Development of underwater laser cutting technology

International Nuclear Information System (INIS)

Sato, Seiichi; Inaba, Takanori; Inose, Koutarou; Matsumoto, Naoyuki; Sakakibara, Yuji

2015-01-01

In is desirable to use remote underwater device for the decommissioning work of highly radioactive components such as the nuclear internals from a view point of reducing the ranitidine exposure to the worker. Underwater laser cutting technology has advantages. First advantage in underwater laser cutting technology is that low reaction force during cutting, namely, remote operability is superior. Second point is that underwater laser cutting generates a little amount of secondary waste, because cutting kerf size is very small. Third point is that underwater laser cutting has low risk of the process delay, because device trouble is hard to happen. While underwater laser cutting has many advantages, the careful consideration in the safe treatment of the offgas which underwater laser cutting generates is necessary. This paper describes outline of underwater laser cutting technology developed by IHI Corporation (IHI) and that this technology is effective in various dismantling works in water. (author)

Determination of cut front position in laser cutting

International Nuclear Information System (INIS)

Pereira, M; Thombansen, U

2016-01-01

Laser cutting has a huge importance to manufacturing industry. Laser cutting machines operate with fixed technological parameters and this does not guarantee the best productivity. The adjustment of the cutting parameters during operation can improve the machine performance. Based on a coaxial measuring device it is possible to identify the cut front position during the cutting process. This paper describes the data analysis approach used to determine the cut front position for different feed rates. The cut front position was determined with good resolution, but improvements are needed to make the whole process more stable. (paper)

Characteristics of laser assisted machining for silicon nitride ceramic according to machining parameters

International Nuclear Information System (INIS)

Kim, Jong Do; Lee, Su Jin; Suh, Jeong

2011-01-01

This paper describes the Laser Assisted Machining (LAM) that cuts and removes softened parts by locally heating the ceramic with laser. Silicon nitride ceramics can be machined with general machining tools as well, because YSiAlON, which was made up ceramics, is soften at about 1,000 .deg. C. In particular, the laser, which concentrates on highly dense energy, can locally heat materials and very effectively control the temperature of the heated part of specimen. Therefore, this paper intends to propose an efficient machining method of ceramic by deducing the machining governing factors of laser assisted machining and understanding its mechanism. While laser power is the machining factor that controls the temperature, the CBN cutting tool could cut the material more easily as the material gets deteriorated from the temperature increase by increasing the laser power, but excessive oxidation can negatively affect the quality of the material surface after machining. As the feed rate and cutting depth increase, the cutting force increases and tool lifespan decreases, but surface oxidation also decreases. In this experiment, the material can be cut to 3 mm of cutting depth. And based on the results of the experiment, the laser assisted machining mechanism is clarified

Laser cutting or water-jet cutting. Laser setsudan ka water-jet setsudan ka

Energy Technology Data Exchange (ETDEWEB)

Yamada, T. (Shibuya Kogyo Co. Ltd., Ishikawa (Japan))

1991-05-01

The recent spread of carbon oxide laser cutter is so startlingly fast, but at the same time, water jet cutting using ultra high pressure water stream is drawing attention as it has identical characteristics, and opens the way to cutting materials that have been hitherto difficult to cut. The authors, who are fabricators of cutters of both types, gave the comparisons and explanations on several examples referring to materials that can be cut, cutting accuracy, speed, shape and thermal effects to cut face, and running cost in detail. However, simple comparison is difficult. For instance, cutting 6 mm thick SUS sheet costs a running cost of 65 yen per meter in laser cutting, and 535 yen per meter in water jet cutting, but this situation is often reversed when other material or sheet thickness is selected. The actual situation in the sheet metal processing industry at the present time is that it uses by far more laser processing machines, and uses water jet cutters to supplement for cutting materials more difficult to cut. 10 figs., 3 tabs.

Advanced cutting techniques: laser and fissuration cutting

International Nuclear Information System (INIS)

Migliorati, B.; Gay, P.

1984-01-01

Experimental tests have been performed using CO 2 laser with output power 1 to 15 kW to evaluate the effect of varying the following parameters: material (carbon steel Fe 42 C, stainless steel AISI 304, concrete), laser power, beam characteristics, work piece velocity, gas type and distribution on the laser interaction zone. In the case of concrete, drilling depths of 80 mm were obtained in a few seconds using a 10 kW laser beam. Moreover pieces of 160 mm were cut at 0.01 meters per minute. Results with carbon steel indicated maximum thicknesses of 110 mm, cut at 0.01 meters per minute with 10 kW, depths about 20% lower were obtained with the AISI 304 stainless steel. A parallel investigation was aimed at characterizing particulate emission during the laser cutting process. At the end of the research it was possible to elaborate a preliminary proposal concerning a laser based dismantling system for the application to a typical Nuclear Power Station. (author)

Some possibilities for determining cutting data when using laser cutting:

OpenAIRE

Radovanović, Miroslav

2006-01-01

The technological problems faced in the field of the application of laser-cutting machines lie in insufficient knowledge of the laser technique and the absence of both sufficiently reliable practical data and knowledge about the parameters affecting the work process itself. A significant parameter that is necessary to determine and to enter in an NC-program is the cutting speed. Various authors analyze the laser-cutting process and give mathematical models where laser cutting is modeled by us...

Theoretical aspects of fibre laser cutting

Energy Technology Data Exchange (ETDEWEB)

Mahrle, A; Beyer, E, E-mail: achim.mahrle@iws.fraunhofer.d [University of Technology Dresden, Institute for Surface and Manufacturing Technology, PO Box, 01062 Dresden (Germany)

2009-09-07

Fibre lasers offer distinct advantages over established laser systems with respect to power efficiency, beam guidance and beam quality. Consequently, the potential of these new laser beam sources will be increasingly exploited for laser cutting applications that are conventionally carried out with CO{sub 2} lasers. However, theoretical estimates of the effective absorptivity at the cut front suggest that the shorter wavelength of the fibre laser in combination with its high focusability seems to be primarily advantageous for thin sheet metal cutting whereas the CO{sub 2} laser is probably still capable of cutting thicker materials more efficiently. This surprising result is a consequence of the absorptivity behaviour of metals that shows essential quantitative differences for the corresponding wavelengths of both laser sources as a function of the angle of incidence between the laser beam and the material to be cut. In evaluation of the revealed dependences, solution strategies for an improvement of the efficiency of fibre laser cutting of thicker metal sheets are suggested.

Practical side of cutting. Part 3. ; CO2 laser cutting. Setsudan gijutsu no jissai. 3. ; Laser setsudan

Energy Technology Data Exchange (ETDEWEB)

Miyazaki, T.; Shinonaga, H. (Toshiba Corp., Tokyo (Japan))

1993-03-05

The nature peculiar to laser beam makes it difficult to understand the phenomena in laser cutting. Quoting an example of cutting steel materials, practical minimum basic subjects, factors governing the cutting phenomena with points to be considered, and the current state of the technology are outlined. Various kinds of expert systems and automatic programming devices have been placed on the market to make NC input easier in laser cutting. Shape accuracy, cutting quality, cutting speed, applicable plate thickness, etc. are among the subjects required for laser cutting. The factors are the method of scanning, characteristics of laser beam, work, machining conditions, etc. The factors obstructing stable processing are the change in the ambient temperature, humidity, dust, oil mist, vibration, etc. The basic factors which control the laser cutting are the power density and its distribution at the working point. Pulse cutting is employed when continuous laser heat input is not appropriate. Summarized report is made on the focal point and assist gas. 16 refs., 9 figs., 1 tab.

A novel patterning effect during high frequency laser micro-cutting of hard ceramics for microelectronics applications

Energy Technology Data Exchange (ETDEWEB)

Savriama, Guillaume, E-mail: guillaume.savriama@gmail.com [GREMI-UMR 7344, CNRS/Univ-Orléans, 14 rue d’Issoudun, BP 6744, F-45067 Orléans (France); STMicroelectronics, 10 rue Thalès de Milet, CS 97155, 37071 Tours Cedex 2 (France); Jarry, Vincent; Barreau, Laurent [STMicroelectronics, 10 rue Thalès de Milet, CS 97155, 37071 Tours Cedex 2 (France); Boulmer-Leborgne, Chantal; Semmar, Nadjib [GREMI-UMR 7344, CNRS/Univ-Orléans, 14 rue d’Issoudun, BP 6744, F-45067 Orléans (France)

2014-05-01

This paper investigates the laser micro-cutting of wide band gap materials for microelectronics industry purposes. An ultraviolet (355 nm) diode-pumped solid-state (DPSS) nanosecond laser was used in this investigation. The laser energy varied from 7 to 140 μJ/pulse with typical frequencies from 40 to 200 kHz. The effect of pulse energy and scanning speed on the depth of the cutting street of α-Al{sub 2}O{sub 3} and glass was studied. Typical depths of 200 μm were achieved on α-Al{sub 2}O{sub 3} for 140 μJ/pulse, 40 kHz at 13 mm/s. SEM images showed periodic patterns produced by periodic explosive boiling that can influence the achieved depth. The shape, size and periodicity of the recast material depended on the feed rate and the laser beam frequency. This periodic removal mechanism seems to be specific to dielectrics since it was not observed for semiconductors such as silicon or silicon carbide.

Laser cutting: industrial relevance, process optimization, and laser safety

Science.gov (United States)

Haferkamp, Heinz; Goede, Martin; von Busse, Alexander; Thuerk, Oliver

1998-09-01

Compared to other technological relevant laser machining processes, up to now laser cutting is the application most frequently used. With respect to the large amount of possible fields of application and the variety of different materials that can be machined, this technology has reached a stable position within the world market of material processing. Reachable machining quality for laser beam cutting is influenced by various laser and process parameters. Process integrated quality techniques have to be applied to ensure high-quality products and a cost effective use of the laser manufacturing plant. Therefore, rugged and versatile online process monitoring techniques at an affordable price would be desirable. Methods for the characterization of single plant components (e.g. laser source and optical path) have to be substituted by an omnivalent control system, capable of process data acquisition and analysis as well as the automatic adaptation of machining and laser parameters to changes in process and ambient conditions. At the Laser Zentrum Hannover eV, locally highly resolved thermographic measurements of the temperature distribution within the processing zone using cost effective measuring devices are performed. Characteristic values for cutting quality and plunge control as well as for the optimization of the surface roughness at the cutting edges can be deducted from the spatial distribution of the temperature field and the measured temperature gradients. Main influencing parameters on the temperature characteristic within the cutting zone are the laser beam intensity and pulse duration in pulse operation mode. For continuous operation mode, the temperature distribution is mainly determined by the laser output power related to the cutting velocity. With higher cutting velocities temperatures at the cutting front increase, reaching their maximum at the optimum cutting velocity. Here absorption of the incident laser radiation is drastically increased due to

Strain of laser annealed silicon surfaces

Science.gov (United States)

Nemanich, R. J.; Haneman, D.

1982-05-01

High resolution Raman scattering measurements have been carried out on pulse and continuous-wave laser annealed silicon samples with various surface preparations. These included polished and ion-bombarded wafers, and saw-cut crystals. The pulse annealing treatments were carried out in ultrahigh vacuum and in air. The residual strain was inferred from the frequency shift of the first-order Raman active mode of Si, and was detectable in the range 10-2-10-3 in all except the polished samples.

Fibre laser cutting stainless steel: Fluid dynamics and cut front morphology

Science.gov (United States)

Pocorni, Jetro; Powell, John; Deichsel, Eckard; Frostevarg, Jan; Kaplan, Alexander F. H.

2017-01-01

In this paper the morphology of the laser cut front generated by fibre lasers was investigated by observation of the 'frozen' cut front, additionally high speed imaging (HSI) was employed to study the fluid dynamics on the cut front while cutting. During laser cutting the morphology and flow properties of the melt film on the cut front affect cut quality parameters such as cut edge roughness and dross (residual melt attached to the bottom of the cut edge). HSI observation of melt flow down a laser cutting front using standard cutting parameters is experimentally problematic because the cut front is narrow and surrounded by the kerf walls. To compensate for this, artificial parameters are usually chosen to obtain wide cut fronts which are unrepresentative of the actual industrial process. This paper presents a new experimental cutting geometry which permits HSI of the laser cut front using standard, commercial parameters. These results suggest that the cut front produced when cutting medium section (10 mm thick) stainless steel with a fibre laser and a nitrogen assist gas is covered in humps which themselves are covered by a thin layer of liquid. HSI observation and theoretical analysis reveal that under these conditions the humps move down the cut front at an average speed of approximately 0.4 m/s while the covering liquid flows at an average speed of approximately 1.1 m/s, with an average melt depth at the bottom of the cut zone of approximately 0.17 mm.

Laser Cutting of Different Materials

Directory of Open Access Journals (Sweden)

Kadir ÇAVDAR

2013-08-01

Full Text Available In this paper; in general potential developments and trends of a particular machining field by extensively evaluating present studies of laser beam machining have been discussed. As it is indicated below, technical literatures have been subsumed under five major headlines: Experimental studies, reviews, optimization researches of the cutting parameters, theoretical modelling studies of laser beam cutting and academic studies relating to laser cutting

Experiment and simulation study of laser dicing silicon with water-jet

Energy Technology Data Exchange (ETDEWEB)

Bao, Jiading; Long, Yuhong, E-mail: longyuhong@guet.edu.cn; Tong, Youqun; Yang, Xiaoqing; Zhang, Bin; Zhou, Zupeng

2016-11-30

Highlights: • The explosive melt expulsion could be a dominant process for the laser ablating silicon in liquids with ns-pulsed laser of 1064 nm irradiating. • Self-focusing phenomenon was found and its causes are analyzed. • SPH modeling technique was employed to understand the effect of water and water-jet on debris removal during water-jet laser machining. - Abstract: Water-jet laser processing is an internationally advanced technique, which combines the advantages of laser processing with water jet cutting. In the study, the experiment of water-jet laser dicing are conducted with ns pulsed laser of 1064 nm irradiating, and Smooth Particle Hydrodynamic (SPH) technique by AUTODYN software was modeled to research the fluid dynamics of water and melt when water jet impacting molten material. The silicon surface morphology of the irradiated spots has an appearance as one can see in porous formation. The surface morphology exhibits a large number of cavities which indicates as bubble nucleation sites. The observed surface morphology shows that the explosive melt expulsion could be a dominant process for the laser ablating silicon in liquids with nanosecond pulse laser of 1064 nm irradiating. Self-focusing phenomenon was found and its causes are analyzed. Smooth Particle Hydrodynamic (SPH) modeling technique was employed to understand the effect of water and water-jet on debris removal during water-jet laser machining.

Economic technology of laser cutting

Science.gov (United States)

Fedin, Alexander V.; Shilov, Igor V.; Vassiliev, Vladimir V.; Malov, Dmitri V.; Peskov, Vladimir N.

2000-02-01

The laser cutting of color metals and alloys by a thickness more than 2 mm has significant difficulties due to high reflective ability and large thermal conduction. We made it possible to raise energy efficiency and quality of laser cutting by using a laser processing system (LPS) consisting both of the YAG:Nd laser with passive Q-switching on base of LiF:F2- crystals and the CO2 laser. A distinctive feature of the LPS is that the radiation of different lasers incorporated in a coaxial beam has simultaneously high level of peak power (more than 400 kW in a TEM00 mode) and significant level of average power (up to 800 W in a TEM01 mode of the CO2 laser). The application of combined radiation for cutting of an aluminum alloy of D16 type made it possible to decrease the cutting energy threshold in 1.7 times, to increase depth of treatment from 2 up to 4 mm, and velocity from 0.015 up to 0.7 m/min, and also to eliminate application of absorptive coatings. At cutting of steels the velocity of treatment was doubled, and also an oxygen flow was eliminated from the technological process and replaced by the air. The obtained raise of energy efficiency and quality of cutting is explained by an essential size reducing of a formed penetration channel and by the shifting of a thermal cutting mode from melting to evaporation. The evaluation of interaction efficiency of a combined radiation was produced on the basis of non-stationary thermal-hydrodynamic model of a heating source moving as in the cutting direction, and also into the depth of material.

Multi-Criteria Analysis of Laser Cut Surface Characteristics in CO2 Laser Cutting of Stainless Steel

Directory of Open Access Journals (Sweden)

M. Radovanović

2015-06-01

Full Text Available In this paper an approach for multi-criteria analysis of laser cut surface characteristics using multi-criteria decision making (MCDM approach was presented. Laser cutting experiment was conducted based on Taguchi’s L27 experimental design by varying laser power, cutting speed, assist gas pressure and focus position at three levels. Multi-criteria analysis was performed by using the weighted aggregated sum product assessment (WASPAS method while considering burr height, drag line separation, depth of separation line, surface roughness and perpendicularity of the cut as assessment criteria. Based on conducted experimental investigation the MCDM model with 27 alternatives (laser cuts and five criteria was developed. The relative importance of criteria was determined by using pair-wise comparison matrix and geometric mean method of the analytic hierarchy process (AHP method.

Laser-assisted turning of components made of silicon-nitride ceramics

International Nuclear Information System (INIS)

Klocke, F.; Bausch, S.

2001-01-01

The manufacture of high-precision parts made of silicon-nitride ceramic, such as roller bearing rings or valves, currently involves finishing in the form of time and cost intensive grinding operations. This has resulted in demands for the development of more efficient machining techniques and for the subsequent provision of these within a manufacturing environment. A prototype of a precision lathe with an integrated high power diode laser for laser-assisted turning has been developed at the Fraunhofer IPT in close co-operation with industrial partners. When the workpiece is heated continuously by the laser, the resultant localized material softening enables the ceramic to be machined using a defined cutting edge. The application of this technique allows complex silicon nitride ceramic parts with surface qualities of up to R a = 0.3 μm to be produced considerably more flexibly than before, with no requirement for cooling lubricant. (author)

Wedge cutting of mild steel by CO 2 laser and cut-quality assessment in relation to normal cutting

Science.gov (United States)

Yilbas, B. S.; Karatas, C.; Uslan, I.; Keles, O.; Usta, Y.; Yilbas, Z.; Ahsan, M.

2008-10-01

In some applications, laser cutting of wedge surfaces cannot be avoided in sheet metal processing and the quality of the end product defines the applicability of the laser-cutting process in such situations. In the present study, CO 2 laser cutting of the wedge surfaces as well as normal surfaces (normal to laser beam axis) is considered and the end product quality is assessed using the international standards for thermal cutting. The cut surfaces are examined by the optical microscopy and geometric features of the cut edges such as out of flatness and dross height are measured from the micrographs. A neural network is introduced to classify the striation patterns of the cut surfaces. It is found that the dross height and out of flatness are influenced significantly by the laser output power, particularly for wedge-cutting situation. Moreover, the cut quality improves at certain value of the laser power intensity.

Laser Cutting of Thick Diamond Films Using Low-Power Laser

Energy Technology Data Exchange (ETDEWEB)

Park, Y.J.; Baik, Y.J. [Korea Institute of Science and Technology, Seoul (Korea)

2000-02-01

Laser cutting of thick diamond films is studied rising a low-power(10 W) copper vapor laser. Due to the existence of the saturation depth in laser cutting, thick diamond films are not easily cut by low-power lasers. In this study, we have adopted a low thermal- conductivity underlayer of alumina and a heating stage (up to 500 deg. C in air) to prevent the laser energy from consuming-out and, in turn, enhance the cutting efficiency. Aspect ratio increases twice from 3.5 to 7 when the alumina underlayer used. Adopting a heating stage also increases aspect ratio and more than 10 is obtained at higher temperatures than 400 deg. C. These results show that thick diamond films can be cut, with low-power lasers, simply by modifying the thermal property of underlayer. (author). 13 refs., 5 figs.

Cutting using the CO laser. Trennen mit dem CO-Laser

Energy Technology Data Exchange (ETDEWEB)

Maisenhaelder, F.; Stoehr, M. (DLR, Inst. fuer Technische Physik, Stuttgart (Germany))

1991-02-01

Several cutting experiments were performed to investigate the maximum cutting speed when using CO or CO{sub 2} laser radiation. The material which was used for these experiments was mild steel (St 37) and stainless steel (V2A; X5CrNi 189), the material thickness varied from 0.5 mm to 4 mm. The cutting parameters, especially the focal power density and the focal diameter, were equal for both laser wavelengths. The experimental result shows an increased cutting speed with CO laser beams in comparison to CO{sub 2} laser beams.

Underwater laser cutting of metallic structures

International Nuclear Information System (INIS)

Alfille, J.P.; Schildknecht, J.; Ramaswami, V.S.

1993-01-01

In the frame of an european contract, the feasibility of the underwater cutting with a CO 2 laser power is studied. The aim of this work is the dismantling metallic structures of reactors pools. The paper analyzes the general concept of the experimental device, the underwater cutting head, the experimenting vessel, examples of cuttings in dismantling situation with a 500 W CO 2 laser, and examples of cuttings with a 5 kW CO 2 laser. (author). 2 refs., 9 figs., 2 tabs

Laser Cutting of Carbon Fiber Fabrics

Science.gov (United States)

Fuchs, A. N.; Schoeberl, M.; Tremmer, J.; Zaeh, M. F.

Due to their high weight-specific mechanical stiffness and strength, parts made from carbon fiber reinforced polymers (CFRP) are increasingly used as structural components in the aircraft and automotive industry. However, the cutting of preforms, as with most automated manufacturing processes for CFRP components, has not yet been fully optimized. This paper discusses laser cutting, an alternative method to the mechanical cutting of preforms. Experiments with remote laser cutting and gas assisted laser cutting were carried out in order to identify achievable machining speeds. The advantages of the two different processes as well as their fitness for use in mass production are discussed.

Melt Flow and Energy Limitation of Laser Cutting

Directory of Open Access Journals (Sweden)

Pavel Hudeček

2016-01-01

Full Text Available Laser technology is a convertible technology for plenty of parts in most materials. Laser material processing for industrial manufacturing applications is today a widespread procedure for welding, cutting, marking and micro machining of metal and plastic parts and components. Involvement and support this huge mass-production industry of laser cutting, new technology and dry-process using lasers were and are being actively developed. Fundamentally, industrial laser cutting or other applications on industry should satisfy the four key practical application issues including “Quality or Performance”, “Throughput or Speed”, “Cost or Total Ownership Cost”, and “Reliability”. Laser requires for examples several complicated physical factors to be resolved including die strength to be enable good wire-bonding and survival of severe cycling test, clean cutting wall surface, good cutting of direct attach film, and proper speed of cutting for achieving economy of throughput. Some example of maximum cutting rate, wherewith is normally limited laser energy, cutting speed is depend on type laser, different of cutting with one laser beam and beam pattern and applied laser power/material thickness will be introduced in this paper.

Laser cutting - trends in the development,

DEFF Research Database (Denmark)

Olsen, Flemming Ove

2002-01-01

Since the laser was invented in 1960, the industrial applications of this tool has grown and grown. And - since the beginning of the 1980'ies, the major industrial application of lasers in production has been laser cutting. In this paper a short review of the development of the laser cutting...

Quality Analysis of Cutting Steel Using Laser

Directory of Open Access Journals (Sweden)

Vladislav Markovič

2013-02-01

Full Text Available The article explores the quality dependence of the edge surface of steel C45 LST EN 10083-1 obtained cutting the material using laser on different cutting regimes and variations in the thickness of trial steel. The paper presents the influence of the main modes of laser cutting equipment Trulaser 3030, including cutting speed, pressure, angle and the thickness of the surface on the quality characteristics of the sample. The quality of the edge after laser cutting is the most important indicator influencing such technological spread in industry worldwide. Laser cutting is the most popular method of material cutting. Therefore, the article focuses on cutting equipment, cutting defects and methods of analysis. Research on microstructure, roughness and micro-toughness has been performed with reference to edge samples. At the end of the publication, conclusions are drawn.Article in Lithuanian

Quality Analysis of Cutting Steel Using Laser

Directory of Open Access Journals (Sweden)

Vladislav Markovič

2012-12-01

Full Text Available The article explores the quality dependence of the edge surface of steel C45 LST EN 10083-1 obtained cutting the material using laser on different cutting regimes and variations in the thickness of trial steel. The paper presents the influence of the main modes of laser cutting equipment Trulaser 3030, including cutting speed, pressure, angle and the thickness of the surface on the quality characteristics of the sample. The quality of the edge after laser cutting is the most important indicator influencing such technological spread in industry worldwide. Laser cutting is the most popular method of material cutting. Therefore, the article focuses on cutting equipment, cutting defects and methods of analysis. Research on microstructure, roughness and micro-toughness has been performed with reference to edge samples. At the end of the publication, conclusions are drawn.Article in Lithuanian

Underwater laser cutting of metal structures

Energy Technology Data Exchange (ETDEWEB)

Alfille, J.P.; Prunele, D. de [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Direction des Technologies Avancees; Pilot, G. [CEA Centre d`Etudes de Fontenay-aux-Roses, 92 (France). Dept. de Protection de l`Environnement et des Installations; Fredrick, P.; Ramaswami, V.S.; Muys, P. [Radius Engineering, Gent (Belgium)

1994-12-31

Cutting tests were carried out on stainless steel (304L) in air and under 7 meters of water (application to reactor pools), using CO{sub 2} and YAG lasers; results concerned cutting speed, quality of cut, cutting thickness. By-products of sectioning operations using a CO{sub 2} laser were studied: dross, aerosols, suspended particles in water, gas analysis, chemical analysis of the aerosols. Same measurements are currently being taken in the case of the YAG laser with beam transported via optical fiber. (from author). 16 figs., 2 tabs., 3 refs.

Underwater laser cutting of metal structures

International Nuclear Information System (INIS)

Alfille, J.P.; Prunele, D. de

1994-01-01

Cutting tests were carried out on stainless steel (304L) in air and under 7 meters of water (application to reactor pools), using CO 2 and YAG lasers; results concerned cutting speed, quality of cut, cutting thickness. By-products of sectioning operations using a CO 2 laser were studied: dross, aerosols, suspended particles in water, gas analysis, chemical analysis of the aerosols. Same measurements are currently being taken in the case of the YAG laser with beam transported via optical fiber. (from author). 16 figs., 2 tabs., 3 refs

Laser cutting - from 200 Watt to 12 Kilowatt

DEFF Research Database (Denmark)

Olsen, Flemming Ove; Nielsen, Jakob Skov

2004-01-01

Laser cutting is the most widespread industrial application of high power lasers. The development of this process was initiated around 1970, when scientists at TWI first demonstrated laser cutting with coaxial gas assistance. 10 years later, the polarisation problem was solved and the technology ...... got its breakthrough. Since then some 30,000 laser cutting systems have been installed worldwide, making the laser an important cutting tool in modern industry....

LASER CUTTING MACHINES FOR 3-D THIN SHEET PARTS

Directory of Open Access Journals (Sweden)

Miroslav RADOVANOVIC

2012-11-01

Full Text Available Laser cutting machines are used for precise contour cutting thin sheet. In industrial application nowadays various types and construction of laser cutting machines can be met. For contour cutting 3-D thin sheet parts laser cutting machines with rotation movements and laser robots are used. Laser generates the light beam, that presents a tool in working process. Application of laser cutting machines made possible good quality of products, flexibility of production and enlargement of economy

Laser beam cutting method. Laser ko ni yoru kaitai koho

Energy Technology Data Exchange (ETDEWEB)

Kutsumizu, A. (Obayashi Corp., Osaka (Japan))

1991-07-01

In this special issue paper concerning the demolition of concrete structures, was introduced a demolition of concrete structures using laser, of which practical application is expected due to the remarkable progress of generating power and efficiency of laser radiator. The characteristics of laser beam which can give a temperature of one million centigrade at the irradiated spot, the laser radiator consisting of laser medium, laser resonator and pumping apparatus, and the laser kinds for working, such as CO{sub 2} laser, YAG laser and CO laser, were described. The basic constitution of laser cutting equipment consisting of large generating power radiator, beam transmitter, beam condenser, and nozzle for working was also illustrated. Furthermore, strong and weak points in the laser cutting for concrete and reinforcement were enumerated. Applications of laser to cutting of reinforced and unreinforced concrete constructions were shown, and the concept and safety measure for application of laser to practical demolition was discussed. 5 refs., 8 figs.

Comparison of CO2 Laser Cutting with Different Laser Sources

DEFF Research Database (Denmark)

Ketting, Hans-Ole; Olsen, Flemmming Ove

1996-01-01

This paper contains CO2 laser cutting results in mild and stainless steel with different laser sources. The main factors which affect the cutting speed and quality are the power, the cutting gas and focal point conditions. Keeping the power and cutting gas constant, the focal point conditions have...... size,for the maximum cutting speed. One of the 7 laser sources with different focal length and thus different minimum spot size, was then used to investigate more in details the importance of the focal spot size cutting stainless steel with high pressure nitrogen. It looks as if there is a strong...... connection between the smallest avail-able spot size and cutting speed in mild steel, whereas the conditions in stainless steel, depends strongly on the flow conditions in the cut kerf, and not only on the focal spot size....

Laser Cutting of Thin Nickel Bellows

Science.gov (United States)

Butler, C. L.

1986-01-01

Laser cutting technique produces narrow, precise, fast, and repeatable cuts in thin nickel-allow bellows material. Laser cutting operation uses intense focused beam to melt material and assisting gas to force melted material through part thickness, creating void. When part rotated or moved longitudinally, melting and material removal continuous and creates narrow, fast, precise, and repeatable cut. Technique used to produce cuts of specified depths less than material thickness. Avoids distortion, dents, and nicks produced in delicate materials during lathe trimming operations, which require high cutting-tool pressure and holding-fixture forces.

Theoretical and experimental aspects of laser cutting with a direct diode laser

Science.gov (United States)

Costa Rodrigues, G.; Pencinovsky, J.; Cuypers, M.; Duflou, J. R.

2014-10-01

Recent developments in beam coupling techniques have made it possible to scale up the power of diode lasers with a laser beam quality suitable for laser cutting of metal sheets. In this paper a prototype of a Direct Diode Laser (DDL) source (BPP of 22 mm-mrad) is analyzed in terms of efficiency and cut performance and compared with two established technologies, CO2 and fiber lasers. An analytical model based on absorption calculations is used to predict the performance of the studied laser source with a good agreement with experimental results. Furthermore results of fusion cutting of stainless steel and aluminium alloys as well as oxygen cutting of structural steel are presented, demonstrating that industrial relevant cutting speeds with high cutting quality can now be achieved with DDL.

Thermophysical problems of laser cutting of metals

Directory of Open Access Journals (Sweden)

Orishich Anatoliy

2017-01-01

Full Text Available Variety and complex interaction of physical processes during laser cutting is a critical characteristic of the laser cutting of metals. Small spatial and temporal scales complicate significantly the experimental investigations of the multi-phase fluid flow in the conditions of laser cutting of metals. In these conditions, the surface formed during the cutting is an indicator determining the melt flow character. The quantitative parameter reflecting the peculiarities of the multi-phase fluid flow, is normally the roughness of the forming surface, and the minimal roughness is the criterion of the qualitative flow [1 – 2]. The purpose of this work is to perform the experimental comparative investigation of the thermophysical pattern of the multi-phase melt flow in the conditions of the laser cutting of metals with the laser wavelength of 10.6 μm and 1.07 μm.

Laser cutting of sheets for Tailored Blanks

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove

1999-01-01

sound welds. Laser cutting the sheets may therefore be an alternative to shear cutting, if the cut kerf squareness can be kept below 0.05 mm.In a number of systematic laboratory experiments the effects of the major process parameters in laser cutting have been investigated. Each cut was quantified...... by the squareness, the surface roughness and the burr height. Mild steel as well as high strength steel with and with out galvanisation with thickness' of 0.7(5) and 1.25 were used.In the tests the difference in cut quality between a 5" and a 7.5" focusing lens were tested and the effect of using pulsed mode laser...

Laser tests of silicon detectors

International Nuclear Information System (INIS)

Dolezal, Zdenek; Escobar, Carlos; Gadomski, Szymon; Garcia, Carmen; Gonzalez, Sergio; Kodys, Peter; Kubik, Petr; Lacasta, Carlos; Marti, Salvador; Mitsou, Vasiliki A.; Moorhead, Gareth F.; Phillips, Peter W.; Reznicek, Pavel; Slavik, Radan

2007-01-01

This paper collects experiences from the development of a silicon sensor laser testing setup and from tests of silicon strip modules (ATLAS End-cap SCT), pixel modules (DEPFET) and large-area diodes using semiconductor lasers. Lasers of 1060 and 680 nm wavelengths were used. A sophisticated method of focusing the laser was developed. Timing and interstrip properties of modules were measured. Analysis of optical effects involved and detailed discussion about the usability of laser testing for particle detectors are presented

Trend of CO2 laser cutting; Saikin no CO2 laser setsudan

Energy Technology Data Exchange (ETDEWEB)

Fujii, T.; Sano, Y.; Nagahori, M. [Tanaka Engineering Works Ltd., Saitama (Japan)

1998-08-01

This paper describes CO2 laser cutting of medium thick plates. Carbon dioxide laser is mainly used for laser generators. The generation efficiency of CO2 laser is 5 to 15% which is higher than that of the other lasers. Ninety percent of the usage is for cutting, piercing and welding. Laser cutter having a separated generator with a power from 3 to 6 kW is often used for cutting medium thick plates. The recent trend of new cutting technology is introduced. When power is increased from 3 kW to 6 kW without using oxygen as assist gas, the cutting thickness of stainless steel plate increased into 1.5 times, and the cutting speed increased into 1.5 to 2 times. For the soft steel members with black coating in which the power-up effects have not been obtained, the cutting speed, quality of cutting surface and cutting stability were improved by introducing new technology. Piercing time has been reduced by developing a method by which pulse generation is changed during piercing and a method by which piercing is conducted by irradiating the maximum power of continuous generation. Cutting quality with high accuracy has been realized by developing light weight generator and high performance NC unit. 10 figs.

Remote Laser Cutting of CFRP: Improvements in the Cut Surface

Science.gov (United States)

Stock, Johannes; Zaeh, Michael F.; Conrad, Markus

In the automotive industry carbon fibre reinforced plastics (CFRP) are considered as a future key material to reduce the weight of the vehicle. Therefore, capable production techniques are required to process this material in mass industry. E.g., state of the art methods for cutting are limited by the high tool wear or the feasible feed rate. Laser cutting processes are still under investigation. This paper presents detailed new studies on remote laser cutting of CFRP focusing on the influence of the material properties and the quality of the cut surface. By adding light absorbing soot particles to the resin of the matrix, the cutting process is improved and fewer defects emerge.

Laser cutting of high manganese cast steel; Komangan chuko no laser setsudan

Energy Technology Data Exchange (ETDEWEB)

Kataoka, Y.; Tokunaga, T. [University of Industrial Technology, Kanagawa (Japan); Miyazaki, T. [Chiba Institute of Technology, Chiba (Japan)

1994-08-25

This paper discusses applicability of CO2 laser to cut high manganese cast steel, and investigates the cutting conditions and characteristics. The tested material is made of steel scrap, ferro Mn and ferro Cr of 50 kg in total, which was deoxidized by using pure aluminum and injected into CO2 die by means of the ordinary casting method to make a circular rod with a diameter of 28 mm. The rod was given a heating and water toughening treatment in a muffle furnace maintaining N2 atmosphere. The base structure is an austenite system of Mn 12.4% by mass with hardness of MHV 220 to 230. The paper describes discussions on test pieces (with a thickness of 2 mm) fabricated under a laser beam frequency of 150 Hz, power outputs of 250, 350 and 500 W, and cutting speeds of 100, 300 and 500 mm/min. The cutting width increases as the laser power is increased, but is not governed by the cutting speed. Increased cutting speed roughens the surface of a cut face. The laser cutting has caused no change in hardness of the base material, and no processing deterioration has been recognized. As described, the laser cutting can be applied to finish-cutting if the cutting condition is selected properly. Simplification of the cutting process and improvement of working environment can be expected from the laser cutting. 14 refs., 12 figs., 2 tabs.

Aerodynamic Interactions During Laser Cutting

Science.gov (United States)

Fieret, J.; Terry, M. J.; Ward, B. A.

1986-11-01

Most laser cutting systems utilise a gas jet to remove molten or vaporised material from the kerf. The speed, economy and quality of the cut can be strongly dependent on the aerodynamic conditions created by the nozzle, workpiece proximity and kerf shape. Adverse conditions can be established that may lead to an unwelcome lack of reproducibility of cut quality. Relatively low gas nozzle pressures can result in supersonic flow in the jet with its associated shock fronts. When the nozzle is placed at conventional distances (1-2mm) above the workpiece, the force exerted by the gas on the workpiece and the cut products (the cutting pressure) can be significantly less than the nozzle pressure. Higher cutting pressures can be achieved by increasing the height of the nozzle above the workpiece, to a more damage resistant zone, provided that the shock structure of the jet is taken into account. Conventional conical nozzles with circular exits can be operated with conditions that will result in cutting pressures up to 3 Bar (g) in the more distant zone. At higher pressures in circular tipped nozzles the cutting pressure in this zone decays to inadequate levels. Investigations of a large number of non-circular nozzle tip shapes have resulted in the selection of a few specific shapes that can provide cutting pressures in excess of 6 Bar(g) at distances of 4 to 7mm from the nozzle tip. Since there is a strong correlation between cutting pressure and the speed and quality of laser cutting, the paper describes the aerodynamic requirements for achieving the above effects and reports the cutting results arising from the different nozzle designs and conditions. The results of the work of other investigators, who report anomalous laser cutting results, will be examined and reviewed in the light of the above work.

Recent results in mirror based high power laser cutting

DEFF Research Database (Denmark)

Olsen, Flemming Ove; Nielsen, Jakob Skov; Elvang, Mads

2004-01-01

In this paper, recent results in high power laser cutting, obtained in reseach and development projects are presented. Two types of mirror based focussing systems for laser cutting have been developed and applied in laser cutting studies on CO2-lasers up to 12 kW. In shipyard environment cutting...... speed increase relative to state-of-the-art cutting of over 100 % has been achieved....

Automated Laser Cutting In Three Dimensions

Science.gov (United States)

Bird, Lisa T.; Yvanovich, Mark A.; Angell, Terry R.; Bishop, Patricia J.; Dai, Weimin; Dobbs, Robert D.; He, Mingli; Minardi, Antonio; Shelton, Bret A.

1995-01-01

Computer-controlled machine-tool system uses laser beam assisted by directed flow of air to cut refractory materials into complex three-dimensional shapes. Velocity, position, and angle of cut varied. In original application, materials in question were thermally insulating thick blankets and tiles used on space shuttle. System shapes tile to concave or convex contours and cuts beveled edges on blanket, without cutting through outer layer of quartz fabric part of blanket. For safety, system entirely enclosed to prevent escape of laser energy. No dust generated during cutting operation - all material vaporized; larger solid chips dislodged from workpiece easily removed later.

