Ph. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Schafer, A.; Jacoby, H.D. [MIT, Cambridge (United States)


    This study identifies the environmental conditions under which less CO{sub 2}-emitting and more expensive automobile technology might enter the North American transportation sector. For that purpose, different exogenous CO{sub 2}-reduction targets are imposed and the resulting market shares of hypothetical future automobile technologies calculated. The criteria for the selection of different types of automobiles/fuels is the minimisation of discounted, cumulative transport sector costs over the scenario time horizon. (author) 1 tab., 6 refs.

  11. Environmentally friendly solders 3-4 beyond Pb-based systems

    GAO Yuan; LIU Peng; GUO Fu; XIA Zhidong; LEI Yongping; SHI Yaowu


    Based on environmental considerations, global economic pressures, enacted by legislations in several countries, have warranted the elimination of lead from solders used in electronic applications.Sn3.5Ag, SnAgCu, and Sn0.7Cu have emerged among various lead-free candidates as the most promising solder alloys to be utilized in microelectronic industries.However, with the vast development and miniaturization of modern electronic packaging, new requirements such as superior service capabilities have been posed on lead-free solders.In order to improve the comprehensive property of the solder alloys, two possible approaches were adopted in the current research and new materials developed were patented.One approach was involved with the addition of alloying elements to make new ternary or quaternary solder alloys.Proper addition of rare earth element such as La and Ce have rendered solder alloys with improved mechanical properties, especially creep rupture lives of their joints.Another approach, the composite approach, was developed mainly to improve the service temperature capability of the solder alloys.Composite solders fabricated by mechanically incorporating various reinforcement particles to the solder paste have again exhibited enhanced properties without altering the existing processing characteristics.The recent progress and research efforts carried out on lead-free solder materials in Beijing University of Technology were reported.The effects of rare earth addition on the microstructure, processing properties, and mechanical properties were presented.The behaviors of various Sn-3.5Ag based composite solders were also explicated in terms of the roles of reinforcement particles on intermetallic growth, steady-state creep rate, the onset of tertiary creep, as well as the overall creep deformation in the solder joints.Thermomechanical fatigue (TMF) behavior of the solder alloys and composite solders were investigated with different parameters such as ramp rate

  12. Effects of particle size on the mechanical properties of particle-reinforced Sn-Ag composite solder joint


    Particulate size has significant influenced on the mechanical properties of particle-reinforced composite solder joints. In this current research, Cu or Ni reinforcement particles were mechanically added to the Sn-3.5Ag eutectic solder, and the effects of the particle size on the mechanical properties of particle-reinforced composite solder joint were systematically studied. This investigation touched on how mechanical properties of the solder joints are affected by particles size. A quantitative formula was set up to correlate the mechanical property of the solder joint with particle size in different processing conditions. Besides, the fracture mechanism of the composite solder joint was analyzed.

  13. The Mechanical Behavior of Sn-Ag4 Solder Joints Subjected to Thermal Cycling

    CHENGuohai; MAJusheng


    The method of mount strain gages is used to measure the stress/strain hysteresis loops of the solder joints under thermal cycling. The results show that different solders have different loops; the shape of the loops will change less, and finally become a line along with the thermal cycle increase. The shear module decreases along with the thermal cycling process. But the creep index of the solder joints is not sensitive to the cycling process,which fluctuates between 5 and 7. Because the elements of the solder and matrix materials diffuse during the process, the voids induced in the solder joints expand. The expansion of the voids will lead to the crystal lattice aberrance of solder crystal.

  14. Root Cause Investigation of Lead-Free Solder Joint Interfacial Failures After Multiple Reflows

    Li, Yan; Hatch, Olen; Liu, Pilin; Goyal, Deepak


    Solder joint interconnects in three-dimensional (3D) packages with package stacking configurations typically must undergo multiple reflow cycles during the assembly process. In this work, interfacial open joint failures between the bulk solder and the intermetallic compound (IMC) layer were found in Sn-Ag-Cu (SAC) solder joints connecting a small package to a large package after multiple reflow reliability tests. Systematic progressive 3D x-ray computed tomography experiments were performed on both incoming and assembled parts to reveal the initiation and evolution of the open failures in the same solder joints before and after the reliability tests. Characterization studies, including focused ion beam cross-sections, scanning electron microscopy, and energy-dispersive x-ray spectroscopy, were conducted to determine the correlation between IMC phase transformation and failure initiation in the solder joints. A comprehensive failure mechanism, along with solution paths for the solder joint interfacial failures after multiple reflow cycles, is discussed in detail.

  15. Corrosive microenvironments at lead solder surfaces arising from galvanic corrosion with copper pipe.

    Nguyen, Caroline K; Stone, Kendall R; Dudi, Abhijeet; Edwards, Marc A


    As stagnant water contacts copper pipe and lead solder (simulated soldered joints), a corrosion cell is formed between the metals in solder (Pb, Sn) and the copper. If the resulting galvanic current exceeds about 2 μA/cm(2), a highly corrosive microenvironment can form at the solder surface, with pH galvanic currents, preventing passivation of the solder surface, and contributing to lead contamination of potable water supplies. The total mass of lead corroded was consistent with predictions based on the galvanic current, and lead leaching to water was correlated with galvanic current. If the concentration of sulfate in the water increased relative to chloride, galvanic currents and associated lead contamination could be greatly reduced, and solder surfaces were readily passivated.

  16. 76 FR 44402 - Proposed Information Collection (Application for Automobile or Other Conveyance and Adaptive...


    ... AFFAIRS Proposed Information Collection (Application for Automobile or Other Conveyance and Adaptive...' eligibility for automobile adaptation equipment or other conveyance allowance. DATES: Written comments and... techniques or the use of other forms of information technology. Title: Application for Automobile or...

  17. Reaction of Liquid Sn-Ag-Cu-Ce Solders with Solid Copper

    Chriaštel'Ová, J.; Rízeková Trnková, L.; Pocisková Dimová, K.; Ožvold, M.


    Small amounts of the rare-earth element Ce were added to the Sn-rich lead-free eutectic solders Sn-3.5Ag-0.7Cu, Sn-0.7Cu, and Sn-3.5Ag to improve their properties. The microstructures of the solders without Ce and with different amounts (0.1 wt.%, 0.2 wt.%, and 0.5 wt.%) of Ce were compared. The microstructure of the solders became finer with increasing Ce content. Deviation from this rule was observed for the Sn-Ag-Cu solder with 0.2 wt.% Ce, and for the Sn-0.7Cu eutectic alloy, which showed the finest microstructure without Ce. The melting temperatures of the solders were not affected. The morphology of intermetallic compounds (IMC) formed at the interface between the liquid solders and a Cu substrate at temperatures about 40°C above the melting point of the solder for dipping times from 2 s to 256 s was studied for the basic solder and for solder with 0.5 wt.% Ce addition. The morphology of the Cu6Sn5 IMC layer developed at the interface between the solders and the substrate exhibited the typical scallop-type shape without significant difference between solders with and without Ce for the shortest dipping time. Addition of Ce decreased the thickness of the Cu6Sn5 IMC layer only at the Cu/Sn-Ag-Cu solder interface for the 2-s dipping. A different morphology of the IMC layer was observed for the 256-s dipping time: The layers were less continuous and exhibited a broken relief. Massive scallops were not observed. For longer dipping times, Cu3Sn IMC layers located near the Cu substrate were also observed.


    Heinemann, D.; S. Knabner; Baumgarten, D.


    Printed Circuit Boards (PCB) play an important role in the manufacturing of electronic devices. To ensure a correct function of the PCBs a certain amount of solder paste is needed during the placement of components. The aim of the current research is to develop an real-time, closed-loop solution for the analysis of the printing process where solder is printed onto PCBs. Close range photogrammetry allows for determination of the solder volume and a subsequent correction if necessary. ...

  19. Investigation of moisture uptake into printed circuit board laminate and solder mask materials

    Conseil, Helene; Gudla, Visweswara Chakravarthy; Borgaonkar, Shruti


    Presence of moisture in a printed circuit board (PCB) laminate, typically made of glass fibres reinforced epoxy polymer, significantly influences the electrical functionality in various ways and causes problems during soldering process. This paper investigates the water uptake of laminates coated...... with different solder mask materials and exposed to saturated water vapour and liquid water. The solder masks are characterised for their microstructure and constituent phases using scanning electron microscopy and X-ray diffraction. The observations are correlated with themoisture absorption characteristic...

  20. Bladder exstrophy repair

    Bladder birth defect repair; Everted bladder repair; Exposed bladder repair; Repair of bladder exstrophy ... Bladder exstrophy repair involves two surgeries. The first surgery is to repair the bladder and the second one is to attach ...

  1. Repairing an implant titanium milled framework using laser welding technology: a clinical report.

    Prasad, Soni; Monaco, Edward A


    The application of laser welding technology allows titanium to be welded predictably and precisely to achieve accurate fit of a milled framework. Laser energy results in localized heat production, thereby reducing thermal expansion. Unlike soldering, laser energy can be directed to a small area, making it possible to laser weld close to acrylic resin or ceramic. This article describes the use of laser welding to repair an implant titanium milled fixed denture. A quick, cost-effective, accurate repair was accomplished, and the repaired framework possessed adequate strength and the same precise fit as the original framework.

  2. High-Temperature Lead-Free Solder Alternatives: Possibilities and Properties

    and mechanical properties of these potential candidate alloys with respect to the currently used high-lead content solders is made. Finally, the paper presents the superior characteristics as well as some drawbacks of these proposed high-temperature lead-free solder alternatives....... the criteria for the evaluation of a new high-temperature lead-free solder material. A list of potential ternary high-temperature lead-free solder alternatives based on the Au-Sn and Au-Ge systems is proposed. Furthermore, a comprehensive comparison of the high-temperature stability of microstructures...

  3. Research Progress in Solderable Black Pad of Electroless Nickel/Immersion Gold

    Liu Haiping; Li Ning; Bi Sifu; Li Deyu


    Electroless nickel/immersion gold (ENIG) technology is widely used as one of the surface final finish for electronics packaging substrate and printed circuit board (PCB), providing a protective, conductive and solderable surface. However, there is a solder joint interfacial brittle fracture (or solderability failure) of using the ENIG coating. The characteristics and the application of ENIG technology were narrated in this paper. The research progress on the solderability failure of ENIG was introduced. The mechanism of "black pad" and the possible measure of eliminating or alleviating the "black pad" were also introduced. The development direction and market prospects of ENIG were prospected.

  4. Creep Behavior of Lead-Free Sn-Ag-Cu + Ni-Ge Solder Alloys

    Hidaka, N.; Watanabe, H.; Yoshiba, M.


    We developed a new lead-free solder alloy, an Sn-Ag-Cu base to which a small amount of Ni and Ge is added, to improve the mechanical properties of solder alloys. We examined creep deformation in bulk and through-hole (TH) form for two lead-free solder alloys, Sn-3.5Ag-0.5Cu-Ni-Ge and Sn-3.0Ag-0.5Cu, at elevated temperatures, finding that the creep rupture life of the Sn-3.5Ag-0.5Cu-Ni-Ge solder alloy was over three times better than that of the Sn-3.0Ag-0.5Cu solder at 398 K. Adding Ni to the solder appears to make microstructural development finer and more uniform. The Ni added to the solder readily combined with Cu to form stable intermetallic compounds of (Cu, Ni)6Sn5 capable of improving the creep behavior of solder alloys. Moreover, microstructural characterization based on transmission electron microscopy analyses observing creep behavior in detail showed that such particles in the Sn-3.5Ag-0.5Cu-Ni-Ge solder alloy prevent dislocation and movement.

  5. Joining of Bi-2212 high- Tc superconductors and metals using indium solders

    Oh, S. Y.; Kim, H. R.; Jeong, Y. H.; Hyun, O. B.; Kim, C. J.


    BSCCO tubes can be used as a base material for switching devices such as superconducting fault current limiters (SFCLs) that prevent an electrical problem from occurring in an electrical power system. To apply an BSCCO bulk tube to a switching device, the superconducting tube has to be joined with a metallic part to by the over current to the metal part when the FCL is quenched. In this study, joining between Cu-Ni alloy and BSCCO was accomplished by soldering using In-Sn and In-Bi solders. Additionally, an Sn-Ag-Cu/In-Bi solder was used for the soldering of a different kind. For a better joining of the BSCCO superconductor with the In-Bi solder, the surface of the BSCCO was pre-coated with Ag by electro-plating. From the experiments, an intermetallic compound (IMC) of AgxIny chain was observed to be mainly formed from In-Sn and In-Bi soldering process. In case of the soldering of a different kind, IMC of AgxIny and CuxSny was also developed. Finally, we confirmed that the properties of soldering were enhanced by Sn-Ag-Cu/In-Bi twice-soldering process.

  6. Joining of Bi-2212 high-T{sub c} superconductors and metals using indium solders

    Oh, S.Y. [Nuclear Nanomaterials Development Laboratory, Korea Atomic Energy Research Institute (KAERI), 150 Dukjin-dong, Yusong-gu, Daejeon 305-353 (Korea, Republic of); Kim, H.R.; Jeong, Y.H.; Hyun, O.B. [Superconductivity and Applications Group, Korea Electric Power Research Institute (KEPRI), Daejeon 305-380 (Korea, Republic of); Kim, C.J. [Nuclear Nanomaterials Development Laboratory, Korea Atomic Energy Research Institute (KAERI), 150 Dukjin-dong, Yusong-gu, Daejeon 305-353 (Korea, Republic of)], E-mail:


    BSCCO tubes can be used as a base material for switching devices such as superconducting fault current limiters (SFCLs) that prevent an electrical problem from occurring in an electrical power system. To apply an BSCCO bulk tube to a switching device, the superconducting tube has to be joined with a metallic part to by the over current to the metal part when the FCL is quenched. In this study, joining between Cu-Ni alloy and BSCCO was accomplished by soldering using In-Sn and In-Bi solders. Additionally, an Sn-Ag-Cu/In-Bi solder was used for the soldering of a different kind. For a better joining of the BSCCO superconductor with the In-Bi solder, the surface of the BSCCO was pre-coated with Ag by electro-plating. From the experiments, an intermetallic compound (IMC) of Ag{sub x}In{sub y} chain was observed to be mainly formed from In-Sn and In-Bi soldering process. In case of the soldering of a different kind, IMC of Ag{sub x}In{sub y} and Cu{sub x}Sn{sub y} was also developed. Finally, we confirmed that the properties of soldering were enhanced by Sn-Ag-Cu/In-Bi twice-soldering process.

  7. An Evaluation of Prototype Circuit Boards Assembled with a Sn-Ag Bi Solder



    An evaluation was performed which examined the aging of surface mount solder joints assembled with 91.84Sn-3.33Ag-4.83Bi solder. Defect analysis of the as-fabricated test vehicles revealed excellent solderability, good package alignment, and a minimum number of voids. Continuous DC electrical monitoring of the solder joints did not reveal opens during as many as 10,000 thermal cycles (0 C, 100 C). The solder joints exhibited no significant degradation through 2500 cycles, based upon an absence of microstructural damage and sustained shear and pull strengths of chip capacitors and J-leaded solder joints, respectively. Thermal cycles of 5000 and 10,000 resulted in some surface cracking of the solder fillets and coatings. In a few cases, deeper cracks were observed in the thinner reaches of several solder fillets. There was no deformation or cracking in the solder located in the gap between the package I/O and the circuit board pad nor in the interior of the fillets, both locations that would raise concerns of joint mechanical integrity. A drop in the chip capacitor shear strength was attributed to crack growth near the top of the fillet.



    Nonlinear control methods are presented based on theory of sliding mode control (SMC) or variable structure control (VSC) for application to active automobile suspensions. Requirements of reducing manufacturing cost and energy consumption of the active suspension system may be satisfiedby reasonable design of the sliding surface and hydraulic servo system. Emphasis is placed on the study of the discrete sliding mode control method (DSMC) applicable for a new sort of speed on-off solenoid valves of anti-dust capability and low price. Robustness and effectiveness of the feedback linearized controller in typical road conditions are demonstrated by numerical results fora quarter-car suspension model.

  9. Information, complexity and efficiency: The automobile model

    Allenby, B. [Lucent Technologies (United States)]|[Lawrence Livermore National Lab., CA (United States)


    The new, rapidly evolving field of industrial ecology - the objective, multidisciplinary study of industrial and economic systems and their linkages with fundamental natural systems - provides strong ground for believing that a more environmentally and economically efficient economy will be more information intensive and complex. Information and intellectual capital will be substituted for the more traditional inputs of materials and energy in producing a desirable, yet sustainable, quality of life. While at this point this remains a strong hypothesis, the evolution of the automobile industry can be used to illustrate how such substitution may, in fact, already be occurring in an environmentally and economically critical sector.




    Full Text Available This paper deals with implementation of mobile wind driven generator technology to produce electricity in charging of two wheeler (12V automobile battery. The use of PWM methodology with pulse charging method at a constant rate has been adopted for this purpose. The low speed PMSG driven by wind at speed of 15/40 km/hour has been used to eliminate gear box to achieve high efficiency. The output of three phase bridge rectifier is fed to boost converter which provides pulses of constant current to the battery.

  11. Influence of Difference Solders Volume on Intermetallic Growth of Sn-4.0Ag-0.5Cu/ENEPIG

    Saliza Azlina O.


    Full Text Available In recent years, portable electronic packaging products such as smart phones, tablets, notebooks and other gadgets have been developed with reduced size of component packaging, light weight, high speed and with enhanced performance. Thus, flip chip technology with smaller solder sphere sizes that would produce fine solder joint interconnections have become essential in order to fulfill these miniaturization requirements. This study investigates the interfacial reactions and intermetallics formation during reflow soldering and isothermal aging between Sn-4.0Ag-0.5Cu (SAC405 and electroless nickel/immersion palladium/immersion gold (EN(PEPIG. Solder diameters of 300 μm and 700 μm were used to compare the effect of solder volume on the solder joint microstructure. The solid state isothermal aging was performed at 125°C starting from 250 hours until 2000 hours. The results revealed that only (Cu,Ni6Sn5 IMC was found at the interface during reflow soldering while both (Cu,Ni6Sn5 and (Ni,Cu3Sn4 IMC have been observed after aging process. Smaller solder sizes produced thinner IMC than larger solder joints investigated after reflow soldering, whereas the larger solders produced thinner IMC than the smaller solders after isothermal aging. Aging duration of solder joints has been found to be increase the IMC’s thickness and changed the IMC morphologies to spherical-shaped, compacted and larger grain size.

  12. Nano Coated Lead Free Solders for Sustainable Electronic Waste Management

    K. Arun Vasantha Geethan

    Full Text Available ABSTRACT Lead has been used in a wide range of applications, but in the past decades it became clear that its high toxicity could cause various problems. Studies indicate that exposure to high concentrations of lead can cause harmful damages to humans. To eliminate the usage of lead in electronic products as an initiative towards electronic waste management (e waste, lead free solders were produced with suitable methods by replacing lead. But lead free solders are not preferred as a substitute of lead because they are poor in their mechanical properties such as tensile strength, shear strength and hardness which are ultimately required for a material to resist failure.Nano-Structured materials and coatings offer the potential for Vital improvements in engineering properties based on improvements in physical and mechanical properties resulting from reducing micro structural features by factors of 100 to 1000 times compared to current engineering materials.


    A. Kryvokon


    Full Text Available Research of strategy and prospects of Ukrainian automobile motor industry development has been done: the measures of public policy, which must be realized for the development of national automobile industry, a car production volume and expected working place in motor industry under state support have been described.

  14. Morphology and Shear Strength of Lead-Free Solder Joints with Sn3.0Ag0.5Cu Solder Paste Reinforced with Ceramic Nanoparticles

    Yakymovych, A.; Plevachuk, Yu.; Švec, P.; Švec, P.; Janičkovič, D.; Šebo, P.; Beronská, N.; Roshanghias, A.; Ipser, H.


    To date, additions of different oxide nanoparticles is one of the most widespread procedures to improve the mechanical properties of metals and metal alloys. This research deals with the effect of minor ceramic nanoparticle additions (SiO2, TiO2 and ZrO2) on the microstructure and mechanical properties of Cu/solder/Cu joints. The reinforced Sn3.0Ag0.5Cu (SAC305) solder alloy with 0.5 wt.% and 1.0 wt.% of ceramic nanoparticles was prepared through mechanically stirring. The microstructure of as-solidified Cu/solder/Cu joints was studied using scanning electron microscopy. The additions of ceramic nanoparticles suppressed the growth of the intermetallic compound layer Cu6Sn5 at the interface solder/Cu and improved the microstructure of the joints. Furthermore, measurements of mechanical properties showed improved shear strength of Cu/composite solder/Cu joints compared to joints with unreinforced solder. This fact related to all investigated ceramic nanoinclusions and should be attributed to the adsorption of nanoparticles on the grain surface during solidification. However, this effect is less pronounced on increasing the nanoinclusion content from 0.5 wt.% to 1.0 wt.% due to agglomeration of nanoparticles. Moreover, a comparison analysis showed that the most beneficial influence was obtained by minor additions of SiO2 nanoparticles into the SAC305 solder alloy.

  15. Effect of automobiles on global warming: A modeling study

    Shyam Sundar


    Full Text Available Global warming threatens our environment as well as basic human needs. In the present scenario, increasing demand and excessive use of automobiles have increased the level of carbon dioxide emission in the environment, providing a significant contribution to increase the global warming. This paper deals with the modeling of the effect of automobiles on global warming. For this, three nonlinearly interacting variables namely; density of human population, density of automobiles and the concentration of carbon dioxide have been taken into account. In the modeling process, it is assumed that the density of automobiles increases in proportion to human population following a logistic growth. The model is analyzed using stability theory of ordinary differential equations. Local and global stability conditions are established to study the feasibility of the model system. It is shown that with increase in human population, the demand for automobiles increases which has significant effect on global warming increase.

  16. A microstructural analysis of solder joints from the electronic assemblies of dismantled nuclear weapons

    Vianco, P.T.; Rejent, J.A. [Sandia National Labs., Albuquerque, NM (United States). Materials Joining Dept.


    MC1814 Interconnection Boxes from dismantled B57 bombs, and MC2839 firing Sets from retired W70-1 warheads were obtained from the Pantex facility. Printed circuit boards were selected from these components for microstructural analysis of their solder joints. The analysis included a qualitative examination of the solder joints and quantitative assessments of (1) the thickness of the intermetallic compound layer that formed between the solder and circuit board Cu features, and (2) the Pb-rich phase particle distribution within the solder joint microstructure. The MC2839 solder joints had very good workmanship qualities. The intermetallic compound layer stoichiometry was determined to be that of Cu6Sn5. The mean intermetallic compound layer thickness for all solder joints was 0.885 mm. The magnitude of these values did not indicate significant growth over the weapon lifetime. The size distribution of the Pb-rich phase particles for each of the joints were represented by the mean of 9.85 {times} 10{sup {minus}6} mm{sup 2}. Assuming a spherical geometry, the mean particle diameter would be 3.54 mm. The joint-to-joint difference of intermetallic compound layer thickness and Pb-rich particle size distribution was not caused by varying thermal environments, but rather, was a result of natural variations in the joint microstructure that probably existed at the time of manufacture. The microstructural evaluation of the through-hole solder joints form the MC2839 and MC1814 components indicated that the environmental conditions to which these electronic units were exposed in the stockpile, were benign regarding solder joint aging. There was an absence of thermal fatigue damage in MC2839 circuit board, through-hole solder joints. The damage to the eyelet solder joints of the MC1814 more likely represented infant mortality failures at or very near the time of manufacture, resulting from a marginal design status of this type of solder joint design.

  17. Combined thermal, thermodynamic and kinetic modelling for the reliability of high-density lead-free solder interconnections

    Yu, Hao


    Continuous miniaturization of electronics devices as well as increasing complexity of soldering metallurgy introduce more and more challenges to the reliability of modern electronics products. Although loading condition plays an important role, the reliability of solder interconnections is ultimately controlled by microstructures' responses to loading. It is therefore of great importance to understand and control the microstructural evolutions of solder interconnections under different loadin...

  18. Failure Mechanisms of SAC/Fe-Ni Solder Joints During Thermal Cycling

    Gao, Li-Yin; Liu, Zhi-Quan; Li, Cai-Fu


    Thermal cycling tests have been conducted on Sn-Ag-Cu/Fe- xNi ( x = 73 wt.% or 45 wt.%) and Sn-Ag-Cu/Cu solder joints according to the Joint Electron Device Engineering Council industrial standard to study their interfacial reliability under thermal stress. The interfacial intermetallic compounds formed for solder joints on Cu, Fe-73Ni, and Fe-45Ni were 4.5 μm, 1.7 μm, and 1.4 μm thick, respectively, after 3000 cycles, demonstrating excellent diffusion barrier effect of Fe-Ni under bump metallization (UBM). Also, two deformation modes, viz. solder extrusion and fatigue crack formation, were observed by scanning electron microscopy and three-dimensional x-ray microscopy. Solder extrusion dominated for solder joints on Cu, while fatigue cracks dominated for solder joints on Fe-45Ni and both modes were detected for those on Fe-73Ni. Solder joints on Fe-Ni presented inferior reliability during thermal cycling compared with those on Cu, with characteristic lifetime of 3441 h, 3190 h, and 1247 h for Cu, Fe-73Ni, and Fe-45Ni UBM, respectively. This degradation of the interfacial reliability for solder joints on Fe-Ni is attributed to the mismatch in coefficient of thermal expansion (CTE) at interconnection level. The CTE mismatch at microstructure level was also analyzed by electron backscatter diffraction for clearer identification of recrystallization-related deformation mechanisms.

  19. Active soft solder deposition by magnetron-sputter-ion-plating (MSIP)-PVD-process

    Lugscheider, E.; Bobzin, K.; Erdle, A


    In different technical areas micro electro mechanical systems (M.E.M.S.), e.g. micro pumps, micro sensors, actuators and micro dosage systems are in use today. The components of these M.E.M.S. consist of various materials, which have to be joined. To join materials like ceramics, plastics or metals to a hybrid M.E.M.S., established joining technologies have to be adjusted. For the assembling and mounting of temperature sensible micro components, a low temperature joining process, e.g. transient liquid phase (TLP) bonding or an active soft soldering process can be performed. In this article the deposition of a low melting active soft solder by magnetron-sputter (MS)-PVD deposition with an active substrate cooling will be presented. The substrate temperatures were set and controlled by an additional cooling unit, which was integrated into the sputtering facility. In the performed experiments a substrate temperature range from -40 to +20 deg. C was investigated. The effects of these different substrate temperatures to the microstructure and the soldering suitability of the solder system were investigated by scanning electron microscopy (SEM), nanoindentation and soldering tests. The chemical composition of the deposited solder systems was examined by glow discharge optical spectroscopy (GDOS)-analysis. As a suitable substrate temperature range for deposition -10 to -20 deg. C was detected. Solder systems deposited in this temperature range showed good solder abilities.

  20. Development of technique for laser welding of biological tissues using laser welding device and nanocomposite solder.

    Gerasimenko, A; Ichcitidze, L; Podgaetsky, V; Ryabkin, D; Pyankov, E; Saveliev, M; Selishchev, S


    The laser device for welding of biological tissues has been developed involving quality control and temperature stabilization of weld seam. Laser nanocomposite solder applied onto a wound to be weld has been used. Physicochemical properties of the nanocomposite solder have been elucidated. The nature of the tissue-organizing nanoscaffold has been analyzed at the site of biotissue welding.

  1. Development of lead-free solders for high-temperature applications

    Chidambaram, Vivek

    -temperature applications. Unfortunately, even the substitute technologies that are currently being developed cannot address several critical issues of high-temperature soldering. Therefore, further research and development of high-temperature lead-free soldering is obviously needed. It is hoped that this thesis can serve...... as a valuable source of information to those interested in environmentally conscious electronic packaging....

  2. 30 CFR 77.1111 - Welding, cutting, soldering; use of fire extinguisher.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, soldering; use of fire... OF UNDERGROUND COAL MINES Fire Protection § 77.1111 Welding, cutting, soldering; use of fire extinguisher. One portable fire extinguisher shall be provided at each location where welding, cutting,...

  3. Development of a solder bump technique for contacting a three-dimensional multi electrode array

    Frieswijk, T.A.; Frieswijk, T.A.; Bielen, J.A.; Bielen, J.A.; Rutten, Wim; Bergveld, Piet


    The application of a solder bump technique for contacting a three-dimensional multi electrode array is presented. Solder bumping (or C4: Controlled Collapse Chip Connections, also called Flip Chip contacting) is the most suitable contacting technique available for small dimensions and large numbers

  4. The automated system for technological process of spacecraft's waveguide paths soldering

    Tynchenko, V. S.; Murygin, A. V.; Emilova, O. A.; Bocharov, A. N.; Laptenok, V. D.


    The paper solves the problem of automated process control of space vehicles waveguide paths soldering by means of induction heating. The peculiarities of the induction soldering process are analyzed and necessity of information-control system automation is identified. The developed automated system makes the control of the product heating process, by varying the power supplied to the inductor, on the basis of information about the soldering zone temperature, and stabilizing the temperature in a narrow range above the melting point of the solder but below the melting point of the waveguide. This allows the soldering process automating to improve the quality of the waveguides and eliminate burn-troughs. The article shows a block diagram of a software system consisting of five modules, and describes the main algorithm of its work. Also there is a description of the waveguide paths automated soldering system operation, for explaining the basic functions and limitations of the system. The developed software allows setting of the measurement equipment, setting and changing parameters of the soldering process, as well as view graphs of temperatures recorded by the system. There is shown the results of experimental studies that prove high quality of soldering process control and the system applicability to the tasks of automation.

  5. Mechanical properties of FeCo magnetic particles-based Sn-Ag-Cu solder composites

    Xu, Siyang; Prasitthipayong, Anya; Pickel, Andrea D.; Habib, Ashfaque H.; McHenry, Michael E.


    We demonstrate magnetic nanoparticles (MNPs) in enabling lead-free solder reflow in RF fields and improved mechanical properties that impact solder joint reliability. Here, we report on Sn-Ag-Cu (SAC) alloys. SAC solder-FeCo MNP composites with 0, 1, 2, 3, and 4 wt. % FeCo MNP and the use of AC magnetic fields to achieve localized reflow. Electron microscopy of the as-reflowed samples show a decrease in the volume of Sn dendrite regions as well as smaller and more homogeneously dispersed Ag3Sn intermetallic compounds (IMCs) with increasing MNP concentrations. Mechanical properties of the composites were measured by nanoindentation. In pure solder samples and solder composites with 4 wt. % MNP, hardness values increased from 0.18 GPa to 0.20 GPa and the modulus increased from 39.22 GPa to 71.22 GPa. The stress exponent, reflecting creep resistance, increased from 12.85 of pure solder to 16.47 for solder composites with 4 wt. % MNP. Enhanced mechanical properties as compared with the as-prepared solder joints are explained in terms of grain boundary and dispersion strengthening resulting from the microstructural refinement.

  6. Intermetallic compound layer growth kinetics in non-lead bearing solders

    Vianco, P.T.; Kilgo, A.C.; Grant, R.


    The introduction of alternative, non-lead bearing solders into electronic assemblies requires a thorough investigation of product manufacturability and reliability. Both of these attributes can be impacted by the excessive growth of intermetallic compound (IMC) layers at the solder/substrate interface. An extensive study has documented the stoichiometry and solid state growth kinetics of IMC layers formed between copper and the lead-free solders: 96.5Sn-3.5Ag (wt.%), 95Sn-5Sb, 100Sn, and 58Bi-42Sn. Aging temperatures were 70--205 C for the Sn-based solders and 55--120 C for the Bi-rich solder. Time periods were 1--400 days for all of the alloys. The Sn/Cu, Sn-Ag/Cu, and Sn-Sb/Cu IMC layers exhibited sub-layers of Cu{sub 6}Sn{sub 5} and Cu{sub 3}Sn; the latter composition was present only following prolonged aging times or higher temperatures. The total layer growth exhibited a time exponent of n = 0.5 at low temperatures and a value of n = 0.42 at higher temperatures in each of the solder/Cu systems. Similar growth kinetics were observed with the low temperature 58Bi-42Sn solder; however, a considerably more complex sub-layer structure was observed. The kinetic data will be discussed with respect to predicting IMC layer growth based upon solder composition.

  7. Generation of Tin(II) Oxide Crystals on Lead-Free Solder Joints in Deionized Water

    Chang, Hong; Chen, Hongtao; Li, Mingyu; Wang, Ling; Fu, Yonggao


    The effect of the anode and cathode on the electrochemical corrosion behavior of lead-free Sn-Ag-Cu and Sn-Ag-Cu-Bi solder joints in deionized water was investigated. Corrosion studies indicate that SnO crystals were generated on the surfaces of all lead-free solder joints. The constituents of the lead-free solder alloys, such as Ag, Cu, and Bi, did not affect the corrosion reaction significantly. In contrast to lead-free solders, PbO x was formed on the surface of the traditional 63Sn-37Pb solder joint in deionized water. A cathode, such as Au or Cu, was necessary for the electrochemical corrosion reaction of solders to occur. The corrosion reaction rate decreased with reduction of the cathode area. The formation mechanism of SnO crystals was essentially a galvanic cell reaction. The anodic reaction of Sn in the lead-free solder joints occurred through solvation by water molecules to form hydrated cations. In the cathodic reaction, oxygen dissolved in the deionized water captures electrons and is deoxidized to hydroxyl at the Au or Cu cathode. By diffusion, the anodic reaction product Sn2+ and the cathodic reaction product OH- meet to form Sn(OH)2, some of which can dehydrate to form more stable SnO· xH2O crystals on the surface of the solder joints. In addition, thermodynamic analysis confirms that the Sn corrosion reaction could occur spontaneously.

  8. Indium Corporation Introduces New Pb-Free VOC-Free Wave Solder Flux


    The Indium Corporation of America has introduced WF-7742 Wave Solder Flux specifically designed to meet the process demands of Pb-Free manufacturing. WF-7742 is a VOC-Free material formulated for Pb-Free wave soldering of surface-mount, mixed-technology and through-holeelectronics assemblies.

  9. Assessment of circuit board surface finishes for electronic assembly with lead-free solders

    Ray, U.; Artaki, I.; Finley, D.W.; Wenger, G.M. [Bell Labs., Princeton, NJ (United States). Lucent Technologies; Pan, T.; Blair, H.D.; Nicholson, J.M. [Ford Motor Co., Dearborn, MI (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)


    The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

  10. Wettability study of lead free solder paste and its effect towards multiple reflow

    Idris Siti Rabiatull Aisha


    Full Text Available Nowadays, wafer bumping using solder paste has come into focus as it provides a low cost method. However, since the industries are moving towards lead-free electronic packaging, a new type of no-clean flux was produced specifically for lead-free solder paste. Therefore, this study is used to evaluate the wettability of two different types of no-clean flux onto copper substrate. Besides, its effect towards multiple reflow was also studied. Reflow soldering was conducted for both types of solder paste that contained different type of no-clean flux for up to double reflow. Two different reflow profile was used. The results showed that the Flux A exhibit better soldering performance after first and second reflow soldering. In addition, type of intermetallic compound (IMC found after first reflow remain the same even after second reflow which was Cu-Sn based. This is shows that Flux A manage to control the diffusion process which will finally leads to a better solder joint performance. Nevertheless, mechanical testing should be carried out in order to evaluate the solder joint strength.

  11. The challenges of automobile-dependent urban transport strategy

    Jovanović Miomir


    Full Text Available The fundamental aims of sustainable urban development and the pro-automobile oriented economic development are on a collision course. It is obvious that automobile-dependent urban development is under heavy/powerful influence of the automobile lobby (automobile and oil industries, along with construction. In this domain famous land-use-transportation studies (or ‘grand transportation studies’ are, unfortunately, still prevailing - a vicious circle of self-fulfilling prophecy of congestion, road building, sprawl, congestion and more road building. Until recently, it was commonly thought that investment in public transport was not economically sustainable and that focusing on the development of the automobile industry and financing the construction of roadways stimulated economic growth. In this paper we clearly show that automobile industry is now overcapitalized, less profitable than many other industries (and may become even less profitable in the future, that transport market is characterized with huge distortions (more than a third of motor-vehicle use can be explained by underpriced driving, while new road investment does not have a major impact on economic growth (especially in a region with an already well-developed infrastructure, and that pro-automobile transport strategy inexorably incurs harmful global, regional and local ecological consequences. [Projekat Ministarstva nauke Republike Srbije, br. 37010

  12. Opportunities for energy harvesting in automobile factories

    Adegoke, E. I.; Edwards, R. M.; Whittow, Will; Bindel, Axel; Peca, Marco


    This paper investigates the opportunities of deploying distributed sensors within the manufacturing environment of a large scale automobile plant using energy harvesting techniques. Measurements were taken in three domains at the plant in order to characterize ambient energy. Due to the location of the plant, the RF power density for radio access technologies present varied between -127 dBm/cm2 and -113 dBm/cm2. The maximum temperature difference measured within accessible distance from machine parts on the production lines surveyed was 10°C. Indoor lighting was dominant at the plant via fluorescent tubes, with average irradiance of 1 W/m2. The results obtained from this measurement campaign showed that indoor lighting was the most suitable ambient source for energy harvesting.


    González, Eduardo


    Full Text Available This paper evaluates product efficiency in the Spanish automobile market. We use non parametric frontier techniques in order to estimate product efficiency scores for each model. These scores reflect the minimum price for which each car could be sold, given the bundle of tangible features it offers in comparison to the best-buy models. Unlike previous research, we use discounted prices which have been adjusted by car dealerships to meet sale targets. Therefore, we interpret the efficiency scores as indicators of the value of the intangible features of the brand. The results show that Audi, Volvo, Volkswagen and Mercedes offer the greatest intangible value, since they are heavily overpriced in terms of price/product ratios. Conversely, Seat, Kia, Renault and Dacia are the brands that can be taken as referent in terms of price/product ratios.

  14. Female identity discourse in automobile advertisements

    Montserrat López Díaz


    Full Text Available The article analyzes the way in which the modern car-advertisement defines the identity of women as potential purchasers – to whom it is designed to get through. The research includes language and iconic instruments by which this type of advertisement aims to create a feminized market of products formerly recognized as traditionally masculine. The identification of the addressee of each publicity material might be subsumed under a set of stereotypes, thus enabling advertisers to get across their message using the code of addressee’s own values. The present paper concentrates on the linguistic specifity of the ads for high-tech goods (automobiles targeting the feminine public and eventually points out their high degree of markedness according to the sex of addressees. Discourse analysis and a closer look at linguistic means appearing in French, Spanish and Polish automotive commercials both reveals a stereotyped woman’s image and shows how they happen to perpetutate it.

  15. Methemoglobinemia secondary to automobile exhaust fumes

    Laney, R.F.; Hoffman, R.S. (Department of Emergency Medicine, Morristown Memorial Hospital, NJ (United States))


    Methemoglobinemia is an uncommon cause of cyanosis. A 28-year-old male presented to the emergency department cyanotic and short of breath after exposure to noxious automobile fumes. He did not improve with the administration of 100% oxygen therapy. The initial arterial blood gas with cooximetry was: pH of 7.38, PaCO2 of 43 mm Hg, PaO2 of 118 mm Hg, measured oxygen saturation of 70%, and a methemoglobin level of 24.8%. Methylene blue was given (2 mg/kg intravenously) and the patient's symptoms resolved. On the following day he was discharged home without complication. A comprehensive review of the literature revealed no reported cases of methemoglobinemia secondary to accidental exposure to exhaust fumes.17 references.

  16. Stability analysis of automobile driver steering control

    Allen, R. W.


    In steering an automobile, the driver must basically control the direction of the car's trajectory (heading angle) and the lateral deviation of the car relative to a delineated pathway. A previously published linear control model of driver steering behavior which is analyzed from a stability point of view is considered. A simple approximate expression for a stability parameter, phase margin, is derived in terms of various driver and vehicle control parameters, and boundaries for stability are discussed. A field test study is reviewed that includes the measurement of driver steering control parameters. Phase margins derived for a range of vehicle characteristics are found to be generally consistent with known adaptive properties of the human operator. The implications of these results are discussed in terms of driver adaptive behavior.

  17. Complex of automated equipment and technologies for waveguides soldering using induction heating

    Murygin, A. V.; Tynchenko, V. S.; Laptenok, V. D.; Emilova, O. A.; Bocharov, A. N.


    The article deals with the problem of designing complex automated equipment for soldering waveguides based on induction heating technology. A theoretical analysis of the problem, allowing to form a model of the «inductor-waveguide» system and to carry out studies to determine the form of inducing wire, creating a narrow and concentrated heat zone in the area of the solder joint. Also solves the problem of the choice of the temperature control means, the information from which is used later to generate the effective management of induction soldering process. Designed hardware complex in conjunction with the developed software system is a system of automatic control, allowing to manage the process of induction heating, to prevent overheating and destruction of the soldered products, improve the stability of induction soldering process, to improve the quality of products, thereby reducing time and material costs for the production.

  18. Optimization of Pb-Free Solder Joint Reliability from a Metallurgical Perspective

    Zeng, Kejun; Pierce, Mike; Miyazaki, Hiroshi; Holdford, Becky


    To obtain the desired performance of Pb-free packages in mechanical tests, while the solder composition should be carefully selected, the influence of metals dissolved from the soldering pad or under bump metallization (UBM) should also be taken into account. Dissolved metals such as Cu can alter the intermetallic compound (IMC) formation, not only at the local interface but also on the other side of the joint. The high rate of interfacial cracking of Sn-Ag-Cu solder joints on Ni/Au-plated pads is attributed to the high stiffness of the solder and the dual IMC structure of (Cu,Ni)6Sn5 on Ni3Sn4 at the interface. Approaches to avoid this dual IMC structure at the interface are discussed. A rule for selecting the solder alloy composition and the pad surface materials on both sides of the joints is proposed for ball grid array (BGA) packages.

  19. Tensile properties and thermal shock reliability of Sn-Ag-Cu solder joint with indium addition.

    Yu, A-Mi; Jang, Jae-Won; Lee, Jong-Hyun; Kim, Jun-Ki; Kim, Mok-Soon


    The thermal shock reliability and tensile properties of a newly developed quaternary Sn-1.2Ag-0.5Cu-0.4In (wt%) solder alloy were investigated and compared to those of ternary Sn-Ag-Cu based Pb-free solder alloys. It was revealed that the Sn-1.2Ag-0.5Cu-0.4In solder alloy shows better thermal shock reliability compared to the Sn-1.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu solder alloys. The quaternary alloy has higher strength than Sn-1.0Ag-0.5Cu alloy, and higher elongation than Sn-3.0Ag-0.5Cu alloy. It was also revealed that the addition of indium promotes the formation of Ag3(Sn, In) phase in the solder joint during reflow process.

  20. Properties and Microstructures of Sn-Bi-X Lead-Free Solders

    Fan Yang


    Full Text Available The Sn-Bi base lead-free solders are proposed as one of the most popular alloys due to the low melting temperature (eutectic point: 139°C and low cost. However, they are not widely used because of the lower wettability, fatigue resistance, and elongation compared to traditional Sn-Pb solders. So the alloying is considered as an effective way to improve the properties of Sn-Bi solders with the addition of elements (Al, Cu, Zn, Ga, Ag, In, Sb, and rare earth and nanoparticles. In this paper, the development of Sn-Bi lead-free solders bearing elements and nanoparticles was reviewed. The variation of wettability, melting characteristic, electromigration, mechanical properties, microstructures, intermetallic compounds reaction, and creep behaviors was analyzed systematically, which can provide a reference for investigation of Sn-Bi base solders.

  1. Measurement of volatile organic compounds inside automobiles.

    Fedoruk, Marion J; Kerger, Brent D


    The objective of the current study was to evaluate the types and concentrations of volatile organic compounds (VOCs) in the passenger cabin of selected sedan automobiles under static (parked, unventilated) and specified conditions of operation (i.e., driving the vehicle using air conditioning alone, vent mode alone, or driver's window half open). Data were collected on five different passenger sedan vehicles from three major automobile manufacturers. Airborne concentrations were assessed using 90-min time-weighted average (TWA) samples under U.S. Environmental Protection Agency (USEPA) Method IP-1B to assess individual VOC compounds and total VOCs (TVOCs) calibrated to toluene. Static vehicle testing demonstrated TVOC levels of approximately 400-800 microg/m(3) at warm interior vehicle temperatures (approximately 80 degrees F), whereas TVOCs at least fivefold higher were observed under extreme heat conditions (e.g., up to 145 degrees F). The profile of most prevalent individual VOC compounds varied considerably according to vehicle brand, age, and interior temperature tested, with predominant compounds including styrene, toluene, and 8- to 12-carbon VOCs. TVOC levels under varied operating conditions (and ventilation) were generally four- to eightfold lower (at approximately 50-160 microg/m(3)) than the static vehicle measurements under warm conditions, with the lowest measured levels generally observed in the trials with the driver's window half open. These data indicate that while relatively high concentrations of certain VOCs can be measured inside static vehicles under extreme heat conditions, normal modes of operation rapidly reduce the inside-vehicle VOC concentrations even when the air conditioning is set on recirculation mode.

  2. Study on Sn-Zn Solder Used in Cu-Al Soldering%用于铜铝焊接的锡锌焊料研究

    倪广春; 张浩; 韩敏


    Lead-free electronic products led the development of lead-free solder technology. Taking cost factors into account, some copper material has been replaced by aluminum material. When ordinary Sn-Cu and Sn-Ag-Cu solder are used in soldering of Cu-Al, there is the electrochemical corrosion problems. So Sn-Zn solder is used for Cu-Al soldering. However, the joints of Sn-Zn solder are brittle and easy to crack. Focus on problems in Cu-Al soldering joint of electrical and electronic devices, put forward Sn-Zn-X alloy soldering materials, did a large number of experiments, and achieved good results.%电子产品无铅化的推广带动了无铅焊料技术的发展,考虑到成本因素,部分铜材已被铝材取代。普通的锡铜系和锡银铜系焊料在铜铝焊接时,存在电化学腐蚀问题,因此多用锡锌焊料进行焊接。但锡锌焊料的焊点脆,存在易开裂的问题。针对电工电子器件铜铝焊接点存在的问题,提出了Sn一Zn一X多元合金焊接材料,并做了大量实验,取得很好的效果。

  3. Physical properties of lead free solders in liquid and solid state

    Mhiaoui, Souad


    The European legislation prohibits the use of lead containing solders in Europe. However, lead free solders have a higher melting point (typical 20%) and their mechanical characteristics are worse. Additional problems are aging and adhesion of the solder on the electronic circuits. Thus, research activities must focus on the optimization of the properties of Sn-Ag-Cu based lead free solders chosen by the industry. Two main objectives are treated in this work. In the center of the first one is the study of curious hysteresis effects of metallic cadmium-antimony alloys after thermal cycles by measuring electronic transport phenomena (thermoelectric power and electrical resistivity). The second objective, within the framework of ''cotutelle'' between the universities of Metz and of Chemnitz and supported by COST531, is to study more specifically lead free solders. A welding must well conduct electricity and well conduct and dissipate heat. In Metz, we determined the electrical conductivity, the thermoelectric power and the thermal conductivity of various lead free solders (Sn-Ag-Cu, Sn-Cu, Sn-Ag, Sn-Sb) as well in the liquid as well in the solid state. The results have been compared to classical lead-tin (Pb-Sn) solders. In Chemnitz we measured the surface tension, the interfacial tension and the density of lead free solders. We also measured the viscosity of these solders without and with additives, in particular nickel. These properties were related to the industrial problems of wettability and spreadability. Lastly, we solidified alloys under various conditions. We observed undercooling. We developed a technique of mixture of nanocrystalline powder with lead free solders ''to sow'' the liquid bath in order to obtain ''different'' solids which were examined using optical and electron microscopy. (orig.)

  4. The ergonomics simulation and evaluation architecture for the automobile

    Wu, Jianfeng; Yang, Ying; Sun, Shouqian; Liu, Tao


    The architecture of ergonomics simulation and evaluation for the automobile was described. Ergonomics analysis and evaluation is one of the most important processes in product design at present. This ergonomics simulation system based on the elements of ergonomics analysis and evaluation can provide an excellent solution to take human element into account earlier in the design phase and make proactive choices in automobile design than those traditional methods. Thinking of the characteristics of the automobile industry, this system adopted the anatomy-based and parameterized human model for Chinese, the simulation technique using motion editing and the mathematical models of ergonomics to solve real ergonomic design problems in the design phases.

  5. Standardization Boosts the Development ofCHANGAN AUTOMOBILE


    In the past two decades,CHANGAN AUTOMOBILE has been sticking to its core value of "technology innovation and consistent care" and dedicating to lead the automobile culture by technology innovation.Till now,it has a complete product range of micro vehicles,passenger cars,buses,trucks,SUV,MPV,etc.,and engineplatforms ranging from 0.8L to 2.5L.CHANGAN AUTOMOBILE brand output ranked 13th in the world and first in China in 2009.Its brand value reached 30.515 billion RMB in 2011,among most valuable brands in China.

  6. Service Quality Challenges in an Indian Automobile Service Industries

    Mr. Mangesh D. Jadhao


    Full Text Available Market scenario in past decade changes very fast due to computation in a market. Changing a technology and launching new models in market are as per customer demand. Providing service quality is a big task to many organizations. Today automobile service sector faces many problems due to increase of customer expectation from branded company. This study overview the challenges faced by an Indian automobile service sector and find the various gaps which will directly or indirectly affects on service quality and factor which affects the service. The paper concludes with the gaps that affects on current position of four wheeler service industries their market share in automobile service industries.

  7. A Study of the Translation of Automobile Trademark



    Name is an interesting thing, almost everything has its name. Nowadays along with the rising of consumption levels in China, the brand name of the car becomes an important topic. And the translation of the name of the automobile is the primary task for establishing the global image of the brand. In this paper, I summarize the translation methods for automobile trademarks and point out the importance of the translation of automobile’s trademarks. In addition, this paper explores the trend in the trans-lation of automobile names in China.

  8. Reliability-based design for automobiles in China

    Yimin ZHANG


    The level of automobile design and manufac-turing is an important sign of leadership in science and technology and economic power. The achievements of theories and methods for reliability-based design of auto-mobiles in China are reviewed. For reliability-based design, the theories and practices, optimization, sensitiv-ity, and robustness are estimated. The techniques of reli-ability-based design for automobiles are developed. The techniques service to the "hollow" phenomena of kernel technology, product innovative power, and independent development power can be solved.

  9. Hypospadias repair

    ... the problem. If the repair is not done, problems may occur later on such as: Difficulty controlling and directing urine stream A curve in the penis during erection Decreased fertility Embarrassment about appearance of penis Surgery ...

  10. Application of thermoelectric generator for automobile. Application of thermoelectric generation technology using Seebeck effect; Jidosha haikinetsu hatsuden. Seebeck soshi wo mochiita netsuden hatsuden gijutsu no oyo

    Shinohara, K.; Kobayashi, M.; Kushibiki, K.; Furuya, K. [Nissan Motor Co. Ltd., Tokyo (Japan)


    Study was made on energy saving by waste heat power generation for automobiles. In a waste heat generation system for automobiles, exhaust gas is converted into electric energy by a thermoelectric generator through an exhaust pipe and catalyst, and supplied to a battery or electric devices through a voltage control system. The thermoelectric generator is composed of a generating module using a Seebeck element, a heat sink and a radiator. Although an Si-Ge system Peltier element is poor in generation efficiency, it is rich in high-temperature reliability, durability and safety. However, the maximum generation efficiency of the system is as low as 5% in a normal temperature region of exhaust gas around 500degC, and further improvement of its performance is essential. For the thermoelectric module, junction of thermoelectric material and electrodes is one of the issues. Because of high- temperature use, superior solder capable of resisting the peak temperature of the system, and diffusion pressure welding and plasma flame coating techniques are necessary. At present, fuel saving of nearly 5% is possible. 11 refs., 8 figs.

  11. Reliability of Wind Turbine Components-Solder Elements Fatigue Failure

    Kostandyan, Erik; Sørensen, John Dalsgaard


    on the temperature mean and temperature range. Constant terms and model errors are estimated. The proposed methods are useful to predict damage values for solder joint in power electrical components. Based on the proposed methods it is described how to find the damage level for a given temperature loading profile....... The proposed methods are discussed for application in reliability assessment of Wind Turbine’s electrical components considering physical, model and measurement uncertainties. For further research it is proposed to evaluate damage criteria for electrical components due to the operational temperature...

  12. Pb-free Sn-Ag-Cu ternary eutectic solder

    Anderson, I.E.; Yost, F.G.; Smith, J.F.; Miller, C.M.; Terpstra, R.L.


    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217 C and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid ``mushy`` zone) relative to the eutectic melting temperature (e.g. up to 15 C above the eutectic melting temperature). 5 figs.

  13. Analysis for the Dynamic Characteristic of the Automobile Transmission Gearbox

    Fujin Yu


    Full Text Available Automobile transmission gearbox, as one of the major components, which will inevitably bring about the vibration and noise of automobile vehicle. The objective of this study to reduce the noise and vibration of automobile transmission by structural optimization of the gearbox in order to better control its functional operation and improve its performance. For this purpose, based on the working characteristics of the gearbox, modal analysis of automobile transmission gearbox is formulated using 3D graphics software Pro/E together with Finite Element Method. In addition, the modal test of gearbox is conducted also. Through comparing model analysis results to test results, test results verify the correctness of the finite element analysis results, thus provide the theoretic basis to analyze its dynamic characteristics of the gearbox structure as well as its improvement to reduce vibration and noise.

  14. Speakeasy. English for Special Purposes Series: Autobody Repair. Korean Translation Manual.

    Park, Yong-Ok

    This guide to spoken usage with exercises is designed to enrich the English vocabulary of speakers of Korean. Narrative portions of the text are in Korean. Emphasis is on survival skills and automobile repair skills. Chapters include "Time,""Getting to Know You,""Eating Out,""Opening a Savings Account,""Asking and Giving Directions,""Buying Work…

  15. Speakeasy. English for Special Purposes Series: Autobody Repair. Ilocano Translation Manual.

    Berzabal, Ofelia G.

    This guide to spoken usage with exercises is designed to enrich the English vocabulary of speakers of Ilocano. Narrative portions of the text are in Ilocano. Emphasis is on survival language skills and automobile repair skills. Chapters include "Time,""Getting to Know You,""Eating Out,""Opening a Savings Account,""Asking and Giving…

  16. Speakeasy. English for Special Purposes Series: Autobody Repair. Vietnamese Translation Manual.

    Van-Tanh, Phan

    This guide to spoken usage with exercises is designed to enrich the English vocabulary of speakers of Vietnamese. Narrative portions of the text are in Vietnamese. Emphasis is on survival skills and automobile repair skills. Chapters include "Time,""Getting to Know You,""Eating Out,""Opening a Savings Account,""Asking and Giving…

  17. Titanium in the family automobile: The cost challenge

    Froes, F. H.; Friedrich, H.; Kiese, J.; Bergoint, D.