Development of laser cutting method for stainless steel liner

International Nuclear Information System (INIS)

Ishihara, Satoshi; Takahata, Masato; Wignarajah, Sivakumaran; Kamata, Hirofumi

2007-01-01

The present work is an attempt to develop a laser cutting method for cutting and removing stainless steel liners from concrete walls and floors in nuclear facilities. The effect of basic laser cutting parameters such as energy, cutting speed, assist gas flow etc. were first studied through cutting experiments on mock-up concrete specimens lined with 3mm thick stainless steel sheets using a 1kW Nd:YAG laser. These initial studies were followed by further studies on the effect of unevenness of the liner surface and on a new method of confining contamination during the cutting process using a sliding evacuation hood attached to the laser cutting head. The results showed that laser cutting is superior to other conventional cutting methods from the point of view of safety from radioactivity and work efficiency when cutting contaminated stainless steel liners. (author)

CO2 laser cutting

CERN Document Server

Powell, John

1998-01-01

The laser has given manufacturing industry a new tool. When the laser beam is focused it can generate one of the world's most intense energy sources, more intense than flames and arcs, though similar to an electron beam. In fact the intensity is such that it can vaporise most known materials. The laser material processing industry has been growing swiftly as the quality, speed and new manufacturing possibilities become better understood. In the fore of these new technologies is the process of laser cutting. Laser cutting leads because it is a direct process substitu­ tion and the laser can usually do the job with greater flexibility, speed and quality than its competitors. However, to achieve these high speeds with high quality con­ siderable know how and experience is required. This information is usually carefully guarded by the businesses concerned and has to be gained by hard experience and technical understanding. Yet in this book John Powell explains in lucid and almost non­ technical language many o...

Optimisation Of Cutting Parameters Of Composite Material Laser Cutting Process By Taguchi Method

Science.gov (United States)

Lokesh, S.; Niresh, J.; Neelakrishnan, S.; Rahul, S. P. Deepak

2018-03-01

The aim of this work is to develop a laser cutting process model that can predict the relationship between the process input parameters and resultant surface roughness, kerf width characteristics. The research conduct is based on the Design of Experiment (DOE) analysis. Response Surface Methodology (RSM) is used in this work. It is one of the most practical and most effective techniques to develop a process model. Even though RSM has been used for the optimization of the laser process, this research investigates laser cutting of materials like Composite wood (veneer)to be best circumstances of laser cutting using RSM process. The input parameters evaluated are focal length, power supply and cutting speed, the output responses being kerf width, surface roughness, temperature. To efficiently optimize and customize the kerf width and surface roughness characteristics, a machine laser cutting process model using Taguchi L9 orthogonal methodology was proposed.

Cutting of Stainless Steel With Fiber and Disk Laser

DEFF Research Database (Denmark)

Wandera, Catherine; Salminen, Antti; Olsen, Flemming Ove

2006-01-01

Laser cutting is a major application of laser materials processing. The cutting is usually performed with CO2-laser due to its good beam quality and its relatively low costs of ownership. Ever since entering the market the high power solid state lasers have been expected to achieve a dominating...... of both of the new lasers against traditional CO2-laser. The results showed that the new lasers offer a great potential in improving the productivity of cutting phase with an acceptable edge quality. This is emphasized in thin sheets of 1.3 and 2.3 mm thickness. In that case the width of the cut kerf...... of each thickness. The results were very promising and it can be stated that these new laser types have a great potential in cutting and will probably gain a considerable market share not only in 3D cutting applications but also in ordinary flat sheet cutting....

Hybrid III-V/silicon lasers

Science.gov (United States)

Kaspar, P.; Jany, C.; Le Liepvre, A.; Accard, A.; Lamponi, M.; Make, D.; Levaufre, G.; Girard, N.; Lelarge, F.; Shen, A.; Charbonnier, P.; Mallecot, F.; Duan, G.-H.; Gentner, J.-.; Fedeli, J.-M.; Olivier, S.; Descos, A.; Ben Bakir, B.; Messaoudene, S.; Bordel, D.; Malhouitre, S.; Kopp, C.; Menezo, S.

2014-05-01

The lack of potent integrated light emitters is one of the bottlenecks that have so far hindered the silicon photonics platform from revolutionizing the communication market. Photonic circuits with integrated light sources have the potential to address a wide range of applications from short-distance data communication to long-haul optical transmission. Notably, the integration of lasers would allow saving large assembly costs and reduce the footprint of optoelectronic products by combining photonic and microelectronic functionalities on a single chip. Since silicon and germanium-based sources are still in their infancy, hybrid approaches using III-V semiconductor materials are currently pursued by several research laboratories in academia as well as in industry. In this paper we review recent developments of hybrid III-V/silicon lasers and discuss the advantages and drawbacks of several integration schemes. The integration approach followed in our laboratory makes use of wafer-bonded III-V material on structured silicon-on-insulator substrates and is based on adiabatic mode transfers between silicon and III-V waveguides. We will highlight some of the most interesting results from devices such as wavelength-tunable lasers and AWG lasers. The good performance demonstrates that an efficient mode transfer can be achieved between III-V and silicon waveguides and encourages further research efforts in this direction.

Micro-cutting of silicon implanted with hydrogen and post-implantation thermal treatment

Science.gov (United States)

Jelenković, Emil V.; To, Suet; Sundaravel, B.; Xiao, Gaobo; Huang, Hu

2016-07-01

It was reported that non-amorphizing implantation by hydrogen has a potential in improving silicon machining. Post-implantation high-temperature treatment will affect implantation-induced damage, which can have impact on silicon machining. In this article, a relation of a thermal annealing of hydrogen implanted in silicon to micro-cutting experiment is investigated. Hydrogen ions were implanted into 4″ silicon wafers with 175 keV, 150 keV, 125 keV and doses of 2 × 1016 cm-2, 2 × 1016 cm-2 and 3 × 1016 cm-2, respectively. In this way, low hydrogen atom-low defect concentration was created in the region less than ~0.8 μm deep and high hydrogen atom-high defect concentration was obtained at silicon depth of ~0.8-1.5 μm. The post-implantation annealing was carried out at 300 and 400 °C in nitrogen for 1 h. Physical and electrical properties of implanted and annealed samples were characterized by secondary ion mass spectroscopy (SIMS), X-ray diffraction (XRD), Rutherford backscattering (RBS) and nanoindentation. Plunge cutting experiment was carried out in and silicon crystal direction. The critical depth of cut and cutting force were monitored and found to be influenced by the annealing. The limits of hydrogen implantation annealing contribution to the cutting characteristics of silicon are discussed in light of implantation process and redistribution of hydrogen and defects generation during annealing process.

Cutting of nonmetallic materials using Nd:YAG laser beam

Institute of Scientific and Technical Information of China (English)

Bashir Ahmed Tahir; Rashid Ahmed; M. G. B. Ashiq; Afaq Ahmed; M. A. Saeed

2012-01-01

This study deals with Nd:YAG laser cutting nonmetallic materials,which is one of the most important and popular industrial applications of laser.The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed.For approximate cutting depth,a theoretical study is conducted in terms of material property and cutting speed.Results show a nonlinear relation between the cutting depth and input energy.There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s.An extra energy is utilized in the deep cutting.It is inferred that as the laser power increases,cutting depth increases.The experimental outcomes are in good agreement with theoretical results.This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting,scribing,trimming,engraving,and marking nonmetallic materials.

Striation-free fibre laser cutting of mild steel sheets

Energy Technology Data Exchange (ETDEWEB)

Sobih, M.; Crouse, P.L.; Li, L. [University of Manchester, Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, Sackville Street Building, P.O. Box 88, Manchester (United Kingdom)

2008-01-15

High-power laser cutting is extensively used in many industrial applications. An important weakness of this process is the formation of striations, i.e. regular lines on the cut surface, which lowers the quality of the surfaces produced. The elimination of striation formation is thus of considerable importance, since it could open a variety of novel high-precision applications. This study presents the initial results of a laser cutting study using a 1 kW single-mode fibre laser, a relative newcomer in the field of laser metal cutting. Striation-free laser cuts are demonstrated when cutting 1 mm thick mild steel sheets. (orig.)

Laser cutting of Kevlar laminates

Energy Technology Data Exchange (ETDEWEB)

VanCleave, R.A.

1977-09-01

An investigation has been conducted of the use of laser energy for cutting contours, diameters, and holes in flat and shaped Kevlar 49 fiber-reinforced epoxy laminates as an alternate to conventional machining. The investigation has shown that flat laminates 6.35 mm thick may be cut without backup by using a high-powered (1000-watt) continuous wave CO/sub 2/ laser at high feedrates (33.87 mm per second). The cut produced was free of the burrs and delaminations resulting from conventional machining methods without intimate contact backup. In addition, the process cycle time was greatly reduced.

Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

Science.gov (United States)

Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

2018-03-01

Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

Cutting of nonmetallic materials using Nd:YAG laser beam

International Nuclear Information System (INIS)

Tahir, Bashir Ahmed; Ashiq, M.G. B.; Saeed, M.A.; Ahmed, Rashid; Ahmed, Afaq

2012-01-01

This study deals with Nd:YAG laser cutting nonmetallic materials, which is one of the most important and popular industrial applications of laser. The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed. For approximate cutting depth, a theoretical study is conducted in terms of material property and cutting speed. Results show a nonlinear relation between the cutting depth and input energy. There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s. An extra energy is utilized in the deep cutting. It is inferred that as the laser power increases, cutting depth increases. The experimental outcomes are in good agreement with theoretical results. This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting, scribing, trimming, engraving, and marking nonmetallic materials. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

High speed laser cutting machine. Kosoku reza kakoki

Energy Technology Data Exchange (ETDEWEB)

Shinno, N. (Matsushita Electric Industrial Co. Ltd., Kadoma, Osaka (Japan))

1993-11-01

The carbon dioxide gas laser cutting machine is being used widely for from cutting soft steel and stainless steel, etc. to intermetallic welding and in the field of cutting in particular, concerning sheet cutting, it has been changing the existing monopoly of the turret punch press, and as for medium and thick plate cutting, that of the gas plasma fusing device. This article is the general description of high speed laser cutting machine. Concerning the laser cutting (sheet cutting in particular), as the essential items for securing severe cutting accuracy and, at the same time, improving the cutting speed, the following matters are picked up for respective explanation; improvement of stationary machine accuracy, improvement of dynamic machine accuracy, improvement of quality of laser beam as well as optimization of cutting conditions, and shortening of piercing time. Also explanation is given to the respective items, namely speeding-up of medium and thick plate cutting, and reduction of load onto the operator by improved operation. Finally, feeding and removing of a sheet only, and feeding and removing with a pallet are mentioned as the efforts for automation and energy saving. 3 figs., 1 tab.

PULSED MODE LASER CUTTING OF SHEETS FOR TAILORED BLANKS

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove

1999-01-01

This paper describes how the laser cutting process can be optimised in such a way that the cut sheets can subsequently be used to laser weld tailored blanks. In a number of systematic laboratory experiments the effect of cutting speed, assist gas pressure, average laser power and pulse energy...... item for parameter optimisation of laser cut sheets used for tailored blanks. It was concluded that high quality cut edges with a squareness as small as 0.015 mm may be obtained. Such edges are well suited for subsequent laser welding....... was analysed. For quality assessment the squareness, roughness and dross attachment of laser cut blanks were measured. In all tests, the medium strength steel GA 260 with a thickness of 1.8 mm was used. In this work it has been successfully demonstrated that the squareness of a cut can be used as a quality...

Innovations: laser-cutting nickel-titanium

Energy Technology Data Exchange (ETDEWEB)

Dickson, T.R.; Moore, B.; Toyama, N. [LPL Systems, Inc., Mountain View, CA (United States)

2002-07-01

Laser-cutting is well established as the preferred method for manufacturing many endovascular medical devices. Sometimes laser processing has been poorly understood by nickel-titanium (NiTi) material suppliers, medical device manufacturers, and device designers, but the field has made important strides in the past several years. A variety of sample, nonspecific applications are presented for cutting tubing and sheet stock. Limiting constraints, key considerations, and areas for future development are identified. (orig.)

Laser cutting of various materials: Kerf width size analysis and life cycle assessment of cutting process

Science.gov (United States)

Yilbas, Bekir Sami; Shaukat, Mian Mobeen; Ashraf, Farhan

2017-08-01

Laser cutting of various materials including Ti-6Al-4V alloy, steel 304, Inconel 625, and alumina is carried out to assess the kerf width size variation along the cut section. The life cycle assessment is carried out to determine the environmental impact of the laser cutting in terms of the material waste during the cutting process. The kerf width size is formulated and predicted using the lump parameter analysis and it is measured from the experiments. The influence of laser output power and laser cutting speed on the kerf width size variation is analyzed using the analytical tools including scanning electron and optical microscopes. In the experiments, high pressure nitrogen assisting gas is used to prevent oxidation reactions in the cutting section. It is found that the kerf width size predicted from the lump parameter analysis agrees well with the experimental data. The kerf width size variation increases with increasing laser output power. However, this behavior reverses with increasing laser cutting speed. The life cycle assessment reveals that material selection for laser cutting is critical for the environmental protection point of view. Inconel 625 contributes the most to the environmental damages; however, recycling of the waste of the laser cutting reduces this contribution.

Craterlike structures on the laser cut surface

Science.gov (United States)

Shulyatyev, V. B.; Orishich, A. M.

2017-10-01

Analysis of the laser cut surface morphology remain topical. It is related with the fact that the surface roughness is the main index of the cut quality. The present paper deals with the experimental study of the relatively unstudied type of defects on the laser cut surface, dimples, or craters. According to the measurement results, amount of craters per unit of the laser cut surface area rises as the sheet thickness rises. The crater diameter rises together with the sheet thickness and distance from the upper sheet edge. The obtained data permit concluding that the defects like craters are observed predominantly in the case of thick sheets. The results agree with the hypothesis of crater formation as impact structures resulting from the melt drops getting on the cut channel walls upon separation from the cut front by the gas flow.

Development of YAG laser cutting system for decommissioning nuclear equipments

International Nuclear Information System (INIS)

Kasai, Takeshi; Nitta, Kazuhiko; Hosoda, Hiroshi.

1995-01-01

Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. As a result, the stainless steel plate with a thickness of 22mm could be cut by using an optical fiber which can flexibly propagate laser power, and possibility of application of this laser cutting system to decommissioning nuclear equipments was verified. (author)

Development of YAG laser cutting system for decommissioning nuclear equipments

Energy Technology Data Exchange (ETDEWEB)

Kasai, Takeshi [Fuji Electric Co. Research and Development Ltd., Yokosuka, Kanagawa (Japan); Nitta, Kazuhiko; Hosoda, Hiroshi

1995-07-01

Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. As a result, the stainless steel plate with a thickness of 22mm could be cut by using an optical fiber which can flexibly propagate laser power, and possibility of application of this laser cutting system to decommissioning nuclear equipments was verified. (author).

Cutting weeds with a CO2 laser

DEFF Research Database (Denmark)

Heisel, T.; Schou, Jørgen; Christensen, S.

2001-01-01

Stems of Chenopodium album. and Sinapis arvensis. and leaves of Lolium perenne. were cut with a CO2 laser or with a pair of scissors. Treatments were carried out on greenhouse-grown pot plants at three different growth stages and at two heights. Plant dry matter was measured 2 to 5 weeks after...... treatment. The relationship between dry weight and laser energy was analysed using a non-linear dose-response regression model. The regression parameters differed significantly between the weed species. At all growth stages and heights S. arvensis was more difficult to cut with a CO2 laser than C. album....... When stems were cut below the meristems, 0.9 and 2.3 J mm(-1) of CO2 laser energy dose was sufficient to reduce by 90% the biomass of C. album and S. arvensis respectively. Regrowth appeared when dicotyledonous plant stems were cut above meristems, indicating that it is important to cut close...

High power YAG laser cutting; Koshutsuryoku YAG laser ni yoru setsudan gijutsu

Energy Technology Data Exchange (ETDEWEB)

Owaki, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

1998-08-01

This paper describes features of high power YAG cutting. The optical fiber transmission YAG laser machining system has some advantages in which optical path length compensation unit is not required and measures for low power loss and dust are not required, when compared with the CO2 laser system. Its application to the cutting of stainless steel plates has attracted attention. Cutting tests of SUS304 were conducted using high power YAG laser. Cutting of SUS304 plate with a thickness of 40 mm could be successfully done at the power of 3.5 kW. Cutting tests of SUS304 pipes with a thickness of 8 mm in water under the depth of 20 m were also conducted using air as assist gas at the power of 2.5 kW. Excellent results were obtained without scale deposition. For the tests by the composite beam using 3 kW and 4 kW systems, SUS304 plate with a thickness of 50 mm could be cut at the cutting speed of 0.1 m/min. Laser cutting of pipes from the internal surface was conducted using a newly developed small machining head which can rotate in the peripheral direction. Excellent quality for welding was confirmed. Cutting speed and plate thickness were improved by combining water jet cutter and YAG laser unit. 6 refs., 10 figs.

Anisotropy of Single-Crystal Silicon in Nanometric Cutting.

Science.gov (United States)

Wang, Zhiguo; Chen, Jiaxuan; Wang, Guilian; Bai, Qingshun; Liang, Yingchun

2017-12-01

The anisotropy exhibited by single-crystal silicon in nanometric cutting is very significant. In order to profoundly understand the effect of crystal anisotropy on cutting behaviors, a large-scale molecular dynamics model was conducted to simulate the nanometric cutting of single-crystal silicon in the (100)[0-10], (100)[0-1-1], (110)[-110], (110)[00-1], (111)[-101], and (111)[-12-1] crystal directions in this study. The simulation results show the variations of different degrees in chip, subsurface damage, cutting force, and friction coefficient with changes in crystal plane and crystal direction. Shear deformation is the formation mechanism of subsurface damage, and the direction and complexity it forms are the primary causes that result in the anisotropy of subsurface damage. Structurally, chips could be classified into completely amorphous ones and incompletely amorphous ones containing a few crystallites. The formation mechanism of the former is high-pressure phase transformation, while the latter is obtained under the combined action of high-pressure phase transformation and cleavage. Based on an analysis of the material removal mode, it can be found that compared with the other crystal direction on the same crystal plane, the (100)[0-10], (110)[-110], and (111)[-101] directions are more suitable for ductile cutting.

High-Power Laser Cutting of Steel Plates: Heat Affected Zone Analysis

Directory of Open Access Journals (Sweden)

Imed Miraoui

2016-01-01

Full Text Available The thermal effect of CO2 high-power laser cutting on cut surface of steel plates is investigated. The effect of the input laser cutting parameters on the melted zone depth (MZ, the heat affected zone depth (HAZ, and the microhardness beneath the cut surface is analyzed. A mathematical model is developed to relate the output process parameters to the input laser cutting parameters. Three input process parameters such as laser beam diameter, cutting speed, and laser power are investigated. Mathematical models for the melted zone and the heat affected zone depth are developed by using design of experiment approach (DOE. The results indicate that the input laser cutting parameters have major effect on melted zone, heat affected zone, and microhardness beneath cut surface. The MZ depth, the HAZ depth, and the microhardness beneath cut surface increase as laser power increases, but they decrease with increasing cutting speed. Laser beam diameter has a negligible effect on HAZ depth but it has a remarkable effect on MZ depth and HAZ microhardness. The melted zone depth and the heat affected zone depth can be reduced by increasing laser cutting speed and decreasing laser power and laser beam diameter.

Methods for Optimisation of the Laser Cutting Process

DEFF Research Database (Denmark)

Dragsted, Birgitte

This thesis deals with the adaptation and implementation of various optimisation methods, in the field of experimental design, for the laser cutting process. The problem in optimising the laser cutting process has been defined and a structure for at Decision Support System (DSS......) for the optimisation of the laser cutting process has been suggested. The DSS consists of a database with the currently used and old parameter settings. Also one of the optimisation methods has been implemented in the DSS in order to facilitate the optimisation procedure for the laser operator. The Simplex Method has...... been adapted in two versions. A qualitative one, that by comparing the laser cut items optimise the process and a quantitative one that uses a weighted quality response in order to achieve a satisfactory quality and after that maximises the cutting speed thus increasing the productivity of the process...

Effects of laser fluence on silicon modification by four-beam laser interference

International Nuclear Information System (INIS)

Zhao, Le; Li, Dayou; Wang, Zuobin; Yue, Yong; Zhang, Jinjin; Yu, Miao; Li, Siwei

2015-01-01

This paper discusses the effects of laser fluence on silicon modification by four-beam laser interference. In this work, four-beam laser interference was used to pattern single crystal silicon wafers for the fabrication of surface structures, and the number of laser pulses was applied to the process in air. By controlling the parameters of laser irradiation, different shapes of silicon structures were fabricated. The results were obtained with the single laser fluence of 354 mJ/cm 2 , 495 mJ/cm 2 , and 637 mJ/cm 2 , the pulse repetition rate of 10 Hz, the laser exposure pulses of 30, 100, and 300, the laser wavelength of 1064 nm, and the pulse duration of 7–9 ns. The effects of the heat transfer and the radiation of laser interference plasma on silicon wafer surfaces were investigated. The equations of heat flow and radiation effects of laser plasma of interfering patterns in a four-beam laser interference distribution were proposed to describe their impacts on silicon wafer surfaces. The experimental results have shown that the laser fluence has to be properly selected for the fabrication of well-defined surface structures in a four-beam laser interference process. Laser interference patterns can directly fabricate different shape structures for their corresponding applications

LASER ABLATION OF MONOCRYSTALLINE SILICON UNDER PULSED-FREQUENCY FIBER LASER

Directory of Open Access Journals (Sweden)

V. P. Veiko

2015-05-01

Full Text Available Subject of research. The paper deals with research of the surface ablation for single-crystal silicon wafers and properties of materials obtained in response to silicon ablation while scanning beam radiation of pulse fiber ytterbium laser with a wavelenght λ = 1062 nm in view of variation of radiation power and scanning modes. Method. Wafers of commercial p-type conductivity silicon doped with boron (111, n-type conductivity silicon doped with phosphorus (100 have been under research with a layer of intrinsical silicon oxide having the thickness equal to several 10 s of nanometers and SiO2 layer thickness from 120 to 300 nm grown by thermal oxidation method. The learning system comprises pulse fiber ytterbium laser with a wavelenght λ = 1062 nm. The laser rated-power output is equal to 20 W, pulse length is 100 ns. Pulses frequency is in the range from 20 kHz to 100 kHz. Rated energy in the pulse is equal to 1.0 mJ. Scanning has been carried out by means of two axial scanning device driven by VM2500+ and controlled by personal computer with «SinMarkТМ» software package. Scanning velocity is in the range from 10 mm/s to 4000 mm/s, the covering varies from 100 lines per mm to 3000 lines per mm. Control of samples has been carried out by means of Axio Imager A1m optical microscope Carl Zeiss production with a high definition digital video camera. All experiments have been carried out in the mode of focused laser beam with a radiation spot diameter at the substrate equal to 50 μm. The change of temperature and its distribution along the surface have been evaluated by FLIR IR imager of SC7000 series. Main results. It is shown that ablation occurs without silicon melting and with plasma torch origination. The particles of ejected silicon take part in formation of silicon ions plasma and atmosphere gases supporting the plasmo-chemical growth of SiO2. The range of beam scanning modes is determined where the growth of SiO2 layer is observed

Laser Cutting of Materials of Various Thicknesses

Directory of Open Access Journals (Sweden)

Martin Grepl

2012-01-01

Full Text Available Thise paper deals with the application of laser technology and optimizing the parameters for cutting nickel alloy. The theoretical part of the paper describes various types of lasers, their principles and usage. The experimental part focuses on optimizing the section parameteres of Haynes 718 alloy using a CO2 gas laser. This alloy is employed in the production of components for the aircraft industry. The experiment was performed on the Wibro Delta laser system designed for sizable parts. The actual section is measured with respect to its quality and any accompanying side effects that occur during the process. In this case, laser output and cutting speed were the parameters with most influence on the final cut. The summary explains the results achieved in a metallographic laboratory.

CALCULATION OF LASER CUTTING COSTS

OpenAIRE

Bogdan Nedic; Milan Eric; Marijana Aleksijevic

2016-01-01

The paper presents description methods of metal cutting and calculation of treatment costs based on model that is developed on Faculty of mechanical engineering in Kragujevac. Based on systematization and analysis of large number of calculation models of cutting with unconventional methods, mathematical model is derived, which is used for creating a software for calculation costs of metal cutting. Software solution enables resolving the problem of calculating the cost of laser cutting, compar...

The chemo-mechanical effect of cutting fluid on material removal in diamond scribing of silicon

Science.gov (United States)

Kumar, Arkadeep; Melkote, Shreyes N.

2017-07-01

The mechanical integrity of silicon wafers cut by diamond wire sawing depends on the damage (e.g., micro-cracks) caused by the cutting process. The damage type and extent depends on the material removal mode, i.e., ductile or brittle. This paper investigates the effect of cutting fluid on the mode of material removal in diamond scribing of single crystal silicon, which simulates the material removal process in diamond wire sawing of silicon wafers. We conducted scribing experiments with a diamond tipped indenter in the absence (dry) and in the presence of a water-based cutting fluid. We found that the cutting mode is more ductile when scribing in the presence of cutting fluid compared to dry scribing. We explain the experimental observations by the chemo-mechanical effect of the cutting fluid on silicon, which lowers its hardness and promotes ductile mode material removal.

Vapor-melt Ratio in Laser Fine Cutting of Slot Arrays

International Nuclear Information System (INIS)

Wang Xuyue; Meng Qingxuan; Kang Renke; Xu Wenji; Guo Dongming; Wang Lianji

2011-01-01

In order to improve cut quality for slot arrays, a new method of laser fine cutting under the consideration of the ratio of vapor to melt is presented. Laser cutting of 6063 aluminum alloy sheet, 0.5 mm in thickness, was carried out on a JK701H Nd:YAG pulse laser cutting system. The effects of vapor-melt ratio on kerf width, surface roughness and recast layer were studied which relate cutting qualities. Observation on the cut samples with different vapor-melt ratios (0.687, 1.574, 3.601 varied with laser power increasing, and 1.535, 3.601, 7.661 with decreasing of beam cutting speed) shows that high vapor-melt ratio improves laser cut quality clearly. Kerf width 0.2 mm of smooth area on kerf top area and thickness 2.03 μm of recast layer are obtained. No dross was found on the kerf bottom and the percentage of the smooth area is up to 40% out of whole kerf side. The research on vapor-melt ratio provides a deeper understanding of laser cutting and improves laser cut quality effectively.

Gluebond strength of laser cut wood

Science.gov (United States)

Charles W. McMillin; Henry A. Huber

1985-01-01

The degree of strength loss when gluing laser cut wood as compared to conventionally sawn wood and the amount of additional surface treatment needed to improve bond quality were assessed under normal furniture plant operating conditions. The strength of laser cut oak glued with polyvinyl acetate adhesive was reduced to 75 percent of sawn joints and gum was reduced 43...

Effect of Moisture Content of Paper Material on Laser Cutting

Science.gov (United States)

Stepanov, Alexander; Saukkonen, Esa; Piili, Heidi; Salminen, Antti

Laser technology has been used in industrial processes for several decades. The most advanced development and implementation took place in laser welding and cutting of metals in automotive and ship building industries. However, there is high potential to apply laser processing to other materials in various industrial fields. One of these potential fields could be paper industry to fulfill the demand for high quality, fast and reliable cutting technology. Difficulties in industrial application of laser cutting for paper industry are associated to lack of basic information, awareness of technology and its application possibilities. Nowadays possibilities of using laser cutting for paper materials are widened and high automation level of equipment has made this technology more interesting for manufacturing processes. Promising area of laser cutting application at paper making machines is longitudinal cutting of paper web (edge trimming). There are few locations at a paper making machine where edge trimming is usually done: wet press section, calender or rewinder. Paper web is characterized with different moisture content at different points of the paper making machine. The objective of this study was to investigate the effect of moisture content of paper material on laser cutting parameters. Effect of moisture content on cellulose fibers, laser absorption and energy needed for cutting is described as well. Laser cutting tests were carried out using CO2 laser.

High power laser downhole cutting tools and systems

Science.gov (United States)

Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

2015-01-20

Downhole cutting systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser cutting operations within a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform cutting operations in such boreholes deep within the earth.

Cutting thin glass by femtosecond laser ablation

Science.gov (United States)

Shin, Hyesung; Kim, Dongsik

2018-06-01

The femtosecond laser ablation process for cutting thin aluminoborosilicate glass sheets of thickness 100 μm was investigated with emphasis on effective cutting speed (Veff) and mechanical strength of diced samples. The process parameters including the laser fluence (F), overlap ratio (r) of the laser beam and polarization direction were varied at a fixed pulse repetition rate f = 1 kHz to find the optimal process condition that maximizes Veff and edge strength. A three-point bending test was performed to evaluate the front-side and back-side bending (edge) strength of the laser-cut samples. Veff was proportional to F unless r exceeded a critical value, at which excessive energy began to be delivered at the same spot. The front-side edge strength was bigger than the back-side strength because of the back-side damages such as chipping. Good edge strength, as high as ∼280 MPa (front-side) and ∼230 MPa (back-side), was obtained at F = 19 J/m2, r = 0.99, with laser polarization vertical to the cutting path.

Elimination of striation in laser cutting of mild steel

International Nuclear Information System (INIS)

Sobih, M; Crouse, P L; Li, L

2007-01-01

High-power laser cutting is extensively used in many industrial applications. An important weakness of this process is the formation of striations (regular lines down the cut surface), which affect the quality of the surfaces produced. The elimination of striation formation is of considerable importance, since it could open up a variety of novel high-precision applications. This study presents the results of oxygen-assisted laser cutting of EN43 mild steel sheets, using a high-power fibre laser. Striation-free laser cuts are demonstrated for cutting 1 and 2 mm thick mild steel sheets. The optimal operating windows are presented and a mathematical method is proposed to estimate the critical speed at which striation-free cut can be obtained

Elimination of striation in laser cutting of mild steel

Energy Technology Data Exchange (ETDEWEB)

Sobih, M; Crouse, P L; Li, L [Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street Building, PO Box 88, Manchester M60 1QD (United Kingdom)

2007-11-21

High-power laser cutting is extensively used in many industrial applications. An important weakness of this process is the formation of striations (regular lines down the cut surface), which affect the quality of the surfaces produced. The elimination of striation formation is of considerable importance, since it could open up a variety of novel high-precision applications. This study presents the results of oxygen-assisted laser cutting of EN43 mild steel sheets, using a high-power fibre laser. Striation-free laser cuts are demonstrated for cutting 1 and 2 mm thick mild steel sheets. The optimal operating windows are presented and a mathematical method is proposed to estimate the critical speed at which striation-free cut can be obtaine000.

Doping of silicon by laser-induced diffusion

International Nuclear Information System (INIS)

Pretorius, R.; Allie, M.S.

1986-01-01

This report gives information on the doping of silicon by laser-induced diffusion, modelling and heat-flow calculation, doping from evaporated layers and silicon self-diffusion during pulsed laser irradiation. In order to tailor dopant profiles accurately a knowledge of the heat flow and the melt depths attained as a function of laser energy and material type is crucial. The heat flow calculations described can be used in conjuntion with most diffusion equations in order to predict the redistribution of the deposited dopant which occurs as a result of liquid phase diffusion during the melting period. Doping of Si was carried out by evaporating this films of Sb, In and Bi 10 to 300 A thick, onto the substrates. During pulsed laser irradiation the dopant film and underlying silicon substrate is melted and the dopant incorporated into the crystal lattice during recrystallization. Radioactive 31 Si(T1/2=2,62h) was used as a tracer to measure the self-diffusion of silicon in silicon during pulsed laser (pulsewidth = 30ns, wavelength = 694nm) irradiation

Reviews on laser cutting technology for industrial applications

Science.gov (United States)

Muangpool, T.; Pullteap, S.

2018-03-01

In this paper, an overview of the laser technology applied for the industrial has been reviewed. In general, this technology was used in several engineering applications such as industrial, medical, science, research sectors, etc. Focusing on the laser technology in the industrial section, it was, normally, employed for many purposes i.e. target marking, welding, drilling, and also cutting. Consequently, the laser cutting technology was, however, divided into three classifications YAG, CO2, and fiber laser, respectively. Each laser types have different advantages and disadvantages depending on the material type. The advantages by using laser cutting compared with the general cutting machines were exploited in terms of narrow kerf, high cutting speed, low heat-affected zone (HAZ), improve efficiency of the cutting process, high accuracy, etc. However, the main objectives from the technology used were increasing of the products and also decreasing the production cost. In the opposite way, some disadvantages of the technology were summarized by complexity to operate, high maintenance cost, and also high power consumption. In Thailand industry, there were many factories used this technology as a cutting process. Unfortunately, only few researches were published. It might explains that this technology were difficulty to develop, high investment, and also easy to import from aboard. For becoming to the Thailand 4.0 community, the Thailand industry might awareness to reduce the importing machine and boosting some policies to create novel innovative / know-how from the own country.

Laser desorption ionization and peptide sequencing on laser induced silicon microcolumn arrays

Science.gov (United States)

Vertes, Akos [Reston, VA; Chen, Yong [San Diego, CA

2011-12-27

The present invention provides a method of producing a laser-patterned silicon surface, especially silicon wafers for use in laser desorption ionization (LDI-MS) (including MALDI-MS and SELDI-MS), devices containing the same, and methods of testing samples employing the same. The surface is prepared by subjecting a silicon substrate to multiple laser shots from a high-power picosecond or femtosecond laser while in a processing environment, e.g., underwater, and generates a remarkable homogenous microcolumn array capable of providing an improved substrate for LDI-MS.

Quality and performance of laser cutting with a high power SM fiber laser

DEFF Research Database (Denmark)

Kristiansen, Morten; Selchau, Jacob; Olsen, F. O.

2013-01-01

The introduction of high power single mode fiber lasers allows for a beam of high power and a good beam quality factor (M2 ” 1.2), compared to the multimode fiber lasers often utilised in macro laser metal cutting. This paper describes fundamental studies of macro laser metal cutting with a singl...

Cutting and machining energetic materials with a femtosecond laser

Energy Technology Data Exchange (ETDEWEB)

Roeske, Frank; Benterou, Jerry; Lee, Ronald; Roos, Edward [Energetic Materials Center, Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, CA 94550 (United States)

2003-04-01

A femtosecond (fs) laser has been used as a tool for solving many problems involving access, machining, disassembly, inspection and avoidance of undesirable hazardous waste streams in systems containing energetic materials. Because of the unique properties of the interaction of ultrashort laser pulses with matter, the femtosecond laser can be used to safely cut these energetic materials in a precise manner without creating an unacceptable waste stream. Many types of secondary high explosives (HE) and propellants have been cut with the laser for a variety of applications ranging from disassembly of aging conventional weapons (demilitarization), inspection of energetic components of aging systems to creating unique shapes of HE for purposes of initiation and detonation physics studies. Hundreds of samples of energetic materials have been cut with the fs laser without ignition and, in most cases, without changing the surface morphology of the cut surfaces. The laser has also been useful in cutting nonenergetic components in close proximity to energetic materials. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Test of remote control cutting equipment by Nd:YAG laser

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Akio [Fuji Electric Corp. Research and Development Ltd., Yokosuka, Kanagawa (Japan); Hosoda, Hiroshi

1997-11-01

Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. This report is described the result of experiment by test equipment, about element technology of remote controlled cutting nuclear equipments. (author)

Test of remote control cutting equipment by Nd:YAG laser

International Nuclear Information System (INIS)

Shimizu, Akio; Hosoda, Hiroshi.

1997-01-01

Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. This report is described the result of experiment by test equipment, about element technology of remote controlled cutting nuclear equipments. (author)

A cutting-edge solution for 1µm laser metal processing

Science.gov (United States)

Baumbach, N.; Kühl, P.; Karam, J.; Jonkers, J.; Villarreal-Saucedo, F.; Reyes, M.

2017-02-01

The recent 1μm-laser cutting market is dominated by fiber and disk lasers due to their excellent beam quality of below 4mm*mrad. Teradiode's 4kW direct diode laser source achieves similar beam quality while having a different beam shape and shorter wavelengths which are known for higher absorption rates at the inclined front of the cutting keyhole. Research projects, such as the HALO Project, have additionally shown that polarized radiation and beams with shapes different from the typical LG00 lead to improved cut quality for ferrous and non-ferrous metals. [1] Diode laser have the inherent property of not being sensitive to back reflection which brings advantages in cutting high-reflective materials. The II-VI HIGHYAG laser cutting head BIMO-FSC offers the unique feature of machine controlled and continuous adjustment of both the focus diameter and the focus position. This feature is proven to be beneficial for cutting and piercing with high speed and small hole diameters. In addition, the optics are designed for lowest focus shift. As a leading laser processing head manufacturer, II-VI HIGHYAG qualified its BIMO-FSC MZ (M=magnification, Z=focus position) cutting head for Teradiode's 4kW direct diode laser source to offer a cutting-edge solution for highpower laser cutting. Combining the magnification ability of the cutting head with this laser source, customers experience strong advantages in cutting metals in broad thickness ranges. Thicknesses up to 25mm mild steel can easily be cut with excellent edge quality. Furthermore, a new optical setup equivalent to an axicon with a variable axicon angle is demonstrated which generates variable sized ring spots. The setup provides new degrees of freedom to tailor the energy distribution for even higher productivity and quality.

The laser revolution in shipbuilding: laser welding and cutting at Blohm + Voss

Energy Technology Data Exchange (ETDEWEB)

Minsks, T. [Blohm und Voss GmbH, Hamburg (Germany). Laser Production Line

2000-12-01

Precision manufacturing in steel shipbuilding has gained significantly in importance in recent years as a means of raising productivity and thus enhancing competitiveness. Precision manufacturing means working to very narrow tolerances, minimizing assembly costs by eliminating the need for straightening and adjustment, reducing reworking requirements and shortening throughput times. Blohm+Voss GmbH is the world's first shipbuilding company to use laser technology as part of its precision manufacturing approach, combined with complex clamping techniques which render exact prepositioning and tack welding of components superfluous. Laser cutting makes it possible to cut large formats with virtually parallel cut edges and very narrow cutting gaps which - in conjunction with suitable clamping - allow laser welding without the use of fillers. With a smaller heat-affected zone, laser welding causes less part distortion than conventional methods. This makes it possible to use thinner sheets and sections and thus supports the very low-weight constructions required for the types of ship built by Blohm+Voss. By combining laser cutting and laser welding in a single production line, Blohm+Voss currently boasts the most advanced prefabrication facility in shipbuilding, capable of producing components up to 12 meters long and 4 meters wide. (orig.)

Laser cutting, State of the art and technological trends

DEFF Research Database (Denmark)

Olsen, Flemming Ove

1999-01-01

In this paper a short review of the development trends in laser cutting will be given. The technoloty which is the fastest expanding industrial production technology will develop in both its core market segment: Flat bed cutting of sheet metal as it will expand in heavy industry and in cutting of 3......-dimensional shapes. The CO2 laser will also in the near futre be the domination laser source in the market, although the new developments in ND-YAG-lasers opens for new possibilities for this laser type....

Demonstration of Laser Cutting System for Tube Specimen

Energy Technology Data Exchange (ETDEWEB)

Jin, Y. G.; Kim, G. S.; Heo, G. S.; Baik, S. J.; Kim, H. M.; Ahn, S. B. [KAERI, Daejeon (Korea, Republic of)

2016-05-15

The oxide layer removal system was also developed because the oxide layer on the surface of the irradiated fuel cladding and components interrupted the applying the electric current during the processing. However, it was found that the mechanical testing data of the irradiated specimens with removal of oxide layer was less reliable than the specimens with oxide layer . The laser cutting system using Nd:YAG with fiber optic beam delivery has great potential in material processing applications of the irradiated fuel cladding and components due to non-contact process. Thus, the oxide layer doesn't interrupt the fabrication process during the laser cutting system. In the present study, the laser cutting system was designed to fabricate the mechanical testing specimens from the unirradiated fuel cladding with and without oxide. The feasibility of the laser cutting system was demonstrated for the fabrication of various types of unirradiated specimens. The effect of surface oxide layer was also investigated for machining process of the zirlo fuel cladding and it was found that laser beam machining could be a useful tool to fabricate the specimens with surface oxide layer. Based on the feasibility studies and demonstration, the design of the laser cutting machine for fully or partially automatic and remotely operable system will be proposed and made.