    With advances in extraction/fabrication techniques and ever-increasing gasoline prices, the advantage of using lightweight materials such as aluminum, magnesium, and titanium in automobiles continues to increase, particularly for the first two metals. The major drawback for titanium, much more so than the other light metals, is high cost. However, innovative extraction and fabrication approaches are leading to decreased cost. This paper discusses the present status and future potential for titanium use in the family automobile.

  18. Strength Check Analysis for Gear Shaft of Automobile Transmission

    Yongxiang Li; Weiqiang Xia; Liwen Nan; Youjia Zhao; Fujin Yu


    As the main drive components of the automobile transmission, the performance of gear shaft plays an important role on transmission performance. Aiming at the existing problems of the traditional strength check method of gear shaft, the objective of this study is to take a five-speed transmission as an example, to accomplish the strength analysis of gear shaft of the automobile transmission based on the MASTA software. Furthermore, the simulation modeling of the transmission is built completel...

  19. Emissions reductions as a result of automobile improvement.

    Pokharel, Sajal S; Bishop, Gary A; Stedman, Donald H; Slott, Robert


    Remote sensing of light duty vehicle on-road tailpipe exhaust has been used to measure on-road mass emissions of automobile fleets in Denver for 13 years and in two other U.S. cities for 5 years. Analysis of these fleets shows that newer automobiles, during a period of fairly constant new car standards, have become continually less polluting independent of measurement location. Improving emissions control technology spurred by federal regulations is thought to have brought about these trends.

  20. Laser ablative fluxless soldering (LAFS): 60Sn-40Pb solder wettability tests on laser cleaned OFHC copper substrates

    Peebles, H. C.; Keicher, D. M.; Hosking, F. M.; Hlava, P. F.; Creager, N. A.


    OFHC copper substrates, cleaned by laser ablation under argon and helium gas, were tested for solder wettability by 60Sn-40Pb using an area-of-spread method. The wettability of copper surfaces cleaned under both argon and helium gas was found to equal or exceed the wettability obtained on this surface in air using a standard RMA flux. The area of spread on copper substrates cleaned under helium was eight times larger than the area of spread of substrates cleaned under argon. The enhanced spreading observed on the substrates cleaned under helium gas was found to be due to surface roughness. 11 refs., 8 figs., 2 tabs.

  1. Detection of micro solder balls using active thermography and probabilistic neural network

    He, Zhenzhi; Wei, Li; Shao, Minghui; Lu, Xingning


    Micro solder ball/bump has been widely used in electronic packaging. It has been challenging to inspect these structures as the solder balls/bumps are often embedded between the component and substrates, especially in flip-chip packaging. In this paper, a detection method for micro solder ball/bump based on the active thermography and the probabilistic neural network is investigated. A VH680 infrared imager is used to capture the thermal image of the test vehicle, SFA10 packages. The temperature curves are processed using moving average technique to remove the peak noise. And the principal component analysis (PCA) is adopted to reconstruct the thermal images. The missed solder balls can be recognized explicitly in the second principal component image. Probabilistic neural network (PNN) is then established to identify the defective bump intelligently. The hot spots corresponding to the solder balls are segmented from the PCA reconstructed image, and statistic parameters are calculated. To characterize the thermal properties of solder bump quantitatively, three representative features are selected and used as the input vector in PNN clustering. The results show that the actual outputs and the expected outputs are consistent in identification of the missed solder balls, and all the bumps were recognized accurately, which demonstrates the viability of the PNN in effective defect inspection in high-density microelectronic packaging.

  2. A microstructural study of creep and thermal fatigue deformation in 60Sn-40Pb solder joints

    Tribula, D.


    Thermal fatigue failures of solder joints in electronic devices often arise from cyclic shear strains imposed by the mismatched thermal expansion coefficients of the materials that bind the joint as temperature changes are encountered. Increased solder joint reliability demands a fundamental understanding of the metallurigical mechanisms that control the fatigue to design accurate accelerated probative tests and new, more fatigue resistant solder alloys. The high temperatures and slow strain rates that pertain to thermal fatigue imply that creep is an important deformation mode in the thermal fatigue cycle. In this work, the creep behaviour of a solder joint is studied to determine the solder's microstructural response to this type of deformation and to relate this to the more complex problem of thermal fatigue. It is shown that creep failures arise from the inherent inhomogeneity and instability of the solder microstructure and suggest that small compositional changes of the binary near-eutectic Pn-Sn alloy may defeat the observed failure mechanisms. This work presents creep and thermal fatigue data for several near-eutectic Pb-Sn solder compositions and concludes that a 58Sn-40Pb-2In and a 58Sn-40Pb-2Cd alloy show significantly enhanced fatigue resistance over that of the simple binary material. 80 refs., 33 figs., 1 tab.

  3. Evaluation of Scattered Wave and Stress Concentration Field in a Damaged Solder Joint

    Dineva, P.; Gross, D.; Rangelov, T.


    Two different, but equally important problems for solder joint reliability are solved. The evaluation of the dynamic stress concentration field in the thin base layer of a damaged solder joint is the first one. It is considered as a rectangular plate with a central macro-crack surrounded with randomly distributed micro-cracks, subjected to uniform time-harmonic tension. The damaged solder joint state is described by the model of Gross and Zhang [1] (International Journal of Solids and Structures29, 1763-1779). The information of the stress concentration field in a damaged solder joint is important to understand the mechanisms in the base components of all electronic packages.The second problem is ultrasonic wave scattering in a solder joint damaged by micro-cracks, considered as a two-dimensional finite multi-layered system. The solution of this problem may aid the creation of the modern non-destructive evaluation method (NDEM) for a high quality control of products in electronic industry.The method of the solution of both boundary-value problems is a direct BIEM (boundary integral equation method). The numerical results obtained for a solder joint with real geometry and physical properties show how the acoustic and stress concentration fields depend on the solder joint damage state. The character of this dependence is discussed.

  4. Wettability Studies of Pb-Free Soldering Materials

    Moser, Z.; Gąsior, W.; Pstruś, J.; Dębski, A.


    For Pb-free soldering materials, two main substitutes are currently being considered, consisting of Sn-Ag and Sn-Ag-Cu eutectics, both with melting points higher than that of the Sn-Pb eutectic. Therefore, both will require higher soldering temperatures for industrial applications. Also, both eutectics have a higher surface tension than the Sn-Pb eutectic, requiring wettability studies on adding Bi, Sb, and In to the eutectics to decrease the melting points and surface tension. The experimental results for the surface tension were compared with thermodynamic modeling by Butler’s method and were used to create the SURDAT database, which also includes densities for pure metals, binary, ternary, quaternary, and quinary alloys. To model the surface tension, excess Gibbs energies of the molten components were taken from the ADAMIS database. For the case of the Ag-Sn system, enthalpies of formation of Ag3Sn from solution calorimetry were used for checking optimized thermodynamic parameters. In the study of Sn-Ag-Cu-Bi-Sb liquid alloys, the range of possible Bi compositions for practical applications has been used to formulate a generalized metric of wettability, which was checked by measurements of the influence of In on the Sn-Ag-Cu system.

  5. Effect of contact metallization on electromigration reliability of Pb-free solder joints

    Ding, Min; Wang, Guotao; Chao, Brook; Ho, Paul S.; Su, Peng; Uehling, Trent


    The effect of underbump metallization (UBM) on electromigration (EM) lifetime and failure mechanism has been investigated for Pb-free solder bumps of 97Sn3Ag composition in the temperature range of 110-155 °C. The EM lifetime of the SnAg Pb-free solders with either Cu or Ni UBM was found to be better than the eutectic SnPb (63Sn37Pb) solders but worse than high-Pb (95Pb5Sn) solders. In the test temperature range, the EM lifetimes were found to be comparable for Cu and Ni UBMs but with different activation energies: 0.64-0.72 eV for Cu UBM and 1.03-1.11 eV for Ni UBM. EM failure was observed only in solder bumps with electron current flow from UBM to the substrate. Failure analysis revealed that EM damage was initiated by the formation of intermetallic compounds (IMC) at the UBM/solder interface which was found to be significantly enhanced by mass transport driven by the electron current. Under EM, the continued growth of IMC with the dissolution of the UBM and the accumulation of Kirkendall voids resulted in the formation of interfacial cracks and eventual EM failure of the solder bump. For Ni UBM, the IMC formation was dominated by the Ni3Sn4 phase while for Cu UBM, a bilayer of Cu3Sn/Cu6Sn5 was found. Void formation at the Cu6Sn5/solder interface was found to be important in controlling the EM lifetime of the Cu UBM solder.

  6. The influence of silver content on structure and properties of Sn–Bi–Ag solder and Cu/solder/Cu joints

    Šebo, P. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3 (Slovakia); Švec, P. Sr., E-mail: [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia); Faculty of Materials Science and Technology, Slovak University of Technology, J. Bottu 25, 917 24 Trnava (Slovakia); Janičkovič, D.; Illeková, E. [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia); Zemánková, M. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3 (Slovakia); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 79005 Lviv (Ukraine); Sidorov, V. [Ural State Pedagogical University, Cosmonavtov 26, 620017 Ekaterinburg (Russian Federation); Švec, P. [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia)


    The effect of silver content on structure and properties of Sn{sub 100−x}Bi{sub 10}Ag{sub x} (x=3–10 at%) lead-free solder and Cu–solder–Cu joints was investigated. The microstructure of the solder in both bulk and rapidly solidified ribbon forms was analyzed by scanning electron microscopy (SEM) and X-ray diffraction. The peculiarities in melting kinetic, studied by differential scanning calorimetry (DSC), and silver influence on it are described and discussed. The wetting of a copper substrate was examined by the sessile drop method in the temperature range of 553–673 K in air and deoxidizing gas (N{sub 2}+10%H{sub 2}) at atmospheric pressure. Cu–solder–Cu joints were also prepared in both atmospheres, and their shear strength was measured by the push-off method. The produced solders consisted of tin, bismuth and Ag{sub 3}Sn phases. The product of the interaction between the solder and the copper substrate consists of two phases: Cu{sub 3}Sn, which is adjacent to the substrate, and a Cu{sub 6}Sn{sub 5} phase. The wetting angle in air increased slightly as the silver concentration in the solder increased. Wetting of the copper substrate in N{sub 2}+10H{sub 2} gas shows the opposite tendency: the wetting angle slightly decreased as the silver content in the solder increased. The shear strength of the joints prepared in air (using flux) tends to decrease with increasing production temperature and increasing silver content in the solder. The equivalent decrease in the shear strength of the joints prepared in N{sub 2}+10H{sub 2} is more apparent.

  7. Femoral hernia repair

    Femorocele repair; Herniorrhaphy; Hernioplasty - femoral ... During surgery to repair the hernia, the bulging tissue is pushed back in. The weakened area is sewn closed or strengthened. This repair ...

  8. Undescended testicle repair

    Orchidopexy; Inguinal orchidopexy; Orchiopexy; Repair of undescended testicle; Cryptorchidism repair ... first year of life without treatment. Undescended testicle repair surgery is recommended for patients whose testicles do ...

  9. A scaffold-enhanced light-activated surgical adhesive technique: surface selection for enhanced tensile strength in wound repair

    Soller, Eric C.; Hoffman, Grant T.; Heintzelman, Douglas L.; Duffy, Mark T.; Bloom, Jeffrey N.; McNally-Heintzelman, Karen M.


    An ex vivo study was conducted to determine the effect of the irregularity of the scaffold surface on the tensile strength of repairs formed using our Scaffold-Enhanced Biological Adhesive (SEBA). Two different scaffold materials were investigated: (i) a synthetic biodegradable material fabricated from poly(L-lactic-co-glycolic acid); and (ii) a biological material, small intestinal submucosa, manufactured by Cook BioTech. The scaffolds were doped with protein solder composed of 50%(w/v) bovine serum albumin solder and 0.5mg/ml indocyanine green dye mixed in deionized water, and activated with an 808-nm diode laser. The tensile strength of repairs performed on bovine thoracic aorta, liver, spleen, small intestine and lung, using the smooth and irregular surfaces of the above scaffold-enhanced materials were measured and the time-to-failure was recorded. The tensile strength of repairs formed using the irregular surfaces of the scaffolds were consistently higher than those formed using the smooth surfaces of the scaffolds. The largest difference was observed on repairs formed on the aorta and small intestine, where the repairs were, on average, 50% stronger using the irregular versus the smooth scaffold surfaces. In addition, the time-to-failure of repairs formed using the irregular surfaces of the scaffolds were between 50% and 100% longer than that achieved using the smooth surfaces of the scaffolds. It has previously been shown that distributing or dispersing the adhesive forces over the increased surface area of the scaffold, either smooth or irregular, produces stronger repairs than albumin solder alone. The increase in the absolute strength and longevity of repairs seen in this new study when the irregular surfaces of the scaffolds are used is thought to be due to the distribution of forces between the many independent micro-adhesions provided by the irregular surfaces.

  10. Direct Numerical Simulation of Automobile Cavity Tones

    Kurbatskii, Konstantin; Tam, Christopher K. W.


    The Navier Stokes equation is solved computationally by the Dispersion-Relation-Preserving (DRP) scheme for the flow and acoustic fields associated with a laminar boundary layer flow over an automobile door cavity. In this work, the flow Reynolds number is restricted to R(sub delta*) < 3400; the range of Reynolds number for which laminar flow may be maintained. This investigation focuses on two aspects of the problem, namely, the effect of boundary layer thickness on the cavity tone frequency and intensity and the effect of the size of the computation domain on the accuracy of the numerical simulation. It is found that the tone frequency decreases with an increase in boundary layer thickness. When the boundary layer is thicker than a certain critical value, depending on the flow speed, no tone is emitted by the cavity. Computationally, solutions of aeroacoustics problems are known to be sensitive to the size of the computation domain. Numerical experiments indicate that the use of a small domain could result in normal mode type acoustic oscillations in the entire computation domain leading to an increase in tone frequency and intensity. When the computation domain is expanded so that the boundaries are at least one wavelength away from the noise source, the computed tone frequency and intensity are found to be computation domain size independent.

  11. Research on Defects Inspection of Solder Balls Based on Eddy Current Pulsed Thermography

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe


    In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT). Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique. PMID:26473871

  12. Life Prediction of Ball Grid Array Soldered Joints under Thermal Cycling Loading by Fracture Mechanics Method


    Fatigue crack propagation life of ball grid array (BGA) soldered joints during thermal cycling loading was investigated by fracture mechanics approach using finite element analysis. The relationships between the strain energy release rate (G) and crack size (α), thermal cycle numbers (N) can be derived. Based on the relationships, fatigue life of the soldered joints was determined. The results showed that crack propagation life was higher than crack initiation life. Therefore, it appears that it is more appropriate to predict the fatigue life of soldered joints using the fracture mechanics method.

  13. Research on defects inspection of solder balls based on eddy current pulsed thermography.

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe


    In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT). Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique.

  14. Research on Defects Inspection of Solder Balls Based on Eddy Current Pulsed Thermography

    Xiuyun Zhou


    Full Text Available In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT. Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique.

  15. Effect of constraint on crack propagation behavior in BGA soldered joints

    王莉; 王国忠; 方洪渊; 钱乙余


    The effects of stress triaxiality on crack propagation behavior in the BGA soldered joint were analyzed using FEM method. The computation results verified that stress triaxiality factor has an important effect on crack growth behavior. Crack growth rate increased with increasing stress triaxiality at the near-tip region, which is caused by increasing crack lengths or decreasing solder joint heights. Solder joint deformation is subjected to constraint effect provided by its surrounding rigid ceramic substrate, the constraint can be scaled by stress triaxiality near crack tip region. Therefore, it can be concluded that crack growth rate increased when the constraint effect increases.

  16. Observations of microstructural coarsening in micro flip-chip solder joints

    Barney, Monica M.; Morris, J. W.


    Coarsening of solder microstructures dramatically affects fatigue lifetimes. This paper presents a study of microstructural evolution due to thermal cycling and aging of small solder joints. The lead-tin solder joints in this study have a height of 55 5 m and a tin content of 65 70 wt.%, with a degenerate eutectic microstructure. The joint microstructure coarsens more rapidly during aging at 160°C than cycling from 0 160°C. No coarsened bands are observed. The cycling data scales with standard coarsening equations, while the aging data fits to an enhanced trend. The joints experiencing 2.8% strain during cycling fail by 1000 cycles.

  17. Eddy current quality control of soldered current-carrying busbar splices of superconducting magnets

    Kogan, L; Savary, F; Principe, R; Datskov, V; Rozenfel'd, E; Khudjakov, B


    The eddy current technique associated with a U-shaped transducer is studied for the quality control of soldered joints between superconducting busbars ('splices'). Two other quality control techniques, based on X-rays and direct measurement of the electrical resistance, are also studied for comparison. A comparative analysis of the advantages and disadvantages of these three methods in relation to the quality control of soldered superconducting busbar cables enclosed in copper shells is used for benchmarking. The results of inspections with the U-shaped eddy current transducer carried out on several sample joints presenting different types of soldering defects show the potential of this type of nondestructive (ND) quality control technique.

  18. A cause of the non-solderability of ceramic capacitor terminations

    Cozzolino, M. J.; Kumar, A.; Ewell, G. J.


    The results of an analysis into the cause of the non-solderability of multiple defective part lots from two capacitor manufacturers are described. This analysis consisted of visual, scanning electron microscopic, surface, and metalographic examinations and analyses. The results indicated that non-solderability results from areas of excess porosity in the termination which are caused by segregation of ink constituents during manufacturing. This segregation can be minimized by proper monitoring and control of process variables; where excess porosity does occur, solderability can be improved by proper precleaning of parts.

  19. Wettability study of lead free solder paste and its effect towards multiple reflow

    Idris Siti Rabiatull Aisha; Zuleikha Siti; Abd Malek Zetty Akhtar


    Nowadays, wafer bumping using solder paste has come into focus as it provides a low cost method. However, since the industries are moving towards lead-free electronic packaging, a new type of no-clean flux was produced specifically for lead-free solder paste. Therefore, this study is used to evaluate the wettability of two different types of no-clean flux onto copper substrate. Besides, its effect towards multiple reflow was also studied. Reflow soldering was conducted for both types of solde...

  20. (1) H-NMR with Multivariate Analysis for Automobile Lubricant Comparison.

    Kim, Siwon; Yoon, Dahye; Lee, Dong-Kye; Yoon, Changshin; Kim, Suhkmann


    Identification of suspected automobile-related lubricants could provide valuable information in forensic cases. We examined that automobile lubricants might exhibit the chemometric characteristics to their individual usages. To compare the degree of clustering in the plots, we co-plotted general industrial oils that were highly dissimilar with automobile lubricants in additive compositions. (1) H-NMR spectroscopy was used with multivariate statistics as a tool for grouping, clustering, and identification of automobile lubricants in laboratory conditions. We analyzed automobile lubricants including automobile engine oils, automobile transmission oils, automobile gear oils, and motorcycle oils. In contrast to the general industrial oils, automobile lubricants showed relatively high tendencies of clustering to their usages. Our pilot study demonstrated that the comparison of known and questioned samples to their usages might be possible in forensic fields.

  1. Effect of Surface Finish of Substrate on Mechanical Reliability of in-48SN Solder Joints in Moems Package

    Koo, Ja-Myeong


    Interfacial reactions and shear properties of the In-48Sn (in wt.%) ball grid array (BGA) solder joints after bonding were investigated with four different surface finishes of the substrate over an underlying Cu pad: electroplated Ni/Au (hereafter E-NG), electroless Ni/immersion Au (hereafter ENIG), immersion Ag (hereafter I-Ag) and organic solderability preservative (hereafter OSP). During bonding, continuous AuIn2, Ni3(Sn,In)4 and Cu6(Sn,In)5 intermetallic compound (IMC) layers were formed at the solder/E-NG, solder/ENIG and solder/OSP interface, respectively. The interfacial reactions between the solder and I-Ag substrate during bonding resulted in the formation of Cu6(Sn,In)5 and Cu(Sn,In)2 IMCs with a minor Ag element. The In-48Sn/I-Ag solder joint showed the best shear properties among the four solder joints after bonding, whereas the solder/ENIG solder joint exhibited the weakest mechanical integrity.

  2. Electromigration Reliability and Morphologies of Cu Pillar Flip-Chip Solder Joints with Cu Substrate Pad Metallization

    Lai, Yi-Shao; Chiu, Ying-Ta; Chen, Jiunn


    The Cu pillar is a thick underbump metallurgy (UBM) structure developed to alleviate current crowding in a flip-chip solder joint under operating conditions. We present in this work an examination of the electromigration reliability and morphologies of Cu pillar flip-chip solder joints formed by joining Ti/Cu/Ni UBM with largely elongated ˜62 μm Cu onto Cu substrate pad metallization using the Sn-3Ag-0.5Cu solder alloy. Three test conditions that controlled average current densities in solder joints and ambient temperatures were considered: 10 kA/cm2 at 150°C, 10 kA/cm2 at 160°C, and 15 kA/cm2 at 125°C. Electromigration reliability of this particular solder joint turns out to be greatly enhanced compared to a conventional solder joint with a thin-film-stack UBM. Cross-sectional examinations of solder joints upon failure indicate that cracks formed in (Cu,Ni)6Sn5 or Cu6Sn5 intermetallic compounds (IMCs) near the cathode side of the solder joint. Moreover, the ~52- μm-thick Sn-Ag-Cu solder after long-term current stressing has turned into a combination of ~80% Cu-Ni-Sn IMC and ~20% Sn-rich phases, which appeared in the form of large aggregates that in general were distributed on the cathode side of the solder joint.

  3. Intestinal obstruction repair

    Repair of volvulus; Intestinal volvulus - repair; Bowel obstruction - repair ... Intestinal obstruction repair is done while you are under general anesthesia . This means you are asleep and DO NOT feel pain. ...

  4. Aortic aneurysm repair - endovascular

    EVAR; Endovascular aneurysm repair - aorta; AAA repair - endovascular; Repair - aortic aneurysm - endovascular ... Endovascular aortic repair is done because your aneurysm is very large, growing quickly, or is leaking or bleeding. You may have ...

  5. Motorcycle Repair.

    Hein, Jim; Bundy, Mike

    This motorcycle repair curriculum guide contains the following ten areas of study: brake systems, clutches, constant mesh transmissions, final drives, suspension, mechanical starting mechanisms, electrical systems, fuel systems, lubrication systems, and overhead camshafts. Each area consists of one or more units of instruction. Each instructional…

  6. Mind the Gap: The Vicious Circle of Measuring Automobile Fuel Use

    Figueroa, Maria; author), L. Schipper (main; Price, L.


    We review the circularity between estimates of automobile use, fuel consumption and fuel intensity. We find that major gaps exist between estimates of road gasoline, the quantity most often used to represent automobile fuel use in economic studies of transport fuel use, and the actual sales data...... of gasoline, diesel and other fuels used for automobiles. We note that significant uncertainties exist in values of both the number of automobiles in use and the distance each is driven, which together yield total automobile use. We present our own calculations for total automobile fuel use for a variety...

  7. Abnormal growth of Ag3Sn intermetallic compounds in Sn-Ag lead-free solder

    SHEN Jun; LIU Yongchang; GAO Houxiu


    The abnormal growth of Ag3Sn intermetallic compounds in eutectic Sn-3.5% Ag solder was investigated through high-temperature aging treatment. Microstructural evolutions of this solder before and after the aging treatment were observed by optical microscopy and scanning electron microscopy. Precise differential thermal analysis was made to study the changes in enthalpies of the solder under different conditions. The results reveal that the water-cooled solder is in metastable thermodynamic state due to the high free energy of Ag3Sn nanoparticles, which sporadically distribute in the matrix as second-phase. The second-phase Ag3Sn nanoparticles aggregate rapidly and grow to form bulk intermetallic compounds due to the migration of grain boundary between primary Sn-rich phase and the Ag3Sn nanoparticles during high temperature aging treatment.

  8. Climate specific thermomechanical fatigue of flat plate photovoltaic module solder joints

    Bosco, Nick; Silverman, Timothy J.; Kurtz, Sarah


    FEM simulations of PbSn solder fatigue damage are used to evaluate seven cities that represent a variety of climatic zones. It is shown that the rate of solder fatigue damage is not ranked with the cities' climate designations. For an accurate ranking, the mean maximum daily temperature, daily temperature change and a characteristic of clouding events are all required. A physics-based empirical equation is presented that accurately calculates solder fatigue damage according to these three factors. An FEM comparison of solder damage accumulated through service and thermal cycling demonstrates the number of cycles required for an equivalent exposure. For an equivalent 25-year exposure, the number of thermal cycles (-40 degrees C to 85 degrees C) required ranged from roughly 100 to 630 for the cities examined. It is demonstrated that increasing the maximum cycle temperature may significantly reduce the number of thermal cycles required for an equivalent exposure.

  9. Thermal analysis of selected tin-based lead-free solder alloys

    Palcut, Marián; Sopoušek, J.; Trnková, L.


    The Sn-Ag-Cu alloys have favourable solderability and wetting properties and are, therefore, being considered as potential lead-free solder materials. In the present study, tin-based Sn-Ag-Cu and Sn-Ag-Cu-Bi alloys were studied in detail by a differential scanning calorimetry (DSC) and thermodyna......The Sn-Ag-Cu alloys have favourable solderability and wetting properties and are, therefore, being considered as potential lead-free solder materials. In the present study, tin-based Sn-Ag-Cu and Sn-Ag-Cu-Bi alloys were studied in detail by a differential scanning calorimetry (DSC...... was simulated using the Thermo-Calc software package. This approach enabled us to obtain the enthalpy of cooling for each alloy and to compare its temperature derivative with the experimental DSC curves....

  10. Shear Deformation Behaviors of Sn3.5Ag Lead-free Solder Samples

    Jing Han; Hongtao Chen; Mingyu Li; Chunqing Wang


    In this study,shear tests have been performed on the as-reflowed Sn3.5Ag solder bumps and joints to investigate the deformation behavior of Sn3.5Ag lead-free solder samples.Scanning electron microscopy (SEM) was employed to characterize the microstructures of the samples and orientation imaging microscopy (OIM) with electron backscattered diffraction (EBSD) in SEM was used to obtain crystallographic orientation of grains to provide a detailed characterization of the deformation behavior in Sn3.5Ag solder samples after shear tests.The deformation behavior in solder samples under shear stress was discussed.The experimental results suggest that the dynamic recrystallization could occur under shear stress at room temperature and recrystallized grains should evolve from subgrains by rotation.Compared with that of non-recrystallized and as-reflowed microstructures,the microhardness of the recrystallized microstructure decreased after shear tests.

  11. Joint Strength with Soldering of Al2O3 Ceramics After Ni-P Chemical Plating

    邹贵生; 吴爱萍; 张德库; 孟繁明; 白海林; 张永清; 黎义; 巫世杰; 顾兆旃


    Ni-P alloy was chemically plated on Al2O3 ceramics to produce uniform alloy coatings at temperatures below 70℃. Cu metal was electroplated onto the Ni-P coating to facilitate the soldering and shorten the chemical plating time. Then, the electroplated ceramic specimens were soldered with 60 wt.% Sn-40 wt.% Pb solder in active colophony. The highest shear strength was acquired after the heat treatment at 170℃ for 15 min. The joint fractures mostly propagated along the interface between the ceramics and the Ni-P coating, with some fracture in both the ceramics and the Ni-P coating near the interface and some along the interface between the Cu and Ni-P coatings. The results show that ceramic surface roughness and the chemical plating parameters influence the coating quality, and that suitable heat treatment before the soldering also improves the adhesion between the ceramics and Ni-P coatings, thus strengthening the joints.

  12. Correlation Between Sn Grain Orientation and Corrosion in Sn-Ag-Cu Solder Interconnects

    Lee, Tae-Kyu; Liu, Bo; Zhou, Bite; Bieler, Thomas; Liu, Kuo-Chuan


    The impact of a marine environment on Sn-Ag-Cu interconnect reliability is examined using salt spray exposure followed by thermal cycling. Sn-Ag-Cu solder alloy wafer-level packages, with and without pretreatment with 5% NaCl salt spray, were thermally cycled to failure. The prior salt spray reduced the characteristic lifetime of the Sn-Ag-Cu solder joints by over 43%. Although Sn-based materials show strong resistance to corrosion, the nature of localized corroded areas at critical locations in the solder joint caused significant degradation in the Sn-Ag-Cu solder joints. An important link between the corrosion path and Sn grain orientation was observed using orientation imaging microscopy (OIM). A strong correlation between the corrosion path and grain orientation was identified, indicating that the corrosion attack preferentially followed the basal plane of the Sn lattice.

  13. Influence of Asymmetrical Waveform on Low-Cycle Fatigue Life of Micro Solder Joint

    Kanda, Yoshihiko; Kariya, Yoshiharu


    The effects of waveform symmetry on the low-cycle fatigue life of the Sn-3.0Ag-0.5Cu alloy have been investigated, using micro solder joint specimens with approximately the same volume of solder as is used in actual products. Focusing on crack initiation life, fatigue tests on Sn-Ag-Cu micro solder joints using asymmetrical triangular waveforms revealed no significant reduction in fatigue life. A slight reduction in fatigue life at low strain ranges caused by an increase in the fatigue ductility exponent, which is the result of a weakening microstructure due to loads applied at high temperature for long testing time, was observed. This was due to the fact that grain boundary damage, which has been reported in large-size specimens subjected to asymmetrical triangular waveforms, does not occur in Sn-Ag-Cu micro size solder joints with only a small number of crystal grain boundaries.

  14. Long-Term Effects of Soldering By-Products on Nickel-Coated Copper Wire

    Rolin, T. D.; Hodge, R. E.


    An analysis of thirty-year-old, down graded flight cables was conducted to determine the makeup of a green material on the surface of the shielded wire near soldered areas and to ascertain if the green material had corroded the nickel-coated copper wire. Two likely candidates were possible due to the handling and environments to which these cables were exposed. The flux used to solder the cables is known to contain abietic acid, a carboxylic acid found in many pine rosins used for the soldering process. The resulting material copper abietate is green in color and is formed during the application of heat during soldering operations. Copper (II) chloride, which is also green in color is known to contaminate flight parts and is corrosive. Data is presented that shows the material is copper abietate, not copper (II) chloride, and more importantly that the abietate does not aggressively attack nickel-plated copper wire.

  15. Evaluation of Detachable Ga-Based Solder Contacts for Thermoelectric Materials

    Kolb, H.; Sottong, R.; Dasgupta, T.; Mueller, E.; de Boor, J.


    Low electrical and thermal contact resistances are a prerequisite for highly efficient thermoelectric generators. Likewise, certain measurement setups for characterization of thermoelectric materials rely on good-quality contacts between sample and setup. Detachable contacts are an interesting alternative to permanent contacting solutions due to ease of handling and nondestructive disassembly of valuable samples. Therefore, the applicability of gallium-based liquid metal solder as detachable contact material was studied, particularly with regard to compatibility of the solder with state-of-the-art thermoelectric materials CoSb3, Mg2Si, and FeSi2. Tungsten, nickel, chromium, and titanium were tested as protective coatings between the thermoelectric material and liquid metal solder. Electrical measurements showed that some materials form excellent and stable contacts with the solder for a limited temperature range. At higher temperatures, application of a protective layer was found to be necessary for all investigated materials. Tungsten and nickel showed promising results as protective layer.

  16. Nano ZrO2 Particulate-reinforced Lead-Free Solder Composite

    Jun SHEN; Yongchang LIU; Dongjiang WANG; Houxiu GAO


    A lead-free solder composite was prepared by adding ZrO2 nanopowders in eutectic Sn-Ag alloy. Microstructural features and microhardness properties of those solders with different ZrO2 nanopowder fraction were examined. Results indicate that the addition of ZrO2 nanopowders reduced the size ofβ-Sn grains and restrained the formation of bulk Ag3Sn intermetallic compounds (IMCs) due to the adsorption effect of the ZrO2 particles. The Vicker's hardness of the obtained lead-free solder composites fits well with the Hall-Petch relationship. The refinement of β-Sn grains favors to improve the microhardness of composite solders.

  17. Microstructurally based thermomechanical fatigue lifetime model of solder joints for electronic applications

    Frear, D.R.; Rashid, M.M.; Burchett, S.N.


    We present a new methodology for predicting the fatigue life of solder joints for electronics applications. This approach involves integration of experimental and computational techniques. The first stage involves correlating the manufacturing and processing parameters with the starting microstructure of the solder joint. The second stage involves a series of experiments that characterize the evolution of the microstructure during thermal cycling. The third stage consists of a computer modeling and simulation effort that utilizes the starting microstructure and experimental data to produce a reliability prediction of the solder joint. This approach is an improvement over current methodologies because it incorporates the microstructure and properties of the solder directly into the model and allows these properties to evolve as the microstructure changes during fatigue.

  18. Interfacial Reactions and Joint Strengths of Sn- xZn Solders with Immersion Ag UBM

    Jee, Y. K.; Yu, Jin


    The solder joint microstructures of immersion Ag with Sn- xZn ( x = 0 wt.%, 1 wt.%, 5 wt.%, and 9 wt.%) solders were analyzed and correlated with their drop impact reliability. Addition of 1 wt.% Zn to Sn did not change the interface microstructure and was only marginally effective. In comparison, the addition of 5 wt.% or 9 wt.% Zn formed layers of AgZn3/Ag5Zn8 at the solder joint interface, which increased drop reliability significantly. Under extensive aging, Ag-Zn intermetallic compounds (IMCs) transformed into Cu5Zn8 and Ag3Sn, and the drop impact resistance at the solder joints deteriorated up to a point. The beneficial role of Zn on immersion Ag pads was ascribed to the formation of Ag-Zn IMC layers, which were fairly resistant to the drop impact, and to the suppression of the brittle Cu6Sn5 phase at the joint interface.

  19. Turbine repair process, repaired coating, and repaired turbine component

    Das, Rupak; Delvaux, John McConnell; Garcia-Crespo, Andres Jose


    A turbine repair process, a repaired coating, and a repaired turbine component are disclosed. The turbine repair process includes providing a turbine component having a higher-pressure region and a lower-pressure region, introducing particles into the higher-pressure region, and at least partially repairing an opening between the higher-pressure region and the lower-pressure region with at least one of the particles to form a repaired turbine component. The repaired coating includes a silicon material, a ceramic matrix composite material, and a repaired region having the silicon material deposited on and surrounded by the ceramic matrix composite material. The repaired turbine component a ceramic matrix composite layer and a repaired region having silicon material deposited on and surrounded by the ceramic matrix composite material.

  20. 49 CFR 536.9 - Use of credits with regard to the domestically manufactured passenger automobile minimum standard.


    ... manufactured passenger automobile minimum standard. 536.9 Section 536.9 Transportation Other Regulations... domestically manufactured passenger automobile minimum standard. (a) Each manufacturer is responsible for..., the domestically manufactured passenger automobile compliance category credit excess or shortfall...

  1. Studies of intermetallic growth in Cu-solder systems and wettability at solid-liquid interfaces

    Martin, Raymond W.


    Approved for public release; distribution is unlimited The metallurgical bond formed between tin-lead solder and the copper substrate is characterized by the formation of an intermetallic compound layer. The growth of the intermetallic layer is the result of competing mechanisms, growth of the intermetallic at the intermetallic/copper interface and its dissolution at the intermetallic/liquid solder interface. These were studied by determining the dissolution rates of the copper and the i...

  2. Joint Lead-Free Solder Test Program for High Reliability Military and Space Applications

    Brown, Christina


    Current and future space and defense systems face potential risks from the continued use of tin-lead solder, including: compliance with current environmental regulations, concerns about potential environmental legislation banning lead-containing products, reduced mission readiness, and component obsolescence with lead surface finishes. For example, the United States Environmental Protection Agency (USEPA) has lowered the Toxic Chemical Release reporting threshold for lead to 100 pounds. Overseas, the Waste Electrical and Electronic Equipment (WEEE) and the Restriction on Hazardous Substances (RoHS) Dicctives in Europe and similar mandates in Japan have instilled concern that a legislative body will prohibit the use of lead in aerospace/military electronics soldering. Any potential banning of lead compounds could reduce the supplier base and adversely affect the readiness of missions led by the National Aeronautics and Space Administration (NASA) and the U.S. Department of Defense (DoD). Before considering lead-free electronics for system upgrades or future designs, however, it is important for the DoD and NASA to know whether lead-free solders can meet their systems' requirements. No single lead-free solder is likely to qualify for all defense and space applications. Therefore, it is important to validate alternative solders for discrete applications. As a result of the need for comprehensive test data on the reliability of lead-free solders, a partnership was formed between the DoD, NASA, and several original equipment manufactures (OEMs) to conduct solder-joint reliability (laboratory) testing of three lead-free solder alloys on newly manufactured and reworked circuit cards to generate performance data for high-reliability (IPC Class 3) applications.

  3. Thermomechanical cycling investigation of CU particulate and NITI reinforced lead-free solder

    Horton, W. Scott.


    In todayâ s Flip Chip (FC) and Ball Grid Array (BGA) electronic packages solder joints provide both the electrical as well as the mechanical connections between the silicon chip and the substrate. Due to coefficient of thermal expansion (CTE) differences between the chip and substrate the solder joints undergo thermomechanical stresses and strains as an electronic package is heated and cooled with power on/off cycles. Advances in chip designs result in chips that are larger, run hotter and d...

  4. Effects of voids on thermal-mechanical reliability of lead-free solder joints

    Benabou Lahouari


    Full Text Available Reliability of electronic packages has become a major issue, particularly in systems used in electrical or hybrid cars where severe operating conditions must be met. Many studies have shown that solder interconnects are critical elements since many failure mechanisms originate from their typical response under thermal cycles. In this study, effects of voids in solder interconnects on the electronic assembly lifetime are estimated based on finite element simulations.

  5. Packaging of hard solder 500W QCW diode laser array

    Li, Xiaoning; Wang, Jingwei; Hou, Dong; Nie, Zhiqiang; Liu, Xingsheng


    The package structure critically influences the major characteristics of diode laser, such as thermal behavior, output power, wavelength and smile effect. In this work, a novel micro channel cooler (MCC) for stack array laser with good heat dissipation capability and high reliability is presented. Numerical simulations of thermal management with different MCC structure are conducted and analyzed. Based on this new MCC packaging structure, a series of QCW 500W high power laser arrays with hard solder packaging technology has been fabricated. The performances of the laser arrays are characterized. A narrow spectrum of 3.12 nm and an excellent smile value are obtained. The lifetime of the laser array is more than 1.38×109 shots and still ongoing.

  6. Modeling of thermal processes in waveguide tracts induction soldering

    Murygin, A. V.; Tynchenko, V. S.; Laptenok, V. D.; Emilova, O. A.; Seregin, Yu N.


    The problem solving of the induction heating models development, which describe the heating of the separate structural assembly components of the waveguide path and product generally, is presented in this paper. Proposed mathematical models are based on the thermodynamics equation and on the heat balance law. The system of the heating process mathematical models, such as surge tube and flange heating, and the mathematical model of the energy distribution are presented. During the modeling process with Matlab system by using mathematical models graphs of the tube, flange and coupling heating were obtained. These design charts are confirmed by the results of the experimental study. During the experimental studies pyrometers for temperature control and a video camera for visual control of the process parameters were used. On the basis of obtained models the induction soldering process features analysis is carried out and the need of its automation by the using of the information control systems for thermal management between the connection elements is revealed.

  7. Evaluation of low-residue soldering for military and commercial applications: A report from the Low-Residue Soldering Task Force

    Iman, R.L.; Anderson, D.J. [Sandia National Labs., Albuquerque, NM (United States); Burress, R.V. [SEHO (United States)] [and others


    The LRSTF combined the efforts of industry, military, and government to evaluate low-residue soldering processes for military and commercial applications. These processes were selected for evaluation because they provide a means for the military to support the presidential mandate while producing reliable hardware at a lower cost. This report presents the complete details and results of a testing program conducted by the LRSTF to evaluate low-residue soldering for printed wiring assemblies. A previous informal document provided details of the test plan used in this evaluation. Many of the details of that test plan are contained in this report. The test data are too massive to include in this report, however, these data are available on disk as Excel spreadsheets upon request. The main purpose of low-residue soldering is to eliminate waste streams during the manufacturing process.

  8. Study on Stratification Cultivation of Automobile after-sale Service Talents in Higher Vocational Colleges Based on AHP%基于AHP法的高职汽车售后服务人才分层培养研究



    汽车售后服务人才是影响汽车维修企业发展的核心要素。运用AHP法对汽车售后服务人才所需要的能力进行分析,从专业技能、社会技能和概念技能三个方面构建人才评价体系,并提出了相应的分层培养策略。%Automobile after-sale service talents are the key factor of the development of automobile repair enterprises. This paper an⁃alyzes the abilities required by automobile after-sale service talents based on AHP. The talents evaluating system is constructed from the three aspects of professional skills, social skills and conceptual skills, and corresponding tactics for stratification cultivation are put forward.

  9. Properties and Microstructures of Sn-Ag-Cu-X Lead-Free Solder Joints in Electronic Packaging

    Lei Sun


    Full Text Available SnAgCu solder alloys were considered as one of the most popular lead-free solders because of its good reliability and mechanical properties. However, there are also many problems that need to be solved for the SnAgCu solders, such as high melting point and poor wettability. In order to overcome these shortcomings, and further enhance the properties of SnAgCu solders, many researchers choose to add a series of alloying elements (In, Ti, Fe, Zn, Bi, Ni, Sb, Ga, Al, and rare earth and nanoparticles to the SnAgCu solders. In this paper, the work of SnAgCu lead-free solders containing alloying elements and nanoparticles was reviewed, and the effects of alloying elements and nanoparticles on the melting temperature, wettability, mechanical properties, hardness properties, microstructures, intermetallic compounds, and whiskers were discussed.

  10. Solder-Filling of a Cicc Cable for the Efda Dipole Magnet

    Bauer, P.; Bruzzone, P.; Cau, F.; Weiss, K.; Portone, A.; Salpietro, E.; Vogel, M.; Vostner, A.


    Several prototype Cable-In-Conduit-Conductors (CICC) for the superconducting EDIPO (Efda DIPOle) revealed a degradation of their critical current (Ic) increasing with each loading cycle. The strong Lorentz-forces during operation in combination with the limited support of the single strands against these forces are thought to be the cause of the permanent degradation of the brittle Nb3Sn superconductor from which the multi-stranded CICC are made. In summer 2006 EFDA started to explore the possibility to remedy the Ic degradation by solder-filling the conductor in order to mechanically stabilize the twisted-strand cable inside the conduit. This solution was not considered as the main one, but as an emergency solution to be applied to the completed magnet, should every other option fail. The solder-filling approach was previously applied with success in some cases. Some issues, however, needed to be clarified before this solution could be proposed for the EDIPO project. The most important among them are the choice of solder material, details of the solder filling process, and the thermo-mechanical implications of a solder-filled, high-field, high-current cable. This work, being reported here, made use not only of simulation but also of experiments, such as the mechanical testing of solder filled cables at cryogenic temperatures.

  11. Preliminary Study on Synthesis of Organolead Halide with Lead Derived from Solder Wire

    Pratiwi, P.; Rahmi, G. N.; Aimon, A. H.; Iskandar, F.; Abdullah, M.; Nuryadin, B. W.


    Organolead halide has attracted great attention for application in perovskite solar cells due to its high power conversion efficiency (PCE) of up to 20.1%. One of the most common perovskite materials is lead based reagent. In this research, we have synthesized organolead halide with lead extracted from solder wire. In the preparation procedure, first PbCl2 and PbI2 are produced by reacting lead from the solder wire with NaCl and KI, which are used as the basic substance for the perovskite material. Then, in order to get perovskite solution, the powders are reacted with methylamine iodide (MAI) in dimethylformamide (DMF) using a solution based method. Further, the spin coating method is used to fabricate perovskite thin film. The XRD peak results agreed with JCPDS Powder Diffraction of PbCl2 and PbI2. Based on FTIR, the transmittance spectra of the organolead mixed halide that was prepared using solder wire lead exhibited absorption peaks identical to organolead mixed halide using commercial lead. The UV-Vis absorbance spectra of the organolead mixed halide from solder wire lead also exhibited the same absorption ability as from commercial lead. Morever, EDS measurement showed that the element composition of the perovskite thin film using lead from solder wire identical to that from commercial lead. This indicates that solder wire lead is suitable enough for organolead halide material synthesis.

  12. Effect of Cu concentration on morphology of Sn-Ag-Cu solders by mechanical alloying

    Kao, Szu-Tsung; Duh, Jenq-Gong


    The mechanical alloying (MA) process is considered an alternative approach to produce solder materials. In this study, the effect of Cu concentration in the ternary Sn-3.5Ag-xCu (x=0.2, 0.7, and 1) solder by MA was investigated. The (Cu,Sn) solid solution was precipitated as the Cu6Sn5 intermetallic compound (IMC), which was distributed nonuniformly through the microstructure. The Cu6Sn5 IMC, which was present in the SnAgCu solder with high Cu composition, causes the as-milled MA particle to fracture to a smaller size. Appreciable distinction on morphology of as-milled MA powders with different Cu content was revealed. When the Cu concentration was low (x=0.2), MA particle aggregated to a spherical ingot with large particle size. For higher Cu concentration (x=0.7 and x=1), the MA particle turned to flakes with smaller particle size. The distinction of the milling mechanism of Sn-3.5Ag-xCu (x=0.2, 0.7, and 1) solder by the MA process was discussed. An effective approach was developed to reduce the particle size of the SnAgCu solder from 1 mm down to 10-100 µm by doping the Cu6Sn5 nanoparticle during the MA process. In addition, the differential scanning calorimetry (DSC) results also ensure the compatibility to apply the solder material for the reflow process.

  13. Development of high strength Sn-Mg solder alloys with reasonable ductility

    Alam, Md Ershadul; Gupta, Manoj


    This study discussed the development of a series of new lead-free Sn-Mg solders by incorporating varying amounts of Mg (0.8, 1.5 and 2.5 wt. %) into pure Sn using disintegrated melt deposition technique followed by room temperature extrusion. All extruded Sn and Sn-Mg solder samples were characterized. Microstructural characterization studies revealed equiaxed grain morphology, minimal porosity and relatively uniform distribution of secondary phase. Better coefficient of thermal expansion was observed for Sn-2.5Mg sample when compared to conventional Sn-37Pb solder. Melting temperature of Sn-1.5Mg was found to be 212°C which is much lower than the conventional Sn-Ag-Cu or Sn-Cu (227°C) solders. Microhardness was increased with increasing amount of Mg in pure Sn. Room temperature tensile test results revealed that newly developed Sn-Mg solders exhibit enhanced strengths (0.2% yield strength and ultimate tensile strength) with comparable (if not better) ductility when compared to other commercially available and widely used Sn-based solder alloys.

  14. Effect of interface microstructure on the mechanical properties of Pb-free hybrid microcircuit solder joints

    Hernandez, C.L.; Vianco, P.T.; Rejent, J.A.


    Although Sn-Pb eutectic alloy is widely used as a joining material in the electronics industry, it has well documented environmental and toxicity issues. Sandia National Laboratories is developing alternative solder materials to replace traditional Pb-containing alloys. The alloys are based on the Sn-Ag, Sn-Ag-Bi and Sn-Ag-Bi-Au systems. Prototype hybrid microcircuit (HMC) test vehicles have been developed to evaluate these Pb-free solders, using Au-Pt-Pd thick film metallization. Populated test vehicles with surface mount devices have been designed and fabricated to evaluate the reliability of surface mount solder joints. The test components consist of a variety of dummy chip capacitors and leadless ceramic chip carriers (LCCC`s). Intermetallic compound (IMC) layer reaction products that form at the solder/substrate interface have been characterized and their respective growth kinetics quantified. Thicker IMC layers pose a potential reliability problem with solder joint integrity. Since the IMC layer is brittle, the likelihood of mechanical failure of a joint in service is increased. The effect of microstructure and the response of these different materials to wetting, aging and mechanical testing was also investigated. Solid-state reaction data for intermetallic formation and mechanical properties of the solder joints are reported.

  15. Mechanical properties of Pb-free solder alloys on thick film hybrid microcircuits

    Hernandez, C.L.; Vianco, P.T.; Rejent, J.A.; Hosking, F.M.


    The technology drivers of the electronics industry continue to be systems miniaturization and reliability, in addition to addressing a variety of important environmental issues. Although the Sn-Pb eutectic alloy is widely used as a joining material in the electronics industry, it has drawn environmental concern due to its Pb content. The solder acts both as an electrical and mechanical connection within the different packaging levels in an electronic device. New Pb-free solders are being developed at Sandia National Laboratories. The alloys are based on the Sn-Ag alloy, having Bi and Au additions. Prototype hybrid microcircuit (HMC) test vehicles have been assembled to evaluate Pb-free solders for Au-Pt-Pd thick film soldering. The test components consist of a variety of dummy chip capacitors and leadless ceramic chip carriers (LCCC`s). The mechanical properties of the joints were evaluated. The reflow profiles and the solid state intermetallic formation reaction will also be presented. Improved solder joint manufacturability and increased fatigue resistance solder alloys are the goals of these materials.

  16. Numerical simulation of soldered joints and reliability analysis of PLCC components with J-shape leads

    Zhang Liang; Xue Songbai; Lu Fangyan; Han Zongjie; Wang Jianxin


    This paper deals with a study on SnPb and lead-free soldered joint reliability of PLCC devices with different lead counts under three kinds of temperature cycle profiles, which is based on non-linear finite element method. By analyzing the stress of soldered joints, it is found that the largest stress is at the area between the soldered joints and the leads, and analysis results indicate that the von Mises stress at the location slightly increases with the increase of lead counts. For PLCC with 84 leads the soldered joints was modeled for three typical loading (273-398 K, 218-398 K and 198-398 K) in order to study the influence of acceleration factors on the reliability of soldered joints. And the estimation of equivalent plastic strain of three different lead-free solder alloys (Sn3.8Ag0.7Cu, Sn3.5Ag and Sn37Pb) was also carried out.

  17. Comparative shear tests of some low temperature lead-free solder pastes

    Branzei, Mihai; Plotog, Ioan; Varzaru, Gaudentiu; Cucu, Traian C.


    The range of electronic components and as a consequence, all parts of automotive electronic equipment operating temperatures in a vehicle is given by the location of that equipment, so the maximum temperature can vary between 358K and 478K1. The solder joints could be defined as passive parts of the interconnection structure of automotive electronic equipment, at a different level, from boards of electronic modules to systems. The manufacturing costs reduction necessity and the RoHS EU Directive3, 7 consequences generate the trend to create new Low-Temperature Lead-Free (LTLF) solder pastes family9. In the paper, the mechanical strength of solder joints and samples having the same transversal section as resistor 1206 case type made using the same LTLF alloys into Vapour Phase Soldering (VPS) process characterized by different cooling rates (slow and rapid) and two types of test PCBs pads finish, were benchmarked at room temperature. The presented work extends the theoretical studies and experiments upon heat transfer in VPSP in order to optimize the technology for soldering process (SP) of automotive electronic modules and could be extended for home and modern agriculture appliances industry. The shear forces (SF) values of the LTLF alloy samples having the same transversal section as resistor 1206 case type will be considered as references values of a database useful in the new solder alloy creation processes and their qualification for automotive electronics domain.

  18. A Novel Technique for the Connection of Ceramic and Titanium Implant Components Using Glass Solder Bonding

    Enrico Mick


    Full Text Available Both titanium and ceramic materials provide specific advantages in dental implant technology. However, some problems, like hypersensitivity reactions, corrosion and mechanical failure, have been reported. Therefore, the combining of both materials to take advantage of their pros, while eliminating their respective cons, would be desirable. Hence, we introduced a new technique to bond titanium and ceramic materials by means of a silica-based glass ceramic solder. Cylindrical compound samples (Ø10 mm × 56 mm made of alumina toughened zirconia (ATZ, as well as titanium grade 5, were bonded by glass solder on their end faces. As a control, a two-component adhesive glue was utilized. The samples were investigated without further treatment, after 30 and 90 days of storage in distilled water at room temperature, and after aging. All samples were subjected to quasi-static four-point-bending tests. We found that the glass solder bonding provided significantly higher bending strength than adhesive glue bonding. In contrast to the glued samples, the bending strength of the soldered samples remained unaltered by the storage and aging treatments. Scanning electron microscopy (SEM and energy-dispersive X-ray (EDX analyses confirmed the presence of a stable solder-ceramic interface. Therefore, the glass solder technique represents a promising method for optimizing dental and orthopedic implant bondings.

  19. Development of new multicomponent Sn–Ag–Cu–Bi lead-free solders for low-cost commercial electronic assembly

    El-Daly, A.A., E-mail: [Physics Department, Faculty of Science, Zagazig Univ., Zagazig (Egypt); Center of Nanotechnology, Zagazig Univ., Zagazig (Egypt); El-Taher, A.M. [Physics Department, Faculty of Science, Zagazig Univ., Zagazig (Egypt); Center of Nanotechnology, Zagazig Univ., Zagazig (Egypt); Gouda, S. [Physics Department, Faculty of Science, Zagazig Univ., Zagazig (Egypt)


    Highlights: • Small amounts of Bi have been added into Sn–1.5Ag–0.7Cu solder. • Bi reduced the undercooling and eutectic temperature of SAC257 solder. • Bi refined the microstructure and diminishes the nucleation rate of IMCs. • Bi increased the creep resistance and fracture lifetime of the solder. • Overall SAC properties can be improved adding not more than 3 wt.% Bi. - Abstract: Eutectic Sn–Ag–Cu (SAC) solder is one of the candidate alternatives to Sn–Pb-based solder alloys. The coupling effect of both minor alloying Bi addition and reducing the amount of Ag phase have been proposed as an important approach to optimize existing and to develop new SAC solders. Characteristics of new Sn–Ag–Cu–Bi solders were analyzed and compared with those of as-solidified Sn–1.5Ag–0.7Cu (SAC157) alloy. The results of differential scanning calorimetry (DSC) indicate significant reduction of both undercooling, eutectic temperature, solidus and liquidus temperatures with the addition of Bi into SAC(157) solder, although the pasty range remains the same or slightly increased. Moreover, SAC(157) solders containing Bi were found to have a higher creep resistance (126.1 times) than SAC(157) solder at the same stress level and testing temperature. The higher creep resistance was contributed by the solid solution and precipitations strengthen effects of Bi. The precipitation of these Bi atoms or particles can significantly refine the microstructure, blocks the movement of dislocations and increases the creep resistance of Bi-containing solders. The creep life time of plain SAC(157) alloy was extremely enlarged 23.7 times with the addition of 3 wt.% Bi. Constitutive Garofalo model of creep for both SAC(157) and Sn–Ag–Cu–Bi solders was assembled based on the experimental data.