Local drying underwater cutting of reactor core internals by CO laser

International Nuclear Information System (INIS)

Beppu, Seiji; Takano, Genta; Matsumoto, Osa; Sugihara, Masaaki; Miya, Kenzo.

1991-01-01

Since the CO laser operates at shorter wavelength than the CO 2 laser, the former has superior ability to cut materials. Its applicability to the cutting of reactor core internals in a nuclear power plant has been studied. In order to use such a laser for cutting actual structures, it would be useful to develop underwater cutting technology for the purpose of minimizing radiation exposure during cutting. However, since the laser beam is absorbed by water, a path needs to be cleared along the laser's line of sight. The authors have developed a nozzle that forms a local dry zone and have demonstrated that CO laser cutting can be carried out under water as it is in air. (author)

CALCULATION OF LASER CUTTING COSTS

Directory of Open Access Journals (Sweden)

Bogdan Nedic

2016-09-01

Full Text Available The paper presents description methods of metal cutting and calculation of treatment costs based on model that is developed on Faculty of mechanical engineering in Kragujevac. Based on systematization and analysis of large number of calculation models of cutting with unconventional methods, mathematical model is derived, which is used for creating a software for calculation costs of metal cutting. Software solution enables resolving the problem of calculating the cost of laser cutting, comparison' of costs made by other unconventional methods and provides documentation that consists of reports on estimated costs.

Laser cutting system in bridge fabricating line; Kyoryo seisaku line ni okeru laser no setsudan system

Energy Technology Data Exchange (ETDEWEB)

Kitaguchi, Y.; Yokotani, K. [Hitachi Zosen Corp., Osaka (Japan)

1994-11-01

This paper describes the laser cutting system established at a new advanced plant that was constructed by Hitachi Shipbuilding and Engineering Co., Ltd. in 1993. At the plant, the cutting line consists of four NC cutting lines: the plasma cutting machine, gas cutting machine, frame planer, and laser cutting machine. The laser cutting machine is used to cut complex shapes of relatively thin (6 - 16 mm) materials with high accuracy. The machine consists of a 3 kW CO2 laser oscillator mounted gantry type NC cutter and a slat conveyor of about 30 m long, with the maximum cutting width of 3.6 m. The NC cutting machine is provided with the automatic printing function using NC data, marking function, scheduled operation function, steel plate detector, and coordinate rotation function, etc. These functions enable unattended operation of the machine to cut multiple materials. This NC laser cutting line has the same performance data collection function for data during the operating time as other production lines. Therefore, the NC laser cutting line can be subjected to the realtime centralized control together with the other lines. All these technologies have provided high accuracy and efficiency for production as well as an environment in which many female operators can successfully work. 10 figs., 4 tabs.

Application of laser cutting technology to high radiation environments

International Nuclear Information System (INIS)

Pauley, K.A.; Mitchell, M.R.; Saget, S.N.

1996-01-01

A 2 kW Nd:YAG laser system manufactured by the Lumonics Corporation will be used to cut various metals during the fall of 1996 as part of a United States Department of Energy (DOE)-funded technology demonstration at the Hanford Site. The laser cutting demonstration will focus on an evaluation of two issues as the technology applies to the decontamination and decommissioning (D ampersand D) of aging nuclear facilities. An assessment will be made as to the ability of laser end effectors to be operated using electromechanical remote manipulators and the ability of both end effector and fiber optics to withstand the damage created by a high radiation field. The laser cutting demonstration will be conducted in two phases. The first phase will be a non-radioactive test to ensure the ability of hot cell remote manipulators to use the laser end effector to successfully cut the types of materials and geometries found in the hot cell. The second phase will introduce the laser end effector and the associated fiber optic cable into the hot cell radiation environment. The testing in the hot cell will investigate the degradation of the optical portions of the end effector and transmission cable in the high radiation field. The objective of the demonstration is to assess the cutting efficiency and life limitations of a laser cutting system for radioactive D ampersand D operations. A successful demonstration will, therefore, allow the laser cutting technology to be integrated into the baseline planning for the D ampersand D of DOE facilities throughout the nation

MULTI-OBJECTIVE OPTIMISATION OF LASER CUTTING USING CUCKOO SEARCH ALGORITHM

Directory of Open Access Journals (Sweden)

M. MADIĆ

2015-03-01

Full Text Available Determining of optimal laser cutting conditions for improving cut quality characteristics is of great importance in process planning. This paper presents multi-objective optimisation of the CO2 laser cutting process considering three cut quality characteristics such as surface roughness, heat affected zone (HAZ and kerf width. It combines an experimental design by using Taguchi’s method, modelling the relationships between the laser cutting factors (laser power, cutting speed, assist gas pressure and focus position and cut quality characteristics by artificial neural networks (ANNs, formulation of the multiobjective optimisation problem using weighting sum method, and solving it by the novel meta-heuristic cuckoo search algorithm (CSA. The objective is to obtain optimal cutting conditions dependent on the importance order of the cut quality characteristics for each of four different case studies presented in this paper. The case studies considered in this study are: minimisation of cut quality characteristics with equal priority, minimisation of cut quality characteristics with priority given to surface roughness, minimisation of cut quality characteristics with priority given to HAZ, and minimisation of cut quality characteristics with priority given to kerf width. The results indicate that the applied CSA for solving the multi-objective optimisation problem is effective, and that the proposed approach can be used for selecting the optimal laser cutting factors for specific production requirements.

Material Properties of Laser-Welded Thin Silicon Foils

Directory of Open Access Journals (Sweden)

M. T. Hessmann

2013-01-01

Full Text Available An extended monocrystalline silicon base foil offers a great opportunity to combine low-cost production with high efficiency silicon solar cells on a large scale. By overcoming the area restriction of ingot-based monocrystalline silicon wafer production, costs could be decreased to thin film solar cell range. The extended monocrystalline silicon base foil consists of several individual thin silicon wafers which are welded together. A comparison of three different approaches to weld 50 μm thin silicon foils is investigated here: (1 laser spot welding with low constant feed speed, (2 laser line welding, and (3 keyhole welding. Cross-sections are prepared and analyzed by electron backscatter diffraction (EBSD to reveal changes in the crystal structure at the welding side after laser irradiation. The treatment leads to the appearance of new grains and boundaries. The induced internal stress, using the three different laser welding processes, was investigated by micro-Raman analysis. We conclude that the keyhole welding process is the most favorable to produce thin silicon foils.

An Evaluation of the Cutting Potential of Different Types of High Power Lasers

DEFF Research Database (Denmark)

Olsen, Flemming Ove

2006-01-01

Laser cutting is a widespread industrial process. The boundaries for the performance of the lasers in terms of cutting capabilities is steadily moving towards higher cutting rates and thicker section cutting. In this paper the potential of different high power laser sources in cutting is evaluated...... based upon the historical development, the available cutting mechanisms understanding and the critical parameters involved in high power laser cutting. From the theoretical point of view, the new laser sources, the Disc-laser and the Fibre laser possess a potential of changing dramatically the limits...... for cutting performance. These theoretical considerations are evaluated against available cutting data....

Acoustic damage detection in laser-cut CFRP composite materials

Science.gov (United States)

Nishino, Michiteru; Harada, Yoshihisa; Suzuki, Takayuki; Niino, Hiroyuki

2012-03-01

Carbon fiber reinforced plastics (CFRP) composite material, which is expected to reduce the weight of automotive, airplane and etc., was cut by laser irradiation with a pulsed-CO2 laser (TRUMPF TFL5000; P=800W, 20kHz, τ=8μs, λ=10.6μm, V=1m/min) and single-mode fiber lasers (IPG YLR-300-SM; P=300W, λ=1.07μm, V=1m/min)(IPG YLR- 2000-SM; P=2kW, λ=1.07μm, V=7m/min). To detect thermal damage at the laser cutting of CFRP materials consisting of thermoset resin matrix and PAN or PITCH-based carbon fiber, the cut quality was observed by X-ray CT. The effect of laser cutting process on the mechanical strength for CFRP tested at the tensile test. Acoustic emission (AE) monitoring, high-speed camera and scanning electron microscopy were used for the failure process analysis. AE signals and fractographic features characteristic of each laser-cut CFRP were identified.

Characterisation of aerosols produced by laser cutting

International Nuclear Information System (INIS)

Fauvel, S.; Pilot, G.; Dinechin, G. de; Gosse, X.; Arnaud, P.

2007-01-01

Powerful lasers represent a promising alternative solution to traditional cutting processes used in dismantling nuclear equipments. The use of optical fibers has an unquestionable advantage when dealing with airtight workshops. A study funded by COGEMA Marcoule was undertaken by IRSN/SERAC in collaboration with GIP/GERAILP in order to characterise the aerosols emitted by the cutting of evaporators elements with a 4 kW continuous wave Nd:YAG laser. For this study, laser cutting has been carried out in a tight room of 35 m 3 connected to a particle sampling pipe. Iso-kinetic samplers allowed the measurement of the aerosol concentration. A diffusional and inertial spectrometer (SDI 2001) - an Andersen impinger coupled to a diffusion battery - provided the size distribution. An electrostatic filter used upstream a HEPA filter, itself placed before the extractor fan, collected the majority of the emitted aerosol. Its efficiency was measured and controlled throughout the experiments. The results show the influence of the cutting conditions on the characteristics of the aerosol, and allow a comparison with other cutting tools. (authors)

Characterisation of debris from laser and mechanical cutting of bone.

Science.gov (United States)

Rachmanis, Nikolaos; McGuinness, Garrett B; McGeough, Joseph A

2014-07-01

Laser cutting of bones has been proposed as a technology in orthopaedic surgery. In this short study, the laser-bone interaction was examined using a pulsed erbium-doped yttrium aluminium garnet laser and compared to a conventional cutting technique. Microscopic analysis revealed the nature of waste debris and showed higher proportions of finer particles for conventional sagittal sawing compared to laser cutting. © IMechE 2014.

Combustion-assisted laser cutting of a difficult-to-machine superalloy

International Nuclear Information System (INIS)

Molian, P.A.

1992-01-01

In laser cutting, the largest single application of lasers in manufacturing, the assist gas plays an important role in affecting the cutting performance. The assist gas is usually oxygen or an inert gas. In this paper acetylene and oxygen was employed to create combustion reactions during CO 2 laser cutting that enabled an improvement in the cutting speed, and cut quality of a difficult-to-machine superalloy. A comparison with laser cutting of a plain carbon steel under identical conditions was also made to determine the usefulness of combustion energy. Results indicate that both cutting speed and quality are enhanced by the reduction in the viscosity of slag formed during cutting (which assisted in ejection of the slag through the bottom of the kerf) due to the heat released by the acetylene burning inside the kerf. Correlations of experimental data with a theoretical model provided the influence of combustion power and gas-flow power on the cutting phenomena

High-quality laser cutting of stainless steel in inert gas atmosphere by ytterbium fibre and CO2 lasers

International Nuclear Information System (INIS)

Golyshev, A A; Malikov, A G; Orishich, A M; Shulyat'ev, V B

2014-01-01

Processes of cutting stainless steel by ytterbium fibre and CO 2 lasers have been experimentally compared. The cut surface roughnesses for 3- and 5-mm-thick stainless steel sheets are determined. The absorption coefficient of laser radiation during cutting is measured. It is established that the power absorbed by metal during cutting by the CO 2 laser exceeds that for the ytterbium laser (provided that the cutting speed remains the same). The fact that the maximum cutting speed of the CO 2 laser is lower than that of the ytterbium fibre laser is explained. (laser technologies)

Laser cutting equipment for dismantling irradiated PFR fuel sub-assemblies

International Nuclear Information System (INIS)

Higginson, P.R.; Campbell, D.A.

1981-01-01

Laser cutting was identified as a possible technique for dismantling irradiated Prototype Fast Reactor (P.F.R.) fuel sub-assemblies and initial trials showed that it could be used to make essentially swarf free cuts in P.F.R. wrapper material provided sufficient laser power was available to allow use of an inert cutting gas. A programme of development work has established a technique for inert gas cutting with the reliable, commercially available Ferranti MF 400 laser and equipment for laser cutting of sub-assemblies has been installed in the Irradiated Fuel Cave at P.F.R. Test cuts carried out with this equipment on un-irradiated wrapper sections have shown it to be easy to operate remotely, optically stable and reliable in operation. (author)

Femtosecond laser irradiation-induced infrared absorption on silicon surfaces

Directory of Open Access Journals (Sweden)

Qinghua Zhu

2015-04-01

Full Text Available The near-infrared (NIR absorption below band gap energy of crystalline silicon is significantly increased after the silicon is irradiated with femtosecond laser pulses at a simple experimental condition. The absorption increase in the NIR range primarily depends on the femtosecond laser pulse energy, pulse number, and pulse duration. The Raman spectroscopy analysis shows that after the laser irradiation, the silicon surface consists of silicon nanostructure and amorphous silicon. The femtosecond laser irradiation leads to the formation of a composite of nanocrystalline, amorphous, and the crystal silicon substrate surface with microstructures. The composite has an optical absorption enhancement at visible wavelengths as well as at NIR wavelength. The composite may be useful for an NIR detector, for example, for gas sensing because of its large surface area.

Laser cutting technology using water jet waveguide

International Nuclear Information System (INIS)

Akiba, Miyuki; Shiihara, Katsunori; Chida, Itaru

2013-01-01

Laser with water jet is examined to cut in-vessel structure. However, it is necessary to increase the break-up length of water jet to cut a thick plate. Therefore, the effects of the water jet parameter (water pressure, assist gas, laser power) on break-up length were investigated. It was found from observation results of water jet that the longest break-up length is about 135mm under condition of water pressure 40 MPa, laser power 30W and helium assist gas 1L/min. (author)

Silicon nanostructures produced by laser direct etching

DEFF Research Database (Denmark)

Müllenborn, Matthias; Dirac, Paul Andreas Holger; Petersen, Jon Wulff

1995-01-01

A laser direct-write process has been applied to structure silicon on a nanometer scale. In this process, a silicon substrate, placed in a chlorine ambience, is locally heated above its melting point by a continuous-wave laser and translated by high-resolution direct-current motor stages. Only...

Trend of laser cutting technology; Laser setsudan gijutsu no saikin no doko

Energy Technology Data Exchange (ETDEWEB)

Murai, T. [Mitsubishi Electric Corp., Tokyo (Japan)

1997-10-05

Recent trend of CO2 laser cutting is described. The cutting speed has increased five times in these seven years, and cutting is now performed at 8m/min for a hole that satisfies a circularity of 50{mu}m. In the low-speed domain, again, cutting accuracy is as high as 20{mu}m. In the cutting of thick plates, laser encounters some difficulties, which include the increased thermal load on optical parts and devices in the oscillator, lessened cutting condition tolerance, variation in the accuracy of products, difficult cutting, etc. Discussed in this report are measures for correcting factors affecting product quality with reference taken to a thick soft steel plate. A laser beam emitted by an oscillator is condensed by and projected through a condenser lens, and the condensing capability is affected by various factors, such as the beam mode order, beam diameter, and focal length, etc. What is important is to find out the optimal conditions. The assist gas has to satisfy certain conditions because it assumes an important role in controlling the discharge of molten metal from cut grooves, heat generated by oxidation reaction, and cooling. The properties of the material to be cut also exert some influence. In the case of thick plate cutting, the cutting capability is governed by the geometry to be fabricated. Also employed for the prevention of poor jobs due to improper condition switchover and cutting routes is an optimal cutting condition control technique. 3 refs., 12 figs.

Parametric studies of cutting zircaloy-2 sheets with a laser beam

International Nuclear Information System (INIS)

Ghosh, S.; Badgujar, B.P.; Goswami, G.L.

1996-01-01

The highly reactive and pyrophoric nature of zirconium alloys limits the use of conventional thermal sources (e.g., plasma arc cutting, oxygen flame cutting, etc.) for the cutting and drilling of these alloys. In this context, a highly coherent laser beam provides a good alternative for the cutting and drilling. In the present paper, laser beam cutting of zircaloy-2 sheets of 1.1 mm and 0.74 mm thickness is performed using a 300 W average power pulsed Nd:YAG laser. Pulse energy, pulse repetition rate, nozzle gap, gas pressure and cutting speed were varied to give different laser cutting conditions. Metallographic study of the cut surfaces showed the presence of transformed beta phase in the heat affected zone (HAZ) near the cut surface. The microhardness value across the cut surface was also measured. It showed a gradual increase in microhardness from the base metal (160 VHN) towards the HAZ having a maximum value of 365 VHN. The results of parametric studies of the cutting indicated that, with proper selection of process parameters, very narrow cuts can be easily made in zircaloy-2 using a pulsed Nd:YAG laser with a saving in material and at a much faster rate than alternative processes such as plasma arc cutting and oxygen flame cutting

CO2 Laser Cutting of Hot Stamping Boron Steel Sheets

OpenAIRE

Pasquale Russo Spena

2017-01-01

This study investigates the quality of CO2 laser cutting of hot stamping boron steel sheets that are employed in the fabrication of automotive body-in-white. For this purpose, experimental laser cutting tests were conducted on 1.2 mm sheets at varying levels of laser power, cutting speed, and oxygen pressure. The resulting quality of cut edges was evaluated in terms of perpendicularity tolerance, surface irregularity, kerf width, heat affected zone, and dross extension. Experimental tests wer...

Ann modeling of kerf transfer in Co2 laser cutting and optimization of cutting parameters using monte carlo method

Directory of Open Access Journals (Sweden)

Miloš Madić

2015-01-01

Full Text Available In this paper, an attempt has been made to develop a mathematical model in order to study the relationship between laser cutting parameters such as laser power, cutting speed, assist gas pressure and focus position, and kerf taper angle obtained in CO2 laser cutting of AISI 304 stainless steel. To this aim, a single hidden layer artificial neural network (ANN trained with gradient descent with momentum algorithm was used. To obtain an experimental database for the ANN training, laser cutting experiment was planned as per Taguchi’s L27 orthogonal array with three levels for each of the cutting parameters. Statistically assessed as adequate, ANN model was then used to investigate the effect of the laser cutting parameters on the kerf taper angle by generating 2D and 3D plots. It was observed that the kerf taper angle was highly sensitive to the selected laser cutting parameters, as well as their interactions. In addition to modeling, by applying the Monte Carlo method on the developed kerf taper angle ANN model, the near optimal laser cutting parameter settings, which minimize kerf taper angle, were determined.

Effect of Cut Quality on Hybrid Laser Arc Welding of Thick Section Steels

Science.gov (United States)

Farrokhi, F.; Nielsen, S. E.; Schmidt, R. H.; Pedersen, S. S.; Kristiansen, M.

From an industrial point of view, in a laser cutting-welding production chain, it is of great importance to know the influence of the attainable laser cut quality on the subsequent hybrid laser arc welding process. Many studies have been carried out in the literature to obtain lower surface roughness values on the laser cut edge. However, in practice, the cost and reliability of the cutting process is crucial and it does not always comply with obtaining the highest surface quality. In this study, a number of experiments on 25 mm steel plates were carried out to evaluate the influence of cut surface quality on the final quality of the subsequent hybrid laser welded joints. The different cut surfaces were obtained by different industrial cutting methods including laser cutting, abrasive water cutting, plasma cutting, and milling. It was found that the mentioned cutting methods could be used as preparation processes for the subsequent hybrid laser arc welding. However, cut quality could determine the choice of process parameters of the following hybrid laser arc welding.

Mode-locked silicon evanescent lasers.

Science.gov (United States)

Koch, Brian R; Fang, Alexander W; Cohen, Oded; Bowers, John E

2007-09-03

We demonstrate electrically pumped lasers on silicon that produce pulses at repetition rates up to 40 GHz. The mode locked lasers generate 4 ps pulses with low jitter and extinction ratios above 18 dB, making them suitable for data and telecommunication transmitters and for clock generation and distribution. Results of both passive and hybrid mode locking are discussed. This type of device could enable new silicon based integrated technologies, such as optical time division multiplexing (OTDM), wavelength division multiplexing (WDM), and optical code division multiple access (OCDMA).

Femtosecond laser ablation and cutting technology on PMP foam

International Nuclear Information System (INIS)

Song Chengwei; Li Guo; Huang Yanhua; Du Kai; Yang Liang

2013-01-01

The femtosecond laser ablation results of PMP foam (density of 90 mg/cm 3 ) were analyzed. The laser pulses used for the study were 800 nm in wavelength, 50 fs in pulse duration and the repetition rate was 1000 Hz. The ablation threshold of the foam was 0.91 J/cm 2 when it was shot by 100 laser pulses. The impacts of laser power, the pulse number and the numerical aperture of the focusing objective on the crater diameter were obtained. In the same femtosecond laser machining system, comparing with the ablation shape into copper foil, the important factor causing the irregular shape of the ablation region was verified that there were many different sizes and randomly distributed pores inside PMP foam. The carbonation phenomenon was observed on the edge of the ablated areas when the sample was ablated using high laser power or/and more laser pulses. Thermal effect was considered to be the causes of the carbonation. A new method based on coupling laser beam to cut thickness greater than 1 mm film-foam with femtosecond laser was proposed. Using this method, the femtosecond laser cutting thickness was greater than 1.5 mm, the angle between the cutting side wall and the laser beam optical axis might be less than 5°, and the cutting surface was clean. (authors)

High-power fiber laser cutting parameter optimization for nuclear Decommissioning

Directory of Open Access Journals (Sweden)

Ana Beatriz Lopez

2017-06-01

Full Text Available For more than 10 years, the laser process has been studied for dismantling work; however, relatively few research works have addressed the effect of high-power fiber laser cutting for thick sections. Since in the nuclear sector, a significant quantity of thick material is required to be cut, this study aims to improve the reliability of laser cutting for such work and indicates guidelines to optimize the cutting procedure, in particular, nozzle combinations (standoff distance and focus position, to minimize waste material. The results obtained show the performance levels that can be reached with 10 kW fiber lasers, using which it is possible to obtain narrower kerfs than those found in published results obtained with other lasers. Nonetheless, fiber lasers appear to show the same effects as those of CO2 and ND:YAG lasers. Thus, the main factor that affects the kerf width is the focal position, which means that minimum laser spot diameters are advised for smaller kerf widths.

High-power fiber laser cutting parameter optimization for nuclear decommissioning

Energy Technology Data Exchange (ETDEWEB)

Lopez, Ana Beatriz; Assuncao, Eurico; Quintino, Luisa [IDMEC, Instituto Superior Tecnico, Universidade de Lisboa, Lisboa (Portugal); Khan, Ali; Blackbun, Jonathan [TWI Ltd., Cambridge (United States)

2017-06-15

For more than 10 years, the laser process has been studied for dismantling work; however, relatively few research works have addressed the effect of high-power fiber laser cutting for thick sections. Since in the nuclear sector, a significant quantity of thick material is required to be cut, this study aims to improve the reliability of laser cutting for such work and indicates guidelines to optimize the cutting procedure, in particular, nozzle combinations (standoff distance and focus position), to minimize waste material. The results obtained show the performance levels that can be reached with 10 kW fiber lasers, using which it is possible to obtain narrower kerfs than those found in published results obtained with other lasers. Nonetheless, fiber lasers appear to show the same effects as those of CO{sub 2} and ND:YAG lasers. Thus, the main factor that affects the kerf width is the focal position, which means that minimum laser spot diameters are advised for smaller kerf widths.

Photodiode-based cutting interruption sensor for near-infrared lasers.

Science.gov (United States)

Adelmann, B; Schleier, M; Neumeier, B; Hellmann, R

2016-03-01

We report on a photodiode-based sensor system to detect cutting interruptions during laser cutting with a fiber laser. An InGaAs diode records the thermal radiation from the process zone with a ring mirror and optical filter arrangement mounted between a collimation unit and a cutting head. The photodiode current is digitalized with a sample rate of 20 kHz and filtered with a Chebyshev Type I filter. From the measured signal during the piercing, a threshold value is calculated. When the diode signal exceeds this threshold during cutting, a cutting interruption is indicated. This method is applied to sensor signals from cutting mild steel, stainless steel, and aluminum, as well as different material thicknesses and also laser flame cutting, showing the possibility to detect cutting interruptions in a broad variety of applications. In a series of 83 incomplete cuts, every cutting interruption is successfully detected (alpha error of 0%), while no cutting interruption is reported in 266 complete cuts (beta error of 0%). With this remarkable high detection rate and low error rate, the possibility to work with different materials and thicknesses in combination with the easy mounting of the sensor unit also to existing cutting machines highlight the enormous potential for this sensor system in industrial applications.

Innovation Study for Laser Cutting of Complex Geometries with Paper Materials

Science.gov (United States)

Happonen, A.; Stepanov, A.; Piili, H.; Salminen, A.

Even though technology for laser cutting of paper materials has existed for over 30 years, it seems that results of applications of this technology and possibilities of laser cutting systems are not easily available. The aim of this study was to analyze the feasibility of the complex geometry laser cutting of paper materials and to analyze the innovation challenges and potential of current laser cutting technologies offer. This research studied the potential and possible challenges in applying CO2 laser cutting technology for cutting of paper materials in current supply chains trying to fulfil the changing needs of customer in respect of shape, fast response during rapid delivery cycle. The study is focused on examining and analyzing the different possibilities of laser cutting of paper material in application area of complex low volume geometry cutting. The goal of this case was to analyze the feasibility of the laser cutting from technical, quality and implementation points of view and to discuss availability of new business opportunities. It was noticed that there are new business models still available within laser technology applications in complex geometry cutting. Application of laser technology, in business-to-consume markets, in synergy with Internet service platforms can widen the customer base and offer new value streams for technology and service companies. Because of this, existing markets and competition has to be identified, and appropriate new and innovative business model needs to be developed. And to be competitive in the markets, models like these need to include the earning logic and the stages from production to delivery as discussed in the paper.

Finite element simulation of laser cutting process of steel sheet

Directory of Open Access Journals (Sweden)

Meško Jozef

2018-01-01

Full Text Available Lasers are widely used in industry as cutting tools due to ultra flexibility of the cutting conditions, obtaining high quality end product, quick set up, non-mechanical contact between the workpiece and the tool, and small size of the heat affected zone. In the present study, laser gas assisted cutting process is examined. The laser cutting sheet solution is practically always very convenient compared to conventional technologies and brings the greatest cost savings in the manufacturing process.

High-quality laser cutting of stainless steel in inert gas atmosphere by ytterbium fibre and CO{sub 2} lasers

Energy Technology Data Exchange (ETDEWEB)

Golyshev, A A; Malikov, A G; Orishich, A M; Shulyat' ev, V B [S.A. Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

2014-03-28

Processes of cutting stainless steel by ytterbium fibre and CO{sub 2} lasers have been experimentally compared. The cut surface roughnesses for 3- and 5-mm-thick stainless steel sheets are determined. The absorption coefficient of laser radiation during cutting is measured. It is established that the power absorbed by metal during cutting by the CO{sub 2} laser exceeds that for the ytterbium laser (provided that the cutting speed remains the same). The fact that the maximum cutting speed of the CO{sub 2} laser is lower than that of the ytterbium fibre laser is explained. (laser technologies)

Cutting performances with new industrial continuous wave ND:YAG high power lasers

International Nuclear Information System (INIS)

Chagnot, C.; Dinechin, G. de; Canneau, G.

2010-01-01

Dismantling is a great challenge for nuclear companies which are facing with the cleaning of former nuclear sites. Among the available cutting processes is the multi-kilowatts laser whose power is transmitted through optical fibers. Unlike other cutting processes such as the plasma arc cutting process or the oxy-cutting process, the laser process can be easily implemented by robotic equipments. The mechanised robotic arm carries a laser cutting head to perform, with remote-controlled equipments, the cutting operation. The present study deals with the performances which can be reached with high power continuous wave ND:YAG lasers. The cutting tests were carried out up to 8 kW. The laser power was delivered through a specific power supply chain: a 0.4 mm fiber was transporting the power from the laser to a first interface (coupler) then a second 0.6 mm fiber was bringing the laser power to the cutting head. This solution allowed a power delivery chain whose length could be as high as 100 + 20/50 m. Another advantage of this kind of power supply is that the first fiber can be set in a non-contaminated environment whereas the second fiber lies in the contaminated area. The cutting head used for these tests was a specific tool developed for this laser dismantling work: it is a laser cutting head cooled by pressurized air. This tool was developed with the requirement to be able to sustain a laser power of 14 kW. The pressurized air used to cool the head is also used as cutting gas. The cutting capability was about 10 mm by kW. At the power of 8 kW, austenitic steel plates of thickness 100 mm were cut. These performances were reached with the cut started on the plate's edge. If the cut started in the middle of the plate, the cutting performances were not so high: 8 kW became the power to drill and to cut plates of thickness 40 mm.

Numerical simulation of the shape of laser cut for fiber and CO2 lasers

Science.gov (United States)

Zaitsev, A. V.; Ermolaev, G. V.; Polyanskiy, T. A.; Gurin, A. M.

2017-10-01

The results of numerical modeling of steel plate laser cutting with nitrogen as assist gas with consideration of heat transfer into a bulk material are presented. In this work we studied a distribution of absorbed radiation energy inside cut kerf and the difference between CO2 and fiber laser radiation propagation and absorption. The influence of secondary absorption of reflected from the cut front radiation on stability of melt hydrodynamics is discussed for different laser types.

Laser welding, cutting and surface treatment

International Nuclear Information System (INIS)

Crafer, R.C.

1984-01-01

Fourteen articles cover a wide range of laser applications in welding, cutting and surface treatment. Future trends are covered as well as specific applications in shipbuilding, the manufacture of heart pacemakers, in the electronics industry, in automobile production and in the aeroengine industry. Safety with industrial lasers and the measurement of laser beam parameters are also included. One article on 'Lasers in the Nuclear Industry' is indexed separately. (U.K.)

Investigating the CO2 laser cutting parameters of MDF wood composite material

OpenAIRE

Eltawahni, Hayat; Olabi, Abdul-Ghani; Benyounis, Khaled

2011-01-01

Laser cutting of medium density fibreboard (MDF) is a complicated process and the selection of the process parameters combinations is essential to get the highest quality of the cut section. This paper presents laser cutting of MDF based on design of experiments (DOE). CO2 laser was used to cut three thicknesses 4, 6 and 9 mm of MDF panels. The process factors investigated are: laser power, cutting speed, air pressure and focal point position. In this work, cutting quality was evaluated by me...

Efficiency of laser beam utilization in gas laser cutting of materials

Science.gov (United States)

Galushkin, M. G.; Grishaev, R. V.

2018-02-01

Relying on the condition of dynamic matching of the process parameters in gas laser cutting, the dependence of the beam utilization factor on the cutting speed and the beam power has been determined. An energy balance equation has been derived for a wide range of cutting speed values.

Cutting and drilling studies using high power visible lasers

International Nuclear Information System (INIS)

Kautz, D.D.; Dragon, E.P.; Werve, M.E.; Hargrove, R.S.; Warner, B.E.

1993-01-01

High power and radiance laser technologies developed at Lawrence Livermore National Laboratory such as copper-vapor and dye lasers show great promise for material processing tasks. Evaluation of models suggests significant increases in welding, cutting, and drilling capabilities, as well as applications in emerging technologies such as micromachining, surface treatment, and stereolithography. Copper lasers currently operate at 1.8 kW output at approximately three times the diffraction limit and achieve mean time between failures of more than 1,000 hours. Dye lasers have near diffraction limited beam quality at greater than 1.0 kW. Results from cutting and drilling studies in titanium and stainless steel alloys show that cuts and holes with extremely fine features can be made with dye and copper-vapor lasers. High radiance beams produce low distortion and small heat-affected zones. The authors have accomplished very high aspect ratios (> 60:1) and features with micron scale (5-50 μm) sizes. The paper gives a description of the equipment; discusses cutting theory; and gives experimental results of cutting and drilling studies on Ti-6Al-4V and 304 stainless steel

Experimental study on concrete cutting by CO2 laser beam

International Nuclear Information System (INIS)

Kutsumizu, Akira; Tomura, Hidemasa; Wakizaka, Tatsuya; Hishikawa, Kyoichi; Moriya, Masahiro

1994-01-01

Methods for dismantling nuclear reactor facilities must meet particularly exacting requirements imposed by heavily reinforced and radioactivated reactor shield walls. Conventional methods do not meet all such requirements, however. Intrigued by excellent characteristics of the laser cutting method relative to nuclear facility demolition, we carried out an experimental study to make a comprehensive evaluation of its characteristics, especially for deep cutting, with success in identifying main factors affecting the cutting depth of a laser and characterizing its cutting behavior. The study results indicate that a 50 kW class CO 2 laser has a potential to provide a practicable cutting speed and depth. (author)

Photon-phonon laser on crystalline silicon: a feasibility study

International Nuclear Information System (INIS)

Zadernovsky, A A

2015-01-01

We discuss a feasibility of photon-phonon laser action in bulk silicon with electron population inversion. It is well known, that only direct gap semiconductors are used as an active medium in optical lasers. In indirect gap semiconductors, such as crystalline silicon, the near-to-gap radiative electron transitions must be assisted by emission or absorption of phonons to conserve the momentum. The rate of such two-quantum transitions is much less than in direct gap semiconductors, where the similar radiative transitions are single-quantum. As a result, the quantum efficiency of luminescence in silicon is too small to get it as a laser material. Numerous proposals to overcome this problem are aimed at increasing the rate of radiative recombination. We suggest enhancing the quantum efficiency of luminescence in silicon by stimulating the photon part of the two-quantum transitions by light from an appropriate external laser source. This allows us to obtain initially an external-source-assisted lasing in silicon and then a true photon-phonon lasing without any external source of radiation. Performed analysis revealed a number of requirements to the silicon laser medium (temperature, purity and perfection of crystals) and to the intensity of stimulating radiation. We discuss different mechanisms that may hinder the implementation of photon-phonon lasing in silicon

Effect of laser cutting parameters on surface roughness of stainless steel 307

Directory of Open Access Journals (Sweden)

Amal NASSAR

2016-12-01

Full Text Available Optimal parameters of laser cutting are an important step to improve surface quality of cutting edge in the laser cutting of stainless steel 307. This paper presents a new approach for optimizing the cutting parameters on stainless steel. Based on 33 full factorial experimental design, cutting experiments were conducted for stainless steel 307 plates using a laser machine (AMADA FONT 3015. The cutting parameters such as, cutting speed, cutting power and gas pressure are optimized for maximizing surface quality. The results indicated that cutting power and cutting speed play an important role in surface quality.

Laser process for extended silicon thin film solar cells

International Nuclear Information System (INIS)

Hessmann, M.T.; Kunz, T.; Burkert, I.; Gawehns, N.; Schaefer, L.; Frick, T.; Schmidt, M.; Meidel, B.; Auer, R.; Brabec, C.J.

2011-01-01

We present a large area thin film base substrate for the epitaxy of crystalline silicon. The concept of epitaxial growth of silicon on large area thin film substrates overcomes the area restrictions of an ingot based monocrystalline silicon process. Further it opens the possibility for a roll to roll process for crystalline silicon production. This concept suggests a technical pathway to overcome the limitations of silicon ingot production in terms of costs, throughput and completely prevents any sawing losses. The core idea behind these thin film substrates is a laser welding process of individual, thin silicon wafers. In this manuscript we investigate the properties of laser welded monocrystalline silicon foils (100) by micro-Raman mapping and spectroscopy. It is shown that the laser beam changes the crystalline structure of float zone grown silicon along the welding seam. This is illustrated by Raman mapping which visualizes compressive stress as well as tensile stress in a range of - 147.5 to 32.5 MPa along the welding area.

Investigation of Physical Phenomena and Cutting Efficiency for Laser Cutting on Anode for Li-Ion Batteries

Directory of Open Access Journals (Sweden)

Dongkyoung Lee

2018-02-01

Full Text Available Lithium-ion batteries have a higher energy density than other secondary batteries. Among the lithium-ion battery manufacturing process, electrode cutting is one of the most important processes since poor cut quality leads to performance degradation, separator protrusion, and local electric stress concentration. This may, eventually, lead to malfunction of lithium-ion batteries or explosion. The current mechanical cutting technology uses a contact process and this may lead to process instability. Furthermore, there are additional costs if the tools and cell design are changed. To solve these issues, laser cutting has been used. Conventional dependent parameters have limitations in investigating and explaining many physical phenomena during the laser cutting of electrodes. Therefore, this study proposes specific widths such as melting, top, and kerf width. Moreover, the relationship between laser parameters and multiphysical phenomena with the proposed widths are investigated. Five types of classification with regard to physical phenomena are presented and explained with SEM images. Cutting efficiency is estimated with the proposed widths. The proposed specific cutting widths, five types of geometrical classification, and cutting efficiency can be used as standardized parameters to evaluate the cutting quality.

Optical Cutting Interruption Sensor for Fiber Lasers

Directory of Open Access Journals (Sweden)

Benedikt Adelmann

2015-09-01

Full Text Available We report on an optical sensor system attached to a 4 kW fiber laser cutting machine to detect cutting interruptions. The sensor records the thermal radiation from the process zone with a modified ring mirror and optical filter arrangement, which is placed between the cutting head and the collimator. The process radiation is sensed by a Si and InGaAs diode combination with the detected signals being digitalized with 20 kHz. To demonstrate the function of the sensor, signals arising during fusion cutting of 1 mm stainless steel and mild steel with and without cutting interruptions are evaluated and typical signatures derived. In the recorded signals the piercing process, the laser switch on and switch off point and waiting period are clearly resolved. To identify the cutting interruption, the signals of both Si and InGaAs diodes are high pass filtered and the signal fluctuation ranges being subsequently calculated. Introducing a correction factor, we identify that only in case of a cutting interruption the fluctuation range of the Si diode exceeds the InGaAs diode. This characteristic signature was successfully used to detect 80 cutting interruptions of 83 incomplete cuts (alpha error 3.6% and system recorded no cutting interruption from 110 faultless cuts (beta error of 0. This particularly high detection rate in combination with the easy integration of the sensor, highlight its potential for cutting interruption detection in industrial applications.

Qualitative analysis of laser cutting of CV joints for automobile industry

Science.gov (United States)

Aboites, Vicente; Ramirez, Roberto; Rayas, Juan

2005-02-01

The optimization of an automatic laser cutting system is reported. This CO2 laser system assisted by an O2 gas jet is used in the cutting of Constant Velocity (CV) joint for the automotive industry. The experimental parameters varied in order to obtain cuts with low roughness were the laser power, cutting speed and oxygen pressure. A mathematical model is presented which explains many of the features of the qualitative optimization realized.

Laser beam machining of polycrystalline diamond for cutting tool manufacturing

Science.gov (United States)

Wyszyński, Dominik; Ostrowski, Robert; Zwolak, Marek; Bryk, Witold

2017-10-01

The paper concerns application of DPSS Nd: YAG 532nm pulse laser source for machining of polycrystalline WC based diamond inserts (PCD). The goal of the research was to determine optimal laser cutting parameters for cutting tool shaping. Basic criteria to reach the goal was cutting edge quality (minimalization of finishing operations), material removal rate (time and cost efficiency), choice of laser beam characteristics (polarization, power, focused beam diameter). The research was planned and realised and analysed according to design of experiment rules (DOE). The analysis of the cutting edge was prepared with use of Alicona Infinite Focus measurement system.

Nitinol laser cutting: microstructure and functional properties of femtosecond and continuous wave laser processing

Science.gov (United States)

Biffi, C. A.; Tuissi, A.

2017-03-01

Thermal processing can affect the properties of smart materials, and the correct selection of the best manufacturing technology is fundamental for producing high tech smart devices, containing embedded functional properties. In this work cutting of thin superelastic Nitinol plates using a femtosecond (fs) and continuous wave (CW) laser was studied. Diamond shaped elements were cut to characterize the kerf qualitative features; microstructural analysis of the cross sections allowed identification of thermal damage characteristics introduced into the material during the laser processes. A thermally undamaged microstructure was observed for fs laser cutting, while CW was seen to be characterized by a large heat-affected zone. Functional properties were investigated by differential scanning calorimetry and tensile testing of laser cut microelements and of the reference material. It was seen that the martensitic transformation behavior of Nitinol is not affected by fs regime, while cw cutting provokes an effect equivalent to a high temperature thermal treatment in the material surrounding the cutting kerf, degradating the material properties. Finally, tensile testing indicated that superelastic performances were guaranteed by fs regime, while strong reduction of the recoverable strain was detected in the CW processed sample.

Are the same tapes really the same? Ultrasound study of laser-cut and mechanically cut TVT-O post-operative behavior.

Science.gov (United States)

Rusavy, Zdenek; Masata, Jaromir; Svabik, Kamil; Hubka, Petr; Zvara, Karel; Martan, Alois

2017-11-25

TVT-O production has been modified to laser cutting from mechanical cutting. We compared the behavior of laser and mechanically cut tension-free vaginal tape-obturator (TVT-O) using ultrasound at various time points after surgery. This is a retrospective analysis of clinical and ultrasound data from two previously reported randomized controlled trials with TVT-O. Behavior of mechanically cut TVT-O implanted in January 2007 to November 2009 and laser-cut TVT-O implanted in May 2010 to May 2012 was assessed by ultrasound at day 1, the 2nd week, the 3rd month, and the 1st and 2nd years post-operatively. Bladder neck and tape margins positions were described by coordinates in the orthogonal system calculated from polar coordinates. Tape mobility was measured as a change in the upper and lower tape margin position from rest to maximal Valsalva. Comparison of 2-year subjective and objective surgery outcomes was also performed. In total, 68 mechanically cut and 50 laser-cut TVT-Os were implanted. Follow-up data were available from 49 and 45 women respectively. No differences in any baseline characteristics or bladder neck mobility were observed. Significantly lower tape mobility was observed on day 1 and week 2 after mechanically cut TVT-O, although subsequent mobility was comparable to laser-cut TVT-O. The subjective and objective surgery outcomes were comparable. Although without clinical significance, early postoperative behavior of the mechanically cut and laser-cut TVT-O tapes differs. The less stiff, mechanically-cut TVT-O loosens within 2 weeks of implantation, whereas the stiffer, laser-cut TVT-O keeps its tension.

Remote Fiber Laser Cutting System for Dismantling Glass Melter - 13071

Energy Technology Data Exchange (ETDEWEB)

Mitsui, Takashi; Miura, Noriaki [IHI Corporation, 1 Shin-Nakahara-cho, Isogo-ku, Yokohama, Kanagawa (Japan); Oowaki, Katsura; Kawaguchi, Isao [IHI Inspection and Instrumentation Co., Ltd, 1 Shin-Nakahara-cho, Isogo-ku, Yokohama, Kanagawa (Japan); Miura, Yasuhiko; Ino, Tooru [Japan Nuclear Fuel Limited, 4-108, Aza Okitsuke, Oaza Obuchi, Rokkasho-Mura, Kamikita-gun, Aomori (Japan)

2013-07-01

Since 2008, the equipment for dismantling the used glass melter has been developed in High-level Liquid Waste (HLW) Vitrification Facility in the Japanese Rokkasho Reprocessing Plant (RRP). Due to the high radioactivity of the glass melter, the equipment requires a fully-remote operation in the vitrification cell. The remote fiber laser cutting system was adopted as one of the major pieces of equipment. An output power of fiber laser is typically higher than other types of laser and so can provide high-cutting performance. The fiber laser can cut thick stainless steel and Inconel, which are parts of the glass melter such as casings, electrodes and nozzles. As a result, it can make the whole of the dismantling work efficiently done for a shorter period. Various conditions of the cutting test have been evaluated in the process of developing the remote fiber cutting system. In addition, the expected remote operations of the power manipulator with the laser torch have been fully verified and optimized using 3D simulations. (authors)

Enhancement of low power CO2 laser cutting process for injection molded polycarbonate

Science.gov (United States)

Moradi, Mahmoud; Mehrabi, Omid; Azdast, Taher; Benyounis, Khaled Y.

2017-11-01

Laser cutting technology is a non-contact process that typically is used for industrial manufacturing applications. Laser cut quality is strongly influenced by the cutting processing parameters. In this research, CO2 laser cutting specifications have been investigated by using design of experiments (DOE) with considering laser cutting speed, laser power and focal plane position as process input parameters and kerf geometry dimensions (i.e. top and bottom kerf width, ratio of the upper kerf to lower kerf, upper heat affected zone (HAZ)) and surface roughness of the kerf wall as process output responses. A 60 Watts CO2 laser cutting machine is used for cutting the injection molded samples of polycarbonate sheet with the thickness of 3.2 mm. Results reveal that by decreasing the laser focal plane position and laser power, the bottom kerf width will be decreased. Also the bottom kerf width decreases by increasing the cutting speed. As a general result, locating the laser spot point in the depth of the workpiece the laser cutting quality increases. Minimum value of the responses (top kerf, heat affected zone, ratio of the upper kerf to lower kerf, and surface roughness) are considered as optimization criteria. Validating the theoretical results using the experimental tests is carried out in order to analyze the results obtained via software.

Multiple-objective optimization in precision laser cutting of different thermoplastics

Science.gov (United States)

Tamrin, K. F.; Nukman, Y.; Choudhury, I. A.; Shirley, S.

2015-04-01

Thermoplastics are increasingly being used in biomedical, automotive and electronics industries due to their excellent physical and chemical properties. Due to the localized and non-contact process, use of lasers for cutting could result in precise cut with small heat-affected zone (HAZ). Precision laser cutting involving various materials is important in high-volume manufacturing processes to minimize operational cost, error reduction and improve product quality. This study uses grey relational analysis to determine a single optimized set of cutting parameters for three different thermoplastics. The set of the optimized processing parameters is determined based on the highest relational grade and was found at low laser power (200 W), high cutting speed (0.4 m/min) and low compressed air pressure (2.5 bar). The result matches with the objective set in the present study. Analysis of variance (ANOVA) is then carried out to ascertain the relative influence of process parameters on the cutting characteristics. It was found that the laser power has dominant effect on HAZ for all thermoplastics.

Silicon carbide detectors for diagnostics of ion emission from laser plasmas

International Nuclear Information System (INIS)

Musumeci, Paolo; Zimbone, Massimo; Calcagno, Lucia; Cutroneo, Maria; Torrisi, Lorenzo; Velyhan, Andry

2014-01-01

Silicon carbide (SiC) detectors have been employed to analyze the multi-MeV ions generated from laser plasma. The irradiation was performed with the iodine laser of Prague Asterix Laser System Laboratory operating at 10 16  W cm −2 pulse intensity. Thin metallic and polymeric targets were irradiated and the produced plasmas were monitored in the forward direction. The use of SiC detectors ensures the cutting of the visible and soft UV radiation emitted from plasma, enhancing the sensitivity to protons and very fast heavy ions. The time-of-flight spectra obtained by irradiating polymeric films with high laser pulse energy produce protons with energy in the range 1.0–2.5 MeV and all the charge states of carbon ions. The metallic Al target allows achieving energy up to 3.0 MeV for protons and 40 MeV for Al ions. All the results reveal the high performances of these detectors in terms of resolution and response time. (paper)

Experimental Investigation of Multi-mode Fiber Laser Cutting of Cement Mortar

Science.gov (United States)

2018-01-01

This study successfully applied multi-mode laser cutting with the variation of the laser cutting speed to cement mortar for the first time. The effects of the amount of silica sand in the cement mortar on laser cutting are tested and analyzed. The kerf width and penetration depth of the specimens after laser cutting are investigated. As the laser cutting speed increases, the penetration depth decreases for both cement paste and cement mortar, whereas the kerf width becomes saturated and increases, respectively, for cement paste and cement mortar. Cross sections of the specimens are compared with illustrations. Top-view images of the cement mortar with indicators of the physical characteristics, such as re-solidification, burning, and cracks are examined, and the possible causes of these characteristics are explained. The optical absorption rates of cement-based materials are quantified at wide ranges of wavelength to compare the absorption rates in accordance with the materials compositions. The chemical composition variation before and after laser cutting is also compared by EDX (Energy Dispersive X-Ray) analysis. In addition to these observations, material removal mechanisms for cement mortar are proposed. PMID:29439431

Experimental Investigation of Multi-mode Fiber Laser Cutting of Cement Mortar.

Science.gov (United States)

Lee, Dongkyoung; Pyo, Sukhoon

2018-02-10

This study successfully applied multi-mode laser cutting with the variation of the laser cutting speed to cement mortar for the first time. The effects of the amount of silica sand in the cement mortar on laser cutting are tested and analyzed. The kerf width and penetration depth of the specimens after laser cutting are investigated. As the laser cutting speed increases, the penetration depth decreases for both cement paste and cement mortar, whereas the kerf width becomes saturated and increases, respectively, for cement paste and cement mortar. Cross sections of the specimens are compared with illustrations. Top-view images of the cement mortar with indicators of the physical characteristics, such as re-solidification, burning, and cracks are examined, and the possible causes of these characteristics are explained. The optical absorption rates of cement-based materials are quantified at wide ranges of wavelength to compare the absorption rates in accordance with the materials compositions. The chemical composition variation before and after laser cutting is also compared by EDX (Energy Dispersive X-Ray) analysis. In addition to these observations, material removal mechanisms for cement mortar are proposed.

Experimental analysis of Nd-YAG laser cutting of sheet materials - A review

Science.gov (United States)

Sharma, Amit; Yadava, Vinod

2018-01-01

Cutting of sheet material is considered as an important process due to its relevance among products of everyday life such as aircrafts, ships, cars, furniture etc. Among various sheet cutting processes (ASCPs), laser beam cutting is one of the most capable ASCP to create complex geometries with stringent design requirements in difficult-to-cut sheet materials. Based on the recent research work in the area of sheet cutting, it is found that the Nd-YAG laser is used for cutting of sheet material in general and reflective sheet material in particular. This paper reviews the experimental analysis of Nd-YAG laser cutting process, carried out to study the influence of laser cutting parameters on the process performance index. The significance of experimental modeling and different optimization approaches employed by various researchers has also been discussed in this study.

Wavelength dependency in high power laser cutting and welding

Science.gov (United States)

Havrilla, David; Ziermann, Stephan; Holzer, Marco

2012-03-01

Laser cutting and welding have been around for more than 30 years. Within those three decades there has never been a greater variety of high power laser types and wavelengths to choose from than there is today. There are many considerations when choosing the right laser for any given application - capital investment, cost of ownership, footprint, serviceability, along with a myriad of other commercial & economic considerations. However, one of the most fundamental questions that must be asked and answered is this - "what type of laser is best suited for the application?". Manufacturers and users alike are realizing what, in retrospect, may seem obvious - there is no such thing as a universal laser. In many cases there is one laser type and wavelength that clearly provides the highest quality application results. This paper will examine the application fields of high power, high brightness 10.6 & 1 micron laser welding & cutting and will provide guidelines for selecting the laser that is best suited for the application. Processing speed & edge quality serve as key criteria for cutting. Whereas speed, seam quality & spatter ejection provide the paradigm for welding.

Laser cutting of concretes with various ballasts

International Nuclear Information System (INIS)

Hamasaki, Masanobu; Katsumura, Munehide; Utsumi, Hiroaki

1985-01-01

The biological shield concrete and the radiation shield concrete which construct a part of the atomic reactor must be demolished with the decommissioning of the atomic reactor plants. In a case, the demolition using a laser is expected as one of excellent method for the decommissioning of these radioactive concretes. The fundamental cuttings of a mortar, the concretes with andesite, lime stone and gray wacke as ballast and a concrete reinforced with mild steel rods were therefore carried out using a 5 kW output CO 2 laser. As the results of experiment, it was cleared that cutting results varied with ballasts, 100 mm thick reinforced concrete could be cut, safety was high because few dross and few fume were produced. (author)

Evaluation of laser cutting process with auxiliary gas pressure by soft computing approach

Science.gov (United States)

Lazov, Lyubomir; Nikolić, Vlastimir; Jovic, Srdjan; Milovančević, Miloš; Deneva, Heristina; Teirumenieka, Erika; Arsic, Nebojsa

2018-06-01

Evaluation of the optimal laser cutting parameters is very important for the high cut quality. This is highly nonlinear process with different parameters which is the main challenge in the optimization process. Data mining methodology is one of most versatile method which can be used laser cutting process optimization. Support vector regression (SVR) procedure is implemented since it is a versatile and robust technique for very nonlinear data regression. The goal in this study was to determine the optimal laser cutting parameters to ensure robust condition for minimization of average surface roughness. Three cutting parameters, the cutting speed, the laser power, and the assist gas pressure, were used in the investigation. As a laser type TruLaser 1030 technological system was used. Nitrogen as an assisted gas was used in the laser cutting process. As the data mining method, support vector regression procedure was used. Data mining prediction accuracy was very high according the coefficient (R2) of determination and root mean square error (RMSE): R2 = 0.9975 and RMSE = 0.0337. Therefore the data mining approach could be used effectively for determination of the optimal conditions of the laser cutting process.

Experimental comparison of laser energy losses in high-quality laser-oxygen cutting of low-carbon steel using radiation from fibre and CO2 lasers

International Nuclear Information System (INIS)

Golyshev, A A; Malikov, A G; Orishich, A M; Shulyat'ev, V B

2015-01-01

We report a comparative experimental study of laseroxygen cutting of low-carbon steel using a fibre laser with a wavelength of 1.07 μm and a CO 2 laser with a wavelength of 10.6 μm at the sheet thickness of 3 – 16 mm. For the two lasers we have measured the dependence of the cutting speed on the radiation power and determined the cutting speed at which the surface roughness is minimal. The coefficient of laser radiation absorption in the laser cutting process is measured for these lasers at different values of the cutting speed and radiation power. It is found that the minimal roughness of the cut surface is reached at the absorbed laser energy per unit volume of the removed material, equal to 11 – 13 J mm -3 ; this value is the same for the two lasers and does not depend on the sheet thickness. (laser technologies)

Development of cutting technique of reactor core internals by CO laser

International Nuclear Information System (INIS)

Takano, G.; Beppu, S.; Matsumoto, O.; Sakamoto, N.; Onozawa, T.; Sugihara, M.; Miya, K.

1995-01-01

The CO laser is superior in the absorption characteristic to materials to the CO 2 laser due to its shorter wavelength. In consideration of this characteristic Nuclear Power Engineering Corporation is studying this applicability sponsored by the Ministry of International Trade Industry of Japan to cutting of reactor core internals of commercial nuclear power plant. In decommissioning of reactor core internals it is necessary to cut stainless steel plates of 305 mm thick. The authors cut stainless steel plates of up to 310mm thick in air and those of up to 150 mm thick underwater with a 20kW class laser. Further, models simulating key structural elements of PWR core internals were cut and secondary products to clarify the applicability of the CO laser cutting to reactor core internals were evaluated. (author)

Gas flow parameters in laser cutting of wood- nozzle design

Science.gov (United States)

Kali Mukherjee; Tom Grendzwell; Parwaiz A.A. Khan; Charles McMillin

1990-01-01

The Automated Lumber Processing System (ALPS) is an ongoing team research effort to optimize the yield of parts in a furniture rough mill. The process is designed to couple aspects of computer vision, computer optimization of yield, and laser cutting. This research is focused on optimizing laser wood cutting. Laser machining of lumber has the advantage over...

Investigating the CO 2 laser cutting parameters of MDF wood composite material

Science.gov (United States)

Eltawahni, H. A.; Olabi, A. G.; Benyounis, K. Y.

2011-04-01

Laser cutting of medium density fibreboard (MDF) is a complicated process and the selection of the process parameters combinations is essential to get the highest quality cut section. This paper presents a means for selecting the process parameters for laser cutting of MDF based on the design of experiments (DOE) approach. A CO 2 laser was used to cut three thicknesses, 4, 6 and 9 mm, of MDF panels. The process factors investigated are: laser power, cutting speed, air pressure and focal point position. In this work, cutting quality was evaluated by measuring the upper kerf width, the lower kerf width, the ratio between the upper kerf width to the lower kerf width, the cut section roughness and the operating cost. The effect of each factor on the quality measures was determined. The optimal cutting combinations were presented in favours of high quality process output and in favours of low cutting cost.

Statistical characteristics of surface integrity by fiber laser cutting of Nitinol vascular stents

International Nuclear Information System (INIS)

Fu, C.H.; Liu, J.F.; Guo, Andrew

2015-01-01

Graphical abstract: - Highlights: • Precision kerf with tight tolerance of Nitinol stents can be cut by fiber laser. • No HAZ in the subsurface was detected due to large grain size. • Recast layer has lower hardness than the bulk. • Laser cutting speed has a higher influence on surface integrity than laser power. - Abstract: Nitinol alloys have been widely used in manufacturing of vascular stents due to the outstanding properties such as superelasticity, shape memory, and superior biocompatibility. Laser cutting is the dominant process for manufacturing Nitinol stents. Conventional laser cutting usually produces unsatisfactory surface integrity which has a significant detrimental impact on stent performance. Emerging as a competitive process, fiber laser with high beam quality is expected to produce much less thermal damage such as striation, dross, heat affected zone (HAZ), and recast layer. To understand the process capability of fiber laser cutting of Nitinol alloy, a design-of-experiment based laser cutting experiment was performed. The kerf geometry, roughness, topography, microstructure, and hardness were studied to better understand the nature of the HAZ and recast layer in fiber laser cutting. Moreover, effect size analysis was conducted to investigate the relationship between surface integrity and process parameters.

Statistical characteristics of surface integrity by fiber laser cutting of Nitinol vascular stents

Energy Technology Data Exchange (ETDEWEB)

Fu, C.H., E-mail: cfu5@crimson.ua.edu [Dept of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Liu, J.F. [Dept of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Guo, Andrew [Dept of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); College of Arts and Science, Vanderbilt University, Nashville, TN 37235 (United States)

2015-10-30

Graphical abstract: - Highlights: • Precision kerf with tight tolerance of Nitinol stents can be cut by fiber laser. • No HAZ in the subsurface was detected due to large grain size. • Recast layer has lower hardness than the bulk. • Laser cutting speed has a higher influence on surface integrity than laser power. - Abstract: Nitinol alloys have been widely used in manufacturing of vascular stents due to the outstanding properties such as superelasticity, shape memory, and superior biocompatibility. Laser cutting is the dominant process for manufacturing Nitinol stents. Conventional laser cutting usually produces unsatisfactory surface integrity which has a significant detrimental impact on stent performance. Emerging as a competitive process, fiber laser with high beam quality is expected to produce much less thermal damage such as striation, dross, heat affected zone (HAZ), and recast layer. To understand the process capability of fiber laser cutting of Nitinol alloy, a design-of-experiment based laser cutting experiment was performed. The kerf geometry, roughness, topography, microstructure, and hardness were studied to better understand the nature of the HAZ and recast layer in fiber laser cutting. Moreover, effect size analysis was conducted to investigate the relationship between surface integrity and process parameters.

Neodymium:YAG laser cutting of intraocular lens haptics.

Science.gov (United States)

Gorn, R A; Steinert, R F

1985-11-01

Neodymium:YAG laser cutting of polymethylmethacrylate and polypropylene anterior chamber and posterior chamber intraocular lens haptics was studied in terms of ease of transection and physical structure of the cut areas as seen by scanning electron microscopy. A marked difference was discovered, with the polymethylmethacrylate cutting easily along transverse planes, whereas the polypropylene resisted cutting along longitudinal fibers. Clinical guidelines are presented.

Excimer laser decomposition of silicone

International Nuclear Information System (INIS)

Laude, L.D.; Cochrane, C.; Dicara, Cl.; Dupas-Bruzek, C.; Kolev, K.

2003-01-01

Excimer laser irradiation of silicone foils is shown in this work to induce decomposition, ablation and activation of such materials. Thin (100 μm) laminated silicone foils are irradiated at 248 nm as a function of impacting laser fluence and number of pulsed irradiations at 1 s intervals. Above a threshold fluence of 0.7 J/cm 2 , material starts decomposing. At higher fluences, this decomposition develops and gives rise to (i) swelling of the irradiated surface and then (ii) emission of matter (ablation) at a rate that is not proportioned to the number of pulses. Taking into consideration the polymer structure and the foil lamination process, these results help defining the phenomenology of silicone ablation. The polymer decomposition results in two parts: one which is organic and volatile, and another part which is inorganic and remains, forming an ever thickening screen to light penetration as the number of light pulses increases. A mathematical model is developed that accounts successfully for this physical screening effect

Experimental study on concrete cutting by CO{sub 2} laser beam

Energy Technology Data Exchange (ETDEWEB)

Kutsumizu, Akira; Tomura, Hidemasa; Wakizaka, Tatsuya; Hishikawa, Kyoichi; Moriya, Masahiro [Ohbayashi Corp., Tokyo (Japan)

1994-10-01

Methods for dismantling nuclear reactor facilities must meet particularly exacting requirements imposed by heavily reinforced and radioactivated reactor shield walls. Conventional methods do not meet all such requirements, however. Intrigued by excellent characteristics of the laser cutting method relative to nuclear facility demolition, we carried out an experimental study to make a comprehensive evaluation of its characteristics, especially for deep cutting, with success in identifying main factors affecting the cutting depth of a laser and characterizing its cutting behavior. The study results indicate that a 50 kW class CO{sub 2} laser has a potential to provide a practicable cutting speed and depth. (author).

Factors influencing laser cutting of wood

Science.gov (United States)

V.G. Barnekov; C.W. McMillin; H.A. Huber

1986-01-01

Factors influencing the ability of lasers to cut wood may be generally classified into these three areas: 1) characteristics of the laser beam; 2) equipment and processing variables; and 3) properties of the workpiece. Effects of beam power, mode, polarization, and stability are discussed as are aspects of optics, location of focal point, feed speed, gas-jet assist...

SOFTWARE TOOL FOR LASER CUTTING PROCESS CONTROL – SOLVING REAL INDUSTRIAL CASE STUDIES

Directory of Open Access Journals (Sweden)

Miloš Madić

2016-08-01

Full Text Available Laser cutting is one of the leading non-conventional machining technologies with a wide spectrum of application in modern industry. It order to exploit a number of advantages that this technology offers for contour cutting of materials, it is necessary to carefully select laser cutting conditions for each given workpiece material, thickness and desired cut qualities. In other words, there is a need for process control of laser cutting. After a comprehensive analysis of the main laser cutting parameters and process performance characteristics, the application of the developed software tool “BRUTOMIZER” for off-line control of CO2 laser cutting process of three different workpiece materials (mild steel, stainless steel and aluminum is illustrated. Advantages and abilities of the developed software tool are also illustrated.

Qualitative analysis of laser cutting of CV joints for the automobile industry

Science.gov (United States)

Aboites, V.; Ramírez, R.; Rayas, J.

2006-02-01

The optimization of an automatic laser cutting system is reported. This CO II laser system assisted by an O II gas jet is used in the cutting of Constant Velocity (CV) joint for the automotive industry. The experimental parameters varied in order to obtain cuts with low roughness were the laser power, cutting speed and oxygen pressure. A mathematical model is presented which explains many of the features of the qualitative optimization realized.

Cutting efficiency of a mid-infrared laser on human enamel.

Science.gov (United States)

Levy, G; Koubi, G F; Miserendino, L J

1998-02-01

In this study, the cutting ability of a newly developed dental laser was compared with a dental high-speed handpiece and rotary bur for removal of enamel. Measurements of the volume of tissue removed, energy emitted, and time of exposure were used to quantify the ablation rate (rate of tissue removal) for each test group and compared. Cutting efficiency (mm3/s) of the laser was calculated based on the mean volume of tissue removed per pulse (mm3/pulse) and unit energy expended (mm3/J) over the range of applied powers (2, 4, 6, and 8 W). The specimens were then examined by light microscopy and scanning electron micrographs for qualitative analysis of the amount of remaining debris and the presence of the smear layer on the prepared enamel surface. Calculations of the cutting efficiency of the laser over the range of powers tested revealed a linear relationship with the level of applied power. The maximum average rate of tissue removal by the laser was 0.256 mm3/s at 8 W, compared with 0.945 mm3/s by the dental handpiece. Light microscopy and scanning electron micrograph examinations revealed a reduction in the amount of remaining debris and smear layer in the laser-prepared enamel surfaces, compared with the conventional method. Based on the results of this study, the cutting efficiency of the high-speed handpiece and dental bur was 3.7 times greater than the laser over the range of powers tested, but the laser appeared to create a cleaner enamel surface with minimal thermal damage. Further modifications of the laser system are suggested for improvement of laser cutting efficiency.

New pulsed YAG laser performances in cutting thick metallic materials for nuclear applications

International Nuclear Information System (INIS)

Alfille, J.P.; Prunele, D. de; Pilot, G.

1996-01-01

The purpose of this study was to evaluate the capacities of the pulsed YAG laser thick cutting on metallic material and to compare with the CO 2 laser capacities. Stainless steel (304L) cutting tests were made in air and underwater using CO 2 and YAG lasers. A performance assessment was made for each laser and the wastes produced in the cutting operation were measured and the gases and the aerosols analyzed. The results show that the pulsed YAG laser is high performance tool for thick cutting and particularly attractive for nuclear applications

Experimental comparison of laser energy losses in high-quality laser-oxygen cutting of low-carbon steel using radiation from fibre and CO{sub 2} lasers

Energy Technology Data Exchange (ETDEWEB)

Golyshev, A A; Malikov, A G; Orishich, A M; Shulyat' ev, V B [S.A. Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

2015-09-30

We report a comparative experimental study of laseroxygen cutting of low-carbon steel using a fibre laser with a wavelength of 1.07 μm and a CO{sub 2} laser with a wavelength of 10.6 μm at the sheet thickness of 3 – 16 mm. For the two lasers we have measured the dependence of the cutting speed on the radiation power and determined the cutting speed at which the surface roughness is minimal. The coefficient of laser radiation absorption in the laser cutting process is measured for these lasers at different values of the cutting speed and radiation power. It is found that the minimal roughness of the cut surface is reached at the absorbed laser energy per unit volume of the removed material, equal to 11 – 13 J mm{sup -3}; this value is the same for the two lasers and does not depend on the sheet thickness. (laser technologies)

Setup and maintenance of manufacturing quality in CO2 laser cutting

OpenAIRE

Thombansen, U.; Hermanns, T.; Stoyanov, S.

2014-01-01

Manufacturing of parts by laser cutting is widely accepted in industry. In the market there are systems which are highly focused on special applications such as robot based 3D cutting in the automotive industry but also all-round machines which cut a diverse set of sheet steels at a variety of thicknesses. Most of these machines use a melt based cutting process where the molten material is ejected by an assist gas. Quality of the laser cut part is determined by a dross free cut with minimal r...

6kW class laser cutting equipment; 6kW daishutsuryoku laser setsudanki ni yoru atsuita setsudan

Energy Technology Data Exchange (ETDEWEB)

Nagata, Y.; Nagahori, M. [Tanaka Engineering Works Ltd., Saitama (Japan)

1994-11-01

Application of the laser cutting machine to the area of cutting steel plates of 5 mm thick or more was first enabled in 1990 by the 2 kW oscillator that was introduced in that year. The thick plate cutting industry has a short history. This paper describes the features and performance of the 6 kW laser cutting machine that was announced in April, 1994. The machine uses a newly developed high-speed axial flow type carbon dioxide laser oscillater with the rated output of 6 kW. As the discharge excitation method, the machine adopted the RF (radio frequency) method that causes low contamination in the discharge tube. The 6 kW laser cutting machine has a number of features such as a large cutting area provided by the oscillator contained in the cutting machine, cutting quality stabilized by the optical path length fixing unit, and automatic functions such as automatic setting of the cutting conditions and scheduled operation. The machine can cut mild steel plates of up to 40 mm thick (or up to 16 mm for stainless steel plates) at the cutting speed of 1600 mm/min for a 16 mm thick plate and 2200 mm/min for a 12 mm thick plate, with the good cut sectional surface. 5 figs., 1 tab.

Measurement of secondary emissions during laser cutting of steel equipments

Energy Technology Data Exchange (ETDEWEB)

Pilot, Guy [Institut de Radioprotection et de Surete Nucleaire, BP 68, 91192 Gif-sur-Yvette Cedex (France)], E-mail: guy.pilot@irsn.fr; Fauvel, Sylvain [Institut de Radioprotection et de Surete Nucleaire, BP 68, 91192 Gif-sur-Yvette Cedex (France); Gosse, Xavier [AREVA NC, Centre de Marcoule, 30200 Bagnols-sur-Ceze Cedex (France); Dinechin, Guillaume de [Commissariat a l' Energie Atomique, DEN/DM2S/SEMT, Saclay, Bat. 611, 91191 Gif-sur-Yvette Cedex (France); Vernhet, Didier [Commissariat a l' Energie Atomique, DEN/VRH/UMODD, Centre de Valrho, BP 17171, 20207 Bagnols-sur-Ceze Cedex (France)

2008-08-15

In order to dismantle some equipments of an obsolete reprocessing plant in Marcoule, studies were carried out by IRSN (Institut de Radioprotection et de Surete Nucleaire)/DSU/SERAC in cooperation with CEA (power laser group) on the laser cutting of steel structures, on the request of AREVA NC/Marcoule (UP1 dismantling project manager) and CEA/UMODD (UP1 dismantling owner). These studies were aimed at: {center_dot}quantifying and characterizing the secondary emissions produced by Nd-YAG laser cutting of Uranus 65 steel pieces and examining the influence of different parameters, {center_dot}qualifying a prefiltration technique and particularly an electrostatic precipitator, {center_dot}comparing the Nd-YAG laser used with other cutting tools previously studied especially on aerosol production and aerosol size distribution.

Application of laser spot cutting on spring contact probe for semiconductor package inspection

Science.gov (United States)

Lee, Dongkyoung; Cho, Jungdon; Kim, Chan Ho; Lee, Seung Hwan

2017-12-01

A packaged semiconductor has to be electrically tested to make sure they are free of any manufacturing defects. The test interface, typically employed between a Printed Circuit Board and the semiconductor devices, consists of densely populated Spring Contact Probe (SCP). A standard SCP typically consists of a plunger, a barrel, and an internal spring. Among these components, plungers are manufactured by a stamping process. After stamping, plunger connecting arms need to be cut into pieces. Currently, mechanical cutting has been used. However, it may damage to the body of plungers due to the mechanical force engaged at the cutting point. Therefore, laser spot cutting is considered to solve this problem. The plunger arm is in the shape of a rectangular beam, 50 μm (H) × 90 μm (W). The plunger material used for this research is gold coated beryllium copper. Laser parameters, such as power and elapsed time, have been selected to study laser spot cutting. Laser material interaction characteristics such as a crater size, material removal zone, ablation depth, ablation threshold, and full penetration are observed. Furthermore, a carefully chosen laser parameter (Etotal = 1000mJ) to test feasibility of laser spot cutting are applied. The result show that laser spot cutting can be applied to cut SCP.

UV laser incorporation of dopants in silicon: comparison of two processes

International Nuclear Information System (INIS)

Fogarassy, E.P.; Narayan, J.; Lowndes, D.H.; White, C.H.

1985-01-01

The rapid deposition of pulsed-laser energy into the near-surface region of silicon leads to melting of crystal, followed by liquid phase epitaxial regrowth from the underlying substrate at a growth velocity of several meters per second. During rapid solidification, implanted or deposited group III and V impurities can be incorporated into substitutional sites in the silicon lattice with concentrations far in excess of their equilibrium solubility limit. The authors have investigated and compared the incorporation of implanted or deposited antimony into the silicon lattice during laser annealing with a pulsed KrF UV laser (lambda = 0.249 μm, Z = 35 ns). The surface melting dynamics resulting from laser irradiation have been studied by time-resolved reflectivity. In the two cases, the sharp transition to the high reflectivity phase (R = 72%, at lambda = 0.633 μm of the HeNe laser probe) is characteristic of molten silicon. Surface melt durations measured on implanted Sb (150 KeV, 5 x 10 16 cm -2 ) and deposited Sb (80 A thick on crystalline silicon) are significantly larger than those for virgin silicon

Prediction of melt geometry in laser cutting

Energy Technology Data Exchange (ETDEWEB)

Tani, Giovanni; Tomesani, Luca; Campana, Giampaolo

2003-03-15

In this paper, an analytical model for the evaluation of the melt film geometry in laser cutting of steels is developed. Using as basis, a previous model for kerf geometry estimation developed by the authors, with both reactive and non-reactive process gases, the film thickness and velocity were determined as a function of the kerf depth in the cutting plate. Two criteria were then adopted to predict the quality of the laser cutting operation: the first is based on a minimum acceptable value of the ejection speed of the melt from the bottom of the kerf, the second on the occlusion of the kerf itself due to an excess of molten material in the boundary layer at the kerf width. These criteria determined a feasibility region in the domain of the process and material variables, such as cutting speed, assistant gas pressure, laser beam power and material characteristics. These factors may be successfully used to build a process-planning tool for parameters optimisation and setting, in order to achieve a satisfactory process quality. The model response is in excellent agreement with the feasibility regions reported from experimental data by various authors and demonstrates a relationship between the occurrence of dross adhesion and the two different mechanisms predicted for such a phenomenon were: unsatisfactory ejection speed of the melt film from the bottom of the kerf and occlusion of the kerf.

High-speed fiber laser cutting of thick stainless steel for dismantling tasks

Science.gov (United States)

Shin, Jae Sung; Oh, Seong Yong; Park, Hyunmin; Chung, Chin-Man; Seon, Sangwoo; Kim, Taek-Soo; Lee, Lim; Choi, Byung-Seon; Moon, Jei-Kwon

2017-09-01

A high-speed fiber laser cutting technology of thick steels for dismantling tasks was achieved using a 6-kW fiber laser system. At first, a new cutting head for efficient cutting of thick steels was developed, which was composed by a collimator with a focal length of 160 mm and mirror-type focusing objects with a long focal length of 600 mm. The long focal length of the focusing object made it possible for the beam size to be small through the thick cutting material and the cutting efficiency was expected to increase compared with the short focal length. In addition, folding the beam facilitated the compact cutting head with a size of 160 mm (width) × 80 mm (height) × 640 mm (length) and a weight of 6.9 kg. In the cutting experiment, the laser beam was delivered to the cutting head by a 25-m long process fiber with a core diameter of 100 μm. The cutting performances were studied against the thicknesses of stainless steel plates. A maximum cutting speed of 72 mm/min was obtained for the 60-mm thick stainless steel plate cutting and the cut specimen showed an excellent kerf shape and a narrow kerf width. To the best of our knowledge, this cutting speed was higher than other previously reported results when cutting with a 6-kW laser power.

Fusion cutting of aluminum, magnesium, and titanium alloys using high-power fiber laser

Science.gov (United States)

Scintilla, Leonardo Daniele; Tricarico, Luigi

2013-07-01

The effects of cutting speed and assist gas pressure on laser cutting of 1-mm thick Al 1050, AZ31, and Ti6Al4V lightweight alloys are experimentally investigated. Fiber laser cutting of these materials is not broadly investigated and the acquisition of a new level of knowledge is of fundamental importance for applications like sheet metal trimming in automotive industry. The main process outputs are in depth compared with results reported in literature and obtained by cutting with CO2 and Nd∶YAG lasers. The good cut quality, the high productivity, and the easy delivery of the beam obtained at the same time, corroborate the advantage of using fiber lasers for thin sheets lightweight alloys cutting.

Effect of cutting temperature on hardness of SiC and diamond in the nano-cutting process of monocrystalline silicon

Science.gov (United States)

Wang, Jiachun; Li, Yuntao; Liu, Xiaoxuan; Lv, Maoqiang

2016-10-01

In the process of cutting silicon by natural diamond tools, groove wear happens on the flank face of cutting tool frequently.Scholars believe that one of the wear reasons is mechanical scratching effect by hard particles like SiC. To reveal the mechanical scratching mechanism, it is essential to study changes in the mechanical properties of hard particles and diamond, especially the effect of cutting temperature on hardness of diamond and hard particles. Molecular dynamics (MD) model that contact-zone temperature between tool and workpiece was calculated by dividing zone while nano-cutting monocrystalline silicon was established, cutting temperature values in different regions were computed as the simulation was carried out.On this basis, the models of molecular dynamics simulation of SiC and diamond were established separately with setting the initial temperature to room temperature. The laws of length change of C-C bond and Si-C bond varing with increase of simulation temperature were studied. And drawing on predecessors' research on theoretical calculation of hardness of covalent crystals and the relationship between crystal valence electron density and bond length, the curves that the hardness of diamond and SiC varing with bond length were obtained. The effect of temperature on the hardness was calculated. Results show that, local cutting temperature can reach 1300K.The rise in cutting temperature leaded to a decrease in the diamond local atomic clusters hardness,SiC local atomic clusters hardness increased. As the cutting temperature was more than 1100K,diamond began to soften, the local clusters hardness was less than that of SiC.

Application of YAG laser processing in underwater welding and cutting

Energy Technology Data Exchange (ETDEWEB)

Ohwaki, Katsura; Morita, Ichiro; Kojima, Toshio; Sato, Shuichi [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

2002-09-01

The high-power YAG laser is a new fabrication tool. The laser torch is easy to combine with complex with complex mechanics because of beam delivery through optical fiber. A direct underwater laser welding technology has been developed and applied to the preservation, maintenance and removal of nuclear power plants. For subdividing or removing operations for retirement of plants, the laser cutting properties were confirmed to allow a maximum cutting thickness of 80 mm. For repairing inner surface of stainless steel tanks, an underwater laser welding system using a remote-controlled robot was developed and the high quality of underwater laser welding was confirmed. (author)

Damage-free laser patterning of silicon nitride on textured crystalline silicon using an amorphous silicon etch mask for Ni/Cu plated silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

Bailly, Mark S., E-mail: mbailly@asu.edu; Karas, Joseph; Jain, Harsh; Dauksher, William J.; Bowden, Stuart

2016-08-01

We investigate the optimization of laser ablation with a femtosecond laser for direct and indirect removal of SiN{sub x} on alkaline textured c-Si. Our proposed resist-free indirect removal process uses an a-Si:H etch mask and is demonstrated to have a drastically improved surface quality of the laser processed areas when compared to our direct removal process. Scanning electron microscope images of ablated sites show the existence of substantial surface defects for the standard direct removal process, and the reduction of those defects with our proposed process. Opening of SiN{sub x} and SiO{sub x} passivating layers with laser ablation is a promising alternative to the standard screen print and fire process for making contact to Si solar cells. The potential for small contacts from laser openings of dielectrics coupled with the selective deposition of metal from light induced plating allows for high-aspect-ratio metal contacts for front grid metallization. The minimization of defects generated in this process would serve to enhance the performance of the device and provides the motivation for our work. - Highlights: • Direct laser removal of silicon nitride (SiN{sub x}) damages textured silicon. • Direct laser removal of amorphous silicon (a-Si) does not damage textured silicon. • a-Si can be used as a laser patterned etch mask for SiN{sub x}. • Chemically patterned SiN{sub x} sites allow for Ni/Cu plating.