  20. Automobile Tire Assessment: A Multi-Criteria Approach



    Full Text Available In response to the present dynamic market, automobile manufacturing industries are constantly evaluating and improving their manufacturing strategies to stay competitive. It is also evident that they evaluate those strategies considering multiple criteria. In one such case, an automobile project manager has to ensure that the selected tire (among the available alternatives complies with the prospective automobile’s performance. This paper presents an approach for the assessment of alternative automobile tires taking into account multiple criteria, such as tire sustainability, tire road performance, environmental issues, tire purchase cost and tire road grip. The presented approach is quite helpful to any decision maker who is interested not only in ranking alternatives but also in establishing the superiority of an alternative over others. The approach also helps to specify the position of each alternative with respect to ideal solution. A case illustration is used to demonstrate an application of the approach.

  1. Automobile air-conditioning its energy and environmental impact; La climatisation automobile impact energetique et environnemental

    Barbusse, St.; Gagnepain, L.


    Over the last three decades, automobile manufacturers have made a lot of progress in specific fuel consumption and engine emissions of pollutants. Yet the impact of these improvements on vehicle consumption has been limited by increased dynamic performances (maxi-mum speed, torque), increased safety (power steering and power brakes) and increased comfort (noise and vibration reduction, electric windows and thermal comfort). Because of this, the real CO{sub 2}-emission levels in vehicles is still high in a context where road transport is a major factor in the balance sheet of greenhouse gas emissions, thus in complying with the inter-national climate convention. Although European, Japanese and Korean manufacturers signed an important agreement with the European Commission for voluntarily reducing CO{sub 2} emissions from their vehicles, with a weighted average emission goal by sales of 140 grams per km on the MVEG approval cycle by 2008, it has to be noted that the European procedures for measuring fuel consumption and CO{sub 2} emissions do not take accessories into account, especially air-condition ng (A/C). The big dissemination of this equipment recognized as a big energy consumer and as using a refrigerant with a high global warming potential ed ADEME to implement a set of assessments of A/C's energy and environmental impact. In particular these assessments include studies of vehicle equipment rates, analyses of impact on fuel consumption as well as regulated pollutant emissions in the exhaust, a characterization of the refrigerant leakage levels and an estimate of greenhouse gas emissions for all air-conditioned vehicles. This leaflet summarizes the results of these actions. All of these studies and additional data are presented in greater detail in the document,-'Automobile Air-conditioning' (ADEME reference no. 4985). (author)

  2. Illustrating Newton's Second Law with the Automobile Coast-Down Test.

    Bryan, Ronald A.; And Others


    Describes a run test of automobiles for applying Newton's second law of motion and the concept of power. Explains some automobile thought-experiments and provides the method and data of an actual coast-down test. (YP)

  3. Interior Noise Prediction of the Automobile Based on Hybrid FE-SEA Method

    Chen, S. M; Wang, D. F; Zan, J. M


    In order to predict the interior noise of the automobile in the low and middle frequency band in the design and development stage, the hybrid FE-SEA model of an automobile was created using hybrid FE-SEA method...

  4. Study on Solder Joint Reliability of Plastic Ball Grid Array Component Based on SMT Products Virtual Assembly Technology

    HUANG Chunyue; WU Zhaohua; ZHOU Dejian


    Based on surface mount products virtual assembly technology, the solder joint reliability of plastic ball grid array (PBGA) was studied. Four process parameters, including the upper pad diameter,the stencil thickness, the chip weight on a single solder joint and the lower pad diameter were chose as four control factors. By using an L25(56) orthogonal array the PBGA solder joints which have 25 different process parameters' levels combinations were designed. The numerical models of all the 25 PBGA solder joints were developed and the finite element analysis models were setup. The stress and strain distribution within the PBGA solder joints under thermal cycles were studied by finite element analysis, and the thermal fatigue life of PBGA solder joint was calculated using Coffin-Manson equation. Based on the calculated thermal fatigue life results, the range analysis was performed. The results of study show that that the impact sequence of the four factors from high to low on the fatigue life of PBGA solder joints are the stencil thickness,the upper pad diameter, the lower pad diameter and the chip weight on a single solder joint; the best level combination ofprocess parameters that results in the longest fatigue life is the lower pad diameter of 0.6 mm, the stencil thickness of 0.175 mm, the chip weight on asingle solder joint of 28×10-5 N and the upper pad diameter of 0.5 mm.

  5. Effect of Lanthanum on Driving Force for Cu6Sn5 Growth and Improvement of Solder Joint Reliability


    By means of adding low content of rare earth element La into Sn60-Pb40 solder alloy, the growth of Cu6Sn5 intermetallic compound at the interface of solder joint is hindered, and the thermal fatigue life of solder joint is increased by 2 times. The results of thermodynamic calculation based on diffusion kinetics show that, the driving force for Cu6Sn5 growth is lowered by adding small content of La in Sn60-Pb40 solder alloy. Meanwhile, there is an effective local mole fraction range of La, in which, 0.18% is the limited value and 0.08% is the best value.

  6. Effects of Aging Treatment on Mechanical Properties of Sn-58Bi Epoxy Solder on ENEPIG-Surface-Finished PCB

    Kim, Jungsoo; Myung, Woo-Ram; Jung, Seung-Boo


    The mechanical properties of Sn-58Bi epoxy solder were evaluated by low-speed shear testing as functions of aging time and temperature. To determine the effects of epoxy, the interfacial reaction and mechanical properties of both Sn-58Bi and Sn-58Bi epoxy solder were investigated after aging treatment. The chemical composition and growth kinetics of the intermetallic compound (IMC) formed at the interface between Sn-58Bi solder and electroless nickel electroless palladium immersion gold (ENEPIG) surface finish were analyzed. Sn-58Bi solder paste was applied by stencil-printing on flame retardant-4 substrate, then reflowed. Reflowed samples were aged at 85°C, 95°C, 105°C, and 115°C for up to 1000 h. (Ni,Pd)3Sn4 IMC formed between Sn-58Bi solder and ENEPIG surface finish after reflow. Ni3Sn4 and Ni3P IMCs formed at the interface between (Ni,Pd)3Sn4 IMC and ENEPIG surface finish after aging at 115°C for 300 h. The overall IMC growth rate of Sn-58Bi solder joint was higher than that of Sn-58Bi epoxy solder joint during aging. The shear strength of Sn-58Bi epoxy solder was about 2.4 times higher than that of Sn-58Bi solder due to the blocking effect of epoxy, and the shear strength decreased with increasing aging time.

  7. Design of a TFT-LCD Based Digital Automobile Instrument

    Yunsong Xu


    instrument and gives an introduction to the sampling circuits and interfaces related to these signals. Following this is the functional categorizing of the circuit modules, such as video buffer circuit, CAN bus interface circuit, and TFT-LCD drive circuit. Additionally, the external EEPROM stores information of the vehicle for history data query, and the external FLASH enables the display of high quality figures. On the whole, the accomplished automobile instrument meets the requirements of automobile instrument markets with its characters of low cost, favorable compatibility, friendly interfaces, and easy upgrading.

  8. Adhesion coefficient of automobile tire and road surface



    The adhesion coefficient of automobile tire and road surface was analyzed and the formula about it was derived.Some suggestions about highway construction,driving safety of the drivers and the judgment of the traffic accidents were presented.The results show that the adhesion coefficient is a function with the extreme value.If there is atmospheric pressure in the tire,the load of the vehicle and the degree of the coarse on the road surface is not selected properly,it will reach the least and affect the safety of the running automobile.

  9. 汽车维修行业现存问题与对策研究%Existing Problems and Countermeasures of Automobile Maintenance Industry



    There are many problems in modern automobile maintenance enterprises.Based on full research, this paper ana-lyzes main problems in domestic automobile repair industry in China,and discusses reform measures for maintenance enterprise to survive and develop.%现代汽车维修企业,存在诸多的问题。文章在充分调研研究的基础上,针对我国国内汽车维修行业现存主要问题进行了分析,并探讨了维修企业要生存和发展所必须采取的改革措施。

  10. Control Method of Solder Joints with Virtual Welding of the Automotive Body%汽车车身焊点虚焊控制方法



    Automotive body connects other sheet metal parts into a whole mainly through resistance spot welding. Weld nugget quality is an important quality index of body parts, which decide the welding spot cannot do the virtual welding. The paper expounds operating principle of resistance spot welding of automobile body sheet metal parts and the definition, influ-ence factors and control methods of solder joints with virtual welding.%  汽车白车身主要是通过电阻点焊将各钣金件连接成一个整体,焊点熔核质量是车身件的重要质量指标,要求焊点不能虚焊。文章阐述了汽车车身钣金件电阻点焊的工作原理和焊点虚焊的定义、影响因素及控制方法。

  11. Electrodeposition of lead-free, tin-based alloy solder films

    Han, Chunfen

    The dominant materials used for solders in electronic assemblies over the past 60 years have been Pb-Sn alloys. Increasing pressure from environmental and health authorities has stimulated the development of various Pb-free solders. Two of the most promising replacements are eutectic Sn-Cu and Sn-Ag-Cu alloys that are produced primarily by electrodeposition. During soldering and solid state aging (storage or in service of the electronic assemblies), interactions take place at the solder/substrate metal interface and form intermetallic compounds (IMCs) which are crucial for the reliability of the solder joints. Simple and "green" Sn-citrate and Sn-Cu-citrate solutions have been developed and optimized to electrodeposit eutectic and near eutectic Sn-Cu solder films. Sn-citrate suspensions with Cu particles and Sn-Cu-citrate suspensions with Ag nano-particles have also been developed and optimized to allow for electrochemical composite deposition of eutectic and near eutectic Sn-Cu and Sn-Ag-Cu solder films. Different plating and post-plating conditions, including solution concentration, current density, agitation, additives, and aging, have been investigated by evaluating their effects on plating rate, deposit composition and microstructure. Tri-ammonium citrate is used as the only complexing agent for Sn, Sn-Cu, and Sn-Ag-Cu deposition. Speciation diagram calculations, reduction potential calculations, and polarization studies are conducted to study Sn-citrate solution chemistry and the kinetics of Sn electrodeposition. X-ray photoelectron spectroscopy (XPS) analysis is used to identify the precipitates formed in Sn-citrate solutions at low pH. Current-controlled and potential-controlled electrochemical techniques, nucleation modeling, and surface morphology characterization techniques are applied to study the nucleation and film growth mechanism of Sn and Sn-Cu electrodeposition from Sn-citrate and Sn-Cu-citrate solutions. Reflow and aging tests for deposited Sn

  12. 40 CFR 600.311-86 - Range of fuel economy for comparable automobiles.


    ... automobiles. 600.311-86 Section 600.311-86 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Regulations for 1977 and Later Model Year Automobiles-Labeling § 600.311-86 Range of fuel economy for comparable automobiles. (a) The Administrator will determine the range of city and the range of highway...

  13. 40 CFR 600.311-08 - Range of fuel economy for comparable automobiles.


    ... automobiles. 600.311-08 Section 600.311-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Regulations for 1977 and Later Model Year Automobiles-Labeling § 600.311-08 Range of fuel economy for comparable automobiles. (a) The Administrator will determine the range of combined fuel economy values...

  14. 76 FR 61779 - Agency Information Collection (Application for Automobile or Other Conveyance and Adaptive...


    ... AFFAIRS Agency Information Collection (Application for Automobile or Other Conveyance and Adaptive... refer to ``OMB Control No. 2900-0067.'' SUPPLEMENTARY INFORMATION: Title: Application for Automobile or..., servicepersons and their survivors complete VA Form 21-4502 to apply for automobile or other conveyance...

  15. 26 CFR 48.4061(a)-5 - Sale of automobile truck bodies and chassis.


    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Sale of automobile truck bodies and chassis. 48..., Tread Rubber, and Taxable Fuel Automotive and Related Items § 48.4061(a)-5 Sale of automobile truck bodies and chassis. (a) Sale of completed vehicle. An automobile truck (as defined by §...

  16. 76 FR 31467 - Guide Concerning Fuel Economy Advertising for New Automobiles


    ... CFR Part 259 Guide Concerning Fuel Economy Advertising for New Automobiles AGENCY: Federal Trade... Advertising for New Automobiles (``Fuel Economy Guide'' or ``Guide'') pending completion of ongoing review by... prevent deceptive fuel economy advertising for new automobiles and to facilitate the use of fuel...

  17. 49 CFR 393.128 - What are the rules for securing automobiles, light trucks and vans?


    ... 49 Transportation 5 2010-10-01 2010-10-01 false What are the rules for securing automobiles, light... automobiles, light trucks and vans? (a) Applicability. The rules in this section apply to the transportation of automobiles, light trucks, and vans which individually weigh 4,536 kg. (10,000 lb) or...

  18. 17 CFR 256.309 - Automobiles, other vehicles, and related garage equipment.


    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Automobiles, other vehicles... § 256.309 Automobiles, other vehicles, and related garage equipment. This account shall include the delivered cost of all service company owned automobiles, vans, trucks, and other vehicles used by...

  19. Intermetallic compound formation at Sn-3.0Ag-0.5Cu-1.0Zn lead-free solder alloy/Cu interface during as-soldered and as-aged conditions

    Wang, Feng-Jiang [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)]. E-mail:; Yu, Zhi-Shui [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Qi, Kai [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)


    Intermetallic formations of Sn-3.0Ag-0.5Cu solder alloy with additional 1.0 wt% Zn were investigated for Cu-substrate during soldering and isothermal aging. During soldering condition, the Cu{sub 5}Zn{sub 8} compound with granular-type morphology is the interfacial IMC for Sn-3.0Ag-0.5Cu-1.0Zn solder, while the Cu{sub 6}Sn{sub 5} compound with scallop-type morphology is the interfacial IMC for Sn-3.0Ag-0.5Cu solder. During thermal aging, the final interfacial structure for Sn-3.0Ag-0.5Cu-1.0Zn solder is solder/Cu{sub 5}Zn{sub 8}/Cu{sub 6}Sn{sub 5}/Cu{sub 3}Sn/Cu, different from the solder/Cu{sub 6}Sn{sub 5}/Cu{sub 3}Sn/Cu for Sn-3.0Ag-0.5Cu solder. The thickness of Cu-Sn IMC layers increases, while the thickness of Cu{sub 5}Zn{sub 8} compound layer decreases with increasing aging time due to the decomposition of the Cu{sub 5}Zn{sub 8} layer by the diffusion of Cu and Zn atoms into the solder and Cu{sub 6}Sn{sub 5} at higher aging temperature. For Sn-3.0Ag-0.5Cu-1.0Zn solder, at higher aging temperature of 150 or 175 {sup o}C, with the formation of Cu{sub 3}Sn at Cu{sub 6}Sn{sub 5}/Cu, Kirkendall voids can be observed at the interface of Cu{sub 3}Sn/Cu.

  20. Effect of diode-laser parameters on shear force of micro-joints soldered with Sn-Ag-Cu lead-free solder on Au/Ni/Cu pad

    WANG Jian-xin; XUE Song-bai; FANG Dian-song; JU Jin-long; HAN Zong-jie; YAO Li-hua


    Soldering experiments with Sn-3.5Ag-0.5Cu lead-free solder on Au/Ni/Cu pad were carried out by means of diode-laser and IR reflow soldering methods respectively. The influence of different heating methods as well as output power of diode-laser on shear force of micro-joints was studied and the relationship between the shear force and microstructures of micro-joints was analyzed.The results indicate that the formation of intermetallic compound Ag3Sn is the key factor to affect the shear force and the fine eutectic network structures of micro-joints as well as the dispersion morphology of fine compound Ag3Sn, in which eutectic network band is responsible for the improvement of the shear force of micro-joints soldered with Sn-Ag-Cu lead-free solder. With the increases of output power of diode-laser, the shear force and the microstructures change obviously. The eutectic network structures of micro-joints soldered with diode-laser soldering method are more homogeneous and the grains of Ag3Sn compounds are finer in the range of near optimal output power than those soldered with IR reflow soldering method, so the shear force is also higher than that using IR reflow soldering method. When the output power value of diode-laser is about 41.0 W, the shear force exhibits the highest value that is 70% higher than that using IR reflow soldering method.

  1. How Many Peripheral Solder Joints in a Surface Mounted Design Experience Inelastic Strains?

    Suhir, E.; Yi, S.; Ghaffarian, R.


    It has been established that it is the peripheral solder joints that are the most vulnerable in the ball-grid-array (BGA) and column-grid-array (CGA) designs and most often fail. As far as the long-term reliability of a soldered microelectronics assembly as a whole is concerned, it makes a difference, if just one or more peripheral joints experience inelastic strains. It is clear that the low cycle fatigue lifetime of the solder system is inversely proportional to the number of joints that simultaneously experience inelastic strains. A simple and physically meaningful analytical expression (formula) is obtained for the prediction, at the design stage, of the number of such joints, if any, for the given effective thermal expansion (contraction) mismatch of the package and PCB; materials and geometrical characteristics of the package/PCB assembly; package size; and, of course, the level of the yield stress in the solder material. The suggested formula can be used to determine if the inelastic strains in the solder material could be avoided by the proper selection of the above characteristics and, if not, how many peripheral joints are expected to simultaneously experience inelastic strains. The general concept is illustrated by a numerical example carried out for a typical BGA package. The suggested analytical model (formula) is applicable to any soldered microelectronics assembly. The roles of other important factors, such as, e.g., solder material anisotropy, grain size, and their random orientation within a joint, are viewed in this analysis as less important factors than the level of the interfacial stress. The roles of these factors will be accounted for in future work and considered, in addition to the location of the joint, in a more complicated, more sophisticated, and more comprehensive reliability/fatigue model.

  2. Effects of Ga Addition on Interfacial Reactions Between Sn-Based Solders and Ni

    Wang, Chao-Hong; Li, Kuan-Ting


    The use of Ga as a micro-alloying element in Sn-based solders can change the microstructure of solder joints to improve the mechanical properties, and even suppress the interfacial intermetallic compound (IMC) growth. This research investigated the effects of Ga addition (0.2-1 wt.%Ga) on the IMC formation and morphological evolution in the Sn-based solder joints with Ni substrate. In the soldering reaction at 250°C and with less than 0.2 wt.%Ga addition, the formed phase was Ni3Sn4. When the Ga addition increased to 0.5 wt.%, it changed to a thin Ni2Ga3 layer of ˜1 μm thick, which stably existed at the interface in the initial 1-h reaction. Subsequently, the whole Ni2Ga3 layer detached from the Ni substrate and drifted into the molten solder. The Ni3Sn4 phase became dominant in the later stage. Notably, the Ga addition significantly reduced the grain size of Ni3Sn4, resulting in the massive spalling of Ni3Sn4 grains. With 1 wt.%Ga addition, the Ni2Ga3 layer remained very thin with no significant growth, and it stably existed at the interface for more than 10 h. In addition, the solid-state reactions were examined at temperatures of 160°C to 200°C. With addition of 0.5 wt.%Ga, the Ni3Sn4 phase dominated the whole reaction. By contrast, with increasing to 1 wt.%Ga, only a thin Ni2Ga3 layer was found even after aging at 160°C for more than 1200 h. The 1 wt.%Ga addition in solder can effectively inhibit the Ni3Sn4 formation in soldering and the long-term aging process.

  3. High-Reliability Low-Ag-Content Sn-Ag-Cu Solder Joints for Electronics Applications

    Shnawah, Dhafer Abdulameer; Said, Suhana Binti Mohd; Sabri, Mohd Faizul Mohd; Badruddin, Irfan Anjum; Che, Fa Xing


    Sn-Ag-Cu (SAC) alloy is currently recognized as the standard lead-free solder alloy for packaging of interconnects in the electronics industry, and high- Ag-content SAC alloys are the most popular choice. However, this choice has been encumbered by the fragility of the solder joints that has been observed in drop testing as well as the high cost of the Ag itself. Therefore, low-Ag-content SAC alloy was considered as a solution for both issues. However, this approach may compromise the thermal-cycling performance of the solders. Therefore, to enhance the thermal-cycling reliability of low-Ag-content SAC alloys without sacrificing their drop-impact performance, alloying elements such as Mn, Ce, Ti, Bi, In, Sb, Ni, Zn, Al, Fe, and Co were selected as additions to these alloys. However, research reports related to these modified SAC alloys are limited. To address this paucity, the present study reviews the effect of these minor alloying elements on the solder joint reliability of low-Ag-content SAC alloys in terms of thermal cycling and drop impact. Addition of Mn, Ce, Bi, and Ni to low-Ag-content SAC solder effectively improves the thermal-cycling reliability of joints without sacrificing the drop-impact performance. Taking into consideration the improvement in the bulk alloy microstructure and mechanical properties, wetting properties, and growth suppression of the interface intermetallic compound (IMC) layers, addition of Ti, In, Sb, Zn, Al, Fe, and Co to low-Ag-content SAC solder has the potential to improve the thermal-cycling reliability of joints without sacrificing the drop-impact performance. Consequently, further investigations of both thermal-cycling and drop reliability of these modified solder joints must be carried out in future work.


    XUE Songbai; WU Yuxiu; HAN Zongjie; WANG Jianxin


    The finite element method(FEM) is used to analyze the effects of lead widths and pitches on reliability of soldered joints. The optimum Simulation for QFP devices is also researched. The results indicate that when the lead pitches are the same, the maximum equivalent stress of the soldered joints increases with the increasing of lead widths, while the reliability of the soldered joints reduces. When the lead widths are the same, the maximum equivalent stress of the soldered joints doesn't decrease completely with the increasing of lead pitches, a minimum value of the maximum equivalent stress values exists in all the curves. Under this condition the maximum equivalent stress of the soldered joints is relatively the least, the reliability of soldered joints is high and the assembly is excellent. The simulating results indicate the best parameter: The lead width is 0.2 mm and lead pitch is 0.3 mm (the distance between two leads is 0.1 mm), which are benefited for the micromation of QFP devices now. The minimum value of the maximum equivalent stress of soldered joints exists while lead width is 0.25 mm and lead pitch is 0.35 mm (the distance between two leads is 0.1 mm), the devices can serve for a long time and the reliability is the highest, the assembly is excellent. The simulating results also indicate the fact that the lead width is 0.15 mm and lead pitch is 0.2 mm maybe the limit of QFP, which is significant for the high lead count and micromation of assembly.

  5. The critical oxide thickness for Pb-free reflow soldering on Cu substrate

    Chung, C. Key [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China); Assembly Test Global Materials, Intel Microelectronics Asia Ltd, B1, No. 205, Tun-Hwa North Road, 10595 Taipei, Taiwan (China); Chen, Y.J.; Li, C.C. [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China); Kao, C.R., E-mail: [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China)


    Oxidation is an undesirable effect of reflow soldering. Non-wetting occurs when the oxide layer grows above the critical thickness. Characterizing the critical oxide thickness for soldering is challenging due to oxide's nano-scale thickness and irregular topographic surface. In this paper, the critical copper oxide thickness was characterized by Time-of-Flight Secondary Ion Mass Spectrometry, Scanning Electron Microscopy, Energy-Dispersive X-ray spectroscopy, and Transmission Electron Microscopy. Copper substrates were coated with an Organic-Solderable-Preservative (OSP) layer and baked at 150 Degree-Sign C and 85% Relative Humidity for different amounts of time. The onset of the non-wetting phenomenon occurred when the oxide thickness reached 18 {+-} 5 nm. As the oxide grew beyond this critical thickness, the percentage of non-wetting solder joint increased exponentially. The growth of the oxide thickness followed a parabolic rate law. The rate constant of oxidation was 0.6 Multiplication-Sign 10{sup -15} cm{sup 2} min{sup -1}. Oxidation resulted from interdiffusion of copper and oxygen atoms through the OSP and oxide layers. The oxidation mechanism will be presented and discussed. - Highlights: Black-Right-Pointing-Pointer Critical oxide thickness for Pb free solder on Cu substrate is 18 {+-} 5 nm. Black-Right-Pointing-Pointer Above the critical oxide, non-wet solder joint increases exponentially. Black-Right-Pointing-Pointer A maximum 13-nm oxide thickness is suggested for good solder joint. Black-Right-Pointing-Pointer Initial growth of oxide thickness is logarithmic and then parabolic after 12 nm. Black-Right-Pointing-Pointer Thick oxide (360-560 nm) is formed as pores shorten the oxidation path.

  6. Effects of Ga Addition on Interfacial Reactions Between Sn-Based Solders and Ni

    Wang, Chao-Hong; Li, Kuan-Ting


    The use of Ga as a micro-alloying element in Sn-based solders can change the microstructure of solder joints to improve the mechanical properties, and even suppress the interfacial intermetallic compound (IMC) growth. This research investigated the effects of Ga addition (0.2-1 wt.%Ga) on the IMC formation and morphological evolution in the Sn-based solder joints with Ni substrate. In the soldering reaction at 250°C and with less than 0.2 wt.%Ga addition, the formed phase was Ni3Sn4. When the Ga addition increased to 0.5 wt.%, it changed to a thin Ni2Ga3 layer of ˜1 μm thick, which stably existed at the interface in the initial 1-h reaction. Subsequently, the whole Ni2Ga3 layer detached from the Ni substrate and drifted into the molten solder. The Ni3Sn4 phase became dominant in the later stage. Notably, the Ga addition significantly reduced the grain size of Ni3Sn4, resulting in the massive spalling of Ni3Sn4 grains. With 1 wt.%Ga addition, the Ni2Ga3 layer remained very thin with no significant growth, and it stably existed at the interface for more than 10 h. In addition, the solid-state reactions were examined at temperatures of 160°C to 200°C. With addition of 0.5 wt.%Ga, the Ni3Sn4 phase dominated the whole reaction. By contrast, with increasing to 1 wt.%Ga, only a thin Ni2Ga3 layer was found even after aging at 160°C for more than 1200 h. The 1 wt.%Ga addition in solder can effectively inhibit the Ni3Sn4 formation in soldering and the long-term aging process.

  7. Mechanical Properties and Microstructure Investigation of Lead Free Solder

    Wang, Qing; Gail, William F.; Johnson, R. Wayne; Strickland, Mark; Blanche, Jim


    While the electronics industry appears to be focusing on Sn-Ag-Cu as the alloy of choice for lead free electronics assembly, ,the exact composition varies by geographic region, supplier and user. Add to that dissolved copper and silver from the printed circuit board traces and surface finish, and there can be significant variation in the final solder joint composition. A systematic study of the mechanical and microstructural properties of Sn-Ag-Cu alloys with Ag varying from 2wt% to 4wt% and Cu varying from 0.5wt% to lSwt%, was undertaken in this research study. Different sample preparation techniques (water quenched, oil quenched and water quenched followed by reflow) were explored and the resulting microstructure compared to that of a typical reflowed lead free chip scale package (CSP) solder joint. Tensile properties (modulus, 0.2% yield strength and the ultimate tensile strength) and creep behavior of selected alloy compositions (Sn-4Ag-1 X u , Sn-4Ag-OSCu, Sn- 2Ag-1 X u , Sn-2Ag-OSCu, Sn-3.5Ag-O.SCu) were determined for three conditions: as- cast; aged for 100 hours at 125OC; and aged for 250 hours at 125OC. There was no significant difference in Young's Modulus as a function of alloy composition. After an initial decrease in modulus after 100 hours at 125"C, there was an insignificant change with further aging. The distribution of 0.2% strain yield stress and ultimate tensile strength as a function of alloy composition was more significant and decreased with aging time and temperature. The microstructures of these alloys were examined using light and scanning electron microscopy (LM and SEM) respectively and SEM based energy dispersive x-ray spectroscopy (EDS). Fracture surface and cross-section analysis were performed on the specimens after creep testing. The creep testing results and the effect of high temperature aging on mechanical properties is presented for the oil quenched samples. In general the microstructure of oil quenched specimen exhibited a

  8. Oxidation kinetics of thin copper films and wetting behaviour of copper and Organic Solderability Preservatives (OSP) with lead-free solder

    Ramirez, Mauricio, E-mail: [Robert Bosch GmbH, Robert-Bosch-Strasse 2, 71701 Schwieberdingen (Germany); Chair for Surface Science and Corrosion, University of Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen (Germany); Henneken, Lothar [Robert Bosch GmbH, Robert-Bosch-Strasse 2, 71701 Schwieberdingen (Germany); Virtanen, Sannakaisa [Chair for Surface Science and Corrosion, University of Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen (Germany)


    The oxide formation on thin copper films deposited on Si wafer was studied by XPS, SEM and Sequential Electrochemical Reduction Analysis SERA. The surfaces were oxidized in air with a reflow oven as used in electronic assembly at temperatures of 100 deg. C, 155 deg. C, 200 deg. C, 230 deg. C and 260 deg. C. The SERA analyses detected only the formation of Cu{sub 2}O but the XPS analysis done for the calibration of the SERA equipment proved also the presence of a CuO layer smaller than 2 nm above the Cu{sub 2}O oxide. The oxide growth follows a power-law dependence on time within this temperature range and an activation energy of 33.1 kJ/mol was obtained. The wettability of these surfaces was also determined by measuring the contact angle between solder and copper substrate after the soldering process. A correlation between oxide thickness and wetting angle was established. It was found that the wetting is acceptable only when the oxide thickness is smaller than 16 nm. An activation energy of 27 kJ/mol was acquired for the spreading of lead free solder on oxidized copper surfaces. From wetting tests on copper surfaces protected by Organic Solderability Preservatives (OSP), it was possible to calculate the activation energy for the thermal decomposition of these protective layers.

  9. Al and Si Alloying Effect on Solder Joint Reliability in Sn-0.5Cu for Automotive Electronics

    Hong, Won Sik; Oh, Chulmin; Kim, Mi-Song; Lee, Young Woo; Kim, Hui Joong; Hong, Sung Jae; Moon, Jeong Tak


    To suppress the bonding strength degradation of solder joints in automotive electronics, we proposed a mid-temperature quaternary Pb-free Sn-0.5Cu solder alloy with minor Pd, Al, Si and Ge alloying elements. We manufactured powders and solder pastes of Sn-0.5Cu-(0.01,0.03)Al-0.005Si-(0.006-0.007)Ge alloys (T m = 230°C), and vehicle electronic control units used for a flame-retardant-4 printed circuit board with an organic solderability preservative finish were assembled by a reflow soldering process. To investigate the degradation properties of solder joints used in engine compartments, thermal cycling tests were conducted from -40°C to 125°C (10 min dwell) for 1500 cycles. We also measured the shear strength of the solder joints in various components and observed the microstructural evolution of the solder joints. Based on these results, intermetallic compound (IMC) growth at the solder joints was suppressed by minor Pd, Al and Si additions to the Sn-0.5Cu alloy. After 1500 thermal cycles, IMC layers thicknesses for 100 parts per million (ppm) and 300 ppm Al alloy additions were 6.7 μm and 10 μm, compared to the as-reflowed bonding thicknesses of 6 μm and 7 μm, respectively. Furthermore, shear strength degradation rates for 100 ppm and 300 ppm Al(Si) alloy additions were at least 19.5%-26.2%. The cause of the improvement in thermal cycling reliability was analyzed using the (Al,Cu)-Sn, Si-Sn and Al-Sn phases dispersed around the Cu6Sn5 intermetallic at the solder matrix and bonding interfaces. From these results, we propose the possibility of a mid-temperature Sn-0.5Cu(Pd)-Al(Si)-Ge Pb-free solder for automotive engine compartment electronics.

  10. Hysteretic Current Controlled Zvs Dc/Dc Converter For Automobile

    Cernat, M.; Scortarul, P.; Tanase, A.


    A novel bi-directional dc-dc converter with ZVS and interleaving for dual voltage systems in automobiles is presented. A variable frequency extended band hysteretic current control method is proposed. In comparison with classical fixed frequency current control PWM, the reverse polarity peak curr...

  11. BEGA-a biaxial excitation Generator for automobiles

    Scridon, S.; Boldea, Ion; Tutelea, L.


    This paper presents the design and test results for a biaxial excitation generator/motor for automobiles (BEGA), which has a three-phase stator and a salient-pole excited heteropolar rotor with multiple flux barriers filled with low-cost permanent magnets (PMs). For this new generator, the low...

  12. Classification of Surface Quality of Automobile Lamp—Reflector

    袁旭军; 贺莉清; 等


    This paper introduces an installation for quickly classifying automobile's metal reflectors based on their roughness.The measuring principle and the mechanical structure are presented.Schematics of circuits and experimental results are given.Elimination and reduction of the effect of background lights or different bulbs on the measuring results are also described in detail.

  13. Vehicles motors and environment; Moteurs automobiles et environnement

    Dionnet, F.


    This paper presents the problem of the pollutants emission by the motors of automobiles. The european regulations lead the automotive industry to develop research programs to decrease the emission level more and more difficult to raise. He discusses the new catalysts, the diesel engines, the direct injection and the natural gas fuels. (A.L.B.)

  14. Market Energy efficient and new fuel automobile developments


    <正>Tsinghua University develops mini electric car OUYANG Mingbao, dean of automotive engineering and director of the key national laboratory of automobile safety and energy efficiency, has recently delivered a speech on the development of mini electric car in the university.

  15. Technology Demonstration of General Black box Standard for Automobiles (GBSA

    Kishor R


    Full Text Available GBSA is an upcoming proposal towards Automobile industry and to the federal governing bodies around the world. Here we are intent to create a disciplinary system to save city sons from accident death and to abolish insurance piracy. The proposal is actually developed from the loss of mankind in society but pulled by technology and humanity facts..

  16. Magnetic properties and heavy metal contents of automobile emission particulates

    LU Sheng-gao; BAI Shi-qiang; CAI Jing-bo; XU Chuang


    Measurements of the magnetic properties and total contents of Cu, Cd, Pb and Fe in 30 automobile emission particulate samples indicated the presence of magnetic particles in them. The values of frequency dependent susceptibility (χfd)showed the absence of superparamagnetic (SP) grains in the samples. The IRM20 mT (isothermal remanent magnetization at 20 mT)being linearly proportional to SIRM (saturation isothermal remanent magnetization) (R2=0.901), suggested that ferrimagnetic minerals were responsible for the magnetic properties of automobile emission particulates. The average contents of Cu, Cd, Pb and Fe in automobile emission particulates were 95.83, 22.14, 30.58 and 34727.31 mg/kg, respectively. Significant positive correlations exist between the magnetic parameters and the contents of Pb, Cu and Fe. The magnetic parameters of automobile emission particulates reflecting concentration of magnetic particles increased linearly with increase of Pb and Cu content, showed that the magnetic measurement could be used as a preliminary index for detection of Pb and Cu pollution.

  17. Six changes with the new Regulations on Automobile Loans


    <正> On Aug 16, 2004, the People’s Bank of China and China Banking Regulatory Commission (CBRC) jointly issued the new version of the Regulations on Automobile Loans. Due to be put into implementation on Oct 1, the new Regulations change radically compared with the previous version in terms of creditors, possible borrowers, rate of down payments, loan periods, etc.


    Tatyana A. Safina


    Full Text Available In this paper the statistical analysis based on results of selective investigation of customers in the market of automobile gasoline is offered. The analysis makes the possibility for finding preferences of respondents in choices of gasoline brand depending of social and economics status of customers.

  19. 40 CFR 600.315-08 - Classes of comparable automobiles.


    ... vehicles (such as battery electric vehicles, fuel cell vehicles, plug-in hybrid electric vehicles and... accordance with 49 CFR part 523. (1) The Administrator will classify passenger automobiles by car line into... seaters. A car line shall be classed as “Two Seater” if the majority of the vehicles in that car line have...

  20. Divorce your car: ending the love affair with the automobile

    Alvord, K.


    This book is a guide for people wishing to liberate themselves from their addiction to cars and the automobile culture. It is a repository of examples and actions that individuals and communities can take to reduce dependence on the automobile. The range of possibilities run from using cars less to not owning one at all. The book provides a humorous yet clear-headed approach to a greener world and maps out the road to how people can live happily ever after by breaking free of 'auto-cracy', without insisting on people in car-dependent countries quit their automotive addiction instantly. Nevertheless, it clearly articulates the connection between automobiles, their arteries (i.e. highways) and effluents (i.e. greenhouse gases and particulate emissions), and the increasing number and severity of natural disasters between the urban renewal and freeway construction that, in the author's view, helped ignite the riots in Watts, Newark and Detroit. The disastrous societal and geophysical effects of the automobile are demonstrated in great abundance, and the mountain of evidence of the systematic abuse of the planet that the book provides is a stunning refutation of the notion that technology is neutral. The automobile is accused of being not only the linchpin of Western and primarily American industrialism and resource extraction, it is also accused of being the chief suspect in a century-long theft of time, conviviality and beauty. How to bring about a change in people's love affair with their cars is difficult to comprehend but this author has a multitude of useful suggestions which seem to suggest that it is possible. There is a list of 104 'selected references' and an extensive list of 'other resources'.

  1. CO₂ laser welding of corneal cuts with albumin solder using radiometric temperature control.

    Strassmann, Eyal; Livny, Eitan; Loya, Nino; Kariv, Noam; Ravid, Avi; Katzir, Abraham; Gaton, Dan D


    To examine the efficacy and reproducibility of CO₂ laser soldering of corneal cuts using real-time infrared fiber-optic radiometric control of tissue temperature in bovine eyes (in vitro) and to evaluate the duration of this procedure in rabbit eyes (in vivo). In vitro experiment: a 6-mm central perforating cut was induced in 40 fresh bovine eyes and sealed with a CO₂ laser, with or without albumin soldering, following placement of a single approximating nylon suture. A fiber-optic radiometric temperature control system for the CO₂ laser was used. Leaking pressure and histological findings were analyzed and compared between groups. In vivo experiment: following creation of a central perforation, 6 rabbit eyes were treated with a CO₂ laser with albumin solder and 6 rabbit eyes were treated with 10-0 nylon sutures. The amount of time needed for completion of the procedures was compared. In vitro experiment: effective sealing was achieved by CO₂ laser soldering. Mean (± SD) leaking pressure was 109 ± 30 mm Hg in the bovine corneas treated by the laser with albumin solder compared to 51 ± 7 mm Hg in the sutured control eyes (n = 10 each; p laser without albumin solder (48 ± 12 mm Hg) and in the cuts sealed only with albumin without laser welding (6.3 ± 4 mm Hg) than in the cuts treated with laser welding and albumin solder. In vivo experiment: mean surgical time was 140 ± 17 s in the laser-treated rabbits compared to 330 ± 30 s in the sutured controls (n = 6; p laser soldering revealed sealed corneal edges with a small gap bridged by coagulated albumin. The inflammatory reaction was minimal in contrast to the sutured controls. No thermal damage was detected at the wound edges. CO₂ laser soldering combined with the fiber-optic radiometer is an effective, reliable, and rapid tool for the closure of corneal wounds, and holds advantages over conventional suturing in terms of leaking pressure and surgical time. Copyright © 2013 S. Karger AG, Basel.

  2. Mechanical Shock Behavior of Environmentally-Benign Lead-free Solders

    Yazzie, Kyle

    The mechanical behavior of Pb-free solder alloys is important, since they must maintain mechanical integrity under thermomechanical fatigue, creep, and mechanical shock conditions. Mechanical shock, in particular, has become an increasing concern in the electronics industry, since electronic packages can be subjected to mechanical shock by mishandling during manufacture or by accidental dropping. In this study, the mechanical shock behavior of Sn and Sn-Ag-Cu alloys was systematically analyzed over the strain rate range 10-3 -- 30 s-1 in bulk samples, and over 10-3 -- 12 s-1 on the single solder joint level. More importantly, the influences of solder microstructure and intermetallic compounds (IMC) on mechanical shock resistance were quantified. A thorough microstructural characterization of Sn-rich alloys was conducted using synchrotron x-ray computed tomography. The three-dimensional morphology and distribution of contiguous phases and precipitates was analyzed. A multiscale approach was utilized to characterize Sn-rich phases on the microscale with x-ray tomography and focused ion beam tomography to characterize nanoscale precipitates. A high strain rate servohydraulic test system was developed in conjunction with a modified tensile specimen geometry and a high speed camera for quantifying deformation. The effect of microstructure and applied strain rate on the local strain and strain rate distributions were quantified using digital image correlation. Necking behavior was analyzed using a novel mirror fixture, and the triaxial stresses associated with necking were corrected using a self-consistent method to obtain the true stress-true strain constitutive behavior. Fracture mechanisms were quantified as a function of strain rate. Finally, the relationship between solder microstructure and intermetallic compound layer thickness with the mechanical shock resistance of Sn-3.8Ag-0.7Cu solder joints was characterized. It was found that at low strain rates the dynamic

  3. Fundamentals of lead-free solder interconnect technology from microstructures to reliability

    Lee, Tae-Kyu; Kim, Choong-Un; Ma, Hongtao


    This unique book provides an up-to-date overview of the fundamental concepts behind lead-free solder and interconnection technology. Readers will find a description of the rapidly increasing presence of electronic systems in all aspects of modern life as well as the increasing need for predictable reliability in electronic systems. The physical and mechanical properties of lead-free solders are examined in detail, and building on fundamental science, the mechanisms responsible for damage and failure evolution, which affect reliability of lead-free solder joints are identified based on microstructure evolution.  The continuing miniaturization of electronic systems will increase the demand on the performance of solder joints, which will require new alloy and processing strategies as well as interconnection design strategies. This book provides a foundation on which improved performance and new design approaches can be based.  In summary, this book:  Provides an up-to-date overview on lead-free soldering tech...

  4. The influence of heat treatment on properties of lead-free solders

    Lýdia Trnková Rízeková


    Full Text Available The article is focused on the analysis of degradation of properties of two eutectic lead-free solders SnCu0.7 and SnAg3.5Cu0.7. The microstructures of the intermetallic compound (IMC layers at the copper substrate - solder interface were examined before and after heat treatment at 150°C for 50, 200, 500 and 1000 hours. The thickness of IMC layers of the Cu6Sn5 phase was growing with the increasing time of annealing and shown the typical scallops. For the heat treatment times of 200 hours and longer, the Cu3Sn IMC layers located near the Cu substrate were also observed. The experiments showed there is a link between the thickness of IMC layers and decrease of the shear strength of solder joints. In general, the joints made of the ternary solder showed higher shear strength before and after heat treatment in comparison to joints from solder SnCu0.7.

  5. Interfacial Reaction and Die Attach Properties of Zn-Sn High-Temperature Solders

    Kim, Seongjun; Kim, Keun-Soo; Kim, Sun-Sik; Suganuma, Katsuaki


    Interfacial reaction and die attach properties of Zn- xSn ( x = 20 wt.%, 30 wt.%, and 40 wt.%) solders on an aluminum nitride-direct bonded copper substrate were investigated. At the interface with Si die coated with Au/TiN thin layers, the TiN layer did not react with the solder and worked as a good protective layer. At the interface with Cu, CuZn5, and Cu5Zn8 IMC layers were formed, the thicknesses of which can be controlled by joining conditions such as peak temperature and holding time. During multiple reflow treatments at 260°C, the die attach structure was quite stable. The shear strength of the Cu/solder/Cu joint with Zn-Sn solder was about 30 MPa to 34 MPa, which was higher than that of Pb-5Sn solder (26 MPa). The thermal conductivity of Zn-Sn alloys of 100 W/m K to 106 W/m K was sufficiently high and superior to those of Au-20Sn (59 W/m K) and Pb-5Sn (35 W/m K).

  6. Application of robust color composite fringe in flip-chip solder bump 3-D measurement

    Kuo, Chung-Feng Jeffrey; Wu, Han-Cheng


    This study developed a 3-D measurement system based on flip-chip solder bump, used fringes with different modulation intensities in color channels, in order to produce color composite fringe with robustness, and proposed a multi-channel composite phase unwrapping algorithm, which uses fringe modulation weights of different channels to recombine the phase information for better measurement accuracy and stability. The experimental results showed that the average measurement accuracy is 0.43μm and the standard deviation is 1.38 μm. The results thus proved that the proposed 3-D measurement system is effective in measuring a plane with a height of 50 μm. In the flip-chip solder bump measuring experiment, different fringe modulation configurations were tested to overcome the problem of reflective coefficient between the flip-chip base board and the solder bump. The proposed system has a good measurement results and robust stability in the solder bump measurement, and can be used for the measurement of 3-D information for micron flip-chip solder bump application.

  7. Effect of Plasma Surface Finish on Wettability and Mechanical Properties of SAC305 Solder Joints

    Kim, Kyoung-Ho; Koike, Junichi; Yoon, Jeong-Won; Yoo, Sehoon


    The wetting behavior, interfacial reactions, and mechanical reliability of Sn-Ag-Cu solder on a plasma-coated printed circuit board (PCB) substrate were evaluated under multiple heat-treatments. Conventional organic solderability preservative (OSP) finished PCBs were used as a reference. The plasma process created a dense and highly cross-linked polymer coating on the Cu substrates. The plasma finished samples had higher wetting forces and shorter zero-cross times than those with OSP surface finish. The OSP sample was degraded after sequential multiple heat treatments and reflow processes, whereas the solderability of the plasma finished sample was retained after multiple heat treatments. After the soldering process, similar microstructures were observed at the interfaces of the two solder joints, where the development of intermetallic compounds was observed. From ball shear tests, it was found that the shear force for the plasma substrate was consistently higher than that for the OSP substrate. Deterioration of the OSP surface finish was observed after multiple heat treatments. Overall, the plasma surface finish was superior to the conventional OSP finish with respect to wettability and joint reliability, indicating that it is a suitable material for the fabrication of complex electronic devices.

  8. Electrical Resistance of the Solder Connections for the Consolidation of the LHC Main Interconnection Splices

    Lutum, R; Scheuerlein, C


    For the consolidation of the LHC 13 kA main interconnection splices, shunts will be soldered onto each of the 10170 splices. The solder alloy selected for this purpose is Sn60Pb40. In this context the electrical resistance of shunt to busbar lap splices has been measured in the temperature range from RT to 20 K. A cryocooler set-up has been adapted such that a test current of 150 A could be injected for accurate resistance measurements in the low nΩ range. To study the influence of the solder bulk resistivity on the overall splice resistance, connections produced with Sn96Ag4 and Sn77.2In20Ag2.8 have been studied as well. The influence of the Sn60Pb40 solder resistance is negligible when measuring the splice resistance in a longitudinal configuration over a length of 6 cm. In a transverse measurement configuration the splice resistance is significantly influenced by the solder. The connections prepared with Sn77.2In20Ag2.8 show significantly higher resistance values, as expected from the relatively high sol...

  9. In situ X-ray observation and simulation of ratcheting-fatigue interactions in solder joints

    Shi, Liting; Mei, Yunhui; Chen, Gang; Chen, Xu


    Reflow voids created by solder oxidation reduce the reliability of lap joints. In situ visualization of reflow voids in Sn-3Ag-0.5Cu (SAC305) lap-shear solder joints under cyclic stressing was realized by X-ray computed tomography (CT), while the ratcheting deformation of the solder joints was monitored by a non-contact displacement detecting system (NDDS). The results revealed that the shape evolution of reflow voids in solder joints, as characterized by the sphericity of the voids, can be divided into three stages: i.e., the initial stage with a sharp drop, a stable stage, and a rapidly declining stage. A new evolution law for describing the progress of sphericity was proposed, and was further introduced into a viscoplastic constitutive model based on the OW-AF nonlinear kinematic hardening rule. The damage-coupled OW-AF model yielded an accurate estimation of the whole-life ratcheting behavior of Sn-3Ag-0.5Cu (SAC305) lap-shear solder joints. [Figure not available: see fulltext.

  10. Improvement of the auto wire feeder machine in a de-soldering process

    Niramon Nonkhukhetkhong


    Full Text Available This paper presents the methodology of the de-soldering process for rework of disk drive Head Stack Assembly (HSA units. The auto wire feeder is a machine that generates Tin (Sn on the product. This machine was determined to be one of the major sources of excess Sn on the HSA. The defect rate due to excess Sn is more than 30%, which leads to increased processing time and cost to perform additional cleaning steps. From process analysis, the major causes of excess Sn are as follows: 1 The machine cannot cut the wire all the way into the flux core area; 2 The sizes and types of soldering irons are not appropriate for the unit parts; and, 3 There are variations introduced into the de-soldering process by the workforce. This paper proposes a methodology to address all three of these causes. First, the auto wire feeder machine in the de-solder process will be adjusted in order to cut wires into flux core. Second, the types of equipment and material used in de-soldering will be optimized. Finally, a new standard method for operators, which can be controlled more easily, will be developed in order to reduce defects due to workforce related variation. After these process controls and machine adjustments were implemented, the overall Sn related problems were significantly improved. Sn contamination was reduced by 41% and cycle time was reduced by an average of 15 seconds.

  11. The Role of Pd in Sn-Ag-Cu Solder Interconnect Mechanical Shock Performance

    Lee, Tae-Kyu; Zhou, Bite; Bieler, Thomas R.; Tseng, Chien-Fu; Duh, Jeng-Gong


    The mechanical stability of solder joints with Pd added to Sn-Ag-Cu alloy with different aging conditions was investigated in a high- G level shock environment. A test vehicle with three different strain and shock level conditions in one board was used to identify the joint stability and failure modes. The results revealed that Pd provided stability at the package-side interface with an overall shock performance improvement of over 65% compared with the Sn-Ag-Cu alloy without Pd. A dependency on the pad structure was also identified. However, the strengthening mechanism was only observed in the non-solder mask defined (NSMD) pad design, whereas the solder mask defined (SMD) pad design boards showed no improvement in shock performance with Pd-added solders. The effects of Sn grain orientation on shock performance, interconnect stability, and crack propagation path with and without Pd are discussed. The SAC305 + Pd solder joints showed more grain refinements, recrystallization, and especially mechanical twin deformation during the shock test, which provides a partial explanation for the ability of SAC305 + Pd to absorb more shock-induced energy through active deformation compared with SAC305.

  12. Interfacial reactions of Sn-Ag-Cu solders modified by minor Zn alloying addition

    Kang, Sung K.; Leonard, Donovan; Shih, Da-Yuan; Gignac, Lynne; Henderson, D. W.; Cho, Sungil; Yu, Jin


    The near-ternary eutectic Sn-Ag-Cu alloys have been identified as leading Pb-free solder candidates to replace Pb-bearing solders in microelectronic applications. However, recent investigations on the processing behavior and solder joints reliability assessment have revealed several potential reliability risk factors associated with the alloy system. The formation of large Ag3Sn plates in Sn-Ag-Cu joints, especially when solidified in a relatively slow cooling rate, is one issue of concern. The implications of large Ag3Sn plates on solder joint performance and several methods to control them have been discussed in previous studies. The minor Zn addition was found to be effective in reducing the amount of undercooling required for tin solidification and thereby to suppress the formation of large Ag3Sn plates. The Zn addition also caused the changes in the bulk microstructure as well as the interfacial reaction. In this paper, an in-depth characterization of the interfacial reaction of Zn-added Sn-Ag-Cu solders on Cu and Au/Ni(P) surface finishes is reported. The effects of a Zn addition on modification of the interfacial IMCs and their growth kinetics are also discussed.

  13. Wetting and Soldering Behavior of Eutectic Au-Ge Alloy on Cu and Ni Substrates

    Leinenbach, C.; Valenza, F.; Giuranno, D.; Elsener, H. R.; Jin, S.; Novakovic, R.


    Au-Ge-based alloys are interesting as novel high-temperature lead-free solders because of their low melting point, good thermal and electrical conductivity, and high corrosion resistance. In the present work, the wetting and soldering behavior of the eutectic Au-28Ge (at.%) alloy on Cu and Ni substrates have been investigated. Good wetting on both substrates with final contact angles of 13° to 14° was observed. In addition, solder joints with bond shear strength of 30 MPa to 35 MPa could be produced under controlled conditions. Cu substrates exhibit pronounced dissolution into the Au-Ge filler metal. On Ni substrates, the NiGe intermetallic compound was formed at the filler/substrate interface, which prevents dissolution of Ni into the solder. Using thin filler metal foils (25 μm), complete consumption of Ge in the reaction at the Ni interface was observed, leading to the formation of an almost pure Au layer in the soldering zone.

  14. Metal ion release from silver soldering and laser welding caused by different types of mouthwash.

    Erdogan, Ayse Tuygun; Nalbantgil, Didem; Ulkur, Feyza; Sahin, Fikrettin


    To compare metal ion release from samples welded with silver soldering and laser welding when immersed into mouthwashes with different ingredients. A total of 72 samples were prepared: 36 laser welded and 36 silver soldered. Four samples were chosen from each subgroup to study the morphologic changes on their surfaces via scanning electron microscopy (SEM). Each group was further divided into four groups where the samples were submerged into mouthwash containing sodium fluoride (NaF), mouthwash containing sodium fluoride + alcohol (NaF + alcohol), mouthwash containing chlorhexidine (CHX), or artificial saliva (AS) for 24 hours and removed thereafter. Subsequently, the metal ion release from the samples was measured with inductively coupled plasma mass spectrometry (ICP-MS). The metal ion release among the solutions and the welding methods were compared. The Kruskal-Wallis and analysis of variance (ANOVA) tests were used for the group comparisons, and post hoc Dunn multiple comparison test was utilized for the two group comparisons. The level of metal ion release from samples of silver soldering was higher than from samples of laser welding. Furthermore, greater amounts of nickel, chrome, and iron were released from silver soldering. With regard to the mouthwash solutions, the lowest amounts of metal ions were released in CHX, and the highest amounts of metal ions were released in NaF + alcohol. SEM images were in accord with these findings. The laser welding should be preferred over silver soldering. CHX can be recommended for patients who have welded appliances for orthodontic reasons.

  15. Eye muscle repair - discharge

    ... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye muscle ... term for crossed eyes is strabismus. Children most often ...

  16. Ventral hernia repair

    ... page: // Ventral hernia repair To use the sharing features on this page, please enable JavaScript. Ventral hernia repair is surgery to repair a ventral hernia. ...

  17. Brain aneurysm repair

    ... aneurysm repair; Dissecting aneurysm repair; Endovascular aneurysm repair - brain; Subarachnoid hemorrhage - aneurysm ... Your scalp, skull, and the coverings of the brain are opened. A metal clip is placed at ...

  18. Competence: sciences, clean engines: the automobile safety; Competences: sciences, moteurs propres: le salut de l'automobile

    Quiret, M.


    In the framework of the greenhouse gases emission reduction in the automobile sector, this paper presents the possible technological innovations for the engines: an optimization prior to the combustion hopeful the electronic of the injections, the consumption decrease and the electromagnetic valves. (A.L.B.)

  19. Effects of Ni-coated Carbon Nanotubes addition on the electromigration of Sn–Ag–Cu solder joints

    Yang, Zhongbao; Zhou, Wei; Wu, Ping, E-mail:


    Highlights: •The electromigration behaviors of the composite solder joints were investigated. •The presence of Ni altered the morphology of the IMC layer after reflow. •Carbon nanotube network was observed in solder matrix. •Current crowding occurred at the carbon nanotube networks. •The electromigration effect of composite solder joint was suppressed effectively. -- Abstract: The electromigration behaviors of line-type Cu/Sn–Ag–Cu/Cu interconnects with and without Ni-Coated multi-walled Carbon Nanotubes addition were investigated in this work. After soldering, the (Cu,Ni){sub 6}Sn{sub 5} intermetallic compounds formed at the solder/Cu interface. The electromigration analysis shows that the presence of Carbon Nanotubes can suppress the atomic diffusion in the solder induced by electromigration effectively. And finite element simulation indicates that the Carbon Nanotube networks can reduce the current density in the solder matrix, which results in the improvement of electromigration resistance of composite solders.