Effect of laser incidence angle on cut quality of 4 mm thick stainless steel sheet using fiber laser

Science.gov (United States)

Mullick, Suvradip; Agrawal, Arpit Kumar; Nath, Ashish Kumar

2016-07-01

Fiber laser has potential to outperform the more traditionally used CO2 lasers in sheet metal cutting applications due to its higher efficiency, better beam quality, reliability and ease of beam delivery through optical fiber. It has been however, reported that the higher focusability and shorter wavelength are advantageous for cutting thin metal sheets up to about 2 mm only. Better focasability results in narrower kerf-width, which leads to an earlier flow separation in the flow of assist gas within the kerf, resulting in uncontrolled material removal and poor cut quality. However, the advarse effect of tight focusability can be taken care by shifting the focal point position towards the bottom surface of work-piece, which results in a wider kerf size. This results in a more stable flow within the kerf for a longer depth, which improves the cut quality. It has also been reported that fiber laser has an unfavourable angle of incidence during cutting of thick sections, resulting in poor absorption at the metal surface. Therefore, the effect of laser incidence angle, along with other process parameters, viz. cutting speed and assist gas pressure on the cut quality of 4 mm thick steel sheet has been investigated. The change in laser incidence angle has been incorporated by inclining the beam towards and away from the cut front, and the quality factors are taken as the ratio of kerf width and the striation depth. Besides the absorption of laser radiation, beam inclination is also expected to influence the gas flow characteristics inside the kerf, shear force phenomena on the molten pool, laser beam coupling and laser power distribution at the inclined cut surface. Design of experiment has been used by implementing response surface methodology (RSM) to study the parametric dependence of cut quality, as well as to find out the optimum cut quality. An improvement in quality has been observed for both the inclination due to the combined effect of multiple phenomena.

Analysis of the heat affected zone in CO2 laser cutting of stainless steel

Directory of Open Access Journals (Sweden)

Madić Miloš J.

2012-01-01

Full Text Available This paper presents an investigation into the effect of the laser cutting parameters on the heat affected zone in CO2 laser cutting of AISI 304 stainless steel. The mathematical model for the heat affected zone was expressed as a function of the laser cutting parameters such as the laser power, cutting speed, assist gas pressure and focus position using the artificial neural network. To obtain experimental database for the artificial neural network training, laser cutting experiment was planned as per Taguchi’s L27 orthogonal array with three levels for each of the cutting parameter. Using the 27 experimental data sets, the artificial neural network was trained with gradient descent with momentum algorithm and the average absolute percentage error was 2.33%. The testing accuracy was then verified with 6 extra experimental data sets and the average predicting error was 6.46%. Statistically assessed as adequate, the artificial neural network model was then used to investigate the effect of the laser cutting parameters on the heat affected zone. To analyze the main and interaction effect of the laser cutting parameters on the heat affected zone, 2-D and 3-D plots were generated. The analysis revealed that the cutting speed had maximum influence on the heat affected zone followed by the laser power, focus position and assist gas pressure. Finally, using the Monte Carlo method the optimal laser cutting parameter values that minimize the heat affected zone were identified.

Heat damage-free laser-microjet cutting achieves highest die fracture strength

Science.gov (United States)

Perrottet, Delphine; Housh, Roy; Richerzhagen, Bernold; Manley, John

2005-04-01

Unlike conventional laser-based technologies, the water jet guided laser does not generate heat damage and contamination is also very low. The negligible heat-affected zone is one reason why die fracture strength is higher than with sawing. This paper first presents the water jet guided laser technology and then explains how it differs from conventional dry laser cutting. Finally, it presents the results obtained by three recent studies conducted to determine die fracture strength after Laser-Microjet cutting.

Correlation between Surface Roughness Characteristics in CO2 Laser Cutting of Mild Steel

Directory of Open Access Journals (Sweden)

M. Radovanović

2012-12-01

Full Text Available CO2 laser oxygen cutting of mild steel is widely used industrial application. Cut surface quality is a very important characteristic of laser cutting that ensures an advantage over other contour cutting processes. In this paper mathematical models for estimating characteristics of surface quality such as average surface roughness and ten-point mean roughness in CO2 laser cutting of mild steel based on laser cutting parameters were developed. Empirical models were developed using artificial neural networks and experimental data collected. Taguchi’s orthogonal array was implemented for experimental plan. From the analysis of the developed mathematical models it was observed that functional dependence between laser cutting parameters, their interactions and surface roughness characteristics is complex and non-linear. It was also observed that there exist region of minimal average surface roughness to ten-point mean roughness ratio. The relationship between average surface roughness and ten-point mean roughness was found to be nonlinear and can be expressed with a second degree polynomial.

The optimization of the cutting process of diamonds with a YAG laser

Directory of Open Access Journals (Sweden)

A. J. Lubbe

1993-07-01

Full Text Available A laser cannot, as generally assumed by the layman, cut right through a diamond with a single cut. A couple of hundred cuts may be necessary to "chip carve" through a diamond. There are several parameters, for example cutting speed, focus point, overlapping of cuts, etc., that influence the cutting process. With a view to optimizing the cutting process, laser cuts in diamonds were studied in a systematic way with the aid of an electron microscope. The method, technique and the results of the research are discussed in this article.

Laser shock ignition of porous silicon based nano-energetic films

International Nuclear Information System (INIS)

Plummer, A.; Gascooke, J.; Shapter, J.; Kuznetsov, V. A.; Voelcker, N. H.

2014-01-01

Nanoporous silicon films on a silicon wafer were loaded with sodium perchlorate and initiated using illumination with infrared laser pulses to cause laser thermal ignition and laser-generated shock waves. Using Photon Doppler Velocimetry, it was determined that these waves are weak stress waves with a threshold intensity of 131 MPa in the silicon substrate. Shock generation was achieved through confinement of a plasma, generated upon irradiation of an absorptive paint layer held against the substrate side of the wafer. These stress waves were below the threshold required for sample fracturing. Exploiting either the laser thermal or laser-generated shock mechanisms of ignition may permit use of pSi energetic materials in applications otherwise precluded due to their environmental sensitivity

Laser shock ignition of porous silicon based nano-energetic films

Energy Technology Data Exchange (ETDEWEB)

Plummer, A.; Gascooke, J.; Shapter, J. [School of Chemical and Physical Sciences, Flinders University, 5042, Bedford Park (Australia); Centre of Expertise in Energetic Materials (CEEM), Bedford Park (Australia); Kuznetsov, V. A., E-mail: nico.voelcker@unisa.edu.au, E-mail: Valerian.Kuznetsov@dsto.defence.gov.au [School of Chemical and Physical Sciences, Flinders University, 5042, Bedford Park (Australia); Centre of Expertise in Energetic Materials (CEEM), Bedford Park (Australia); Weapons and Combat Systems Division, Defence Science and Technology Organisation, Edinburgh 5111 (Australia); Voelcker, N. H., E-mail: nico.voelcker@unisa.edu.au, E-mail: Valerian.Kuznetsov@dsto.defence.gov.au [Mawson Institute, University of South Australia, 5095, Mawson Lakes (Australia)

2014-08-07

Nanoporous silicon films on a silicon wafer were loaded with sodium perchlorate and initiated using illumination with infrared laser pulses to cause laser thermal ignition and laser-generated shock waves. Using Photon Doppler Velocimetry, it was determined that these waves are weak stress waves with a threshold intensity of 131 MPa in the silicon substrate. Shock generation was achieved through confinement of a plasma, generated upon irradiation of an absorptive paint layer held against the substrate side of the wafer. These stress waves were below the threshold required for sample fracturing. Exploiting either the laser thermal or laser-generated shock mechanisms of ignition may permit use of pSi energetic materials in applications otherwise precluded due to their environmental sensitivity.

Descriptive Analysis of In Vitro Cutting of Swine Mitral Cusps: Comparison of High-Power Laser and Scalpel Blade Cutting Techniques.

Science.gov (United States)

Pinto, Nathali Cordeiro; Pomerantzeff, Pablo Maria Alberto; Deana, Alessandro; Zezell, Denise; Benetti, Carolina; Aiello, Vera Demarchi; Lopes, Luciana Almeida; Jatene, Fabio Biscegli; Chavantes, M Cristina

2017-02-01

The most common injury to the heart valve with rheumatic involvement is mitral stenosis, which is the reason for a big number of cardiac operations in Brazil. Commissurotomy is the traditional technique that is still widely used for this condition, although late postoperative restenosis is concerning. This study's purpose was to compare the histological findings of porcine cusp mitral valves treated in vitro with commissurotomy with a scalpel blade to those treated with high-power laser (HPL) cutting, using appropriate staining techniques. Five mitral valves from healthy swine were randomly divided into two groups: Cusp group (G1), cut with a scalpel blade (n = 5), and Cusp group (G2), cut with a laser (n = 5). G2 cusps were treated using a diode laser (λ = 980 nm, power = 9.0 W, time = 12 sec, irradiance = 5625 W/cm 2 , and energy = 108 J). In G1, no histological change was observed in tissue. A hyaline basophilic aspect was focally observed in G2, along with a dark red color on the edges and areas of lower birefringence, when stained with hematoxylin-eosin, Masson's trichrome, and Sirius red. Further, the mean distances from the cutting edge in cusps submitted to laser application and stained with Masson's trichrome and Sirius red were 416.7 and 778.6 μm, respectively, never overcoming 1 mm in length. Thermal changes were unique in the group submitted to HPL and not observed in the cusp group cut with a scalpel blade. The mean distance of the cusps' collagen injury from the cutting edge was less than 1 mm with laser treatment. Additional studies are needed to establish the histological evolution of the laser cutting and to answer whether laser cutting may avoid valvular restenosis better than blade cutting.

Laser cutting of thick steel plates with 30 kW fiber laser for nuclear decommissioning

International Nuclear Information System (INIS)

Tamura, Koji

2015-01-01

Laser cutting technologies of the thick steel plates for the nuclear decommissioning were developed with a 30 kW fiber laser. Plates of stainless steel and carbon steel more than 100 mm thick were successfully cut, indicating that this technology is promising for the application to the nuclear decommissioning. (author)

Laser cutting of thick steel plates and simulated steel components using a 30 kW fiber laser

International Nuclear Information System (INIS)

Tamura, Koji; Ishigami, Ryoya; Yamagishi, Ryuichiro

2016-01-01

Laser cutting of thick steel plates and simulated steel components using a 30 kW fiber laser was studied for application to nuclear decommissioning. Successful cutting of carbon steel and stainless steel plates up to 300 mm in thickness was demonstrated, as was that of thick steel components such as simulated reactor vessel walls, a large pipe, and a gate valve. The results indicate that laser cutting applied to nuclear decommissioning is a promising technology. (author)

Fabricating 40 µm-thin silicon solar cells with different orientations by using SLiM-cut method

Science.gov (United States)

Wang, Teng-Yu; Chen, Chien-Hsun; Shiao, Jui-Chung; Chen, Sung-Yu; Du, Chen-Hsun

2017-10-01

Thin silicon foils with different crystal orientations were fabricated using the stress induced lift-off (SLiM-cut) method. The thickness of the silicon foils was approximately 40 µm. The ≤ft foil had a smoother surface than the ≤ft foil. With surface passivation, the minority carrier lifetimes of the ≤ft and ≤ft silicon foil were 1.0 µs and 1.6 µs, respectively. In this study, 4 cm2-thin silicon solar cells with heterojunction structures were fabricated. The energy conversion efficiencies were determined to be 10.74% and 14.74% for the ≤ft and ≤ft solar cells, respectively. The surface quality of the silicon foils was determined to affect the solar cell character. This study demonstrated that fabricating the solar cell by using silicon foil obtained from the SLiM-cut method is feasible.

Studies of pulsed laser melting and rapid solidification using amorphous silicon

International Nuclear Information System (INIS)

Lowndes, D.H.; Wood, R.F.

1984-06-01

Pulsed-laser melting of ion implantation-amorphized silicon layers, and subsequent solidification were studied. Measurements of the onset of melting of amorphous silicon layers and of the duration of melting, and modified melting model calculations demonstrated that the thermal conductivity, K/sub a/, of amorphous silicon is very low (K/sub a/ approx. = 0.02 W/cm-K). K/sub a/ is also the dominant parameter determining the dynamical response of amorphous silicon to pulsed laser radiation. TEM indicates that bulk (volume) nucleation occurs directly from the highly undercooled liquid silicon that can be prepared by pulsed laser melting of amorphous silicon layers at low laser energy densities. A modified thermal melting model is presented. The model calculations demonstrate that the release of latent heat by bulk nucleation occurring during the melt-in process is essential to obtaining agreement with observed depths of melting. These calculations also show that this release of latent heat accompanying bulk nucleation can result in the existence of buried molten layers of silicon in the interior of the sample after the surface has solidified. The bulk nucleation implies that the liquid-to-amorphous phase transition (produced using picosecond or uv nanosecond laser pulses) cannot be explained using purely thermodynamic considerations

Experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO2 lasers under conditions of minimal roughness

International Nuclear Information System (INIS)

Golyshev, A A; Malikov, A G; Orishich, A M; Shulyatyev, V B

2014-01-01

The results of an experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO 2 lasers are generalised. The dependence of roughness of the cut surface on the cutting parameters is investigated, and the conditions under which the surface roughness is minimal are formulated. It is shown that for both types of lasers these conditions can be expressed in the same way in terms of the dimensionless variables – the Péclet number Pe and the output power Q of laser radiation per unit thickness of the cut sheet – and take the form of the similarity laws: Pe = const, Q = const. The optimal values of Pe and Q are found. We have derived empirical expressions that relate the laser power and cutting speed with the thickness of the cut sheet under the condition of minimal roughness in the case of cutting by means of radiation from fibre and CO 2 lasers. (laser technologies)

Directed dewetting of amorphous silicon film by a donut-shaped laser pulse

International Nuclear Information System (INIS)

Yoo, Jae-Hyuck; Zheng, Cheng; Grigoropoulos, Costas P; In, Jung Bin; Sakellari, Ioanna; Raman, Rajesh N; Matthews, Manyalibo J; Elhadj, Selim

2015-01-01

Irradiation of a thin film with a beam-shaped laser is proposed to achieve site-selectively controlled dewetting of the film into nanoscale structures. As a proof of concept, the laser-directed dewetting of an amorphous silicon thin film on a glass substrate is demonstrated using a donut-shaped laser beam. Upon irradiation of a single laser pulse, the silicon film melts and dewets on the substrate surface. The irradiation with the donut beam induces an unconventional lateral temperature profile in the film, leading to thermocapillary-induced transport of the molten silicon to the center of the beam spot. Upon solidification, the ultrathin amorphous silicon film is transformed to a crystalline silicon nanodome of increased height. This morphological change enables further dimensional reduction of the nanodome as well as removal of the surrounding film material by isotropic silicon etching. These results suggest that laser-based dewetting of thin films can be an effective way for scalable manufacturing of patterned nanostructures. (paper)

Directed dewetting of amorphous silicon film by a donut-shaped laser pulse.

Science.gov (United States)

Yoo, Jae-Hyuck; In, Jung Bin; Zheng, Cheng; Sakellari, Ioanna; Raman, Rajesh N; Matthews, Manyalibo J; Elhadj, Selim; Grigoropoulos, Costas P

2015-04-24

Irradiation of a thin film with a beam-shaped laser is proposed to achieve site-selectively controlled dewetting of the film into nanoscale structures. As a proof of concept, the laser-directed dewetting of an amorphous silicon thin film on a glass substrate is demonstrated using a donut-shaped laser beam. Upon irradiation of a single laser pulse, the silicon film melts and dewets on the substrate surface. The irradiation with the donut beam induces an unconventional lateral temperature profile in the film, leading to thermocapillary-induced transport of the molten silicon to the center of the beam spot. Upon solidification, the ultrathin amorphous silicon film is transformed to a crystalline silicon nanodome of increased height. This morphological change enables further dimensional reduction of the nanodome as well as removal of the surrounding film material by isotropic silicon etching. These results suggest that laser-based dewetting of thin films can be an effective way for scalable manufacturing of patterned nanostructures.

Factors influencing laser cutting of wood

Energy Technology Data Exchange (ETDEWEB)

Barnekov, V. G.; McMillin, C. W.; Huber, H. A.

1986-07-01

Factors influencing the ability of lasers to cut wood may be generally classified into these three areas: 1) characteristics of the laser beam; 2) equipment and processing variables; and 3) properties of the work piece. Effects of beam power, mode, polarization, and stability are discussed as are aspects of optics, location of focal point, feed speed, gas-jet assist system and work piece thickness, density, and moisture content. (author)

Finesse of transparent tissue cutting by ultrafast lasers at various wavelengths

Science.gov (United States)

Wang, Jenny; Schuele, Georg; Palanker, Daniel

2015-12-01

Transparent ocular tissues, such as the cornea and crystalline lens, can be ablated or dissected using short-pulse lasers. In refractive and cataract surgeries, the cornea, lens, and lens capsule can be cut by producing dielectric breakdown in the focus of a near-infrared (IR) femtosecond laser, which results in explosive vaporization of the interstitial water, causing mechanical rupture of the surrounding tissue. Here, we compare the texture of edges of lens capsule cut by femtosecond lasers with IR and ultraviolet (UV) wavelengths and explore differences in interactions of these lasers with biological molecules. Scanning electron microscopy indicates that a 400-nm laser is capable of producing very smooth cut edges compared to 800 or 1030 nm at a similar focusing angle. Using gel electrophoresis and liquid chromatography/mass spectrometry, we observe laser-induced nonlinear breakdown of proteins and polypeptides by 400-nm femtosecond pulses above and below the dielectric breakdown threshold. On the other hand, 800-nm femtosecond lasers do not produce significant dissociation even above the threshold of dielectric breakdown. However, despite this additional interaction of UV femtosecond laser with proteins, we determine that efficient cutting requires plasma-mediated bubble formation and that remarkably smooth edges are the result of reduced thresholds and smaller focal volume.

CO2 laser cutting of advanced high strength steels (AHSS)

International Nuclear Information System (INIS)

Lamikiz, A.; Lacalle, L.N. Lopez de; Sanchez, J.A.; Pozo, D. del; Etayo, J.M.; Lopez, J.M.

2005-01-01

This article demonstrates the optimum working areas and cutting conditions for the laser cutting of a series of advanced high strength steels (AHSS). The parameters that most influence the cutting of sheet metal have been studied and the results have been divided into two large groups with thickness of more and less than 1 mm. The influence of the material and, more important, the effect of coating have been taken into account. The results, have demonstrate very different behaviours between the thinnest and thickest sheets, whilst the variation of the cutting parameters due to the influence of the material is less relevant. The optimum cutting areas and the quality of the cut evaluated with different criteria are presented. Finally, the best position for the laser beam has been observed to be underneath the sheet

Laser circular cutting of Kevlar sheets: Analysis of thermal stress filed and assessment of cutting geometry

Science.gov (United States)

Yilbas, B. S.; Akhtar, S. S.; Karatas, C.

2017-11-01

A Kevlar laminate has negative thermal expansion coefficient, which makes it difficult to machine at room temperaures using the conventional cutting tools. Contararily, laser machining of a Kevlar laminate provides advantages over the conventional methods because of the non-mechanical contact between the cutting tool and the workpiece. In the present study, laser circular cutting of Kevlar laminate is considered. The experiment is carried out to examine and evaluate the cutting sections. Temperature and stress fields formed in the cutting section are simulated in line with the experimental study. The influence of hole diameters on temperature and stress fields are investigated incorporating two different hole diameters. It is found that the Kevlar laminate cutting section is free from large size asperities such as large scale sideways burnings and attachemnt of charred residues. The maximum temperature along the cutting circumference remains higher for the large diameter hole than that of the small diameter hole. Temperature decay is sharp around the cutting section in the region where the cutting terminates. This, in turn, results in high temperature gradients and the thermal strain in the cutting region. von Mises stress remains high in the region where temperature gradients are high. von Mises stress follows similar to the trend of temperature decay around the cutting edges.

Optimization of CO2 Laser Cutting Process using Taguchi and Dual Response Surface Methodology

Directory of Open Access Journals (Sweden)

M. Madić

2014-09-01

Full Text Available Selection of optimal cutting parameter settings for obtaining high cut quality in CO2 laser cutting process is of great importance. Among various analytical and experimental optimization methods, the application of Taguchi and response surface methodology is one of most commonly used for laser cutting process optimization. Although the concept of dual response surface methodology for process optimization has been used with success, till date, no experimental study has been reported in the field of laser cutting. In this paper an approach for optimization of CO2 laser cutting process using Taguchi and dual response surface methodology is presented. The goal was to determine the near optimal laser cutting parameter values in order to ensure robust condition for minimization of average surface roughness. To obtain experimental database for development of response surface models, Taguchi’s L25 orthogonal array was implemented for experimental plan. Three cutting parameters, the cutting speed (3, 4, 5, 6, 7 m/min, the laser power (0.7, 0.9, 1.1, 1.3, 1.5 kW, and the assist gas pressure (3, 4, 5, 6, 7 bar, were used in the experiment. To obtain near optimal cutting parameters settings, multi-stage Monte Carlo simulation procedure was performed on the developed response surface models.

Pulsed Laser Interactions with Silicon Nano structures in Emitter Formation

International Nuclear Information System (INIS)

Huat, V.L.C.; Leong, C.S.; Kamaruzzaman Sopian, Saleem Hussain Zaidi

2015-01-01

Silicon wafer thinning is now approaching fundamental limits for wafer thickness owing to thermal expansion mismatch between Al and Si, reduced yields in wet-chemical processing as a result of fragility, and reduced optical absorption. An alternate manufacturing approach is needed to eliminate current manufacturing issues. In recent years, pulsed lasers have become readily available and costs have been significantly reduced. Pulsed laser interactions with silicon, in terms of micromachining, diffusions, and edge isolation, are well known, and have become industrial manufacturing tools. In this paper, pulsed laser interactions with silicon nano structures were identified as the most desirable solution for the fundamental limitations discussed above. Silicon nano structures have the capability for extremely high absorption that significantly reduces requirements for laser power, as well as thermal shock to the thinner wafer. Laser-assisted crystallization, in the presence of doping materials, leads to nano structure profiles that are highly desirable for sunlight absorption. The objective of this paper is the replacement of high temperature POCl_3 diffusion by laser-assisted phosphorus layers. With these improvements, complete low-temperature processing of thinner wafers was achievable with 3.7 % efficiency. Two-dimensional laser scanning was proved to be able to form uniformly annealed surfaces with higher fill factor and open-circuit voltage. (author)

Pulsed laser ablation of silicon with low laser fluence in a low-pressure of ammonia ambient

International Nuclear Information System (INIS)

Choo, Cheow-Keong; Tohara, Makoto; Enomoto, Kazuhiro; Tanaka, Katsumi

2004-01-01

Silicon was ablated by 532 nm wavelength of Nd:YAG laser in ammonia gas ambient. The influence of laser fluence and gas ambient pressures between 1.33x10 1 to 1.33x10 -5 Pa on the deposited compound was studied by in situ X-ray photoelectron spectroscopy and transmission Fourier transform infrared spectroscopy techniques. The results indicate that the deposited compound is composed of nonstoichiometric silicon nitride (SiN x , x=0-0.84). It has been shown that the composition of nitrogen to silicon is sensitive to the laser fluence; it increases with decreasing laser fluence. However, the ammonia gas ambient in these low pressures range had no influence on the composition of the deposited compound. The reaction of the ablated silicon with low-pressure ambient ammonia is proposed to be occurred on the substrate

Laser annealing of ion implanted silicon

International Nuclear Information System (INIS)

White, C.W.; Narayan, J.; Young, R.T.

1978-11-01

The physical and electrical properties of ion implanted silicon annealed with high powered ruby laser radiation are summarized. Results show that pulsed laser annealing can lead to a complete removal of extended defects in the implanted region accompanied by incorporation of dopants into lattice sites even when their concentration far exceeds the solid solubility limit

CO2 Laser Cutting of Hot Stamping Boron Steel Sheets

Directory of Open Access Journals (Sweden)

Pasquale Russo Spena

2017-10-01

Full Text Available This study investigates the quality of CO2 laser cutting of hot stamping boron steel sheets that are employed in the fabrication of automotive body-in-white. For this purpose, experimental laser cutting tests were conducted on 1.2 mm sheets at varying levels of laser power, cutting speed, and oxygen pressure. The resulting quality of cut edges was evaluated in terms of perpendicularity tolerance, surface irregularity, kerf width, heat affected zone, and dross extension. Experimental tests were based on a L9(34 orthogonal array design, with the effects of the process parameters on the quality responses being determined by means of a statistical analysis of variance (ANOVA. Quadratic mathematical models were developed to determine the relationships between the cutting parameters and the quality responses. Finally, a routine based on an optimization criterion was employed to predict the optimal setting of cutting factors and its effect on the quality responses. A confirmation experiment was conducted to verify the appropriateness of the optimization routine. The results show that all of the examined process parameters have a key role in determining the cut quality of hot stamping boron steel sheets, with cutting speed and their interactions having the most influencing effects. Particularly, interactions can have an opposite behavior for different levels of the process parameters.

Dross formation during laser cutting process

Energy Technology Data Exchange (ETDEWEB)

Yilbas, B S; Aleem, B J Abdul [Mechanical Engineering Department, King Fahd University of Petoleum and Minerals, Dhahran 32161 (Saudi Arabia)

2006-04-07

Melt formation during laser cutting of metallic substrates is considered and the melt thickness is formulated using a lump parameter analysis. The droplet diameter is also predicted and compared with the experimental results. A CO{sub 2} laser with variable pulse frequency is used in the experiment. Oxygen, as assisting gas, impinging coaxially with the laser beam, is used at different pressures. SEM and XRD are carried out to obtain micrographs and oxide compounds formed in the dross. It is found that the liquid layer thickness increases with increasing laser output power and reduces with increasing assisting gas velocity. The droplet formed is spherical and the droplet size predicted agrees well with the experimental results.

Recent Results in High Power CO2-Laser Cutting for Shipbuilding Industry

DEFF Research Database (Denmark)

Olsen, Flemming Ove; Juhl, Thomas Winther; Nielsen, Jakob Skov

2003-01-01

In 1997 a high power laser cutting and welding test facility was established at the Danish shipyard Odense Steel Shipyard (OSS). Research and development projects were initiated in order to establish the basis for applying the full power of the laser for laser-cutting, by developing mirror based...

CO 2 laser cutting of MDF . 1. Determination of process parameter settings

Science.gov (United States)

Lum, K. C. P.; Ng, S. L.; Black, I.

2000-02-01

This paper details an investigation into the laser processing of medium-density fibreboard (MDF). Part 1 reports on the determination of process parameter settings for the effective cutting of MDF by CO 2 laser, using an established experimental methodology developed to study the interrelationship between and effects of varying laser set-up parameters. Results are presented for both continuous wave (CW) and pulse mode (PM) cutting, and the associated cut quality effects have been commented on.

Analysis of laser remote fusion cutting based on a mathematical model

Energy Technology Data Exchange (ETDEWEB)

Matti, R. S. [Department of Engineering Sciences and Mathematics, Luleå University of Technology, S-971 87 Luleå (Sweden); Department of Mechanical Engineering, College of Engineering, University of Mosul, Mosul (Iraq); Ilar, T.; Kaplan, A. F. H. [Department of Engineering Sciences and Mathematics, Luleå University of Technology, S-971 87 Luleå (Sweden)

2013-12-21

Laser remote fusion cutting is analyzed by the aid of a semi-analytical mathematical model of the processing front. By local calculation of the energy balance between the absorbed laser beam and the heat losses, the three-dimensional vaporization front can be calculated. Based on an empirical model for the melt flow field, from a mass balance, the melt film and the melting front can be derived, however only in a simplified manner and for quasi-steady state conditions. Front waviness and multiple reflections are not modelled. The model enables to compare the similarities, differences, and limits between laser remote fusion cutting, laser remote ablation cutting, and even laser keyhole welding. In contrast to the upper part of the vaporization front, the major part only slightly varies with respect to heat flux, laser power density, absorptivity, and angle of front inclination. Statistical analysis shows that for high cutting speed, the domains of high laser power density contribute much more to the formation of the front than for low speed. The semi-analytical modelling approach offers flexibility to simplify part of the process physics while, for example, sophisticated modelling of the complex focused fibre-guided laser beam is taken into account to enable deeper analysis of the beam interaction. Mechanisms like recast layer generation, absorptivity at a wavy processing front, and melt film formation are studied too.

Analysis of laser remote fusion cutting based on a mathematical model

International Nuclear Information System (INIS)

Matti, R. S.; Ilar, T.; Kaplan, A. F. H.

2013-01-01

Laser remote fusion cutting is analyzed by the aid of a semi-analytical mathematical model of the processing front. By local calculation of the energy balance between the absorbed laser beam and the heat losses, the three-dimensional vaporization front can be calculated. Based on an empirical model for the melt flow field, from a mass balance, the melt film and the melting front can be derived, however only in a simplified manner and for quasi-steady state conditions. Front waviness and multiple reflections are not modelled. The model enables to compare the similarities, differences, and limits between laser remote fusion cutting, laser remote ablation cutting, and even laser keyhole welding. In contrast to the upper part of the vaporization front, the major part only slightly varies with respect to heat flux, laser power density, absorptivity, and angle of front inclination. Statistical analysis shows that for high cutting speed, the domains of high laser power density contribute much more to the formation of the front than for low speed. The semi-analytical modelling approach offers flexibility to simplify part of the process physics while, for example, sophisticated modelling of the complex focused fibre-guided laser beam is taken into account to enable deeper analysis of the beam interaction. Mechanisms like recast layer generation, absorptivity at a wavy processing front, and melt film formation are studied too

Hybrid integrated single-wavelength laser with silicon micro-ring reflector

Science.gov (United States)

Ren, Min; Pu, Jing; Krishnamurthy, Vivek; Xu, Zhengji; Lee, Chee-Wei; Li, Dongdong; Gonzaga, Leonard; Toh, Yeow T.; Tjiptoharsono, Febi; Wang, Qian

2018-02-01

A hybrid integrated single-wavelength laser with silicon micro-ring reflector is demonstrated theoretically and experimentally. It consists of a heterogeneously integrated III-V section for optical gain, an adiabatic taper for light coupling, and a silicon micro-ring reflector for both wavelength selection and light reflection. Heterogeneous integration processes for multiple III-V chips bonded to an 8-inch Si wafer have been developed, which is promising for massive production of hybrid lasers on Si. The III-V layer is introduced on top of a 220-nm thick SOI layer through low-temperature wafer-boning technology. The optical coupling efficiency of >85% between III-V and Si waveguide has been achieved. The silicon micro-ring reflector, as the key element of the hybrid laser, is studied, with its maximized reflectivity of 85.6% demonstrated experimentally. The compact single-wavelength laser enables fully monolithic integration on silicon wafer for optical communication and optical sensing application.

Estimation of the laser cutting operating cost by support vector regression methodology

Science.gov (United States)

Jović, Srđan; Radović, Aleksandar; Šarkoćević, Živče; Petković, Dalibor; Alizamir, Meysam

2016-09-01

Laser cutting is a popular manufacturing process utilized to cut various types of materials economically. The operating cost is affected by laser power, cutting speed, assist gas pressure, nozzle diameter and focus point position as well as the workpiece material. In this article, the process factors investigated were: laser power, cutting speed, air pressure and focal point position. The aim of this work is to relate the operating cost to the process parameters mentioned above. CO2 laser cutting of stainless steel of medical grade AISI316L has been investigated. The main goal was to analyze the operating cost through the laser power, cutting speed, air pressure, focal point position and material thickness. Since the laser operating cost is a complex, non-linear task, soft computing optimization algorithms can be used. Intelligent soft computing scheme support vector regression (SVR) was implemented. The performance of the proposed estimator was confirmed with the simulation results. The SVR results are then compared with artificial neural network and genetic programing. According to the results, a greater improvement in estimation accuracy can be achieved through the SVR compared to other soft computing methodologies. The new optimization methods benefit from the soft computing capabilities of global optimization and multiobjective optimization rather than choosing a starting point by trial and error and combining multiple criteria into a single criterion.

Experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO{sub 2} lasers under conditions of minimal roughness

Energy Technology Data Exchange (ETDEWEB)

Golyshev, A A; Malikov, A G; Orishich, A M; Shulyatyev, V B [S.A. Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

2014-10-31

The results of an experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO{sub 2} lasers are generalised. The dependence of roughness of the cut surface on the cutting parameters is investigated, and the conditions under which the surface roughness is minimal are formulated. It is shown that for both types of lasers these conditions can be expressed in the same way in terms of the dimensionless variables – the Péclet number Pe and the output power Q of laser radiation per unit thickness of the cut sheet – and take the form of the similarity laws: Pe = const, Q = const. The optimal values of Pe and Q are found. We have derived empirical expressions that relate the laser power and cutting speed with the thickness of the cut sheet under the condition of minimal roughness in the case of cutting by means of radiation from fibre and CO{sub 2} lasers. (laser technologies)

Metal cutting by radiation from a CO2 laser with a self-filtering cavity

International Nuclear Information System (INIS)

Malikov, A G; Orishich, Anatolii M; Shulyat'ev, Viktor B

2009-01-01

The possibility of quality cutting by radiation from a CO 2 laser with an unstable self-filtering cavity (SFC) is experimentally investigated. The SFC provides the product of the divergence angle by the beam radius close to that for lower modes in a stable cavity (SC), however, at a higher radiation power, which favours faster cutting. In the far-field zone, the SFC beam has a diffraction structure with side maxima, which is usually considered as a negative factor in laser cutting. 25-mm-thick steel slabs have been cut. The comparison of the obtained results with known data on SC lasers shows that the principal characteristics of the cut (the width, edge roughness, specific expenditure of energy) are close in these lasers. A conclusion is made that at the chosen cavity parameters, the specific spatial structure of the SFC laser beam has no significant effect on the cut characteristics. (laser technologies)

Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

Energy Technology Data Exchange (ETDEWEB)

Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)

2000-04-01

Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

Using laser to measure stem thickness and cut weed stems

DEFF Research Database (Denmark)

Heisel, T.; Schou, Jørgen; Andreasen, C.

2002-01-01

Stem thickness of the weed Solanum nigrum and the crop sugarbeet was determined with a He-Ne laser using a novel non-destructive technique measuring stem shadow. Thereafter, the stems were cut close to the soil surface with a CO2 laser. Treatments were carried out on pot plants, grown....... A binary model was also tested. The non-linear model incorporating stem thickness described the data best, indicating that it would be possible to optimize laser cutting by measuring stem thickness before cutting. The general tendency was that more energy was needed the thicker the stem. Energy uses...... in the greenhouse, at two different growth stages, and plant dry matter was measured 2-5 weeks after treatment. The relationship between plant dry weight and laser energy was analysed using two different non-linear dose-response regression models; one model included stem thickness as a variable, the other did not...

A task for laser cutting of lamellae with TruLaser 1030

OpenAIRE

Lazov, Lyubomir; Deneva, Hristina; Narica, Pavels

2015-01-01

The growing development of manufacturing, automotive, aerospace and other sectors in the industry generates the necessity to continuously expanding on modifications of electrical machinery and equipments which are used in them, as well as to improve their performance and reliability. The report presents some results from a study to the process of laser cutting through melting on lamellae for rotor and stator packages by using the laser system TruLaser 1030. Some functional dependencies are of...

Investigation of Cutting Quality of Remote DOE Laser Cutting in 0.5 mm Stainless Steel

Science.gov (United States)

Villumsen, Sigurd Lazic; Kristiansen, Morten

It has previously been shown that the stability of the remote fusion cutting (RFC) process can be increased by modifying the intensity profile of the laser by means of a diffractive optical element (DOE). This paper investigates the quality of remote DOE cutting (RDC) conducted with a 3 kW single mode fiber laser in 0.5 mm stainless steel. An automatic measurement system is used to investigate how the travel speed, focus offset and angle of incidence effect the kerf width and kerf variance. The study shows that the RDC process has a very low kerf width variance, and that the kerf width decreases with cutting speed. Furthermore, selected etched samples show a significant increase in the perpendicularity of the cuts when compared to RFC. Also, on average, the depth of the layer of molten material for RFC is 83% deeper than for RDC.

Optoacoustic monitoring of cutting efficiency and thermal damage during laser ablation.

Science.gov (United States)

Bay, Erwin; Douplik, Alexandre; Razansky, Daniel

2014-05-01

Successful laser surgery is characterized by a precise cut and effective hemostasis with minimal collateral thermal damage to the adjacent tissues. Consequently, the surgeon needs to control several parameters, such as power, pulse repetition rate, and velocity of movements. In this study we propose utilizing optoacoustics for providing the necessary real-time feedback of cutting efficiency and collateral thermal damage. Laser ablation was performed on a bovine meat slab using a Q-switched Nd-YAG laser (532 nm, 4 kHz, 18 W). Due to the short pulse duration of 7.6 ns, the same laser has also been used for generation of optoacoustic signals. Both the shockwaves, generated due to tissue removal, as well as the normal optoacoustic responses from the surrounding tissue were detected using a single broadband piezoelectric transducer. It has been observed that the rapid reduction in the shockwave amplitude occurs as more material is being removed, indicating decrease in cutting efficiency, whereas gradual decrease in the optoacoustic signal likely corresponds to coagulation around the ablation crater. Further heating of the surrounding tissue leads to carbonization accompanied by a significant shift in the optoacoustic spectra. Our results hold promise for real-time monitoring of cutting efficiency and collateral thermal damage during laser surgery. In practice, this could eventually facilitate development of automatic cut-off mechanisms that will guarantee an optimal tradeoff between cutting and heating while avoiding severe thermal damage to the surrounding tissues.

Parameters Influence of CO2 Laser on Cutting Quality of Polymer Materials

OpenAIRE

Robert Cep; Sarka Malotova; Marek Pagac; Marek Sadilek; Jiri Lichovnik

2016-01-01

The article deals with evaluating of the resulting surface state of the three plastic materials and identification of suitable conditions for laser cutting with CO2 tube. As representative were chosen polypropylene, polymethylmethacrylate and polyamide. When cutting these types of materials it could melt eventually their re-sintering. A suitable combination of parameters is possible to achieve of sufficient quality of the cut. The samples were cut at different feed speed and laser power. Then...

Research on NC laser combined cutting optimization model of sheet metal parts

Science.gov (United States)

Wu, Z. Y.; Zhang, Y. L.; Li, L.; Wu, L. H.; Liu, N. B.