  20. Development of aluminum, manganese, and zinc-doped tin-silver-copper-X solders for electronic assembly

    Boesenberg, Adam James

    The global electronic assembly community is striving for a robust replacement for leaded solders due to increased environmental regulations. A family of Pb-free solder alloys based on Sn-Ag-Cu (SAC) compositions has shown promise; but reliability issues in certain assembly and operating environments have arisen. Elemental (X) additions (Al, Mn, Zn) to SAC3595 were developed recently for better control of heterogeneous nucleation in solder joint solidification. Cu substrate solderability of these SAC+X alloys was investigated at concentrations between 0.01-0.25 wt. % using globule wetting balance tests due to concern about increased oxidation during reflow. Asymmetric four point bend (AFPB) tests were conducted on as-soldered and thermally aged specimens to investigate correlation between decreased shear strength and extended aging time; a common phenomenon seen in solder joints in service. Composition dependence of these X additions also was explored in simplified Cu joints by differential scanning calorimetry (DSC) and joint microstructure analysis to determine the coupling between undercooling and solidification morphology on single and multiple reflow cycles. Interesting observations by methods such as x-ray diffraction (XRD) and nano-indentation of SAC solder joints with aluminum elemental additions led to promising results and provided a possible solution to promoting heterogeneous nucleation and high reliability in these solder alloys.

  1. Compatibility of lead-free solders with lead containing surface finishes as a reliability issue in electronic assemblies

    Vianco, P.; Rejent, J. [Sandia National Labs., Albuquerque, NM (United States); Artaki, I.; Ray, U.; Finley, D.; Jackson, A. [AT and T Bell Labs., Princeton, NJ (United States)


    Enhanced performance goals and environmental restrictions have heightened the consideration for use of alternative solders as replacements for the traditional tin-lead (Sn-Pb) eutectic and near-eutectic alloys. However, the implementation of non-Pb bearing surface finishes may lag behind solder alloy development. A study was performed which examined the effect(s) of Pb contamination on the performance of Sn-Ag-Bi and Sn-Ag-Cu-Sb lead-free solders by the controlled addition of 63Sn-37Pb solder at levels of 0.5 {minus} 8.0 wt.%. Thermal analysis and ring-in-plug shear strength studies were conducted on bulk solder properties. Circuit board prototype studies centered on the performance of 20I/O SOIC gull wing joints. Both alloys exhibited declines in their melting temperatures with greater Sn-Pb additions. The ring-in-plug shear strength of the Sn-Ag-Cu-Sb solder increased slightly with Sn-Pb levels while the Sn-Ag-Bi alloy experienced a strength loss. The mechanical behavior of the SOIC (Small Outline Integrated Circuit) Sn-Ag-Bi solder joints reproduced the strength levels were insensitive to 10,106 thermal cycles. The Sn-Ag-Cu-Sb solder showed a slight decrease in the gull wing joint strengths that was sensitive to the Pb content of the surface finish.

  2. Mind the gap; The vicious circle of measuring automobile fuel use

    Schipper, L.; Figueroa, M.J.; Price, L. (Strategic Air Command, Offutt AFB, NE (United States). Aircraft Engineering Div.); Espey, M. (California Univ., Davis, CA (United States). Dept. of Agricultural Economics)


    We review the circularity between estimates of automobile use, fuel consumption and fuel intensity. We find that major gaps exist between estimates of road gasoline, the quantity most often used to represent automobile fuel use in economic studies of transport fuel use, and the actual sales data of gasoline, diesel and other fuels used for automobiles. Significant uncertainties exist in values of both the number of automobiles in use and the distance each is driven, which together yield total automobile use. We present our own calculations for total automobile fuel use for a variety of OECD countries. We comment briefly on the impact of these gaps on econometric estimates of the price and income elasticities of automobile fuel use. (author)

  3. Hopes in the Crisis——Chinese Automobile Market in the World Auto manufacturing Industry Shuffle

    Gao Shurong


    @@ Global automobile markets shuffle against the economic crisis The economic crisis spread rapidly around the world,making automobile industry one of the victims who are shocked hardest,leading to an industrial shuffle in global automobile industry.USA,EU and Japan,the traditional top three leading countries in global automobile industry,could not have their lucks to escape from the crisis.The weak global automobile market forces these transnational auto companies to be more cautious about the future than ever.As reflected in the latest performance reports,though governments took measures to maintain the market,the sharp decline in global automobile sales volume continued in the first quarter.Automobile market bottomed out in the second quarter.US auto industrywas affected the most,with two out of the top three manufacturers getting bankrupt and regrouped.

  4. Modeling Material Properties of Lead-Free Solder Alloys

    Guo, Zhanli; Saunders, Nigel; Miodownik, Peter; Schillé, Jean-Philippe


    A full set of physical and thermophysical properties for lead-free solder (LFS) alloys have been calculated, including liquidus/solidus temperatures, fraction solid, density, coefficient of thermal expansion, thermal conductivity, Young’s modulus, viscosity, and liquid surface tension, all as a function of composition and temperature (extending into the liquid state). The results have been extensively validated against data available in the literature. A detailed comparison of the properties of two LFS alloys Sn-20In-2.8Ag and Sn-5.5Zn-4.5In-3.5Bi with Sn-37Pb has been made to show the utility and need for calculations that cover a wide range of properties, including the need to consider the effect of nonequilibrium cooling. The modeling of many of these properties follows well-established procedures previously used in JMatPro software for a range of structural alloys. This paper describes an additional procedure for the calculation of the liquid surface tension for multicomponent systems, based on the Butler equation. Future software developments are reviewed, including the addition of mechanical properties, but the present calculations can already make a useful contribution to the selection of appropriate new LFS alloys.

  5. Understanding the Influence of Copper Nanoparticles on Thermal Characteristics and Microstructural Development of a Tin-Silver Solder

    Lin, D. C.; Srivatsan, T. S.; Wang, G.-X.; Kovacevic, R.


    This paper presents and discusses issues relevant to solidification of a chosen lead-free solder, the eutectic Sn-3.5%Ag, and its composite counterparts. Direct temperature recordings for the no-clean solder paste during the simulated reflow process revealed a significant amount of undercooling to occur prior to the initiation of solidification of the eutectic Sn-3.5%Ag solder, which is 6.5 °C, and for the composite counterparts, it is dependent on the percentage of copper nanopowder. Temperature recordings revealed the same temperature level of 221 °C for both melting (from solid to liquid) and final solidification (after recalescence) of the Sn-3.5%Ag solder. Addition of copper nanoparticles was observed to have no appreciable influence on melting temperature of the composite solder. However, it does influence solidification of the composite solder. The addition of 0.5 wt.% copper nanoparticles lowered the solidification temperature to 219.5 °C, while addition of 1.0 wt.% copper nanoparticles lowered the solidification temperature to 217.5 °C, which is close to the melting point of the ternary eutectic Sn-Ag-Cu solder alloy, Sn-3.7Ag-0.9Cu. This indicates the copper nanoparticles are completely dissolved in the eutectic Sn-3.5%Ag solder and precipitate as the Cu6Sn5, which reinforces the eutectic solder. Optical microscopy observations revealed the addition of 1.0 wt.% of copper nanoparticles to the Sn-3.5%Ag solder results in the formation and presence of the intermetallic compound Cu6Sn5. These particles are polygonal in morphology and dispersed randomly through the solder matrix. Addition of microsized copper particles cannot completely dissolve in the eutectic solder and projects a sunflower morphology with the solid copper particle surrounded by the Cu6Sn5 intermetallic compound coupled with residual porosity present in the solder sample. Microhardness measurements revealed the addition of copper nanopowder to the eutectic Sn-3.5%Ag solder resulted in

  6. Polímeros e a indústria automobilística Polymers and the automobile industry

    Carlos A. Hemais


    Full Text Available Gradativamente, devido a razões econômicas e tecnológicas, nos últimos trinta anos, os plásticos passaram a ocupar um lugar de destaque como um dos materiais mais utilizados pela indústria automobilística. Este trabalho tem por objetivo identificar a intensidade do uso de polímeros pela indústria automobilística brasileira. Inicialmente é apresentada uma classificação dos polímeros, de acordo com suas características técnicas e econômicas. Em seguida, é feita uma breve explanação sobre a indústria de polímeros no Brasil, bem como sobre a indústria automobilística, com seu grande potencial de atrair inovações tecnológicas. São apresentados, também, os principais polímeros com aplicação no automóvel. Por último, é discutida a questão da inovação tecnológica na indústria brasileira de polímeros, tendo como fator catalisador a indústria automobilística.Gradually, owing to economic and technological reasons, in the last thirty years, plastics have gained an increasing presence in automobiles. This paper examines the use of plastics in the Brazilian car industry. First, polymers are classified according to their technical and economic characteristics. The paper then reports briefly on the Brazilian polymer industry, as well as on the auto industry, focusing on its great potential for attracting technological innovations. The main applications for plastics in cars are also outlined. Finally, the paper discusses the question of technological innovation in the Brazilian polymer industry, with the auto industry as a catalyst.

  7. Evaluation of a new range of light-activated surgical adhesives for tissue repair in a porcine model

    Riley, Jill N.; Hodges, Diane E.; March, Keith L.; McNally-Heintzelman, Karen M.


    An in vitro study was conducted to determine the feasibility of using a new range of light-activated surgical adhesives for incision repair in a wide range of tissue types. Biodegradable polymer membranes of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) (PLGA) and salt particles using a solvent-casting and particulate- leaching technique. The porous membranes were doped with protein solder composed of 50%(w/v) bovine serum albumin solder and 0.5 mg/ml indocyanine green (ICG) dye mixed in deionized water. Tissue incisions were repaired using the surgical adhesive in conjunction with an 805-nm diode laser. Nine organs were tested ranging from skin to liver to the small intestine, as well as the coronary, pulmonary, carotid, femoral and splenetic arteries. Acute breaking strengths were measured and the data were analyzed by Student's T-test. Repairs formed on the small intestine were most successful followed by spleen, atrium, kidney, muscle and skin. The strongest vascular repairs were achieved in the carotid artery and femoral artery. The new surgical adhesive could possibly be used as a simple and effective method to stop bleeding and repair tissue quickly in an emergency situation, or as a substitute to mechanical staples or sutures in many clinical applications.

  8. An Investigation of TiO2 Addition on Microstructure Evolution of Sn-Cu-Ni Solder Paste Composite

    Saud Norainiza


    Full Text Available In this research, varying fraction of titanium oxide (TiO2 reinforcement particles was successfully incorporated into Sn-Cu-Ni solder paste in an effort to study the influence of TiO2 addition on microstructure evolution of Sn-Cu-Ni solder paste composite. Sn-Cu-Ni solder paste composite was produced by mixing TiO2 particle with Sn-Cu-Ni solder paste. The microstructure analysis was carried out by Scanning Electron Microscopy-Energy dispersive X-ray (SEM-EDX. The addition TiO2 particle helps to refine the bulk solder microstructure and suppress the intermetallic compound (IMC formation at the interface as will be discussed further.

  9. Effects of rapid solidification on the microstructure and microhardness of a lead-free Sn-3.5Ag solder

    SHEN Jun; LIU Yongchang; Han Yajing; GAO Houxiu


    A lead-free Sn-3.5Ag solder was prepared by rapid solidification technology. The high solidification rate, obtained by rapid cooling, promotes nucleation, and suppresses the growth of Ag3Sn intermetallic compounds (IMCs) in Ag-rich zone, yielding fine Ag3Sn nanoparticulates with spherical morphology in the matrix of the solder. The large amount of tough homogeneously-dispersed IMCs helps to improve the surface area per unit volume and obstructs the dislocation lines passing through the solder, which fits with the dispersion-strengthening theory. Hence, the rapidly-solidified Sn-3.5Ag solder exhibits a higher microhardness when compared with a slowly-solidified Sn-3.5Ag solder.


    Pavol Šebo


    Full Text Available Developing and microstructure of lead-free Sn-Cu solders containing 3, 5 and 10 wt. % of copper in bulk as well as in ribbon form is presented. Wetting of copper substrate by these solders at the temperatures 300, 350 and 400°C in air (partially in N2+10H2 during 1800 s was studied by sessile drop method. Joints Cu – solder – Cu were prepared at 300°C and 1800 s in air as well as in gas mix and their shear strength was measured. The microstructure was studied by light and scanning electron microscopy (SEM equipped with energy dispersive X-ray analyzer and standard X-ray diffraction machine. Wetting angle decreases with increasing wetting temperature. Wetting angle increased for higher (10 wt. % amount of copper in solder. Shear strength of the joints decreases with increasing the copper concentration in solder.

  11. Alloying influences on low melt temperature SnZn and SnBi solder alloys for electronic interconnections

    Ren, Guang [Stokes Laboratories, Bernal Institute, University of Limerick (Ireland); Department of Civil Engineering and Materials Science, University of Limerick (Ireland); Wilding, Ian J. [Henkel Ltd, Hemel Hempstead (United Kingdom); Collins, Maurice N., E-mail: [Stokes Laboratories, Bernal Institute, University of Limerick (Ireland)


    Due to its commercial potential and the technological challenges associated with processing, low temperature soldering is a topic gaining widespread interest in both industry and academia in the application space of consumer and “throw away” electronics. This review focuses on the latest metallurgical alloys, tin zinc (Sn–Zn) and tin bismuth (Sn–Bi), for lower temperature processed electronic interconnections. The fundamentals of solder paste production and flux development for these highly surface active metallic powders are introduced. Intermetallic compounds that underpin low temperature solder joint production and reliability are discussed. The influence of alloying on these alloys is described in terms of critical microstructural changes, mechanical properties and reliability. The review concludes with an outlook for next generation electronic interconnect materials. - Highlights: • Review of the latest advances in Sn–Zn and Sn–Bi solder alloys. • Technological developments underpinning low temperature soldering. • Micro alloying influences on next generation interconnect materials.

  12. In-situ study of electromigration-induced grain rotation in Pb-free solder joint by synchrotron microdiffraction

    Chen, Kai; Tamura, Nobumichi; Tu, King-Ning


    The rotation of Sn grains in Pb-free flip chip solder joints hasn't been reported in literature so far although it has been observed in Sn strips. In this letter, we report the detailed study of the grain orientation evolution induced by electromigration by synchrotron based white beam X-ray microdiffraction. It is found that the grains in solder joint rotate more slowly than in Sn strip even under higher current density. On the other hand, based on our estimation, the reorientation of the grains in solder joints also results in the reduction of electric resistivity, similar to the case of Sn strip. We will also discuss the reason why the electric resistance decreases much more in strips than in the Sn-based solders, and the different driving force for the grain growth in solder joint and in thin film interconnect lines.

  13. Spreading Behavior and Evolution of IMCs During Reactive Wetting of SAC Solders on Smooth and Rough Copper Substrates

    Satyanarayan; Prabhu, K. N.


    The effect of surface roughness of copper substrate on the reactive wetting of Sn-Ag-Cu solder alloys and morphology of intermetallic compounds (IMCs) was investigated. The spreading behavior of solder alloys on smooth and rough Cu substrates was categorized into capillary, diffusion/reaction, and contact angle stabilization zones. The increase in substrate surface roughness improved the wetting of solder alloys, being attributed to the presence of thick Cu3Sn IMC at the interface. The morphology of IMCs transformed from long needle shaped to short protruded type with an increase in the substrate surface roughness for the Sn-0.3Ag-0.7Cu and Sn-3Ag-0.5Cu solder alloys. However, for the Sn-2.5Ag-0.5Cu solder alloy the needle-shaped IMCs transformed to the completely scallop type with increase in the substrate surface roughness. The effect of Ag content on wetting behavior was not significant.

  14. A statistical mechanics model to predict electromigration induced damage and void growth in solder interconnects

    Wang, Yuexing; Yao, Yao; Keer, Leon M.


    Electromigration is an irreversible mass diffusion process with damage accumulation in microelectronic materials and components under high current density. Based on experimental observations, cotton type voids dominate the electromigration damage accumulation prior to cracking in the solder interconnect. To clarify the damage evolution process corresponding to cotton type void growth, a statistical model is proposed to predict the stochastic characteristic of void growth under high current density. An analytical solution of the cotton type void volume growth over time is obtained. The synchronous electromigration induced damage accumulation is predicted by combining the statistical void growth and the entropy increment. The electromigration induced damage evolution in solder joints is developed and applied to verify the tensile strength deterioration of solder joints due to electromigration. The predictions agree well with the experimental results.

  15. Bosonisation and Soldering of Dual Symmetries in Two and Three Dimensions

    Banerjee, R


    We develop a technique that solders the dual aspects of some symmetry following from the bosonisation of two distinct fermionic models, thereby leading to new results which cannot be otherwise obtained. Exploiting this technique, the two dimensional chiral determinants with opposite chirality are soldered to reproduce either the usual gauge invariant expression leading to the Schwinger model or, alternatively, the Thirring model. Likewise, two apparently independent three dimensional massive Thirring models with same coupling but opposite mass signatures, in the long wavelegth limit, combine by the process of bosonisation and soldering to yield an effective massive Maxwell theory. The current bosonisation formulas are given, both in the original independent formulation as well as the effective theory, and shown to yield consistent results for the correlation functions. Similar features also hold for quantum electrodynamics in three dimensions.

  16. Multistate Degradation Mo del for Prognostics of Solder Joints Under Vibration Conditions

    TANG Wei; JING Bo; HUANG Yifeng; SHENG Zengjin; JIAO Xiaoxuan


    This paper develops a multistate degra-dation structure of the solder joints which can be used under various vibration conditions based on nonhomoge-neous continuous-time hidden semi-Markov process. The parameters of the structure were estimated to illustrate the stochastic relationship between the degradation pro-cess and the monitoring indicator by using unsupervised learning methods. Random vibration tests on solder joints with different levels of power spectral density and fixed forms were conducted with a real time monitoring electri-cal resistance to examine the suitability of the model. It was experimentally verified that the multistate degrada-tion structure matches the experimental process reason-ably and accurately. Based on this multistate degradation model, the online prognostics of solder joint were analyzed and the results indicated that faults or failures can be de-tected timely, leading to appreciate maintenance actions scheduled to avoid catastrophic failures of electronics.

  17. The Lead-Free Solder Selection Method and Process Optimization Based on Design of Experiment

    Wang Bing


    Full Text Available In the study, through researching the characteristic of the lead-free solder, we introduce the method of QFD (Quality Function Deployment to transform the demand of production properties and process into the technical demand of the lead-free solder, thus we could transform the demand concept of sampling into a concrete performance index. Finally we can obtain two parameters of the technological competitive power index and market competitive power index to evaluate performance of the lead-free solder through making a series of experiments. We utilize the design of experiment method to find out key parameter of process and the best collocation of parameter, which make the co planarity of tin ball descend to 149 from 178 and promote the process’s ability up to 95.2 from 85%.

  18. Design of Experiments to Determine Causes of Flex Cable Solder Wicking, Discoloration and Hole Location Defects

    Wolfe, Larry


    Design of Experiments (DoE) were developed and performed in an effort to discover and resolve the causes of three different manufacturing issues; large panel voids after Hot Air Solder Leveling (HASL), cable hole locations out of tolerance after lamination and delamination/solder wicking around flat flex cable circuit lands after HASL. Results from a first DoE indicated large panel voids could be eliminated by removing the pre-HASL cleaning. It also revealed eliminating the pre-HASL bake would not be detrimental when using a hard press pad lamination stackup. A second DoE indicated a reduction in hard press pad stackup lamination pressure reduced panel stretch in the y axis approximately 70%. A third DoE illustrated increasing the pre-HASL bake temperature could reduce delamination/solder wicking when using a soft press pad lamination stackup.

  19. High-precision optomechanical lens system for space applications assembled by a local soldering technique

    Pleguezuelo, Pol Ribes; Koechlin, Charlie; Hornaff, Marcel; Kamm, Andreas; Beckert, Erik; Fiault, Guillaume; Eberhardt, Ramona; Tünnermann, Andreas


    Soldering using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glass, ceramics, and optical crystals. This is due to a localized and minimized input of thermal energy. Solderjet bumping technology has been used to assemble a lens mount breadboard using specifications and requirements found for the optical beam expander for the European Space Agency EarthCare Mission. The silica lens and a titanium barrel have been designed and assembled with this technology in order to withstand the stringent mission demands of handling high mechanical and thermal loads without losing the optical performance. Finally, a high-precision optomechanical lens mount has been assembled with minimal localized stress (<1 MPa) showing outstanding performance in terms of wave-front error and beam depolarization ratio before and after environmental tests.

  20. Research and application of visual location technology for solder paste printing based on machine vision

    Luosi WEI; Zongxia JIAO


    A location system is very important for solder paste printing in the process of surface mount technology (SMT). Using machine vision technology to complete the location mission is new and very efficient. This paper presents an integrated visual location system for solder paste printing based on machine vision. The working principle of solder paste printing is introduced and then the design and implementation of the visual location system are described. In the system, two key techniques are completed by secondary development based on VisionPro.One is accurate image location solved by the pattern-based location algorithms of PatMax. The other one is camera calibration that is achieved by image warping technology through the checkerboard plate. Moreover, the system can provide good performances such as high image locating accuracy with 1/40 sub-pixels, high anti-jamming, and high-speed location of objects whose appearance is rotated, scaled, and/or stretched.

  1. Universal solders for direct and powerful bonding on semiconductors, diamond, and optical materials

    Mavoori, Hareesh; Ramirez, Ainissa G.; Jin, Sungho


    The surfaces of electronic and optical materials such as nitrides, carbides, oxides, sulfides, fluorides, selenides, diamond, silicon, and GaAs are known to be very difficult to bond with low melting point solders (<300 °C). We have achieved a direct and powerful bonding on these surfaces by using low temperature solders doped with rare-earth elements. The rare earth is stored in micron-scale, finely-dispersed intermetallic islands (Sn3Lu or Au4Lu), and when released, causes chemical reactions at the interface producing strong bonds. These solders directly bond to semiconductor surfaces and provide ohmic contacts. They can be useful for providing direct electrical contacts and interconnects in a variety of electronic assemblies, dimensionally stable and reliable bonding in optical fiber, laser, or thermal management assemblies.

  2. Single Image Camera Calibration in Close Range Photogrammetry for Solder Joint Analysis

    Heinemann, D.; Knabner, S.; Baumgarten, D.


    Printed Circuit Boards (PCB) play an important role in the manufacturing of electronic devices. To ensure a correct function of the PCBs a certain amount of solder paste is needed during the placement of components. The aim of the current research is to develop an real-time, closed-loop solution for the analysis of the printing process where solder is printed onto PCBs. Close range photogrammetry allows for determination of the solder volume and a subsequent correction if necessary. Photogrammetry is an image based method for three dimensional reconstruction from two dimensional image data of an object. A precise camera calibration is indispensable for an accurate reconstruction. In our certain application it is not possible to use calibration methods with two dimensional calibration targets. Therefore a special calibration target was developed and manufactured, which allows for single image camera calibration.

  3. Investigation Of The Effects Of Reflow Profile Parameters On Lead-free Solder Bump Volumes And Joint Integrity

    Amalu, E. H.; Lui, Y. T.; Ekere, N. N.; Bhatti, R. S.; Takyi, G.


    The electronics manufacturing industry was quick to adopt and use the Surface Mount Technology (SMT) assembly technique on realization of its huge potentials in achieving smaller, lighter and low cost product implementations. Increasing global customer demand for miniaturized electronic products is a key driver in the design, development and wide application of high-density area array package format. Electronic components and their associated solder joints have reduced in size as the miniaturization trend in packaging continues to be challenged by printing through very small stencil apertures required for fine pitch flip-chip applications. At very narrow aperture sizes, solder paste rheology becomes crucial for consistent paste withdrawal. The deposition of consistent volume of solder from pad-to-pad is fundamental to minimizing surface mount assembly defects. This study investigates the relationship between volume of solder paste deposit (VSPD) and the volume of solder bump formed (VSBF) after reflow, and the effect of reflow profile parameters on lead-free solder bump formation and the associated solder joint integrity. The study uses a fractional factorial design (FFD) of 24-1 Ramp-Soak-Spike reflow profile, with all main effects and two-way interactions estimable to determine the optimal factorial combination. The results from the study show that the percentage change in the VSPD depends on the combination of the process parameters and reliability issues could become critical as the size of solder joints soldered on the same board assembly vary greatly. Mathematical models describe the relationships among VSPD, VSBF and theoretical volume of solder paste. Some factors have main effects across the volumes and a number of interactions exist among them. These results would be useful for R&D personnel in designing and implementing newer applications with finer-pitch interconnect.

  4. Effect of Ag on Sn–Cu and Sn–Zn lead free solders

    Alam S.N.


    Full Text Available Lead and lead-containing compounds are considered as toxic substances due to their detrimental effect on the environment. Sn-based soldering systems, like Sn-Cu and Sn-Zn are considered as the most promising candidates to replace the eutectic Sn-Pb solder compared to other solders because of their low melting temperature and favorable properties. Eutectic Sn-0.7 wt.% Cu and near eutectic composition Sn-8 wt.% Zn solders have been considered here for study. For the Sn-Cu system, besides the eutectic Sn-0.7 wt.% Cu composition, Sn-1Cu and Sn-2Cu were studied. Three compositions containing Ag: Sn-2Ag-0.7Cu, Sn-2.5Ag-0.7Cu and Sn-4.5Ag-0.7Cu were also developed. Ag was added to the eutectic Sn-0.7 wt.% Cu composition in order to reduce the melting temperature of the eutectic alloy and to enhance the mechanical properties. For the Sn-Zn system, besides the Sn-8 wt.% Zn near eutectic composition, Sn-8Zn-0.05Ag, Sn-8Zn-0.1Ag and Sn-8Zn-0.2Ag solder alloys were developed. The structure and morphology of the solder alloys were analyzed using a scanning electron microscope (SEM, filed emission scanning electron microscope (FESEM, electron diffraction X-ray spectroscopy (EDX and X-ray diffraction (XRD. Thermal analysis of the alloys was also done using a differential scanning calorimeter (DSC. Trace additions of Ag have been found to significantly reduce the melting temperature of the Sn-0.7 wt.% Cu and Sn-8 wt.% Zn alloys.

  5. The microstructure and properties of as-cast Sn-Zn-Bi solder alloys

    Mladenović Srba A.


    Full Text Available Research on the lead-free solders has attracted wide attention, mostly as the result of the implementation of the Directive on the Restriction of the Use of Hazardous Substances in Electrical and Electronic Equipment. The Sn-Zn solder alloys have been considered to be one of the most attractive lead-free solders due to its ability to easily replace Sn-Pb eutectic alloy without increasing the soldering temperature. Furthermore, the mechanical properties are comparable or even superior to those of Sn-Pb solder. However, other problems still persist. The solution to overcoming these drawbacks is to add a small amount of alloying elements (Bi, Ag, Cr, Cu, and Sb to the Sn-Zn alloys. Microstructure, tensile strength, and hardness of the selected Sn-Zn-Bi ternary alloys have been investigated in this study. The SEM-EDS was used for the identification of co-existing phases in the samples. The specimens’ microstructures are composed of three phases: Sn-rich solid solution as the matrix, Bi-phase and Zn-rich phase. The Bi precipitates are formed around the Sn-dendrit grains as well as around the Zn-rich phase. The amount of Bi segregation increases with the increase of Bi content. The Sn-Zn-Bi alloys exhibit the high tensile strength and hardness, but the values of these mechanical properties decrease with the increase of Bi content, as well as the reduction of Zn content. The results presented in this paper may offer further knowledge of the effects various parameters have on the properties of lead-free Sn-Zn-Bi solders.

  6. Mechanical performances of lead-free solder joint connections with applications in the aerospace domain

    Georgiana PADURARU


    Full Text Available The paper presents some theoretical and experimental aspects regarding the tribological performances of lead-free solder joint connections, with application in the aerospace domain. In order to highlight the mechanical and tribological properties of solder joint in correlation with different pad finishes, there were made some mechanical determinations using a dedicated Share Test System. The theoretical model highlights the link between the experimental results and the influence of gravitational acceleration on the mechanical and functional integrity of the electronic assemblies that works in vibration environment. The paper novelty is provided by the interdisciplinary experiment that offers results that can be used in the mechanical, tribological, electronical and aerospace domains.

  7. Suppressing tin whisker growth in lead-free solders and platings

    Hoffman, Elizabeth N; Lam, Poh-Sang


    A process of irradiation Sn containing Pb-free solder to mitigate whisker formation and growth thereon is provided. The use of gamma radiation such as cobalt-60 has been applied to a substrate of Sn on copper has been found to change the morphology of the crystalline whisker growth to a more truncated hillock pattern. The change in morphology greatly reduces the tendency of whiskers to contribute to electrical short-circuits being used as a Pb-free solder system on a copper substrate.

  8. The Numerical Analysis of Strain Behavior at Solder Joint and Interface of Flip Chip Package

    S; C; Chen; Y; C; Lin


    The flip chip package is a kind of advanced electri ca l packages. Due to the requirement of miniaturization, lower weight, higher dens ity and higher performance in the advanced electric package, it is expected that flip chip package will soon be a mainstream technology. The silicon chip is dir ectly connected to printing circuit substrate by SnPb solder joints. Also, the u nderfill, a composite of polymer and silica particles, is filled in the gap betw een the chip and substrate around the solder joint...

  9. Physics of Failure as a Basis for Solder Elements Reliability Assessment in Wind Turbines

    Kostandyan, Erik; Sørensen, John Dalsgaard


    Traditionally assessment of reliability of electrical components is done by classical reliability techniques using failure rates as the basic measure of reliability. In this paper a structural reliability approach is applied in order to include all relevant uncertainties and to give a more detailed...... description of the reliability. A physics of failure approach is applied. A SnAg solder component used in power electronics is used as an example. Crack propagation in the SnAg solder is modeled and a model to assess the accumulated plastic strain is proposed based on a physics of failure approach. Based...

  10. Contamination profile of Printed Circuit Board Assemblies in relation to soldering types and conformal coating

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan


    , and concentration are profiled and reported. Presence of localized flux residues were visualized using a commercial Residue RAT gel test and chemical structure was identified by FT-IR, while the concentration was measured using ion chromatography, and the electrical properties of the extracts were determined...... by an appropriate cleaning. Selective soldering process generates significantly higher levels of residues compared to the wave and reflow process. For conformal coated PCBAs, the contamination levels generated from the tested wave and selective soldering process are found to be enough to generate blisters under...

  11. Sensitivity of Solder Joint Fatigue to Sources of Variation in Advanced Vehicular Power Electronics Cooling

    Vlahinos, A.; O' Keefe, M.


    This paper demonstrates a methodology for taking variation into account in thermal and fatigue analyses of the die attach for an inverter of an electric traction drive vehicle. This method can be used to understand how variation and mission profile affect parameters of interest in a design. Three parameters are varied to represent manufacturing, material, and loading variation: solder joint voiding, aluminum nitride substrate thermal conductivity, and heat generation at the integrated gate bipolar transistor. The influence of these parameters on temperature and solder fatigue life is presented. The heat generation loading variation shows the largest influence on the results for the assumptions used in this problem setup.

  12. Finite element simulation for mechanical response of surface mounted solder joints under different temperature cycling

    马鑫; 钱乙余


    Nonlinear finite element simulation for mechanical response of surface mounted solder joint under different temperature cycling was carried out. Seven sets of parameters were used in order to evaluate the influence of temperature cycling profile parameters. The results show that temperature cycling history has significant effect on the stress response of the solder joint. Based on the concept of relative damage stress proposed by the authors, it is found that enough high temperature holding time is necessary for designing the temperature cycling profile in accelerated thermal fatigue test.

  13. Observation of amorphous chromium in modified C4 flip chip solder joints after thermal stress testing

    Hooghan, T.K.; Nakahara, S.; Hooghan, K.; Privette, R.W.; Bachman, M.A.; Moyer, R.S


    Flip chip reliability was evaluated using thermal stress tests at 150 deg. C. Electrical failures of flip chip devices were found to occur at the solder/under-bump-metallization interface by forming a porous amorphous chromium layer. The formation of the porous amorphous layer responsible for electrical failures resulted from the outdiffusion of copper atoms from a copper-chromium co-deposit, used as one of the under-bump-metallization layers. A strong interaction of Cu with the Sn component of the solder is the driving force of the Cu outdiffusion.

  14. Effect of Electromigration on the Type of Drop Failure of Sn-3.0Ag-0.5Cu Solder Joints in PBGA Packages

    Huang, M. L.; Zhao, N.


    Board-level drop tests of plastic ball grid array (PBGA) packages were performed in accordance with the Joint Electron Devices Engineering Council standard to investigate the effect of electromigration (EM) on the drop reliability of Sn-3.0Ag-0.5Cu solder joints with two substrate surface finishes, organic solderability preservative (OSP) and electroless nickel electroless palladium immersion gold (ENEPIG). In the as-soldered state, drop failures occurred at the substrate sides only, with cracks propagating within the interfacial intermetallic compound (IMC) layer for OSP solder joints and along the IMC/Ni-P interface for ENEPIG solder joints. The drop lifetime of OSP solder joints was approximately twice that of ENEPIG joints. EM had an important effect on crack formation and drop lifetime of the PBGA solder joints. ENEPIG solder joints performed better in drop reliability tests after EM, that is, the drop lifetime of ENEPIG joints decreased by 43% whereas that of OSP solder joints decreased by 91%, compared with the as-soldered cases. The more serious polarity effect, i.e., excessive growth of the interfacial IMC at the anode, was responsible for the sharper decrease in drop lifetime. The different types of drop failure of PBGA solder joints before and after EM, including the position of initiation and the propagation path of cracks, are discussed on the basis of the growth behavior of interfacial IMC.

  15. Automobile ride quality experiments correlated to iso-weighted criteria

    Healey, A. J.; Young, R. K.; Smith, C. C.


    As part of an overall study to evaluate the usefulness of ride quality criteria for the design of improved ground transportation systems an experiment was conducted involving subjective and objective measurement of ride vibrations found in an automobile riding over roadways of various roughness. Correlation of the results led to some very significant relationships between passenger rating and ride accelerations. The latter were collapsed using a frequency-weighted root mean square measure of the random vibration. The results suggest the form of a design criterion giving the relationship between ride vibration and acceptable automobile ride quality. Further the ride criterion is expressed in terms that relate to rides with which most people are familiar. The design of the experiment, the ride vibration data acquisition, the concept of frequency weighting and the correlations found between subjective and objective measurements are presented.

  16. Design of MEMS accelerometer based acceleration measurement system for automobiles

    Venkatesh, K. Arun; Mathivanan, N.


    Design of an acceleration measurement system using a MEMS accelerometer to measure acceleration of automobiles in all the three axes is presented. Electronic stability control and anti-lock breaking systems in automobiles use the acceleration measurements to offer safety in driving. The system uses an ARM microcontroller to quantize the outputs of accelerometer and save the measurement data on a microSD card. A LabVIEW program has been developed to analyze the longitudinal acceleration measurement data and test the measurement system. Random noises generated and added with measurement data during measurement are filtered by a Kalman filter implemented in LabVIEW. Longitudinal velocity of the vehicle is computed from the measurement data and displayed on a graphical chart. Typical measurement of velocity of a vehicle at different accelerations and decelerations is presented.

  17. Study on the Fuzzy COntrol Strategy of Automobile with CVT

    HuJianjun; QINDatong; 等


    In order to study the dynamic characteristics of automobile with a CVT system, a bond graph analysis model of continuously variable transmission is established.On the base of the simulation state space equations that are established with bond graph theory,a fuzzy control strategy with an expert system of starting process has been introduced.Considering uncertain system parameters and exterior resistance disturbing,the effect of the profile of membership function and the defuzzification algorthm on the capacity of the fuzzy controller has been studied.The result of simulation proves that the proposed fuzzy controller is effective and feasible,Such controller has been employed in the actual control and has proved practicable.The study lays a foundation for design of the fuzzy controller for automobile with a CVT system.


    YAN Shuwang; ZHANG Xinqiang; LIU Run


    An FE analysis procedure was presented to predict the behavior of soil-geogrid interaction under automobile loading. The dynamic interactions between the transverse bars, the longitudinal ribs and the soil were simulated by a system consisting of nonlinear springs, dashpots and masses, to study the deformation properties of the reinforced soil. The equivalent stiffness and damping ratios could be determined with the shaking table. The dynamic responses of a reinforced subgrade were analyzed with the 3D finite element approach. This approach is programmed and applied to analyze the soil-geogrid interaction under dynamic loading. The comparative analysis of the response of the reinforced subgrade and that of the subgrade without reinforcement shows that the geogrid placed at the bottom of the base layer may effectively reduce the accumulative plastic deformation due to the cyclic automobile loading.

  19. Performance evaluation of effluent treatment plant for automobile industry

    Ansari, Farid [Department of Applied Science and Humanities, PDM College of Engineering, Bahadurgarh (Haryana) (India); Pandey, Yashwant K. [School of Energy and Environmental Studies, Devi Ahilya Vishwavidyalaya, Indore (India); Kumar, P.; Pandey, Priyanka [Department of Environmental Science, Post Graduate College Ghazipur (IN


    The automobile industry’s wastewater not only contains high levels of suspended and total solids such as oil, grease, dyestuff, chromium, phosphate in washing products, and coloring, at various stages of manufacturing but also, a significant amount of dissolved organics, resulting in high BOD or COD loads. The study reveals the performance, evaluation and operational aspects of effluent treatment plant and its treatability, rather than the contamination status of the real property. The Results revealed that the treated effluent shows most of the parameters are within permissible limits of Central Pollution Control Board (CPCB), India and based on the site visits, discussion with operation peoples, evaluation of process design, treatment system, existing effluent discharge, results of sample analyzed and found that effluent treatment plant of automobile industry are under performance satisfactory.

  20. The Inherited Traditional Culture of Automobile Molding DNA Design Research

    Song Qiang


    Full Text Available Design of automobile modeling DNA is the core that makes enterprises establish a good and unique brand image to win on market. This paper described the definition and meaning of production DNA, also discussed the composition of production DNA and researched the design ideas of production DNA from both macro and micro aspects. Finally, it recommended would research the traditional culture into the past, present and future of three periods, explored the idea of traditional culture that the automobile modeling DNA inherited under these three periods and analyzed with the red flag car as an example. This research provided a guideline to help automotive corporations to implement brand strategies, and helped to design autos with Chinese elements, sense of the times and fashion trends and can perform the modern mental outlook of Chinese people.

  1. Research Into Automobile Movement on a Curve Under Winter Conditions

    Kristina Kemzūraitė


    Full Text Available The article analyzes the movement of the car on the curve on the slippery and snowy road surface with asphalted ruts. The paper reviews literature related to lateral and longitudinal vehicle acceleration and dynamics of vehicle movement. The experimental facts of vehicle lateral acceleration are given in graphical charts. The article also describes the acceleration values and stability of the automobile depending on the speed in the curve. The findings are given based on the results.Article in Lithuanian

  2. Ensuring the quality of logistic service of automobile dealers

    Tatyana A. Salimova; Lyudmila A. Fedos’kina


    Objective to substantiate the functional directions of activities of the enterprises of dealer chain of an automotive company aimed at ensuring the quality of logistics servicing of automobiles. Methods the study is based on the use of general scientific methods comparison scientific generalization logical analysis analogy and specific scientific methods systemic functional simulation. Results the article states that one of the key criteria of consumer behavior of car buye...

  3. Public health, autonomous automobiles, and the rush to market.

    Kelley, Ben


    The USA has the worst motor vehicle safety problem among high-income countries and is pressing forward with the development of autonomous automobiles to address it. Government guidance and regulation, still inadequate, will be critical to the safety of the public. The analysis of this public health problem in the USA reveals the key factors that will determine the benefits and risks of autonomous vehicles around the world.

  4. Chang Jiang and Her "Automobiles and China" Program


    ANCHORWOMAN Chang Jiang of China Central Television (CCTV) enjoys popularity for her Automobiles and China program, which she writes and hosts. The program which started in 1994 aroused a comparatively strong response in the society because of its serious and deep thought about this absorbing topic. It took her twenty months to finish this program. Hundreds of people were interviewed and five notebooks were filled with reference materials. The script was revised seven times.

  5. Simulation Research in Mutualism Behavior ofAutomobile Industry Cluster

    Chen Zhang; Guangle Yan


    This paper adopts the concept and mechanism of mathematical ecology theory, researches the revolutionary of automobile industry chain by setting up mutualism model of two species. Results of simulation show that automakers are more sensitive to the change of environmental resource. Automakers depending on suppliers excessively will increase the structural risk of the industry. Suppliers must make efficient utilization of the system resources; otherwise they inhibit the growth of automakers.

  6. Comment la production modulaire transforme l'industrie automobile

    Vincent Frigant; Bernard Jullien


    ?In this paper, we explain why and how the ado? ?ption of a modular product-architecture transforms the organisation of industry. Considering the auto industry, we show that modularity-as-process transforms the overall automobile industry: carmakers, suppliers and buyer/suppliers relationships. Modularity-as-process is a key driver of carmakers’ vertical disintegration, growth of suppliers and emergence of mega-suppliers, international division of labour and delocalizations. This single-indus...

  7. Automobile shredder residue: some recycling, resource recovery and disposal options

    Day, M. [National Research Council of Canada, Inst. for Chemical Process and Environmental Technology, Ottawa, ON (Canada)


    Obsolete automobiles are the most recycled high-volume consumer product, with a recovery rate of between 75 and 80 per cent by weight. Ferrous scrap metal from old automobiles in North America amounts to about 10 million tons per year. However, each ton of steel that is recovered, produces about 300 kg of automobile shredder residue (ASR), comprised of plastics, rubber, glass, foam, and textiles, contaminated by oil and other fluids. All combined, this represents about 0.3 million tons of waste materials from the 22 shredders in Canada. This amount is likely to increase as the amount of steel in automobiles decreases due to downsizing and weight reduction, emphasizing the need for new resource recovery and application techniques to deal with the ASR problem. This paper describes a number of new initiatives primarily in two areas: separation technologies, ranging from selective disassembly to physical/mechanical/chemical separation processes, and pyrolysis techniques for the recovery of valuable hydrocarbon resources contained in the plastics in the ASR. Recycling of the material into high performance composite materials, such as additives to concrete for increased tensile strength, shrinkage and crack resistance, without adverse effect on other properties such as durability and workability, also received attention. Energy recovery options and engineered landfilling wherein ASR is used as a landfill day cover material, are some other techniques that show considerable promise. In landfill applications the high absorption capacity of ASR for heavy metals such as lead, its high compressibility, erosion resistance, and good traction make it a highly desirable choice for use as day cover material. 25 refs.

  8. Image Branding of Locally Manufactured Automobiles (Cars & Motorcycles

    S. Ehtisham Ali


    Full Text Available The objective of this study was to measure the brand identity and image of locally manufactured automobiles of Pakistan. A composite model for assessing image branding was developed and close ended questionnaire based on a Likert rating scale was administered to vendors. The field survey was carried out in November 2006. Results present individual vehicle scores on different dimensions of brand image and standard statistical tests were applied to assess significant difference among mean scores.


    Beuren, Ilse Maria; Universidade Regional de Blumenau - FURB; Guth, Sérgio Cavagnoli; Universidade Regional de Blumenau - FURB


    The durability of business strategies is diminishing at the same rate as the rhythm of environmental changes is increasing, which implies the necessity for uninterrupted transformations and processes of restructuring within organizations. From this perspective, this work’s objective is to demonstrate the management tools that were, are or will be used in those automobile industries established in Brazil. To this purpose, an empirical descriptive study, in the form of a survey, was conducted e...

  10. 130 Modeling of the automobile suspension by the functional model

    桐山, 啓; 角田, 鎭男; 長松, 昭男; 御法川, 学; 岩原, 光男; Kiriyama, Akira; Sumida, Shizuo; Nagamatsu, Akio; Minorikawa, Gaku; Iwahara, Mitsuo


    Modeling for an action simulation is performed focusing on the suspension system of a car using the modeling technique called the functional model that had been developed by one of the authors. Simulation analysis of the suspension system of a car was performed in the three dimensional field. It was shown that the method based on the modeling concept of functional model can express the general dynamic characteristic of the automobile suspension.

  11. Coatings Manufacturing Technology for China's Automobile Industry Conference


    China's automobile industry is experiencing continued phenomenal growth with the first 11 months of 2003 seeing an output of over 4 million units.This has lead to a huge growth in the consumption of automotive coatings with a 30% growth expected in 2004,reaching 200,000 tons-compared to a 7% average growth for the coatings industry as a whole.Output is predieted to reach 300,000 tons by 2010!

  12. Translation of Automobile Brands from the Perspective of Skopos Theory

    刘竹林; 王俊


    With the steady growth of the Chinese economy, more and more countries are focusing on China. A great number of brands are entering the Chinese market and auto brand is one of them. Brand translation plays an important role for success of opening international market. This paper applies the Skopos theory to automobile brand translation, so as to provide a new angle to translation practice.

  13. Automobile park and greenhouse effect. Acting upon the automobile park to reduce the greenhouse effect; Parc automobile et effet de serre. Agir sur le parc automobile pour reduire l'effet de serre

    Cauret, L. [INESTENE, 75 - Paris (France); Crozet, Y. [Lyon-1 Univ. Louis Lumiere, LET, 69 (France); Darbera, R. [Ecole Nationale des Ponts et Chaussees (ENPC-LATTS), 75 - Paris (France); Faudry, D. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France); Golovtchenko, N.; Zelem, M.C. [Toulouse-2 Univ., CERTOP, 31 (France); Mirabel, F. [Universite de Montpellier, CREDEN, 34 - Montpellier (France); Nicolas, J.P. [Centre International de Recherche sur l' Evironnement et le Developpement (CIRED), 75 - Paris (France)


    This study is the result of the works carried out by eight research teams (LET, LATTS, IEPE-CNRS, CERTOP, CREDEN, ENTPE, CIRED and INESTENE). These teams belong to the same coordinated research program named Ecodev and which aims at studying the institutional, economical, fiscal, regulatory etc. conditions of selective diffusion policies of technical advances for the benefit of durable development. This study analyzes the impact of automobile development on the consumption of fossil fuels and its consequences on the local and global environment. It deals with the conditions of renewal of the automobile park for a better mastery of its impact on the greenhouse effect (purchase criteria, conditions of use and public policies to be developed): 1 - the evolution of the automobile park: development factors (economic and socio-demographic factors, pollution and public opinion), the aging of the park (causes, role of public policies), development of diesel vehicles, increase of vehicles power (impact on fuel consumptions and pollutant emissions, purchase criteria and lifestyles, fiscality regulation and evolution of vehicles characteristics); 2 - instruments of action: action on the demand (fiscality, regulation, financial incentives for an anticipated withdrawal), action on the offer (average consumption standards, voluntary agreement with makers, labelling etc..), the role of mediators, public information and education. (J.S.)


    Afonso Carneiro Lima


    Full Text Available This work addresses an entrepreneurial phenomenon of strategic administration within the automobile industry: the creation of the automaker Troller Veículos Especiais (TVE. The case study at hand is justified by the positioning of this company around two market niches and its relative success in an industry characterized by few and powerful players. Our aim was to analyze the entrepreneurial and strategic process of discovering opportunity, the analysis used for internal and external factors, and the adoption of its strategic positioning in exploring two automobile market niches: in the B2B market, vehicles adapted to specific operational functions; and in the B2C, off-road vehicles with a strong appeal to consumers’ life styles. This case study allowed us to visualize the challenging path of a genuinely Brazilian small company in a sector dominated by large multinational groups, besides demonstrating decision-related dilemmas and aspects related to managerial creativity.Key-words: Automobile industry. Case study. Strategic entrepreneurship. Discovery theory. Strategic positioning.

  15. Strength Check Analysis for Gear Shaft of Automobile Transmission

    Yongxiang Li


    Full Text Available As the main drive components of the automobile transmission, the performance of gear shaft plays an important role on transmission performance. Aiming at the existing problems of the traditional strength check method of gear shaft, the objective of this study is to take a five-speed transmission as an example, to accomplish the strength analysis of gear shaft of the automobile transmission based on the MASTA software. Furthermore, the simulation modeling of the transmission is built completely to simulate the actual load conditions and complete the process of analysis for the gear shaft. Analytical results show that all gear shafts can fully meet the strength requirements, in addition to the input shaft which has any further improvements. Hence, it is indicated that a new design concept is put forward, that is, using specialized software MASTA for transmission modeling and simulation analysis can heavily improve the design level of the gear shaft, provide the theoretic basis to analyze the dynamic characteristics of gear shaft as well. Finally, it can provide references for the development and application of gear shaft of the automobile transmission.

  16. Hybrid modeling and empirical analysis of automobile supply chain network

    Sun, Jun-yan; Tang, Jian-ming; Fu, Wei-ping; Wu, Bing-ying


    Based on the connection mechanism of nodes which automatically select upstream and downstream agents, a simulation model for dynamic evolutionary process of consumer-driven automobile supply chain is established by integrating ABM and discrete modeling in the GIS-based map. Firstly, the rationality is proved by analyzing the consistency of sales and changes in various agent parameters between the simulation model and a real automobile supply chain. Second, through complex network theory, hierarchical structures of the model and relationships of networks at different levels are analyzed to calculate various characteristic parameters such as mean distance, mean clustering coefficients, and degree distributions. By doing so, it verifies that the model is a typical scale-free network and small-world network. Finally, the motion law of this model is analyzed from the perspective of complex self-adaptive systems. The chaotic state of the simulation system is verified, which suggests that this system has typical nonlinear characteristics. This model not only macroscopically illustrates the dynamic evolution of complex networks of automobile supply chain but also microcosmically reflects the business process of each agent. Moreover, the model construction and simulation of the system by means of combining CAS theory and complex networks supplies a novel method for supply chain analysis, as well as theory bases and experience for supply chain analysis of auto companies.

  17. Semi-Automated Diagnosis, Repair, and Rework of Spacecraft Electronics

    Struk, Peter M.; Oeftering, Richard C.; Easton, John W.; Anderson, Eric E.


    NASA's Constellation Program for Exploration of the Moon and Mars places human crews in extreme isolation in resource scarce environments. Near Earth, the discontinuation of Space Shuttle flights after 2010 will alter the up- and down-mass capacity for the International Space Station (ISS). NASA is considering new options for logistics support strategies for future missions. Aerospace systems are often composed of replaceable modular blocks that minimize the need for complex service operations in the field. Such a strategy however, implies a robust and responsive logistics infrastructure with relatively low transportation costs. The modular Orbital Replacement Units (ORU) used for ISS requires relatively large blocks of replacement hardware even though the actual failed component may really be three orders of magnitude smaller. The ability to perform in-situ repair of electronics circuits at the component level can dramatically reduce the scale of spares and related logistics cost. This ability also reduces mission risk, increases crew independence and improves the overall supportability of the program. The Component-Level Electronics Assembly Repair (CLEAR) task under the NASA Supportability program was established to demonstrate the practicality of repair by first investigating widely used soldering materials and processes (M&P) performed by modest manual means. The work will result in program guidelines for performing manual repairs along with design guidance for circuit reparability. The next phase of CLEAR recognizes that manual repair has its limitations and some highly integrated devices are extremely difficult to handle and demand semi-automated equipment. Further, electronics repairs require a broad range of diagnostic capability to isolate the faulty components. Finally repairs must pass functional tests to determine that the repairs are successful and the circuit can be returned to service. To prevent equipment demands from exceeding spacecraft volume

  18. Intermetallic compound formation in Sn-Co-Cu, Sn-Ag-Cu and eutectic Sn-Cu solder joints on electroless Ni(P) immersion Au surface finish after reflow soldering

    Sun Peng [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China) and Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden)]. E-mail:; Andersson, Cristina [Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden); Wei Xicheng [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China); Cheng Zhaonian [Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden); Shangguan Dongkai [Flextronics International, San Jose, CA (United States); Liu Johan [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China); Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden)


    The interfacial reactions between Sn-0.4Co-0.7Cu eutectic alloy and immersion Au/electroless Ni(P)/Cu substrate were investigated after reflow soldering at 260 deg. C for 2 min. Common Sn-4.0Ag-0.5Cu and eutectic Sn-0.7Cu solders were used as reference. Two types of intermetallic compounds (IMC) were found in the solder matrix of the Sn-0.4Co-0.7Cu alloy, namely coarser CoSn{sub 2} and finer Cu{sub 6}Sn{sub 5} particles, while only one ternary (Cu, Ni){sub 6}Sn{sub 5} interfacial compound was detected between the solder alloy and the electroless nickel and immersion gold (ENIG) coated substrate. The same trend was also observed for the Sn-Ag-Cu and Sn-Cu solder joints. Compared with the CoSn{sub 2} particles found in the Sn-Co-Cu solder and the Ag{sub 3}Sn particles found in the Sn-Ag-Cu solder, the Cu{sub 6}Sn{sub 5} particles found in both solder systems exhibited finer structure and more uniform distribution. It was noted that the thickness of the interfacial IMCs for the Sn-Co-Cu, Sn-Ag-Cu and Sn-Cu alloys was 3.5 {mu}m, 4.3 {mu}m and 4.1 {mu}m, respectively, as a result of longer reflow time above the alloy's melting temperature since the Sn-Ag-Cu solder alloy has the lowest melting point.

  19. DNA repair. [UV radiation

    Setlow, R.


    Some topics discussed are as follows: difficulty in extrapolating data from E. coli to mammalian systems; mutations caused by UV-induced changes in DNA; mutants deficient in excision repair; other postreplication mechanisms; kinds of excision repair systems; detection of repair by biochemical or biophysical means; human mutants deficient in repair; mutagenic effects of UV on XP cells; and detection of UV-repair defects among XP individuals. (HLW)

  20. Assessment of airborne asbestos exposure during the servicing and handling of automobile asbestos-containing gaskets.

    Blake, Charles L; Dotson, G Scott; Harbison, Raymond D


    Five test sessions were conducted to assess asbestos exposure during the removal or installation of asbestos-containing gaskets on vehicles. All testing took place within an operative automotive repair facility involving passenger cars and a pickup truck ranging in vintage from late 1960s through 1970s. A professional mechanic performed all shop work including engine disassembly and reassembly, gasket manipulation and parts cleaning. Bulk sample analysis of removed gaskets through polarized light microscopy (PLM) revealed asbestos fiber concentrations ranging between 0 and 75%. Personal and area air samples were collected and analyzed using National Institute of Occupational Safety Health (NIOSH) methods 7400 [phase contrast microscopy (PCM)] and 7402 [transmission electron microscopy (TEM)]. Among all air samples collected, approximately 21% (n = 11) contained chrysotile fibers. The mean PCM and phase contrast microscopy equivalent (PCME) 8-h time weighted average (TWA) concentrations for these samples were 0.0031 fibers/cubic centimeters (f/cc) and 0.0017 f/cc, respectively. Based on these findings, automobile mechanics who worked with asbestos-containing gaskets may have been exposed to concentrations of airborne asbestos concentrations approximately 100 times lower than the current Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) of 0.1 f/cc.