2017-09-01

The optimization problem for NC laser combined cutting of sheet metal parts was taken as the research object in this paper. The problem included two contents: combined packing optimization and combined cutting path optimization. In the problem of combined packing optimization, the method of “genetic algorithm + gravity center NFP + geometric transformation” was used to optimize the packing of sheet metal parts. In the problem of combined cutting path optimization, the mathematical model of cutting path optimization was established based on the parts cutting constraint rules of internal contour priority and cross cutting. The model played an important role in the optimization calculation of NC laser combined cutting.

Improvements of high-power diode laser line generators open up new application fields

Science.gov (United States)

Meinschien, J.; Bayer, A.; Bruns, P.; Aschke, L.; Lissotschenko, V. N.

2009-02-01

Beam shaping improvements of line generators based on high power diode lasers lead to new application fields as hardening, annealing or cutting of various materials. Of special interest is the laser treatment of silicon. An overview of the wide variety of applications is presented with special emphasis of the relevance of unique laser beam parameters like power density and beam uniformity. Complementary to vision application and plastic processing, these new application markets become more and more important and can now be addressed by high power diode laser line generators. Herewith, a family of high power diode laser line generators is presented that covers this wide spectrum of application fields with very different requirements, including new applications as cutting of silicon or glass, as well as the beam shaping concepts behind it. A laser that generates a 5m long and 4mm wide homogeneous laser line is shown with peak intensities of 0.2W/cm2 for inspection of railway catenaries as well as a laser that generates a homogeneous intensity distribution of 60mm x 2mm size with peak intensities of 225W/cm2 for plastic processing. For the annealing of silicon surfaces, a laser was designed that generates an extraordinary uniform intensity distribution with residual inhomogeneities (contrast ratio) of less than 3% over a line length of 11mm and peak intensities of up to 75kW/cm2. Ultimately, a laser line is shown with a peak intensity of 250kW/cm2 used for cutting applications. Results of various application tests performed with the above mentioned lasers are discussed, particularly the surface treatment of silicon and the cutting of glass.

Orthogonal cutting of laser beam melted parts

Science.gov (United States)

Götze, Elisa; Zanger, Frederik; Schulze, Volker

2018-05-01

The finishing process of parts manufactured by laser beam melting is of high concern due to the lack of surface accuracy. Therefore, the focus of this work lies on the influence of the build-up direction of the parts and their effect on the finishing process. The orthogonal cutting reveals findings in the fields of chip formation, involved forces and temperatures appearing during machining. In the investigations, the cutting depth was varied between 0.05 and 0.15 mm representing a finishing process and the cutting velocity ranges from 30 to 200 m/min depending on the material. The experiments contain the materials stainless steel (AISI 316L), titanium (Ti6Al4V) and nickel-base alloy (IN718). The two materials named latter are of high interest in the aerospace sector and at the same time titanium is used in the medical field due to its biocompatibility. For the materials IN718 and Ti6Al4V a negative rake angle of -7.5° and for stainless steel a rake angle of 12.5° are chosen for the cutting experiments. The results provide the base for processing strategies. Therefore, the specimens were solely laser beam melted without post-processing like heat treatment. The evaluation of the experiments shows that an increase in cutting speed has different effects depending on the material. For stainless steel the measured forces regarding the machining direction to the layers approach the same values. In contrast, the influence of the layers regarding the forces appearing during orthogonal cutting of the materials IN718 and Ti6Al4V differ for lower cutting speeds.

Role of Laser Power, Wavelength, and Pulse Duration in Laser Assisted Tin-Induced Crystallization of Amorphous Silicon

Directory of Open Access Journals (Sweden)

V. B. Neimash

2018-01-01

Full Text Available This work describes tin-induced crystallization of amorphous silicon studied with Raman spectroscopy in thin-film structures Si-Sn-Si irradiated with pulsed laser light. We have found and analyzed dependencies of the nanocrystals’ size and concentration on the laser pulse intensity for 10 ns and 150 μm duration laser pulses at the wavelengths of 535 nm and 1070 nm. Efficient transformation of the amorphous silicon into a crystalline phase during the 10 ns time interval of the acting laser pulse in the 200 nm thickness films of the amorphous silicon was demonstrated. The results were analyzed theoretically by modeling the spatial and temporal distribution of temperature in the amorphous silicon sample within the laser spot location. Simulations confirmed importance of light absorption depth (irradiation wavelength in formation and evolution of the temperature profile that affects the crystallization processes in irradiated structures.

Metal-like self-organization of periodic nanostructures on silicon and silicon carbide under femtosecond laser pulses

International Nuclear Information System (INIS)

Gemini, Laura; Hashida, Masaki; Shimizu, Masahiro; Miyasaka, Yasuhiro; Inoue, Shunsuke; Tokita, Shigeki; Sakabe, Shuji; Limpouch, Jiri; Mocek, Tomas

2013-01-01

Periodic structures were generated on Si and SiC surfaces by irradiation with femtosecond laser pulses. Self-organized structures with spatial periodicity of approximately 600 nm appear on silicon and silicon carbide in the laser fluence range just above the ablation threshold and upon irradiation with a large number of pulses. As in the case of metals, the dependence of the spatial periodicity on laser fluence can be explained by the parametric decay of laser light into surface plasma waves. The results show that the proposed model might be universally applicable to any solid state material

Study into penetration speed during laser cutting of brain tissues.

Science.gov (United States)

Yilbas, Z; Sami, M; Patiroglu, T

1998-01-01

The applications of CO2 continuous-wave lasers in neurosurgery have become important in recent years. Theoretical considerations of laser applicability in medicine are subsequently confirmed experimentally. To obtain precision operation in the laser cutting process, further theoretical developments and experimental studies need to be conducted. Consequently, in the present study, the heat transfer mechanism taking place during laser-tissue interaction is introduced using Fourier theory. The results obtained from the theoretical model are compared with the experimental results. In connection with this, an experiment is designed to measure the penetration speed during the laser cutting process. The measurement is carried out using an optical method. It is found that both results for the penetration speed obtained from the theory and experiment are in a good agreement.

Direct modification of silicon surface by nanosecond laser interference lithography

Energy Technology Data Exchange (ETDEWEB)

Wang, Dapeng [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom); Wang, Zuobin, E-mail: wangz@cust.edu.cn [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom); Zhang, Ziang [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); Yue, Yong [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom); Li, Dayou [JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom); Maple, Carsten [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom)

2013-10-01

Periodic and quasi-periodic structures on silicon surface have numerous significant applications in photoelectronics and surface engineering. A number of technologies have been developed to fabricate the structures in various research fields. In this work, we take the strategy of direct nanosecond laser interference lithography technology, and focus on the silicon material to create different well-defined surface structures based on theoretical analysis of the formation of laser interference patterns. Two, three and four-beam laser interference systems were set up to fabricate the grating, regular triangle and square structures on silicon surfaces, respectively. From the AFM micrographs, the critical features of structures have a dependence on laser fluences. For a relative low laser fluence, grating and dot structures formed with bumps due to the Marangoni Effect. With the increase of laser fluences, melt and evaporation behaviors can be responsible for the laser modification. By properly selecting the process parameters, well-defined grating and dot structures can been achieved. It can be demonstrated that direct laser interference lithography is a facile and efficient technology with the advantage of a single process procedure over macroscale areas for the fabrication of micro and nano structures.

Applications of optical sensing for laser cutting and drilling.

Science.gov (United States)

Fox, Mahlen D T; French, Paul; Peters, Chris; Hand, Duncan P; Jones, Julian D C

2002-08-20

Any reliable automated production system must include process control and monitoring techniques. Two laser processing techniques potentially lending themselves to automation are percussion drilling and cutting. For drilling we investigate the performance of a modification of a nonintrusive optical focus control system we previously developed for laser welding, which exploits the chromatic aberrations of the processing optics to determine focal error. We further developed this focus control system for closed-loop control of laser cutting. We show that an extension of the technique can detect deterioration in cut quality, and we describe practical trials carried out on different materials using both oxygen and nitrogen assist gas. We base our techniques on monitoring the light generated by the process, captured nonintrusively by the effector optics and processed remotely from the workpiece. We describe the relationship between the temporal and the chromatic modulation of the detected light and process quality and show how the information can be used as the basis of a process control system.

Optimisation of the Laser Cutting Process

DEFF Research Database (Denmark)

Dragsted, Birgitte; Olsen, Flemmming Ove

1996-01-01

The problem in optimising the laser cutting process is outlined. Basic optimisation criteria and principles for adapting an optimisation method, the simplex method, are presented. The results of implementing a response function in the optimisation are discussed with respect to the quality as well...

A Study on Mechanical behavior of Tensile Specimen Fabricated by Laser Cutting

Energy Technology Data Exchange (ETDEWEB)

Jin, Y. G.; Kim, G. S.; Baik, S. J.; Baek, S. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The mechanical testing data are required for the assessment of dry storage of the spent nuclear fuel. Laser cutting system could be useful tools for material processing such as cutting in radioactive environment due to non-contact nature, ease in handling and the laser cutting process is most advantageous, offering the narrow kerf width and heat affected zone by using small beam spot diameter. The feasibility of the laser cutting system was demonstrated for the fabrication of various types of the unirradiated cladding with and without oxide layer on the specimens. In the present study, the dimensional measurement and tensile test were conducted to investigate the mechanical behavior of the axial tensile test specimens depending on the material processing methods in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. Laser cutting system was used to fabricate the tensile test specimens, and the mechanical behavior was investigated using the dimensional measurement and tensile test. It was shown that the laser beam machining could be a useful tool to fabricate the specimens and this technique will be developed for the fabrication of various types of irradiated specimens in a hotcell.

A Study on Mechanical behavior of Tensile Specimen Fabricated by Laser Cutting

International Nuclear Information System (INIS)

Jin, Y. G.; Kim, G. S.; Baik, S. J.; Baek, S. Y.

2016-01-01

The mechanical testing data are required for the assessment of dry storage of the spent nuclear fuel. Laser cutting system could be useful tools for material processing such as cutting in radioactive environment due to non-contact nature, ease in handling and the laser cutting process is most advantageous, offering the narrow kerf width and heat affected zone by using small beam spot diameter. The feasibility of the laser cutting system was demonstrated for the fabrication of various types of the unirradiated cladding with and without oxide layer on the specimens. In the present study, the dimensional measurement and tensile test were conducted to investigate the mechanical behavior of the axial tensile test specimens depending on the material processing methods in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. Laser cutting system was used to fabricate the tensile test specimens, and the mechanical behavior was investigated using the dimensional measurement and tensile test. It was shown that the laser beam machining could be a useful tool to fabricate the specimens and this technique will be developed for the fabrication of various types of irradiated specimens in a hotcell

Fuzzy Logic Approach for the Prediction of Dross Formation in CO2 Laser Cutting of Mild Steel

Directory of Open Access Journals (Sweden)

Miloš Madić

2015-11-01

Full Text Available Dross free laser cutting is very important in the application of laser cutting technology. This paper focuses on the development of a fuzzy logic model to predict dross formation in CO2 laser oxygen cutting of mild steel. Laser cutting experiment, conducted according to Taguchi’s experimental design using L25 orthogonal array, provided a set of data for the development of a fuzzy rule base. The predicting fuzzy logic model is based on using Mamdani-type inference system. Developed fuzzy logic model considered the cutting speed, laser power and assist gas pressure as inputs. Using this model the effects of the selected laser cutting parameters on the dross formation were investigated. Additionally, 3-D surface plots were generated to study the interaction effects of the laser cutting parameters. The analysis revealed that the cutting speed has the most significant effect, followed by laser power and assist gas pressure. The results indicated that the fuzzy logic modeling approach can be effectively used for the dross formation prediction in CO2 laser cutting of mild steel.

Modelling and optimization of cut quality during pulsed Nd:YAG laser cutting of thin Al-alloy sheet for straight profile

Science.gov (United States)

Sharma, Amit; Yadava, Vinod

2012-02-01

Thin sheets of aluminium alloys are widely used in aerospace and automotive industries for specific applications. Nd:YAG laser beam cutting is one of the most promising sheetmetal cutting process for cutting sheets for any profile. Al-alloy sheets are difficult to cut by laser beam because of its highly reflective nature. This paper presents modelling and optimization of cut quality during pulsed Nd:YAG laser cutting of thin Al-alloy sheet for straight profile. In the present study, four input process parameters such as oxygen pressure, pulse width, pulse frequency, and cutting speed and two output parameters such as average kerf taper ( Ta) and average surface roughness ( Ra) are considered. The hybrid approach comprising of Taguchi methodology (TM) and response surface methodology (RSM) is used for modelling whereas multi-objective optimization is performed using hybrid approach of TM and grey relational analysis (GRA) coupled with entropy measurement methodology. The entropy measurement methodology is employed for the calculation of weight corresponding to each quality characteristic. The results indicate that the hybrid approaches applied for modelling and optimization of the LBC process are reasonable.

CO{sub 2} laser cutting of advanced high strength steels (AHSS)

Energy Technology Data Exchange (ETDEWEB)

Lamikiz, A. [Department of Mechanical Engineering, University of the Basque Country, ETSII-UPV, c/Alameda de Urquijo s/n, 48013 Bilbao (Spain)]. E-mail: implamea@bi.ehu.es; Lacalle, L.N. Lopez de [Department of Mechanical Engineering, University of the Basque Country, ETSII-UPV, c/Alameda de Urquijo s/n, 48013 Bilbao (Spain); Sanchez, J.A. [Department of Mechanical Engineering, University of the Basque Country, ETSII-UPV, c/Alameda de Urquijo s/n, 48013 Bilbao (Spain); Pozo, D. del [ROBOTIKER Technology Centre, Parque Tecnologico, Edif. 202, 48170 Zamudio (Spain); Etayo, J.M. [Department of Mechanical Engineering, University of the Basque Country, ETSII-UPV, c/Alameda de Urquijo s/n, 48013 Bilbao (Spain); ROBOTIKER Technology Centre, Parque Tecnologico, Edif. 202, 48170 Zamudio (Spain); Lopez, J.M. [Department of Mechanical Engineering, University of the Basque Country, ETSII-UPV, c/Alameda de Urquijo s/n, 48013 Bilbao (Spain); ROBOTIKER Technology Centre, Parque Tecnologico, Edif. 202, 48170 Zamudio (Spain)

2005-04-15

This article demonstrates the optimum working areas and cutting conditions for the laser cutting of a series of advanced high strength steels (AHSS). The parameters that most influence the cutting of sheet metal have been studied and the results have been divided into two large groups with thickness of more and less than 1 mm. The influence of the material and, more important, the effect of coating have been taken into account. The results, have demonstrate very different behaviours between the thinnest and thickest sheets, whilst the variation of the cutting parameters due to the influence of the material is less relevant. The optimum cutting areas and the quality of the cut evaluated with different criteria are presented. Finally, the best position for the laser beam has been observed to be underneath the sheet.

Narrow-linewidth lasers on a silicon chip

NARCIS (Netherlands)

Bernhardi, Edward; Pollnau, Markus; Di Bartolo, Baldassare; Collins, John; Silvestri, Luciano

2015-01-01

Diode-pumped distributed-feedback (DFB) channel waveguide lasers were demonstrated in Er3+-doped and Yb3+-doped Al2O3 on standard thermally ox-idized silicon substrates. Uniform surface-relief Bragg gratings were patterned by laser-interference lithography and etched into the SiO2 top cladding. The

Formation of silicon carbide by laser ablation in graphene oxide-N-methyl-2-pyrrolidone suspension on silicon surface

Science.gov (United States)

Jaleh, Babak; Ghasemi, Samaneh; Torkamany, Mohammad Javad; Salehzadeh, Sadegh; Maleki, Farahnaz

2018-01-01

Laser ablation of a silicon wafer in graphene oxide-N-methyl-2-pyrrolidone (GO-NMP) suspension was carried out with a pulsed Nd:YAG laser (pulse duration = 250 ns, wavelength = 1064 nm). The surface of silicon wafer before and after laser ablation was studied using optical microscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The results showed that the ablation of silicon surface in liquid by pulsed laser was done by the process of melt expulsion under the influence of the confined plasma-induced pressure or shock wave trapped between the silicon wafer and the liquid. The X-ray diffraction‌ (XRD) pattern of Si wafer after laser ablation showed that 4H-SiC layer is formed on its surface. The formation of the above layer was also confirmed by Raman spectroscopy, and X-ray photoelectron spectroscopy‌ (XPS), as well as EDX was utilized. The reflectance of samples decreased with increasing pulse energy. Therefore, the morphological alteration and the formation of SiC layer at high energy increase absorption intensity in the UV‌-vis regions. Theoretical calculations confirm that the formation of silicon carbide from graphene oxide and silicon wafer is considerably endothermic. Development of new methods for increasing the reflectance without causing harmful effects is still an important issue for crystalline Si solar cells. By using the method described in this paper, the optical properties of solar cells can be improved.

Hybrid vertical-cavity laser with lateral emission into a silicon waveguide

DEFF Research Database (Denmark)

Park, Gyeong Cheol; Xue, Weiqi; Taghizadeh, Alireza

2015-01-01

into the waveguide integrated with the laser. This laser has the advantages of long-wavelength vertical-cavity surface-emitting lasers, such as low threshold and high side-mode suppression ratio, while allowing integration with silicon photonic circuits, and is fabricated using CMOS compatible processes. It has......We experimentally demonstrate an optically-pumped III-V/Si vertical-cavity laser with lateral emission into a silicon waveguide. This on-chip hybrid laser comprises a distributed Bragg reflector, a III-V active layer, and a high-contrast grating reflector, which simultaneously funnels light...

Simulation of Temperature Field Distribution for Cutting the Temperated Glass by Ultraviolet Laser

Science.gov (United States)

Yang, B. J.; He, Y. C.; Dai, F.; Lin, X. C.

2017-03-01

The finite element software ANSYS was adopted to simulate the temperature field distribution for laser cutting tempered glass, and the influence of different process parameters, including laser power, glass thickness and cutting speed, on temperature field distribution was studied in detail. The results show that the laser power has a greater influence on temperature field distribution than other paremeters, and when the laser power gets to 60W, the highest temperature reaches 749°C, which is higher than the glass softening temperature. It reflects the material near the laser spot is melted and the molten slag is removed by the high-energy water beam quickly. Finally, through the water guided laser cutting tempered glass experiment the FEM theoretical analysis was verified.

Effects of momentum transfer on sizing of current collectors for lithium-ion batteries during laser cutting

Science.gov (United States)

Lee, Dongkyoung; Mazumder, Jyotirmoy

2018-02-01

One of the challenges of the lithium-ion battery manufacturing process is the sizing of electrodes with good cut surface quality. Poor cut surface quality results in internal short circuits in the cells and significant heat generation. One of the solutions that may improve the cut quality with a high cutting speed is laser cutting due to its high energy concentration, fast processing time, high precision, small heat affected zone, flexible range of laser power and contact free process. In order to utilize the advantages of laser electrode cutting, understanding the physical phenomena for each material is crucial. Thus, this study focuses on the laser cutting of current collectors, such as pure copper and aluminum. A 3D self-consistent mathematical model for the laser cutting, including fluid flow, heat transfer, recoil pressure, multiple reflections, capillary and thermo-capillary forces, and phase changes, is presented and solved numerically. Simulation results for the laser cutting are analyzed in terms of penetration time, depth, width, and absorptivity, based on these selected laser parameters. In addition, melt pool flow, melt pool geometry and temperature distribution are investigated.

Use of laser cutting techniques for dismantling tasks in nuclear facilities

International Nuclear Information System (INIS)

Haferkamp, H.; Drygalla, M.; Goede, M.

2001-01-01

A handguided laser processing system developed by laser zentrum Hannover e.V. (LZH) allows impressive cutting, notching, and material removal applications for the dismantling of nuclear power plants. The handguided unit is equipped with a motor drive for consistent processing results and flexible processing for as long as desired. It offers the possibility to adjust the nozzle as well as focal position in order that various materials with different material thicknesses may be processed. The set process parameters may be viewed on a display which also indicates the laser processing programme selected. An integrated exhaust system guarantees a shielded process. The operator is not only protected against process emissions but also against laser beam reflexions. The handguided unit is connected to the laser beam source via an optical fibre and can be used for laser output powers of up to 1500 W with a high beam quality. For handguided laser material processing low emissions at high feed rates as well as cutting kerf widths between 0.5 and 0.3 mm for special applications such as the dismantling of large facilities or units, etc. are decisive, especially when cutting metal sheets for the dismantling of nuclear power plants. (orig.)

Use of laser cutting techniques for dismantling tasks in nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Haferkamp, H.; Drygalla, M.; Goede, M. [Laser Zentrum Hannover e.V. (Germany)

2001-07-01

A handguided laser processing system developed by laser zentrum Hannover e.V. (LZH) allows impressive cutting, notching, and material removal applications for the dismantling of nuclear power plants. The handguided unit is equipped with a motor drive for consistent processing results and flexible processing for as long as desired. It offers the possibility to adjust the nozzle as well as focal position in order that various materials with different material thicknesses may be processed. The set process parameters may be viewed on a display which also indicates the laser processing programme selected. An integrated exhaust system guarantees a shielded process. The operator is not only protected against process emissions but also against laser beam reflexions. The handguided unit is connected to the laser beam source via an optical fibre and can be used for laser output powers of up to 1500 W with a high beam quality. For handguided laser material processing low emissions at high feed rates as well as cutting kerf widths between 0.5 and 0.3 mm for special applications such as the dismantling of large facilities or units, etc. are decisive, especially when cutting metal sheets for the dismantling of nuclear power plants. (orig.)

LASER CUTTING AS AN INNOVATIVE CREATIVITY TOOL IN TEXTILE DESIGN

Directory of Open Access Journals (Sweden)

Banu Hatice Gurcum

2016-12-01

Full Text Available Innovative technologies have become the most widespread rapid and flexible technique of cutting, welding, printing and coloring in fashion and textile sectors in a very short time. Laser systems as the most common used innovative technology engrave, cut, form, print, shade appropriated formatted drawings and sketches as well as they provide reliable placements for the lay out plans and precision cutting and the production sector rapid and qualified. The practical applications and conveniences that innovative Technologies employ, influence design process, designers can design in a more creative, rapid, precise and effective manner. Although design is a context where technology is effective, the style, mood and the background of the designer is still important. Designers while making innovative studies should take the advantage of the developing technologies in experimental processes and should combine technological opportunities with aesthetics. Textile designer as in all other domains of design, should harmonise with the change and should define his/her style with the innovative Technologies in an innovative manner and renew him/herself all the time. This study aims to classify laser cutting technology applications available in textile and fashion sector as well as to present the laser technology as a means of process, product, material innovation and explains the contributions of laser systems to creativity.

Optimization of Cutting Parameters of the Haynes 718 Nickel Alloy With Gas CO2 Laser

Directory of Open Access Journals (Sweden)

Jana PETRŮ

2011-06-01

Full Text Available This article deals with the application of laser technology and the optimization of parameters in the area of nickel alloy laser cutting intended for application in the aircraft industry. The main goal is to outline possibilities of use of the laser technology, primarily its application in the area of 3D material cutting. This experiment is focused on the optimization of cutting parameters of the Haynes 718 alloy with a gas CO2 laser. Originating cuts are evaluated primarily from the point of view of cut quality and accompanying undesirable phenomena occurring in the process of cutting. In conclusion the results achieved in the metallographic laboratory are described and analyzed.

Laser cutting of laminated sheet material: a modeling exercise

NARCIS (Netherlands)

de Graaf, R.F.; Meijer, J.

1997-01-01

Laser cutting has been investigated for a number of aluminum-synthetic laminates, newly developed materials for the aeronautic and automotive industry. The materials consist of alternating aluminum and synthetic layers. It is shown that these materials can be cut at rates comparable to those of

Laser cutting of metal laminates: analysis and experimental validation

NARCIS (Netherlands)

de Graaf, R.F.; Meijer, J.

2000-01-01

Laser cutting has been investigated for a number of aluminum–synthetic laminates, newly developed materials for the aeronautic and automotive industry. The materials consist of alternating aluminum and synthetic layers. It is shown that these materials can be cut at the same speed as homogeneous

Researches Regarding The Circular Interpolation Algorithms At CNC Laser Cutting Machines

Science.gov (United States)

Tîrnovean, Mircea Sorin

2015-09-01

This paper presents an integrated simulation approach for studying the circular interpolation regime of CNC laser cutting machines. The circular interpolation algorithm is studied, taking into consideration the numerical character of the system. A simulation diagram, which is able to generate the kinematic inputs for the feed drives of the CNC laser cutting machine is also presented.

Relation between Cutting Surface Quality and Alloying Element Contents when Using a CO2 Laser

Directory of Open Access Journals (Sweden)

J. Litecká

2011-01-01

Full Text Available This paper deals with the influence of material content on changes in the quality parameters of the cutting surface when cutting with a laser. The study focuses on experiments to find the effect of material structure and cutting parameters on surface roughness, Vickers microhardness and precision of laser cutting. The experimental results are shown in graphs which illustrate the suitability of materials for achieving required cutting surface quality parameters. These results can be used for optimizing production in practical applications using a laser cutting machine.

Analysis about diamond tool wear in nano-metric cutting of single crystal silicon using molecular dynamics method

Science.gov (United States)

Wang, Zhiguo; Liang, Yingchun; Chen, Mingjun; Tong, Zhen; Chen, Jiaxuan

2010-10-01

Tool wear not only changes its geometry accuracy and integrity, but also decrease machining precision and surface integrity of workpiece that affect using performance and service life of workpiece in ultra-precision machining. Scholars made a lot of experimental researches and stimulant analyses, but there is a great difference on the wear mechanism, especially on the nano-scale wear mechanism. In this paper, the three-dimensional simulation model is built to simulate nano-metric cutting of a single crystal silicon with a non-rigid right-angle diamond tool with 0 rake angle and 0 clearance angle by the molecular dynamics (MD) simulation approach, which is used to investigate the diamond tool wear during the nano-metric cutting process. A Tersoff potential is employed for the interaction between carbon-carbon atoms, silicon-silicon atoms and carbon-silicon atoms. The tool gets the high alternating shear stress, the tool wear firstly presents at the cutting edge where intension is low. At the corner the tool is splitted along the {1 1 1} crystal plane, which forms the tipping. The wear at the flank face is the structure transformation of diamond that the diamond structure transforms into the sheet graphite structure. Owing to the tool wear the cutting force increases.

Feasibility Study of Laser Cutting for Fabrication of Tensile Specimen

International Nuclear Information System (INIS)

Jin, Y. G.; Baik, S. J.; Kim, G. S.; Heo, G. S.; Yoo, B. O.; Ahn, S. B.; Chun, Y. B.

2015-01-01

The specimen fabrication technique was established to machine the specimen from the irradiated materials. The wire cut EDM(electric discharge machine) was modified to fabricate the mechanical testing specimens from irradiated components and fuel claddings. The oxide layer removal system was also developed because the oxide layer on the surface of the irradiated components and claddings interrupted the applying the electric current during the processing. However, zirconium oxide is protective against further corrosion as well as beneficial to mechanical strength for the tensile deformation of the cladding. Thus, it is important to fabricate the irradiated specimens without removal of oxide layer on the surface of the irradiated structural components and claddings. In the present study, laser cutting system was introduced to fabricate the various mechanical testing specimens from the unirradiated fuel cladding and the feasibility of the laser cutting system was studied for the fabrication of various types of irradiated specimens in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. Laser beam machining system was introduced to fabricate the various mechanical testing specimens from the unirradiated fuel cladding and the dimensions were compared for the feasibility of the laser cutting system. The effect of surface oxide layer was also investigated for machining process of the zircaloy-4 fuel cladding and it was found that laser beam machining could be a useful tool to fabricate the specimens with surface oxide layer

Feasibility Study of Laser Cutting for Fabrication of Tensile Specimen

Energy Technology Data Exchange (ETDEWEB)

Jin, Y. G.; Baik, S. J.; Kim, G. S.; Heo, G. S.; Yoo, B. O.; Ahn, S. B.; Chun, Y. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

The specimen fabrication technique was established to machine the specimen from the irradiated materials. The wire cut EDM(electric discharge machine) was modified to fabricate the mechanical testing specimens from irradiated components and fuel claddings. The oxide layer removal system was also developed because the oxide layer on the surface of the irradiated components and claddings interrupted the applying the electric current during the processing. However, zirconium oxide is protective against further corrosion as well as beneficial to mechanical strength for the tensile deformation of the cladding. Thus, it is important to fabricate the irradiated specimens without removal of oxide layer on the surface of the irradiated structural components and claddings. In the present study, laser cutting system was introduced to fabricate the various mechanical testing specimens from the unirradiated fuel cladding and the feasibility of the laser cutting system was studied for the fabrication of various types of irradiated specimens in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. Laser beam machining system was introduced to fabricate the various mechanical testing specimens from the unirradiated fuel cladding and the dimensions were compared for the feasibility of the laser cutting system. The effect of surface oxide layer was also investigated for machining process of the zircaloy-4 fuel cladding and it was found that laser beam machining could be a useful tool to fabricate the specimens with surface oxide layer.

Transport of biologically active material in laser cutting.

Science.gov (United States)

Frenz, M; Mathezloic, F; Stoffel, M H; Zweig, A D; Romano, V; Weber, H P

1988-01-01

The transport of biologically active material during laser cutting with CO2 and Er lasers is demonstrated. This transport mechanism removes particles from the surface of gelatin, agar, and liver samples into the depth of the laser-formed craters. The transport phenomenon is explained by a contraction and condensation of enclosed hot water vapor. We show by cultivating transported bacteria in agar that biological particles can survive the shock of the transport. Determination of the numbers of active cells evidences a more pronounced activity of the cultivated bacteria after impact with an Er laser than with a CO2 laser.

CO{sub 2} laser beam cutting with long-focused optics system

Energy Technology Data Exchange (ETDEWEB)

Okimura, Koji [Mitsubishi Heavy Industries, Ltd., Kobe Shipyard and Machinery Works, Kobe, Hyogo (Japan); Nagura, Yasumi; Ishide, Takashi; Hiramoto, Yoneo

1999-07-01

In cutting the decommissioned nuclear facility, it is required to ensure the safety for dismantling workers, to control the amount of wastes generated by cutting, to reduce the costs, etc. Recently, the laser power has increased remarkably and its application tests are carried out at various fields. In this work, cutting tests were carried out with the CO{sub 2} laser having a long-focused optics system of the meter scale. Then, in the optics system of 5 m focal length, it is possible to cut the steel plates of 30 and 40 mm thickness with the laser power of 20 and 40 kW respectively and 42 mm out diameter steel pipe of 5 mm thickness with that of 20 kW without using assistant gas. This cutting process can be developed such a new dismantling method that may dismantle crowded overhead pipes without a scaffolding, so it is expected to ensure the safety for dismantling workers, to decrease the amount of total radiation exposure and to reduce the costs. (author)

Hydrodynamics of material removal by melt expulsion: Perspectives of laser cutting and drilling

Science.gov (United States)

Poprawe, Reinhart; Schulz, Wolfgang; Schmitt, Robert

With the introduction of fiber-guided radiation at 1 μ wavelength emitting in the milti-kW range at better beam quality than CO2-lasers the most established application in laser processing, namely laser fusion cutting, came back into the industrial and scientific focus. Laser sources with extraordinary optical and economical properties - disk and fiber lasers - in a stormy way enter the market of cutting machines so far reserved for the 10 μ radiation source and led to a volatile situation. The new laser sources can already address a market-relevant class of applications, namely, fusion cutting of steel up to a sheet thickness of 2 mm with pronounced advantages in productivity. However, there is a significant lack of cut quality for larger sheet thickness. The main reason for the drawback and its physical background are given. With the availability of cutting machines with 1 μ fiber-guided radiation the race for the worldwide market regarding the larger sheet thickness is opened and the priority issues to improve the cut quality are related to the three levels: wavelength, beam delivery and the application stage of the machine. The stability model called QuCut is presented which for the first time allows to analyze stability of cutting with fiber-guided radiation. Experimental ripple patterns and ripple spectra resolved with respect to the cutting depth are well reproduced by the new stability model. A number of different experimental methods towards an improved understanding of the dynamics in laser drilling are developed, however, there are gaps related to in-situ observation which is obscured by the hole walls. There are four novel experimental methods resolving the dynamics from a μms-down to a ns-time scale having a spatial resolution with respect to transient drilling depth on the μm scale. As result, the different mechanisms contributing to recast formation and dynamical features of drilling are revealed in more detail. In particular, the action of

Towards crack-free ablation cutting of thin glass sheets with picosecond pulsed lasers

Science.gov (United States)

Sun, Mingying; Eppelt, Urs; Hartmann, Claudia; Schulz, Wolfgang; Zhu, Jianqiang; Lin, Zunqi

2017-08-01

We investigated the morphology and mechanism of laser-induced damage in the ablation cutting of thin glass sheets with picosecond laser. Two kinds of damage morphologies observed on the cross-section of the cut channel, are caused by high-density free-electrons and the temperature accumulation, respectively. Notches and micro-cracks can be observed on the top surface of the sample near the cut edge. The surface micro-cracks were related to high energy free-electrons and also the heat-affected zone. Heat-affected-zone and visible-cracks free conditions of glass cutting were achieved by controlling the repetition rate and spatial overlap of laser pulses.

Performance comparison of CO2 and diode lasers for deep-section concrete cutting

International Nuclear Information System (INIS)

Crouse, Philip L.; Li, Lin; Spencer, Julian T.

2004-01-01

Layer-by-layer laser machining with mechanical removal of vitrified dross between passes is a new technique with a demonstrated capability for deep-section cutting, not only of concrete, but of ceramic and refractory materials in general. For this application fairly low power densities are required. A comparison of experimental results using high-power CO 2 and diode lasers under roughly equivalent experimental conditions, cutting to depths of >100 mm, is presented. A marked improvement in cutting depth per pass is observed for the case of the diode laser. The increased cutting rate is rationalized in terms of the combined effects of coupling efficiency and beam shape

Dismantling of Evaporators by Laser Cutting Measurement of Secondary Emissions

International Nuclear Information System (INIS)

Pilot, Guy; Fauvel, Sylvain; Gosse, Xavier; De Dinechin, Guillaume

2006-01-01

In order to dismantle the evaporators of an obsolete reprocessing plant in Marcoule, studies were carried out by IRSN (Institut de Radioprotection et de Surete Nucleaire) / DSU/SERAC in cooperation with CEA (power laser group) on the laser cutting of steel structures, on the request of COGEMA (now AREVA NC) /Marcoule (UP1 dismantling project manager) and CEA/UMODD (UP1 dismantling owner). The aim of these studies was: - to quantify and to characterize the secondary emissions produced by Nd-YAG laser cutting of Uranus 65 steel pieces representative of UP1 evaporator elements and to examine the influence of different parameters, - to qualify a pre-filtration technique and particularly an electrostatic precipitator, - to compare the Nd-YAG used with other cutting tools previously studied. The experiments, which took place in a 35 m 3 ventilated cutting cell, allow to underline the following points: for the Uranus 65 steel, the sedimented dross, the deposits on the walls of the cutting cell and the aerosols drawn in the ventilation exhaust duct (∼ 275 m 3 /h), represent respectively between 92% and 99%, between 0.01% and 0.25% and between 1% and 8% of the total collected mass, the attached slag varies much from one configuration to the other and can sometimes amount to a relatively important fraction of the total mass, the kerves vary from 2 mm up to 7 mm for the Uranus 65 steel plates (thickness: 13.8 mm for the single plate and 12.8 + 3.5 mm for the double plate), the exhausted aerosol mass per cut length (g/m) decreases with the cutting speed, varies neither with the stand-off nor with the gas pressure, is dependent upon the gas nature (for the double plate), increases with the laser power, is strongly affected by the nature of the steel (stainless steel or mild steel) and is independent upon the plate position, the size distribution of aerosols is multimodal with a main mode often around 0.45 μm, the electrostatic precipitator has been a satisfactory prefilter

Morphology of IR and UV Laser-induced Structural Changes on Silicon Surfaces

International Nuclear Information System (INIS)

Jimenez-Jarquin, J.; Haro-Poniatowski, E.; Fernandez-Guasti, M.; Hernandez-Pozos, J.L.

2005-01-01

Using scanning electronic microscopy, we analyze the structural changes induced in silicon (100) wafers by focused IR (1064 nm) and UV (355 nm) nanosecond laser pulses. The experiments were performed in the laser ablation regime. When a silicon surface is irradiated by laser pulses in an O2 atmosphere conical microstructures are obtained. The changes in silicon surface morphology depend both on the incident radiation wavelength and the environmental atmosphere. We have patterned Si surfaces with a single focused laser spot and, in doing the experiments with IR or UV this reveals significant differences in the initial surface cracking and pattern formation, however the final result consist of an array of microcones when the experiment is carried out in oxygen. We employ a random scanning technique to irradiate silicon surfaces over large areas. In this form we have obtained large patterned areas

Optimization of CO2 laser cutting parameters on Austenitic type Stainless steel sheet

Science.gov (United States)

Parthiban, A.; Sathish, S.; Chandrasekaran, M.; Ravikumar, R.

2017-03-01

Thin AISI 316L stainless steel sheet widely used in sheet metal processing industries for specific applications. CO2 laser cutting is one of the most popular sheet metal cutting processes for cutting of sheets in different profile. In present work various cutting parameters such as laser power (2000 watts-4000 watts), cutting speed (3500mm/min - 5500 mm/min) and assist gas pressure (0.7 Mpa-0.9Mpa) for cutting of AISI 316L 2mm thickness stainless sheet. This experimentation was conducted based on Box-Behenken design. The aim of this work is to develop a mathematical model kerf width for straight and curved profile through response surface methodology. The developed mathematical models for straight and curved profile have been compared. The Quadratic models have the best agreement with experimental data, and also the shape of the profile a substantial role in achieving to minimize the kerf width. Finally the numerical optimization technique has been used to find out best optimum laser cutting parameter for both straight and curved profile cut.

Modeling and optimization of laser cutting operations

Directory of Open Access Journals (Sweden)

Gadallah Mohamed Hassan

2015-01-01

Full Text Available Laser beam cutting is one important nontraditional machining process. This paper optimizes the parameters of laser beam cutting parameters of stainless steel (316L considering the effect of input parameters such as power, oxygen pressure, frequency and cutting speed. Statistical design of experiments is carried in three different levels and process responses such as average kerf taper (Ta, surface roughness (Ra and heat affected zones are measured accordingly. A response surface model is developed as a function of the process parameters. Responses predicted by the models (as per Taguchi’s L27OA are employed to search for an optimal combination to achieve desired process yield. Response Surface Models (RSMs are developed for mean responses, S/N ratio, and standard deviation of responses. Optimization models are formulated as single objective optimization problem subject to process constraints. Models are formulated based on Analysis of Variance (ANOVA and optimized using Matlab developed environment. Optimum solutions are compared with Taguchi Methodology results. As such, practicing engineers have means to model, analyze and optimize nontraditional machining processes. Validation experiments are carried to verify the developed models with success.

Novel method of separating macroporous arrays from p-type silicon substrate

International Nuclear Information System (INIS)

Peng Bobo; Wang Fei; Liu Tao; Yang Zhenya; Wang Lianwei; Fu, Ricky K. Y.; Chu, Paul K.

2012-01-01

This paper presents a novel method to fabricate separated macroporous silicon using a single step of photo-assisted electrochemical etching. The method is applied to fabricate silicon microchannel plates in 100 mm p-type silicon wafers, which can be used as electron multipliers and three-dimensional Li-ion microbatteries. Increasing the backside illumination intensity and decreasing the bias simultaneously can generate additional holes during the electrochemical etching which will create lateral etching at the pore tips. In this way the silicon microchannel can be separated from the substrate when the desired depth is reached, then it can be cut into the desired shape by using a laser cutting machine. Also, the mechanism of lateral etching is proposed. (semiconductor materials)

Fibre laser cutting of polycaprolactone sheet for stents manufacturing: A feasibility study

Science.gov (United States)

Guerra, Antonio J.; Farjas, Jordi; Ciurana, Joaquim

2017-10-01

The role of the stent is temporary and it is limited to the intervention and shortly thereafter. Bioresorbable polymer stents were introduced to overcome this problem, making the stent manufacturing process rather difficult considering the complexity of the material. The stent forecast sale makes constant technology development necessary on this field. The adaptation of the laser manufacturing industry to these new materials is costly, thus further studies employing different sorts of lasers are necessary. This paper aims to explore the feasibility of 1.08 μm wavelength fibre laser to cut polycaprolactone sheet, which is especially interesting for long-term implantable devices, such as stents. The laser cut samples were analysed by Differential Scanning Calorimetry (DSC), Tensile Stress Test, and Optical Microscopy in order to study the effects of the laser process over the workpiece. The parameters measured were: taper angle, dimensional precision, material structure changes and mechanical properties changes. Results showed a dimensional precision above 95.75% with a taper angle lower than 0.033°. The laser ablation process has exhibited a minor influence upon material properties. Results exhibit the feasibility of fibre laser to cut polycaprolactone, making the fibre laser an alternative to manufacture stents.

Laser cutting: influence on morphological and physicochemical properties of polyhydroxybutyrate.

Science.gov (United States)

Lootz, D; Behrend, D; Kramer, S; Freier, T; Haubold, A; Benkiesser, G; Schmitz, K P; Becher, B

2001-09-01

Polyhydroxybutyrate (PHB) is a biocompatible and resorbable implant material. For these reasons, it has been used for the fabrication of temporary stents, bone plates, nails and screws (Peng et al. Biomaterials 1996;17:685). In some cases, the brittle mechanical properties of PHB homopolymer limit its application. A typical plasticizer, triethylcitrate (TEC), was used to overcome such limitations by making the material more pliable. In the past few years, CO2-laser cutting of PHB was used in the manufacturing of small medical devices such as stents. Embrittlement of plasticized PHB tubes has been observed, after laser machining. Consequently, the physicochemical and morphological properties of laser-processed surfaces and cut edges of plasticized polymer samples were examined to determine the extent of changes in polymer properties as a result of laser machining. These studies included determination of the depth of the laser-induced heat affected zone by polariscopy of thin polymer sections. Molecular weight changes and changes in the TEC content as a function of distance from the laser-cut edge were determined. In a preliminary test, the cellular response to the processed material was investigated by cell culture study of L929 mouse fibroblasts on laser-machined surfaces. The heat-affected zone was readily classified into four different regions with a total depth of about 60 to 100 microm (Klamp, Master Thesis, University of Rostock, 1998). These results correspond well with the chemical analysis and molecular weight measurements. Furthermore, it was found that cells grew preferentially on the laser-machined area. These findings have significant implications for the manufacture of medical implants from PHB by laser machining.

New developments in laser sintering of diamond cutting disks

NARCIS (Netherlands)

Kovalenko, V.; Golovko, L.; Meijer, J.; Anyakin, M.

2007-01-01

The analysis of techniques and problems in the fabrication of cutting tools based on super hard composites results in a solution by the application of lasers. The results of systematic study of diamond composites sintering with laser radiation are discussed. A mathematical modeling of the heat

Design of an Optical System for High Power CO2 Laser Cutting

DEFF Research Database (Denmark)

de Lange, D.F.; Meijer, J.; Nielsen, Jakob Skov

2003-01-01

The results of a design study for the optical system for cutting with high power CO2 lasers (6 kW and up) will be presented. As transparent materials cannot be used for these power levels, mirrors have been applied. A coaxial cutting gas supply has been designed with a laser beam entrance into th...... independent of the entering beam angle or position. manufacturing tolerances have been compensated in a one time adjustment during the assembly of the optical system. Preliminary cutting results in 13 mm thick steel in a shipyard application show a signinficant improvement in the cutting performance....

Study on processing parameters of glass cutting by nanosecond 532 nm fiber laser

Science.gov (United States)

Wang, Jin; Gao, Fan; Xiong, Baoxing; Zhang, Xiang; Yuan, Xiao

2018-03-01

The processing parameters of soda-lime glass cutting with several nanosecond 532 nm pulsed fiber laser are studied in order to obtain sufficiently large ablation rate and better processing quality. The influences of laser processing parameters on effective cutting speed and cutting quality of 1 2 mm thick soda-lime glass are studied. The experimental results show that larger laser pulse energy will lead to higher effective cutting speed and larger maximum edge collapse of the front side of the glass samples. Compared with that of 1.1 mm thick glass samples, the 2.0 mm thick glass samples is more difficult to cut. With the pulse energy of 51.2 μJ, the maximum edge collapse is more than 200 μm for the 2.0 mm thick glass samples. In order to achieve the high effective cutting speed and good cutting quality at the same time, the dual energy overlapping method is used to obtain the better cutting performance for the 2.0 mm thick glass samples, and the cutting speed of 194 mm/s and the maximum edge collapse of less than 132 μm are realized.

Application of CO2 laser cutting machine to shipbuilding; Zosen no setsudan eno CO2 laser no tekiyo

Energy Technology Data Exchange (ETDEWEB)

Fujimoto, Y. [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)

1998-11-01

Carbon dioxide laser has been applied to cutting works in shipbuilding. As NC cutter was obsolete, CO2 laser cutting machine with a rated output 3 kW was introduced. According to the specifications of the machinable plate, the maximum thickness is 19 mm, and effective width and length are 5.4 m and 29.1 m, respectively. As the cutting width is wide and the running distance of laser beam is long, the error of light axis is expanded only by a small error of irradiation angle, which results in the inconvenience. Stable operation was realized by improving the fixation of reflecting mirror. Right angle cutting section with a cutting curve below 0.5 mm was obtained, and cutting time was reduced by the one-line cutting by which both sections can be available with a single cutting line. For the cutting of thin plate with a thickness less than 10 mm, strain was not formed, and remedy was not required. Block strain was remarkably reduced during the assembly process. Maintenance-free operation without monitoring can be performed for a long time. This machine is operated at night and lunch time, resulting in the reduced processes. The working environment is appropriate without noise and dust. Facility cost and maintenance cost were also reduced. Lower cutting speed is a weak point, when compared with the plasma cutting machine. The present machine is not applied to aluminum plates with high surface reflectivity. 13 figs.

Recent advances in precision laser cutting for the ATLAS hadron calorimeter absorbers production

International Nuclear Information System (INIS)

Alikov, B.; Budagov, Yu.

1995-01-01

The optimised precision laser cutting technology for high tolerances ATLAS hadron calorimeter absorber plates production is described. Some recent results of laser cut absorber plates dimension measurements are presented. The plates have been manufactured by 'Universalmash' (S.-Petersburg) and RCTL RAS (Shatura). It has been shown that the proved accuracy of the laser machines is not worse than 45 microns. 9 figs

Laser cut hole matrices in novel armour plate steel for appliqué battlefield vehicle protection

Directory of Open Access Journals (Sweden)

Daniel J. Thomas

2016-10-01

Full Text Available During this research, experimental rolled homogeneous armour steel was cast, annealed and laser cut to form an appliqué plate. This Martensitic–Bainitic microstructure steel grade was used to test a novel means of engineering lightweight armour. It was determined that a laser cutting speed of 1200 mm/min produced optimum hole formations with limited distortion. The array of holes acts as a double-edged solution, in that they provide weight saving of 45%, providing a protective advantage and increasing the surface area. Data collected were used to generate laser cut-edge hole projections in order to identify the optimum cutting speed, edge condition, cost and deformation performance. These parameters resulted in the generation of a surface, with less stress raising features. This can result in a distribution of stress across the wider surface. Provided that appropriate process parameters are used to generate laser cut edges, then the hardness properties of the surface can be controlled. This is due to compressive residual stresses produced in the near edge region as a result of metallurgical transformations. This way the traverse cutting speed parameter can be adjusted to alter critical surface characteristics and microstructural properties in close proximity to the cut-edge. A relationship was identified between the width of the laser HAZ and the hardness of the cut edge. It is the thickness of the HAZ that is affected by the laser process parameters which can be manipulated with adjusting the traverse cutting speed.

Influence of laser cutting on the fatigue limit of two high strength steels

International Nuclear Information System (INIS)

Mateo, Antonio; Fargas, Gemma; Calvo, Jessica; Roa, Joan Josep

2015-01-01

Laser cutting is widely used in the metal industry, particularly when components of high strength steel sheets are produced. However, the roughness of cut edges produced by laser differs from that obtained by other methods, such as mechanical blanking, and this fact influences the fatigue performance. In the present investigation, specimens of two grades of high strength austenitic steels, i.e. AISI 301LN and TWIP17Mn, were cut by laser and tested in the high cycle fatigue regime to determine their corresponding fatigue limits. A series of fatigue specimens were tested without polishing and other series after a careful polishing of the cut edges, in order to assess the influence of the cut edges condition. Results indicate a significant influence of the edge roughness, more distinctive for AISI 301LN than for TWIP steel.

Influence of laser cutting on the fatigue limit of two high strength steels

Energy Technology Data Exchange (ETDEWEB)

Mateo, Antonio; Fargas, Gemma; Calvo, Jessica; Roa, Joan Josep [Univ. Politecnica de Catalunya, Barcelona (Spain). Dept. of Materials Science and Metallurgical Engineering

2015-02-01

Laser cutting is widely used in the metal industry, particularly when components of high strength steel sheets are produced. However, the roughness of cut edges produced by laser differs from that obtained by other methods, such as mechanical blanking, and this fact influences the fatigue performance. In the present investigation, specimens of two grades of high strength austenitic steels, i.e. AISI 301LN and TWIP17Mn, were cut by laser and tested in the high cycle fatigue regime to determine their corresponding fatigue limits. A series of fatigue specimens were tested without polishing and other series after a careful polishing of the cut edges, in order to assess the influence of the cut edges condition. Results indicate a significant influence of the edge roughness, more distinctive for AISI 301LN than for TWIP steel.

Performance of 3KW laser in cutting industry. Yodan gyokai ni okeru 3KW reza no koyo

Energy Technology Data Exchange (ETDEWEB)

Kita, H.; Miyaji, T.

1993-11-01

Recently, as the CO2 laser oscillator requires bigger power output, steel plates to be cut with a laser cutting machine have become thick plates with thickness of 12mm or more and the size of the plate which can be cut has become from the standard size of 4 inch by 8 inch or 5 inch by 10 inch to a big size of more than several meters because of introduction of the gantry type. In this article, the CO2 laser cutting machine introduced to Komatsu Shearing Co. and its operating conditions are introduced and the trends of powerful laser cutting machines in the cutting industry in the future are predicted. Laser cutting makes high cutting quality, but its device and running costs becomes high. For adopting a laser cutting machine, such items have been individually examined that no bitter work is involved in cutting, no skill is needed, no strain is formed during the press work in the succeeding process and the yield is high (95%), and a Komatsu laser cutting machine has been introduced. As a result, it has been found that the machine can produce a product of higher quality than shearing. Hereafter, this machine will further be used for manufacturing parts of construction machines, etc. for which high accuracy and high quality are demanded. 7 figs., 8 tabs.

Inverse cutting of posterior lamellar corneal grafts by a femtosecond laser.

Science.gov (United States)

Hjortdal, Jesper; Nielsen, Esben; Vestergaard, Anders; Søndergaard, Anders

2012-01-01

Posterior lamellar grafting of the cornea has become the preferred technique for treatment of corneal endothelial dysfunction. Posterior lamellar grafts are usually cut by a micro-keratome or a femto-second laser after the epithelial side of the donor cornea has been applanated. This approach often results in variable central graft thickness in different grafts and an increase in graft thickness towards the periphery in every graft. The purpose of this study was to evaluate if posterior lamellar grafts can be prepared from the endothelial side by a femto-second laser, resulting in reproducible, thin grafts of even thickness. A CZM 500 kHz Visumax femto-second laser was used. Organ cultured donor grafts were mounted in an artifical anterior chamber with the endothelial side up and out. Posterior grafts of 7.8 mm diameter and 130 micron thickness were prepared by femto-second laser cutting. A standard DSAEK procedure was performed in 10 patients with Fuchs endothelial dystrophy. Patients were followed-up regularly and evaluated by measurement of complications, visual acuity, corneal thickness (Pentacam HR), and endothelial cell density. Femto-laser cutting of grafts and surgery was uncomplicated. Rebubbling was necessary in 5 of 10 cases (normally only in 1 of 20 cases). All grafts were attached and cleared up during the first few weeks. After six months, the average visual acuity was 0.30 (range: 0.16 to 0.50), corneal thickness was 0.58 mm (range 0.51 to 0.63), and endothelial cell density was 1.570 per sq. mm (range: 1.400 to 2.000 cells per sq. mm). The grafts were of uniform thickness, but substantial interface haze was present in most grafts. Posterior lamellar corneal grafts can be prepared from the endothelial side using a femto-second laser. All grafts were clear after 6 months with satisfying endothelial cell counts. Poor visual acuity caused by interface scatter was observed in most patients. Femto-second laser cutting parameters needs to be optimised to

High-precision cutting of polyimide film using femtosecond laser for the application in flexible electronics

Science.gov (United States)

Ganin, D. V.; Lapshin, K. E.; Obidin, A. Z.; Vartapetov, S. K.

2018-01-01

The experimental results of cutting a polyimide film on the optical glass substrate by means of femtosecond lasers are given. Two modes of laser cutting of this film without damages to a glass base are determined. The first is the photo graphitization using a high repetition rate femtosecond laser. The second is ablative, under the effect of femtosecond laser pulses with high energy and low repetition rate. Cutting of semiconductor chips formed on the polyimide film surface is successfully demonstrated.

Development in high speed and high quality laser cutting process in fiber reinforced plastics; FRP no laser ni yoru kosoku, kohinshitsu setsudan gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Ishide, T.; Shirota, H.; Matsumoto, O. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

1996-06-01

Trimming was performed and studied by cutting KFRP, an epoxy matrix with Kevlar fiber woven thereinto, using various laser beams. The CO2 laser is capable of high-speed cutting but the product is low in quality. The surface of a cut by the YAG laser is not high in quality even with its peak output elevated. The thermally affected area is smaller under the excimer laser but it is low in cutting speed. The ablation properties of the excimer laser were investigated and the beam was shaped into a linear beam for another experiment, but it failed to attain the target speed of cutting. Next, a combination of excimer laser and CO2 laser was used for cutting. It was so designed that the preceding CO2 laser cuts the KFRP at a high speed to leave behind a carbonized layer, which is followed by a linear beam which vaporizes the carbonized layer for removal. An optical system is adopted for reshaping the excimer oscillated beam into a tube-like beam. Optical conditions were determined for a fluence value required for the removal of the carbonized layer. When the CO2 laser was set at 160W and the excimer laser at 20W, a 1mm-thick sheet was successfully cut at a speed of 16.7mm/sec. 3 refs., 7 figs.

Development of laser repair technique for cutting impurities in secondary side of a steam generator

Energy Technology Data Exchange (ETDEWEB)

Kim, Cheol Jung; Chung, Chin Man; Kim, Min Suk; Jeong, Tae Moon

1999-12-01

In this research, the laser repair technique was investigated for the purpose of cutting impurities in secondary side of a steam generator. For this research, a high quality Nd:YAG laser was manufactured and the beam delivery experiments was performed with multimode optical fibers. Also, the small size focusing system was designed and fabricated for remote cutting and the laser cutting experiment was performed. (author)

Preliminary cutting and drilling studies using new generation lasers

International Nuclear Information System (INIS)

Kautz, D.D.; Sze, J.S.; Dragon, E.P.; Hargrove, R.S.

1992-01-01

High power and radiance dye lasers developed at Lawrence Livermore National Laboratory show promise for material processing tanks. Evaluation using welding heat flow models suggest significant increases in precision and speed are expected. We developed tooling and instrumentation to diagnose important parameters including spot geometry and optical train quality. We started processing studies to determine the viability of these lasers of cutting and drilling. We used titanium alloys first in the studies due to the availability of comparable parametric studies in the technical literature. Results show that cuts and holes with extremely fine features can be made with dye lasers. The high radiance beam produces low distortion and small heat-affected zones. We have accomplished very high aspect ratios and micron scale kerfs and holes. Through continued system improvement and process optimization, we believe that submicron levels will be achieved

The Influence of Different Assist Gases on Ductile Cast Iron Cutting by CO2 Laser

Directory of Open Access Journals (Sweden)

Meško J.

2017-12-01

Full Text Available This article deals with the technology and principles of the laser cutting of ductile cast iron. The properties of the CO2 laser beam, input parameters of the laser cutting, assist gases, the interaction of cut material and the stability of cutting process are described. The commonly used material (nodular cast iron - share of about 25% of all castings on the market and the method of the laser cutting of that material, including the technological parameters that influence the cutting edge, are characterized. Next, the application and use of this method in mechanical engineering practice is described, focusing on fixing and renovation of mechanical components such as removing the inflow gate from castings with the desired quality of the cut, without the further using of the chip machining technology. Experimental samples from the nodular cast iron were created by using different technological parameters of laser cutting. The heat affected zone (HAZ, its width, microstructure and roughness parameter Pt was monitored on the experimental samples (of thickness t = 13 mm. The technological parameters that were varied during the experiments included the type of assist gases (N2 and O2, to be more specific the ratio of gases, and the cutting speed, which ranged from 1.6 m/min to 0.32 m/min. Both parameters were changed until the desired properties were achieved.

Feasible Application Area Study for Linear Laser Cutting in Paper Making Processes

Science.gov (United States)

Happonen, A.; Stepanov, A.; Piili, H.

Traditional industry sectors, like paper making industry, tend to stay within well-known technology rather than going forward towards promising, but still quite new technical solutions and applications. This study analyses the feasibility of the laser cutting in large-scale industrial paper making processes. Aim was to reveal development and process related challenges and improvement potential in paper making processes by utilizing laser technology. This study has been carried out, because there still seems to be only few large-scale industrial laser processing applications in paper converting processes worldwide, even in the beginning of 2010's. Because of this, the small-scale use of lasers in paper material manufacturing industry is related to a shortage of well-known and widely available published research articles and published measurement data (e.g. actual achieved cut speeds with high quality cut edges, set-up times and so on). It was concluded that laser cutting has strong potential in industrial applications for paper making industries. This potential includes quality improvements and a competitive advantage for paper machine manufacturers and industry. The innovations have also added potential, when developing new paper products. An example of these kinds of products are ones with printed intelligence, which could be a new business opportunity for the paper industries all around the world.

Development of remote bore tools for pipe welding/cutting by YAG laser

International Nuclear Information System (INIS)

Oka, Kiyoshi; Nakahira, Masataka; Kakudate, Satoshi; Tada, Eisuke; Obara, Kenjiro; Taguchi, Kou; Nakamori, Naokazu

1996-07-01

In D-T burning reactors such as International Thermonuclear Experimental Reactor (ITER), an internal access welding/cutting of blanket cooling pipe with bend sections is inevitably required because of spatial constraint due to nuclear shield and available port opening space. For this purpose, an internal access pipe welding/cutting using YAG laser beam is being developed according to the agreement of the ITER R and D task (T44). A design concept of welding/cutting processing head with a flexible optical fiber has been developed and the basic feasibility studies on welding, cutting and rewelding are performed using stainless steel plate (SS316L). In this report, the details of a welding/cutting head with a flexible optical fiber for YAG laser are described, together with the basic experiment results relating to the welding/cutting and rewelding. (author)

Hybrid III-V Silicon Lasers

Science.gov (United States)

Bowers, John

2014-03-01

Abstract: A number of important breakthroughs in the past decade have focused attention on Si as a photonic platform. We review here recent progress in this field, focusing on efforts to make lasers, amplifiers, modulators and photodetectors on or in silicon. We also describe optimum quantum well design and distributed feedback cavity design to reduce the threshold and increase the efficiency and power output. The impact active silicon photonic integrated circuits could have on interconnects, telecommunications and on silicon electronics is reviewed. Biography: John Bowers holds the Fred Kavli Chair in Nanotechnology, and is the Director of the Institute for Energy Efficiency and a Professor in the Departments of Electrical and Computer Engineering and Materials at UCSB. He is a cofounder of Aurrion, Aerius Photonics and Calient Networks. Dr. Bowers received his M.S. and Ph.D. degrees from Stanford University and worked for AT&T Bell Laboratories and Honeywell before joining UC Santa Barbara. Dr. Bowers is a member of the National Academy of Engineering and a fellow of the IEEE, OSA and the American Physical Society. He is a recipient of the OSA/IEEE Tyndall Award, the OSA Holonyak Prize, the IEEE LEOS William Streifer Award and the South Coast Business and Technology Entrepreneur of the Year Award. He and coworkers received the EE Times Annual Creativity in Electronics (ACE) Award for Most Promising Technology for the hybrid silicon laser in 2007. Bowers' research is primarily in optoelectronics and photonic integrated circuits. He has published ten book chapters, 600 journal papers, 900 conference papers and has received 54 patents. He has published 180 invited papers and conference papers, and given 16 plenary talks at conferences. As well as Chong Zhang.

Comparison of Transcanalicular Multidiode Laser Dacryocystorhinostomy with and without Silicon Tube Intubation

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Yildiray Yildirim

2016-01-01

Full Text Available Aim. To compare the surgical outcomes of surgery with and without bicanalicular silicon tube intubation for the treatment of patients who have primary uncomplicated nasolacrimal duct obstruction. Methods. This retrospective study is comprised of 113 patients with uncomplicated primary nasolacrimal duct obstruction. There were 2 groups in the study: Group 1 (n=58 patients underwent transcanalicular diode laser dacryocystorhinostomy surgery with bicanalicular silicon tube intubation and Group 2 (n=55 patients underwent transcanalicular diode laser dacryocystorhinostomy surgery without bicanalicular silicon tube intubation. The follow-up period was 18.42±2.8 months for Group 1 and 18.8±2.1 months for Group 2. Results. Success was defined by irrigation of the lacrimal system without regurgitation and by the absence of epiphora. Success rates were 84.4% for Group 1 and 63.6% for Group 2 (P=0.011. Statistically a significant difference was found between the two groups. Conclusion. The results of the study showed that transcanalicular diode laser dacryocystorhinostomy surgery with bicanalicular silicon tube intubation was more successful than the other method of surgery. Consequently, the application of silicone tube intubation in transcanalicular diode laser dacryocystorhinostomy surgery is recommended.

A parametric study of laser induced ablation-oxidation on porous silicon surfaces

International Nuclear Information System (INIS)

De Stefano, Luca; Rea, Ilaria; Nigro, M Arcangela; Della Corte, Francesco G; Rendina, Ivo

2008-01-01

We have investigated the laser induced ablation-oxidation process on porous silicon layers having different porosities and thicknesses by non-destructive optical techniques. In particular, the interaction between a low power blue light laser and the porous silicon surfaces has been characterized by variable angle spectroscopic ellipsometry and Fourier transform infrared spectroscopy. The oxidation profiles etched on the porous samples can be tuned as functions of the layer porosity and laser fluence. Oxide stripes of width less than 2 μm and with thicknesses between 100 nm and 5 μm have been produced, depending on the porosity of the porous silicon, by using a 40 x focusing objective

Diode-pumped two-frequency lasers based on c-cut vanadate crystals

International Nuclear Information System (INIS)

Sirotkin, A A; Garnov, Sergei V; Zagumennyi, A I; Zavartsev, Yu D; Kutovoi, S A; Vlasov, V I; Shcherbakov, Ivan A

2009-01-01

The luminescent and lasing properties of the neo-dymium ion at the 4 F 3/2 - 4 I 11/2 transition in c-cut vanadate crystals (Nd:YVO 4 , Nd:GdVO 4 , and Nd:Gd 1-x Y x VO 4 ) are studied. Tuning of the laser radiation wavelength (Δλ = 5.4 nm) is demonstrated. Two-frequency laser schemes with the use of a Lyot filter, a Fabry-Perot etalon, and a Brewster prism as spectral selection elements are proposed and experimentally realised. Stable two-frequency lasing of a laser based on the c-cut Nd:GdVO 4 crystal was obtained in the cw, Q-switched (nanosecond pulses), and active acousto-optic mode-locked (picosecond pulses) regimes. (lasers)

Composition of silicon fibrous nanostructures synthesized using ultrafast laser pulses under ambient conditions

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Sivakumar M.

2015-01-01

Full Text Available In this study the composition of nanostructures generated owing to ablation of crystalline silicon using high repletion rate femtosecond laser under ambient condition is investigated. The web-like silicon fibrous nanostructures are formed in and around the laser irradiated area. Electron Microscopy investigation revealed that the nanostructures are made of nanoparticles of size about 40 nm. In addition Micro-Raman analysis shows that the nanofibrous structures comprises a mixture of amorphous and polycrystalline silicon. X-ray photoelectron spectroscopy analysis reveals the oxidized and un-oxidized elemental states of silicon in the nanostructures. Moreover web-like fibrous nanostructures are generated due to condensation of super saturated vapour and subsequent nucleus growth in the laser induced plasma plume.

Multifocal laser surgery: cutting enhancement by hydrodynamic interactions between cavitation bubbles.

Science.gov (United States)

Toytman, I; Silbergleit, A; Simanovski, D; Palanker, D

2010-10-01

Transparent biological tissues can be precisely dissected with ultrafast lasers using optical breakdown in the tight focal zone. Typically, tissues are cut by sequential application of pulses, each of which produces a single cavitation bubble. We investigate the hydrodynamic interactions between simultaneous cavitation bubbles originating from multiple laser foci. Simultaneous expansion and collapse of cavitation bubbles can enhance the cutting efficiency, by increasing the resulting deformations in tissue, and the associated rupture zone. An analytical model of the flow induced by the bubbles is presented and experimentally verified. The threshold strain of the material rupture is measured in a model tissue. Using the computational model and the experimental value of the threshold strain one can compute the shape of the rupture zone in tissue resulting from application of multiple bubbles. With the threshold strain of 0.7 two simultaneous bubbles produce a continuous cut when applied at the distance 1.35 times greater than that required in sequential approach. Simultaneous focusing of the laser in multiple spots along the line of intended cut can extend this ratio to 1.7. Counterpropagating jets forming during collapse of two bubbles in materials with low viscosity can further extend the cutting zone-up to approximately a factor of 1.5.

Quantum Dot Laser for a Light Source of an Athermal Silicon Optical Interposer

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Nobuaki Hatori

2015-04-01

Full Text Available This paper reports a hybrid integrated light source fabricated on a silicon platform using a 1.3 μm wavelength quantum dot array laser. Temperature insensitive characteristics up to 120 °C were achieved by the optimum quantum dot structure and laser structure. Light output power was obtained that was high enough to achieve an optical error-free link of a silicon optical interposer. Furthermore, we investigated a novel spot size convertor in a silicon waveguide suitable for a quantum dot laser for lower energy cost operation of the optical interposer.

Measurements of secondary emissions from plasma arc and laser cutting in standard experiments

International Nuclear Information System (INIS)

Pilot, G.; Noel, M.; Leautier, R.; Steiner, H.; Tarroni, G.; Waldie, B.

1990-01-01

As part of an inter-facility comparison of secondary emissions from plasma-arc and laser cutting techniques, standard cutting tests have been done by plasma arc underwater and in air and laser beam in air. The same team, CEA/DPT/SPIN, was commissioned to measure the secondary emissions (solid and gaseous) in each contractor's facility with the same measuring rig. 20 mm and 40 mm thick grade 304 stainless steel plates were cut by plasma-torch in three different facilities: Heriot Watt University of Edinburgh, Institute fuer Werkstoffkunde of Hannover and CEA/CEN Cadarache. 10 mm and sometimes 20 mm thick grade 304 stainless steel plates were cut by laser beam in four different facilities: CEA/CEN Fontenay, CEA/CEN Saclay, Institute fuer Werkstoffkunde of Hannover and ENEA/FRASCATI. The results obtained in the standard experiments are rather similar, the differences that appear can be explained by the various scales of the facilities (semi-industrial and laboratory scale) and by some particularity in the cutting parameters (additional secondary gas flow of oxygen in plasma cutting at Hannover for example). Some supplementary experiments show the importance of some cutting parameters. (author)

Parameters Influence of CO2 Laser on Cutting Quality of Polymer Materials

Directory of Open Access Journals (Sweden)

Robert Cep

2016-09-01

Full Text Available The article deals with evaluating of the resulting surface state of the three plastic materials and identification of suitable conditions for laser cutting with CO2 tube. As representative were chosen polypropylene, polymethylmethacrylate and polyamide. When cutting these types of materials it could melt eventually their re-sintering. A suitable combination of parameters is possible to achieve of sufficient quality of the cut. The samples were cut at different feed speed and laser power. Then they was compared on the basis of the measured roughness parameters Ra a Rz by using a portable touch roughness Hommel-Etamic W5 and dates was processed according to ČSN EN ISO 4287. Cutting of samples was realized at the Department of Machining, Assembly and Engineering Metrology, VŠB-TUO.

Fast femtosecond laser ablation for efficient cutting of sintered alumina substrates

Science.gov (United States)

Oosterbeek, Reece N.; Ward, Thomas; Ashforth, Simon; Bodley, Owen; Rodda, Andrew E.; Simpson, M. Cather

2016-09-01

Fast, accurate cutting of technical ceramics is a significant technological challenge because of these materials' typical high mechanical strength and thermal resistance. Femtosecond pulsed lasers offer significant promise for meeting this challenge. Femtosecond pulses can machine nearly any material with small kerf and little to no collateral damage to the surrounding material. The main drawback to femtosecond laser machining of ceramics is slow processing speed. In this work we report on the improvement of femtosecond laser cutting of sintered alumina substrates through optimisation of laser processing parameters. The femtosecond laser ablation thresholds for sintered alumina were measured using the diagonal scan method. Incubation effects were found to fit a defect accumulation model, with Fth,1=6.0 J/cm2 (±0.3) and Fth,∞=2.5 J/cm2 (±0.2). The focal length and depth, laser power, number of passes, and material translation speed were optimised for ablation speed and high quality. Optimal conditions of 500 mW power, 100 mm focal length, 2000 μm/s material translation speed, with 14 passes, produced complete cutting of the alumina substrate at an overall processing speed of 143 μm/s - more than 4 times faster than the maximum reported overall processing speed previously achieved by Wang et al. [1]. This process significantly increases processing speeds of alumina substrates, thereby reducing costs, making femtosecond laser machining a more viable option for industrial users.

Temperature-feedback direct laser reshaping of silicon nanostructures

Science.gov (United States)

Aouassa, M.; Mitsai, E.; Syubaev, S.; Pavlov, D.; Zhizhchenko, A.; Jadli, I.; Hassayoun, L.; Zograf, G.; Makarov, S.; Kuchmizhak, A.

2017-12-01

Direct laser reshaping of nanostructures is a cost-effective and fast approach to create or tune various designs for nanophotonics. However, the narrow range of required laser parameters along with the lack of in-situ temperature control during the nanostructure reshaping process limits its reproducibility and performance. Here, we present an approach for direct laser nanostructure reshaping with simultaneous temperature control. We employ thermally sensitive Raman spectroscopy during local laser melting of silicon pillar arrays prepared by self-assembly microsphere lithography. Our approach allows establishing the reshaping threshold of an individual nanostructure, resulting in clean laser processing without overheating of the surrounding area.

The potential of laser cutting and snake arm robots in aspects of nuclear decommissioning

International Nuclear Information System (INIS)

Hilton, Paul; Khan, Ali

2013-01-01

This paper will describe recent work conducted in the UK to highlight the potential of applying high power laser cutting to aspects of decommissioning and dismantling in the nuclear sector. A major driver for this activity is size reduction of metallic structures, vessels and tubing, with the objective of efficient stacking of the cut parts for future long term storage. TWI have used a standard 5 kW multi-mode laser with fibre optic delivery of the beam, to demonstrate techniques for cutting stainless steel tubing, at diameters up to 150 mm and wall thicknesses up to 7 mm, and various thicknesses of plate materials. Using specially developed cutting heads, employing long focal length lenses to form the beam, techniques were developed to allow the cutting of tubes from one side only and without changing the focal position of the laser beam with respect to the diameter of the tube perpendicular to the incident beam. The latter means that remote programming of the cutting path becomes much simpler. For cutting plate materials, special gas nozzle dynamics have produced great tolerance of the cutting process to stand-off distance (the distance between the surface of the material being cut and the exit of the cutting nozzle). One particularly interesting method of remote deployment of these cutting techniques is to use 'snake arm' robots. These robots, by nature of their construction, can access areas un-accessible using other techniques. This of course makes them particularly suited to aspects of nuclear decommissioning, particularly in what are termed 'un-structured environments', where the exact disposition of items encountered is not known. The paper will also describe the first time a laser cutting head has been installed on the end of a snake arm robot and the combination used in a simulated nuclear cutting application. (author)

Analysis of correlations of multiple-performance characteristics for optimization of CO2 laser nitrogen cutting of AISI 304 stainless steel

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Miloš Madić

2014-07-01

Full Text Available The identification of laser cutting conditions for satisfying different requirements such as improving cut quality characteristics and material removal rate is of great importance. In this paper, an attempt has been made to develop mathematical models in order to relate laser cutting parameters such as the laser power, cutting speed, assist gas pressure and focus position, and cut quality characteristics such as the surface roughness, kerf width and width of heat affected zone (HAZ. A laser cutting experiment was planned as per Taguchi’s L27 orthogonal array with three levels for each of laser cutting parameters considered. 3 mm thick AISI 304 stainless steel was used as workpiece material. Mathematical models were developed using a single hidden layer artificial neural network (ANN trained with the Levenberg– Marquardt algorithm. On the basis of the developed ANN models the effects of the laser cutting parameters on the cut quality characteristics were presented. It was observed that laser cutting parameters variously affect cut quality characteristics. Also, for the range of operating conditions considered in the experiment, laser cut quality operating diagrams were shown. From these operating diagrams one can see the values of cut quality characteristics that can be achieved and subsequently select laser cutting parameter values. Furthermore, the analysis includes correlations between cut quality characteristics and material removal rate. To this aim, six trade-off operating diagrams for improving multiple responses at the same time were given.

Periodic patterning of silicon by direct nanosecond laser interference ablation

International Nuclear Information System (INIS)

Tavera, T.; Pérez, N.; Rodríguez, A.; Yurrita, P.; Olaizola, S.M.; Castaño, E.

2011-01-01

The production of periodic structures in silicon wafers by four-beam is presented. Because laser interference ablation is a single-step and cost-effective process, there is a great technological interest in the fabrication of these structures for their use as antireflection surfaces. Three different laser fluences are used to modify the silicon surface (0.8 J cm -2 , 1.3 J cm -2 , 2.0 J cm -2 ) creating bumps in the rim of the irradiated area. Laser induced periodic surface structures (LIPSS), in particular micro and nano-ripples, are also observed. Measurements of the reflectivity show a decrease in the reflectance for the samples processed with a laser fluence of 2.0 J cm -2 , probably caused by the appearance of the nano-ripples in the structured area, while bumps start to deteriorate.

Melt flow characteristics in gas-assisted laser cutting

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

industrial applications. In this process the cut ... Under these assumptions the boundary layer theory flow over. Laser beam ... a flat plate can be applied to estimate the distance after which the flow separation takes place by calculating the ...

Direct writing of sub-wavelength ripples on silicon using femtosecond laser at high repetition rate

International Nuclear Information System (INIS)

Xie, Changxin; Li, Xiaohong; Liu, Kaijun; Zhu, Min; Qiu, Rong; Zhou, Qiang

2016-01-01

Graphical abstract: - Highlights: • The NSRs and DSRs are obtained on silicon surface. • With increasing direct writing speed, the NSRs suddenly changes and becomes the DSRs. • We develop a Sipe–Drude interference theory by considering the thermal excitation. - Abstract: The near sub-wavelength and deep sub-wavelength ripples on monocrystalline silicon were formed in air by using linearly polarized and high repetition rate femtosecond laser pulses (f = 76 MHz, λ = 800 nm, τ = 50 fs). The effects of laser pulse energy, direct writing speed and laser polarization on silicon surface morphology are studied. When the laser pulse energy is 2 nJ/pulse and the direct writing speed varies from 10 to 25 mm/s, the near sub-wavelength ripples (NSRs) with orientation perpendicular to the laser polarization are generated. While the direct writing speed reaches 30 mm/s, the direction of the obtained deep sub-wavelength ripples (DSRs) suddenly changes and becomes parallel to the laser polarization, rarely reported so far for femtosecond laser irradiation of silicon. Meanwhile, we extend the Sipe–Drude interference theory by considering the thermal excitation, and numerically calculate the efficacy factor for silicon irradiated by femtosecond laser pulses. The revised Sipe–Drude interference theoretical results show good agreement with the periods and orientations of sub-wavelength ripples.

Ductile cutting of silicon microstructures with surface inclination measurement and compensation by using a force sensor integrated single point diamond tool

International Nuclear Information System (INIS)

Chen, Yuan-Liu; Cai, Yindi; Shimizu, Yuki; Ito, So; Gao, Wei; Ju, Bing-Feng

2016-01-01

This paper presents a measurement and compensation method of surface inclination for ductile cutting of silicon microstructures by using a diamond tool with a force sensor based on a four-axis ultra-precision lathe. The X- and Y-directional inclinations of a single crystal silicon workpiece with respect to the X- and Y-motion axes of the lathe slides were measured respectively by employing the diamond tool as a touch-trigger probe, in which the tool-workpiece contact is sensitively detected by monitoring the force sensor output. Based on the measurement results, fabrication of silicon microstructures can be thus carried out directly along the tilted silicon workpiece by compensating the cutting motion axis to be parallel to the silicon surface without time-consuming pre-adjustment of the surface inclination or turning of a flat surface. A diamond tool with a negative rake angle was used in the experiment for superior ductile cutting performance. The measurement precision by using the diamond tool as a touch-trigger probe was investigated. Experiments of surface inclination measurement and ultra-precision ductile cutting of a micro-pillar array and a micro-pyramid array with inclination compensation were carried out respectively to demonstrate the feasibility of the proposed method. (paper)

Cutting technique for reactor internals by laser beam

International Nuclear Information System (INIS)

Matsumoto, O.; Sugihara, M.; Matsuda, K.; Miya, K.

1990-01-01

At present in Japan the verification tests on the commercial nuclear power reactor decommissioning technology are being conducted as the project of The Ministry of International Trade and Industry by Nuclear Power Engineering Test Center. This paper summarizes the interim results of the verification test for the reactor core internals decommissioning technology, which is being conducted from 1986 as a theme of the above project. All core internals to be studied here are made of stainless steel, and the maximum wall thickness is about 500mm (the maximum one to be cut is about 300mm) for the PWR's, and about 100mm for the BWR's. Though the plasma cutting, arc saw cutting method, etc. have been studied u p to now as the cutting technology for decommissioning these core internals, the authors are carrying out the development and verification test of the cutting technology with the laser beam, which is expected to increase its power in future and can be applied to various materials

Theoretical analysis of material removal mechanisms in pulsed laser fusion cutting of ceramics

Energy Technology Data Exchange (ETDEWEB)

Quintero, F [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Varas, F [Dpto Matematica Aplicada II, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Pou, J [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Lusquinos, F [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Boutinguiza, M [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Soto, R [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Perez-Amor, M [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain)

2005-02-21

It is well known that the efficiency of material removal mechanisms has a crucial influence on the performance and quality of the laser cutting process. However, they are very difficult to study since the physical processes and parameters which govern them are quite complicated to observe and measure experimentally. For this reason, the development of theoretical models to analyse the material removal mechanisms is very important for understanding the characteristics and influence of these processes. In this paper, a theoretical model of the pulsed laser fusion cutting of ceramics is presented. The material removal mechanisms from the cutting front are modelled under the assumption that the ceramic material may be, simultaneously, melted and evaporated by the laser radiation. Therefore, three ejection mechanisms are investigated together: ejection of molten material by the assist gas, evaporation of the liquid and ejection of molten material due to the recoil pressure generated by the evaporation from the cutting front. The temporal evolution of the material removal mechanisms and the thickness of the molten layer are solved for several laser pulse modes. Theoretical results are compared with experimental observations to validate the conclusions regarding the influence of frequency and pulse length on the cutting process.

Measurements of secondary emissions from plasma arc and laser cutting in standard experiments

International Nuclear Information System (INIS)

Pilot, G.; Noel, J.P.; Leautier, R.; Steiner, H.; Tarroni, G.; Waldie, B.

1992-01-01

As part of an inter-facility comparison of secondary emissions from plasma arc and laser-cutting techniques, standard cutting tests have been done by plasma arc underwater and in air, and by laser beam in air. The same team was commissioned to measure the secondary emissions (solid and gaseous) in each contractor's facility with the same measuring rig. 20 mm and 40 mm thick, grade 304 stainless-steel plates were cut by plasma-torch in three different facilities: Heriot Watt University of Edinburgh, Institut fuer Werkstoffkunde of Universitaet Hannover and CEA/CEN Cadarache. 10 mm and in some cases 20 mm thick, grade 304, stainless-steel plates were cut by laser beam in five different facilities: CEA-CEN Fontenay, CEA-CEN Saclay, Institut fuer Werkstoffkunde of Universitaet Hannover and ENEA/Frascati. The results obtained in the standard experiments are rather similar, and the differences that appear can be explained by the various scales of the involved facilities (semi-industrial and laboratory) and by some particularities in the cutting parameters (an additional secondary gas flow of oxygen in plasma cutting at Universitaet Hannover, for example)

Laser cutting of laminated sheet material: a modeling exercise

Science.gov (United States)

de Graaf, Roelof F.; Meijer, Johan

1997-08-01

Laser cutting has been investigated for a number of aluminum-synthetic laminates, newly developed materials for the aeronautic and automotive industry. The materials consist of alternating aluminum and synthetic layers. It is shown that these materials can be cut at rates comparable to those of homogeneous aluminum alloys. The cuts show little dross attachment. Also some damage on the synthetic layers has to be accepted. These results initiated a modeling exercise, which resulted in a numerical simulation code. The applied cutting model is based on describing the material in several horizontal layers, each with its own specific thermophysical and optical properties. The separate layers are coupled by known mass, energy and force balanced equations.

Micro-hole drilling and cutting using femtosecond fiber laser

Science.gov (United States)

Huang, Huan; Yang, Lih-Mei; Liu, Jian

2014-05-01

Micro-hole drilling and cutting in ambient air are presented by using a femtosecond fiber laser. At first, the micro-hole drilling was investigated in both transparent (glasses) and nontransparent (metals and tissues) materials. The shape and morphology of the holes were characterized and evaluated with optical and scanning electron microscopy. Debris-free micro-holes with good roundness and no thermal damage were demonstrated with the aspect ratio of 8∶1. Micro-hole drilling in hard and soft tissues with no crack or collateral thermal damage is also demonstrated. Then, trench micromachining and cutting were studied for different materials and the effect of the laser parameters on the trench properties was investigated. Straight and clean trench edges were obtained with no thermal damage.

Laser annealed HWCVD and PECVD thin silicon films. Electron field emission

International Nuclear Information System (INIS)

O'Neill, K.A.; Shaikh, M.Z.; Lyttle, G.; Anthony, S.; Fan, Y.C.; Persheyev, S.K.; Rose, M.J.

2006-01-01

Electron Field Emission (FE) properties of various laser annealed thin silicon films on different substrates were investigated. HWCVD microcrystalline and PECVD amorphous silicon films were irradiated with Nd : YAG and XeCl Excimer lasers at varying energy densities. Encouraging FE results were mainly from XeCl Excimer laser processed PECVD and HWCVD films on metal backplanes. FE measurements were complemented by the study of film surface morphology. Geometric field enhancement factors from surface measurements and Fowler-Nordheim Theory (FNT) were compared. FE properties of the films were also found to be particularly influenced by the backplane material

Amorphization of silicon by femtosecond laser pulses

International Nuclear Information System (INIS)

Jia, Jimmy; Li Ming; Thompson, Carl V.

2004-01-01

We have used femtosecond laser pulses to drill submicron holes in single crystal silicon films in silicon-on-insulator structures. Cross-sectional transmission electron microscopy and energy dispersive x-ray analysis of material adjacent to the ablated holes indicates the formation of a layer of amorphous Si. This demonstrates that even when material is ablated using femtosecond pulses near the single pulse ablation threshold, sufficient heating of the surrounding material occurs to create a molten zone which solidifies so rapidly that crystallization is bypassed

Characterisation of aerosols produced by laser cutting; Caracterisation de l'aerosol emis lors d'une decoupe laser

Energy Technology Data Exchange (ETDEWEB)

Fauvel, S.; Pilot, G. [Institut de Radioprotection et de Surete Nucleaire (IRSN), DRU/SERAC, Lab. de Physique et Metrologie des Aerosols, 91 - Gif sur Yvette (France); Dinechin, G. de [Groupe d' Interet Public Groupement d' Etudes et de Recherche pour les Applications Industrielles des Lasers de Puissance, 94 - Arcueil (France)]|[CEA Saclay, Dir. de la Recherche Technologique (DRT/LITEN), 91 - Gif sur Yvette (France); Gosse, X. [Cogema, Dir. de l' Assainissement et des Projets, Maitrise d' Oeuvre Projets, 30 - Marcoule (France); Arnaud, P. [Ligne de Produit Demantelement, SGN, 30 - Bagnols sur Ceze (France)

2007-07-01

Powerful lasers represent a promising alternative solution to traditional cutting processes used in dismantling nuclear equipments. The use of optical fibers has an unquestionable advantage when dealing with airtight workshops. A stuunded by COGEMA Marcoule was undertaken by IRSN/SERAC in collaboration with GIP/GERAILP in order to characterise the aerosols emitted by the cutting of evaporators elements with a 4 kW continuous wave Nd:YAG laser. For this study, laser cutting has been carried out in a tight room of 35 m{sup 3} connected to a particle sampling pipe. Iso-kinetic samplers allowed the measurement of the aerosol concentration. A diffusional and inertial spectrometer (SDI 2001) - an Andersen impinger coupled to a diffusion battery - provided the size distribution. An electrostatic filter used upstream a HEPA filter, itself placed before the extractor fan, collected the majority of the emitted aerosol. Its efficiency was measured and controlled throughout the experiments. The results show the influence of the cutting conditions on the characteristics of the aerosol, and allow a comparison with other cutting tools. (authors)

Experimental investigation of the effect of the laser beam polarization state on the quality of steel sheet cutting

Science.gov (United States)

Golyshev, A. A.; Orishich, A. M.; Shulyatyev, V. B.

2017-10-01

The paper presents the results of experimental investigation of the effect of the beam polarization on the quality of the oxygen-assisted laser cutting of steel by a CO2-laser. Under consideration is the effect of the laser cutting parameters by the beam with the linear polarization on the cut surface roughness. It is founded that the minimal roughness is reached when the electric field vector is perpendicular to the cutting speed vector. It is concluded that the absorbed power distribution imposes the essential influence on the surface quality, and that the radiation heating of side walls is important to have lower roughness. Obtained results enabled to present probable reasons of the worse surface quality of the metals cut by a fiber laser than the ones cut by a CO2-laser.

Amorphous-polycrystal transition induced by laser pulse in self-ion implanted silicon

International Nuclear Information System (INIS)

Foti, G.; Rimini, E.; Vitali, G.; Bertolotti, M.

1977-01-01

Reflection high energy electron diffraction has been used to investigate the amorphous to polycrystalline structure transition in silicon induced by laser pulse. The power density of the ruby laser pulse, in the free generation mode, has been maintained below the threshold to induce surface damage. Depth analysis has been carried out in silicon crystal using the channeling effect technique. (orig.) [de

Chalcogen doping of silicon via intense femtosecond-laser irradiation

International Nuclear Information System (INIS)

Sheehy, Michael A.; Tull, Brian R.; Friend, Cynthia M.; Mazur, Eric

2007-01-01

We have previously shown that doping silicon with sulfur via femtosecond-laser irradiation leads to near-unity absorption of radiation from ultraviolet wavelengths to below band gap short-wave infrared wavelengths. Here, we demonstrate that doping silicon with two other group VI elements (chalcogens), selenium and tellurium, also leads to near-unity broadband absorption. A powder of the chalcogen dopant is spread on the silicon substrate and irradiated with femtosecond-laser pulses. We examine and compare the resulting morphology, optical properties, and chemical composition for each chalcogen-doped substrate before and after thermal annealing. Thermal annealing reduces the absorption of below band gap radiation by an amount that correlates with the diffusivity of the chalcogen dopant used to make the sample. We propose a mechanism for the absorption of below band gap radiation based on defects in the lattice brought about by the femtosecond-laser irradiation and the presence of a supersaturated concentration of chalcogen dopant atoms. The selenium and tellurium doped samples show particular promise for use in infrared photodetectors as they retain most of their infrared absorptance even after thermal annealing-a necessary step in many semiconductor device manufacturing processes

Application of laser cutting in shipbuilding factory. Improvement in cutting accuracy and drastic production capacity increase by night-time unmanned operation; Zosen kojo ni okeru laser setsudan no tekiyo. Setsudan seido kojo, yakan mujin unten de seisan noryoku ohaba up

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-06-01

A shipbuilding factory which introduced the laser cutting machine is introduced. The laser cutting machine was selected to improve cutting accuracy, improve working environment, and achieve unmanned operation. In this factory, a thin plate with a plate thickness of approximately 10 mm is expected to be machined, and the cutting line consists of two plasma cutting machines, one laser cutting machine, and one gas cutting line and the NC rate is high (97 %). The laser cutting machine incorporates a CO2 laser oscillation machine with a maximum output of 3.5 kW. The following result was obtained as compared with the plasma cutting machine. The cutting accuracy was 0.5 mm or less of the calf margin and no upper edge did not melt down and the distortion was low. No dross adheres and the secondary treatment man-hour decreased. Since it was not necessary to replace an electrode by a new one, a continuous unmanned operation was enabled. The automatic power off function, etc. achieve safety measures against earthquake, etc. Neither fume nor noise was generated. Since the dust collector is not required, the initial cost is low and the running cost is inexpensive, namely 31 yen per meter (40 yen for the plasma cutting machine). 7 figs., 2 tabs.

A comparative investigation of bone surface after cutting with mechanical tools and Er:YAG laser.

Science.gov (United States)

Baek, Kyung-Won; Deibel, Waldemar; Marinov, Dilyan; Griessen, Mathias; Dard, Michel; Bruno, Alfredo; Zeilhofer, Hans-Florian; Cattin, Philippe; Juergens, Philipp

2015-07-01

Despite of the long history of medical application, laser ablation of bone tissue became successful only recently. Laser bone cutting is proven to have higher accuracy and to increase bone healing compared to conventional mechanical bone cutting. But the reason of subsequent better healing is not biologically explained yet. In this study we present our experience with an integrated miniaturized laser system mounted on a surgical lightweight robotic arm. An Erbium-doped Yttrium Aluminium Garnet (Er:YAG) laser and a piezoelectric (PZE) osteotome were used for comparison. In six grown up female Göttingen minipigs, comparative surgical interventions were done on the edentulous mandibular ridge. Our laser system was used to create different shapes of bone defects on the left side of the mandible. On the contralateral side, similar bone defects were created by PZE osteotome. Small bone samples were harvested to compare the immediate post-operative cut surface. The analysis of the cut surface of the laser osteotomy and conventional mechanical osteotomy revealed an essential difference. The scanning electron microscopy (SEM) analysis showed biologically open cut surfaces from the laser osteotomy. The samples from PZE osteotomy showed a flattened tissue structure over the cut surface, resembling the "smear layer" from tooth preparation. We concluded that our new finding with the mechanical osteotomy suggests a biological explanation to the expected difference in subsequent bone healing. Our hypothesis is that the difference of surface characteristic yields to different bleeding pattern and subsequently results in different bone healing. The analyses of bone healing will support our hypothesis. © 2015 Wiley Periodicals, Inc.

Structural and electronic characterization of 355 nm laser-crystallized silicon: Interplay of film thickness and laser fluence

International Nuclear Information System (INIS)

Semler, Matthew R.; Swenson, Orven F.; Hoey, Justin M.; Guruvenket, Srinivasan; Gette, Cody R.; Hobbie, Erik K.

2014-01-01

We present a detailed study of the laser crystallization of amorphous silicon thin films as a function of laser fluence and film thickness. Silicon films grown through plasma-enhanced chemical vapor deposition were subjected to a Q-switched, diode-pumped solid-state laser operating at 355 nm. The crystallinity, morphology, and optical and electronic properties of the films are characterized through transmission and reflectance spectroscopy, resistivity measurements, Raman spectroscopy, X-ray diffraction, atomic force microscopy, and optical and scanning-electron microscopy. Our results reveal a unique surface morphology that strongly couples to the electronic characteristics of the films, with a minimum laser fluence at which the film properties are optimized. A simple scaling model is used to relate film morphology to conductivity in the laser-processed films

High speed pulsed laser cutting of LiCoO2 Li-ion battery electrodes

Science.gov (United States)

Lutey, Adrian H. A.; Fortunato, Alessandro; Carmignato, Simone; Fiorini, Maurizio

2017-09-01

Laser cutting of Li-ion battery electrodes represents an alternative to mechanical blanking that avoids complications associated with tool wear and allows assembly of different cell geometries with a single device. In this study, laser cutting of LiCoO2 Li-ion battery electrodes is performed at up to 5m /s with a 1064nm wavelength nanosecond pulsed fiber laser with a maximum average power of 500W and a repetition rate of up to 2MHz . Minimum average cutting power for cathode and anode multi-layer films is established for 12 parameter groups with velocities over the range 1 - 5m /s , varying laser pulse fluence and overlap. Within the tested parameter range, minimum energy per unit cut length is found to decrease with increasing repetition rate and velocity. SEM analysis of the resulting cut edges reveals visible clearance widths in the range 20 - 50 μm , with cut quality found to improve with velocity due to a reduction in lateral heat conduction losses. Raman line map spectra reveal changes in the cathode at 60 μm from the cut edge, where bands at 486cm-1 and 595cm-1 , corresponding to the Eg and A1g modes of LiCoO2 , are replaced with a single wide band centered at 544cm-1 , and evidence of carbon black is no longer present. No changes in Raman spectra are observed in the anode. The obtained results suggest that further improvements in cutting efficiency and quality could be achieved by increasing the repetition rate above 2MHz , thereby improving ablation efficiency of the metallic conductor layers. The laser source utilized in the present study nonetheless represents an immediately available solution for repeatability and throughput that are superior to mechanical blanking.

AN ARTIFICIAL INTELLIGENCE APPROACH FOR THE PREDICTION OF SURFACE ROUGHNESS IN CO2 LASER CUTTING

Directory of Open Access Journals (Sweden)

MILOŠ MADIĆ

2012-12-01

Full Text Available In laser cutting, the cut quality is of great importance. Multiple non-linear effects of process parameters and their interactions make very difficult to predict cut quality. In this paper, artificial intelligence (AI approach was applied to predict the surface roughness in CO2 laser cutting. To this aim, artificial neural network (ANN model of surface roughness was developed in terms of cutting speed, laser power and assist gas pressure. The experimental results obtained from Taguchi’s L25 orthogonal array were used to develop ANN model. The ANN mathematical model of surface roughness was expressed as explicit nonlinear function of the selected input parameters. Statistical results indicate that the ANN model can predict the surface roughness with good accuracy. It was showed that ANNs may be used as a good alternative in analyzing the effects of cutting parameters on the surface roughness.

Simultaneous high crystallinity and sub-bandgap optical absorptance in hyperdoped black silicon using nanosecond laser annealing

Energy Technology Data Exchange (ETDEWEB)

Franta, Benjamin, E-mail: bafranta@gmail.com; Pastor, David; Gandhi, Hemi H.; Aziz, Michael J.; Mazur, Eric [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Rekemeyer, Paul H.; Gradečak, Silvija [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2015-12-14

Hyperdoped black silicon fabricated with femtosecond laser irradiation has attracted interest for applications in infrared photodetectors and intermediate band photovoltaics due to its sub-bandgap optical absorptance and light-trapping surface. However, hyperdoped black silicon typically has an amorphous and polyphasic polycrystalline surface that can interfere with carrier transport, electrical rectification, and intermediate band formation. Past studies have used thermal annealing to obtain high crystallinity in hyperdoped black silicon, but thermal annealing causes a deactivation of the sub-bandgap optical absorptance. In this study, nanosecond laser annealing is used to obtain high crystallinity and remove pressure-induced phases in hyperdoped black silicon while maintaining high sub-bandgap optical absorptance and a light-trapping surface morphology. Furthermore, it is shown that nanosecond laser annealing reactivates the sub-bandgap optical absorptance of hyperdoped black silicon after deactivation by thermal annealing. Thermal annealing and nanosecond laser annealing can be combined in sequence to fabricate hyperdoped black silicon that simultaneously shows high crystallinity, high above-bandgap and sub-bandgap absorptance, and a rectifying electrical homojunction. Such nanosecond laser annealing could potentially be applied to non-equilibrium material systems beyond hyperdoped black silicon.

Formation of a Polycrystalline Silicon Thin Film by Using Blue Laser Diode Annealing

Science.gov (United States)

Choi, Young-Hwan; Ryu, Han-Youl

2018-04-01

We report the crystallization of an amorphous silicon thin film deposited on a SiO2/Si wafer using an annealing process with a high-power blue laser diode (LD). The laser annealing process was performed using a continuous-wave blue LD of 450 nm in wavelength with varying laser output power in a nitrogen atmosphere. The crystallinity of the annealed poly-silicon films was investigated using ellipsometry, electron microscope observation, X-ray diffraction, and Raman spectroscopy. Polysilicon grains with > 100-nm diameter were observed to be formed after the blue LD annealing. The crystal quality was found to be improved as the laser power was increased up to 4 W. The demonstrated blue LD annealing is expected to provide a low-cost and versatile solution for lowtemperature poly-silicon processes.

A high-peak-power passively Q-switched composite variable-cut vanadate laser

International Nuclear Information System (INIS)

Sirotkin, A A

2014-01-01

We present laser sources based on a novel method of controlling spectral parameters in diode-pumped vanadate lasers. Angular dependences of the luminescence intensity of Stark transitions at the 4F3/2‒4I11/2 transition in vanadate crystals are investigated. The operation of diode-pumped passively Q-switched composite variable-cut (θ = var, φ = 0) YVO 4 –Nd 3+  : YVO 4 lasers with Cr 4+  : YAG saturable absorber is demonstrated (the narrowest pulse of 2 ns with the highest peak power of 24.3 kW). In the experiment, an efficient self-Raman laser was realized, based on the multifunctional variable-cut (θ = 25°, φ = 0) YVO 4 –Nd 3+  : YVO 4 laser crystal with the passive Q-switched. (letters)

Fundamental experiment for flash removal of aluminum alloy by CO2 laser beam cutting; CO2 laser beam setsudan ni yoru aluminium gokin no ibaritori no kiso jikken

Energy Technology Data Exchange (ETDEWEB)

Kataoka, Y.; Tokunaga, T. [University of Industrial Technology, Kanagawa (Japan); Miyazaki, T. [Chiba Institute of Technology, Chiba (Japan)

1995-08-25

CO2 laser beam has been applied to cut of the aluminum alloy. Average cut width, roughness of cut surface and average thickness of heat affected zone are investigated as functions of laser power, cutting speed and assist gas pressure. The average cut width increases with laser power, but it does not depend on the cutting speed. The narrowest average cut width obtained is 0.22mm under the conditions of laser power of 900W and cutting speeds from 600 to 1000mm/min. The roughness of cut surface decreases with decreasing cutting speed. The best smoothness of cut surface obtained is 17 {mu}m (Rmax) , when the conditions are 1100W and 600mm/min. The average thickness of heat affected zone decreases with increasing assist gas pressure. CO2 laser beam cutting is applicable to flash removal from aluminum alloy casting. This process is expected to reduce the need of physical labor and to improve the working conditions in the foundry industry. 32 refs., 10 figs., 2 tabs.

Neodymium:YAG laser cutting of intraocular lens haptics in vitro and in vivo.

Science.gov (United States)

Feder, J M; Rosenberg, M A; Farber, M D

1989-09-01

Various complications following intraocular lens (IOL) surgery result in explantation of the lenses. Haptic fibrosis may necessitate cutting the IOL haptics prior to removal. In this study we used the neodymium: YAG (Nd:YAG) laser to cut polypropylene and poly(methyl methacrylate) (PMMA) haptics in vitro and in rabbit eyes. In vitro we were able to cut 100% of both haptic types successfully (28 PMMA and 30 polypropylene haptics). In rabbit eyes we were able to cut 50% of the PMMA haptics and 43% of the polypropylene haptics. Poly(methyl methacrylate) haptics were easier to cut in vitro and in vivo than polypropylene haptics, requiring fewer shots for transection. Complications of Nd:YAG laser use frequently interfered with haptic transections in rabbit eyes. Haptic transection may be more easily accomplished in human eyes.

Ageing effects on the wettability behavior of laser textured silicon

International Nuclear Information System (INIS)

Nunes, B.; Serro, A.P.; Oliveira, V.; Montemor, M.F.; Alves, E.; Saramago, B.; Colaco, R.

2011-01-01

In the present work we investigate the ageing of acid cleaned femtosecond laser textured silicon surfaces. Changes in the surface structure and chemistry were analysed by Rutherford backscattering spectrometry (RBS) and X-ray photoelectron spectroscopy (XPS), in order to explain the variation with time of the water contact angles of the laser textured surfaces. It is shown that highly hydrophobic silicon surfaces are obtained immediately after laser texturing and cleaning with acid solutions (water contact angle > 120 o ). However these surfaces are not stable and ageing leads to a decrease of the water contact angle which reaches a value of 80 o . XPS analysis of the surfaces shows that the growth of the native oxide layer is most probably responsible for this behavior.

Critical element development of standard components for pipe welding/cutting by CO{sub 2} laser

Energy Technology Data Exchange (ETDEWEB)

Oka, Kiyoshi; Kakudate, Satoshi; Nakahira, Masataka [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

1994-11-01

In D-T burning reactors such as International Thermonuclear Experimental Reactor(ITER), an internal access is inevitable for welding/cutting of cooling pipes of in-vessel components, because of spatial constraint due to a narrow port opening space. An internal-access pipe welding/cutting equipment is being developed in JAERI. Internal access is to approach through inside a pipe to a welding/cutting position, to use 10kW CO{sub 2} laser beam, and to be applicable to both welding and cutting with using a same processing head. A welding/cutting processing head with 10kW CO{sub 2} laser beam has been fabricated and the basic feasibility has been successfully demonstrated for studies of the internal-access pipe welding/cutting concept using 100-A stainless steel pipe with a thickness of 6.3mm. In this study, the optimum focal point of laser beam, laser power and traveling speed of the head have been investigated together with an adjusting mechanism of a relative distance between the head and the pipe wall. In addition, the radiation resistance of critical elements such as optical lens has been investigated. (author).

Laser desorption/ionization from nanostructured surfaces: nanowires, nanoparticle films and silicon microcolumn arrays

International Nuclear Information System (INIS)

Chen Yong; Luo Guanghong; Diao Jiajie; Chornoguz, Olesya; Reeves, Mark; Vertes, Akos

2007-01-01

Due to their optical properties and morphology, thin films formed of nanoparticles are potentially new platforms for soft laser desorption/ionization (SLDI) mass spectrometry. Thin films of gold nanoparticles (with 12±1 nm particle size) were prepared by evaporation-driven vertical colloidal deposition and used to analyze a series of directly deposited polypeptide samples. In this new SLDI method, the required laser fluence for ion detection was equal or less than what was needed for matrix-assisted laser desorption/ionization (MALDI) but the resulting spectra were free of matrix interferences. A silicon microcolumn array-based substrate (a.k.a. black silicon) was developed as a new matrix-free laser desorption ionization surface. When low-resistivity silicon wafers were processed with a 22 ps pulse length 3xω Nd:YAG laser in air, SF 6 or water environment, regularly arranged conical spikes emerged. The radii of the spike tips varied with the processing environment, ranging from approximately 500 nm in water, to ∼2 μm in SF 6 gas and to ∼5 μm in air. Peptide mass spectra directly induced by a nitrogen laser showed the formation of protonated ions of angiotensin I and II, substance P, bradykinin fragment 1-7, synthetic peptide, pro14-arg, and insulin from the processed silicon surfaces but not from the unprocessed areas. Threshold fluences for desorption/ionization were similar to those used in MALDI. Although compared to silicon nanowires the threshold laser pulse energy for ionization is significantly (∼10x) higher, the ease of production and robustness of microcolumn arrays offer complementary benefits

The analysis of low-energy ion from a gas-puff laser plasma. The observation of ablated particles from the silicon irradiated with a fs laser

International Nuclear Information System (INIS)

Azuma, Hirozumi; Kamiya, Nobuyuki; Takeuchi, Akihiro; Ito, Tadashi; Suzuki, Noritomo; Daido, Hiroyuki; Mori, Michiaki; Ogura, Kouichi; Sagisaka, Akito; Orimo, Satoshi; Hayashi, Yukio; Hazama, Hisanao

2005-01-01

The single-shot creation of tadpolelike silicon nanoparticles constructed with multi-crystalline heads and amorphous tails by a high brightness fs-pulse laser was demonstrated. This is also the first demonstration of the creation of a nanosized connection of multicrystalline silicon with amorphous silicon. This result should expand the creation of new materials by a laser ablation using a high-intensity fs laser, and the created silicon nanoparticles can be applied to scientific and industrial fields. (author)

Effect of laser cutting on microstructure and on magnetic properties of grain non-oriented electrical steels

Energy Technology Data Exchange (ETDEWEB)

Belhadj, A. E-mail: ahmed@metallur.rug.ac.be; Baudouin, P.; Breaban, F.; Deffontaine, A.; Dewulf, M.; Houbaert, Y

2003-01-01

Non-oriented electrical steels have been cut with two different techniques, the laser cutting and the mechanical cutting. In order to investigate the effect of the first technique on magnetic properties, different cutting parameters have been tested. Despite this, the best magnetic properties have been obtained after mechanical cutting. The laser cutting causes a coercive field increase and a permeability drop. Due to thermal effect, internal stress seems to be the main process drawback. No correlation between the heat affected zone and the magnetic properties has been found00.

Metallisation Technology of Silicon Solar Cells Using the Convectional and Laser Technique

Directory of Open Access Journals (Sweden)

Leszek A. Dobrzanski

2013-07-01

Full Text Available The aim of the paper was to optimize the Selective Laser Sintering (SLS and co-firing in the infrared conveyor furnace parameters in front Screen Printed (SP contacts. The co-firing in the infrared conveyor furnace was carried out at various temperature. The SLS was carried out at various a laser beam, scanning speed of the laser beam and front electrode thickness. The investigations were carried out on monocrystalline silicon wafers. During investigations was applied a silver powder with the grain size of 40 μm. The contacts parameters are obtained according to the Transmission Line Model (TLM measurements. Firstly, this paper shows the comparison between the convectional an unconventional method of manufacturing front contacts of monocrystalline silicon solar cells with the different morphology of silicon for comparative purposes. Secondly, the papers shows technological recommendations for both methods in relation to parameters such as: the optimal paste composition, the morphology of the silicon substrate to produce the front electrode of silicon solar cells, which were selected experimentally in order to produce a uniformly melted structure, well adhering to the substrate, with the low resistance of the front electrode-to-substrate joint zone.

Endoscopic removal of laser-cut covered self-expandable metallic biliary stents: A report of six cases.

Science.gov (United States)

Tanisaka, Yuki; Ryozawa, Shomei; Kobayashi, Masanori; Harada, Maiko; Kobatake, Tsutomu; Omiya, Kumiko; Iwano, Hirotoshi; Arai, Shin; Nonaka, Kouichi; Mashimo, Yumi

2018-02-01

Covered self-expandable metallic stents (CSEMS) may provide palliative drainage for unresectable distal malignant biliary strictures. Laser-cut CSEMS allows easy positioning due to its characteristic of minimal stent shortening. Endoscopic stent removal is sometimes recommended for recurrent biliary obstruction (RBO). However, there are no previous reports of endoscopic removal of laser-cut CSEMS. The current study presents data from 6 patients who were placed a laser-cut CSEMS for unresectable distal malignant biliary strictures, and later endoscopic stent removal was attempted for RBO at the present institute. The duration of stent placement, the procedural success rate, the procedural duration, and accidental complications were evaluated. The mean duration of stent placement was 156±37.9 days (range, 117-205). The procedural success rate was 100%. The mean procedural duration was 11.8±7.5 min (range, 5-24). No complications were reported. Laser-cut CSEMS were safely removed from all patients. The present case report is the first to demonstrate that Endoscopic stent removal of laser-cut CSEMS was safely performed.

Studies on nanosecond 532nm and 355nm and ultrafast 515nm and 532nm laser cutting super-hard materials

Science.gov (United States)

Zhang, Jie; Tao, Sha; Wang, Brian; Zhao, Jay

2017-02-01

In this paper, micro-processing of three kinds of super-hard materials of poly-crystal diamond (PCD)/tungsten-carbide (WC), CVD-diamond and cubic boron nitride (CNB) has been systematically studied using nanosecond laser (532nm and 355nm), and ultrafast laser (532nm and 515nm). Our purpose is to investigate a full laser micro-cutting solution to achieve a ready-to-use cutting tool insert (CTI). The results show a clean cut with little burns and recasting at edge. The cutting speed of 2-10mm/min depending on thickness was obtained. The laser ablation process was also studied by varying laser parameters (wavelength, pulse width, pulse energy, repetition rate) and tool path to improve cutting speed. Also, studies on material removal efficiency (MRE) of PCD/WC with 355nm-ns and 515nm-fs laser as a function of laser fluence show that 355nm-ns laser is able to achieve higher MRE for PCD and WC. Thus, ultrafast laser is not necessarily used for superhard material cutting. Instead, post-polishing with ultrafast laser can be used to clean cutting surface and improve smoothness.

Femtosecond laser cutting of human corneas for the subbasal nerve plexus evaluation.

Science.gov (United States)

Kowtharapu, B S; Marfurt, C; Hovakimyan, M; Will, F; Richter, H; Wree, A; Stachs, O; Guthoff, R F

2017-01-01

Assessment of various morphological parameters of the corneal subbasal nerve plexus is a valuable method of documenting the structural and presumably functional integrity of the corneal innervation in health and disease. The aim of this work is to establish a rapid, reliable and reproducible method for visualization of the human corneal SBP using femtosecond laser cut corneal tissue sections. Trephined healthy corneal buttons were fixed and processed using TissueSurgeon-a femtosecond laser based microtome, to obtain thick tissue sections of the corneal epithelium and anterior stroma cut parallel to the ocular surface within approximately 15 min. A near infrared femtosecond laser was focused on to the cornea approximately 70-90 μm from the anterior surface to induce material separation using TissueSurgeon. The obtained corneal sections were stained following standard immunohistochemical procedures with anti-neuronal β-III tubulin antibody for visualization of the corneal nerves. Sections that contained the epithelium and approximately 20-30 μm of anterior stroma yielded excellent visualisation of the SBP with minimal optical interference from underlying stromal nerves. In conclusion, the results of this study have demonstrated that femtosecond laser cutting of the human cornea offers greater speed, ease and reliability than standard tissue preparation methods for obtaining high quality thick sections of the anterior cornea cut parallel to the ocular surface. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Internal energy deposition with silicon nanoparticle-assisted laser desorption/ionization (SPALDI) mass spectrometry

Science.gov (United States)

Dagan, Shai; Hua, Yimin; Boday, Dylan J.; Somogyi, Arpad; Wysocki, Ronald J.; Wysocki, Vicki H.

2009-06-01

The use of silicon nanoparticles for laser desorption/ionization (LDI) is a new appealing matrix-less approach for the selective and sensitive mass spectrometry of small molecules in MALDI instruments. Chemically modified silicon nanoparticles (30 nm) were previously found to require very low laser fluence in order to induce efficient LDI, which raised the question of internal energy deposition processes in that system. Here we report a comparative study of internal energy deposition from silicon nanoparticles to previously explored benzylpyridinium (BP) model compounds during LDI experiments. The internal energy deposition in silicon nanoparticle-assisted laser desorption/ionization (SPALDI) with different fluorinated linear chain modifiers (decyl, hexyl and propyl) was compared to LDI from untreated silicon nanoparticles and from the organic matrix, [alpha]-cyano-4-hydroxycinnamic acid (CHCA). The energy deposition to internal vibrational modes was evaluated by molecular ion survival curves and indicated that the ions produced by SPALDI have an internal energy threshold of 2.8-3.7 eV. This is slightly lower than the internal energy induced using the organic CHCA matrix, with similar molecular survival curves as previously reported for LDI off silicon nanowires. However, the internal energy associated with desorption/ionization from the silicon nanoparticles is significantly lower than that reported for desorption/ionization on silicon (DIOS). The measured survival yields in SPALDI gradually decrease with increasing laser fluence, contrary to reported results for silicon nanowires. The effect of modification of the silicon particle surface with semifluorinated linear chain silanes, including fluorinated decyl (C10), fluorinated hexyl (C6) and fluorinated propyl (C3) was explored too. The internal energy deposited increased with a decrease in the length of the modifier alkyl chain. Unmodified silicon particles exhibited the highest analyte internal energy

Building blocks for future detectors: Silicon test masses and 1550 nm laser light

International Nuclear Information System (INIS)

Schnabel, R; Britzger, M; Burmeister, O; Danzmann, K; Duck, J; Eberle, T; Friedrich, D; Luck, H; Mehmet, M; Steinlechner, S; Willke, B; Brueckner, F; Nawrodt, R

2010-01-01

Current interferometric gravitational wave detectors use the combination of quasi-monochromatic, continuous-wave laser light at 1064 nm and fused silica test masses at room temperature. Detectors of the third generation, such as the Einstein-Telescope, will involve a considerable sensitivity increase. The combination of 1550 nm laser radiation and crystalline silicon test masses at low temperatures might be important ingredients in order to achieve the sensitivity goal. Here we compare some properties of the fused silica and silicon test mass materials relevant for decreasing the thermal noise in future detectors as well as the recent technology achievements in the preparation of laser radiation at 1064 nm and 1550 nm relevant for decreasing the quantum noise. We conclude that silicon test masses and 1550 nm laser light have the potential to form the future building blocks of gravitational wave detection.

New 445 nm blue laser for laryngeal surgery combines photoangiolytic and cutting properties.

Science.gov (United States)

Hess, Markus M; Fleischer, Susanne; Ernstberger, Marcel

2018-06-01

Photoangiolytic lasers have broadened the surgical armamentarium for many phonosurgical interventions. However, the pulse dye laser and potassium titanyl phosphate (KTP) laser have technical drawbacks and a smaller spectrum of indications. The new 445 nm wavelength laser, the so-called 'blue laser', proves to show tissue effects comparable to the KTP laser and is also capable of treating subepithelial vessels due to its photoangiolytic properties, it can coagulate and carbonize at higher energy levels, and can be used via glass fibers in non-contact and contact mode for in-office procedures. In contrast to the KTP, the new 445 nm laser can also be used as a cutting laser, thus combining very much wanted properties of diode or CO2 lasers with photoangiolytic lasers. Further advantages of the new laser are the; (1) portability of the shoe box sized, shock-proof laser machine for in-office and operating room usage, (2) the selection of pulse rates from continuous wave (cw) to less than a millisecond, (3) stronger tissue effects compared to KTP with similar energy and pulse settings, (4) far better cutting properties than the KTP, and thus (5) more possibilities for usage in laryngology as well as in other fields or surgery. We demonstrate the feasibility of the 445 nm laser in several laboratory experiments and show clinical cases where photoangiolysis and cutting was possible. However, this is a preliminary report and further systematic studies in greater numbers are warranted.

Laser capture microdissection: Arcturus(XT) infrared capture and UV cutting methods.

Science.gov (United States)

Gallagher, Rosa I; Blakely, Steven R; Liotta, Lance A; Espina, Virginia

2012-01-01

Laser capture microdissection (LCM) is a technique that allows the precise procurement of enriched cell populations from a heterogeneous tissue under direct microscopic visualization. LCM can be used to harvest the cells of interest directly or can be used to isolate specific cells by ablating the unwanted cells, resulting in histologically enriched cell populations. The fundamental components of laser microdissection technology are (a) visualization of the cells of interest via microscopy, (b) transfer of laser energy to a thermolabile polymer with either the formation of a polymer-cell composite (capture method) or transfer of laser energy via an ultraviolet laser to photovolatize a region of tissue (cutting method), and (c) removal of cells of interest from the heterogeneous tissue section. Laser energy supplied by LCM instruments can be infrared (810 nm) or ultraviolet (355 nm). Infrared lasers melt thermolabile polymers for cell capture, whereas ultraviolet lasers ablate cells for either removal of unwanted cells or excision of a defined area of cells. LCM technology is applicable to an array of applications including mass spectrometry, DNA genotyping and loss-of-heterozygosity analysis, RNA transcript profiling, cDNA library generation, proteomics discovery, and signal kinase pathway profiling. This chapter describes the unique features of the Arcturus(XT) laser capture microdissection instrument, which incorporates both infrared capture and ultraviolet cutting technology in one instrument, using a proteomic downstream assay as a model.

Fast and intuitive programming of adaptive laser cutting of lace enabled by machine vision

Science.gov (United States)

Vaamonde, Iago; Souto-López, Álvaro; García-Díaz, Antón

2015-07-01

A machine vision system has been developed, validated, and integrated in a commercial laser robot cell. It permits an offline graphical programming of laser cutting of lace. The user interface allows loading CAD designs and aligning them with images of lace pieces. Different thread widths are discriminated to generate proper cutting program templates. During online operation, the system aligns CAD models of pieces and lace images, pre-checks quality of lace cuts and adapts laser parameters to thread widths. For pieces detected with the required quality, the program template is adjusted by transforming the coordinates of every trajectory point. A low-cost lace feeding system was also developed for demonstration of full process automation.