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1

Process and part filling control in micro injection molding  

DEFF Research Database (Denmark)

The influence of process parameters on ?-injection molding (?IM) and on ?-injection molded parts has been investigated using Design of Experiments. A mold with a sensor applied at injection location was used to monitor actual injection pressure and to determine the cavity filling time. Flow markers position was measured on the polymer ?-parts to evaluate filling behavior of the polymer melt flowing through ?-features. Experimental results obtained under different processing conditions were evaluated to correlate the process parameter levels influence on the selected responses. Results showed that the injection speed in one of the most influencing process parameters on the ?IM process and on the ?-parts filling.

Tosello, Guido; Hansen, Hans NØrgaard

2008-01-01

2

Study on heat flux from resin to mold in injection molding process  

Energy Technology Data Exchange (ETDEWEB)

Recently, an injection molding of thermoplastic is widely used in many industries, because this manufacturing method is very suitable for mass production. For injection molding processes, a number of software packages for simulating an injection molding process have been developed. It is assumed in these software packages that the heat transfer coefficient between the resin and the mold surface is constant at the filling or cooling stages. In general, when melted resin flows into the mold, heat is generated in the flowing resin because of the high viscosity at the filling stage. Moreover at the cooling stage, a separation of the molded part from the mold surface generally occurs because of shrinkage of the molded material. Therefore, the heat transfer coefficient has not been accurately obtained yet at these stages. In this paper, the temperature near the surface of the mold cavity has been experimentally measured, so the heat flux that flows from the resin to the mold has been able to be analytically estimated by an inverse conduction method. On the other hand, the separating behavior of the resin from the mold surface has been measured using an ultrasonic transducer attached to the outer surface of the stationary mold. The heat flux that flows from the resin to the mold has been analytically estimated. The apparent heat transfer coefficient can be obtained from the heat flux and the representative temperature difference, which is measured by an ultrasonic technique. It was discovered that the heat flux and the apparent heat transfer coefficient are hardly influenced by the separation.

Nishiwaki, Nobuhiko; Hori, Sankei

1999-07-01

3

The effect of mold surface topography on plastic parat in-process shrinkage in injection molding  

DEFF Research Database (Denmark)

An experimental study of the effect of mold surface roughness on in-process in-flow linear part shrinkage in injection molding has been carried out. The investigation is based on an experimental two-cavity tool, where the cavities have different surface topographies, but are otherwise identical. The study has been carried out for typical commercial polystyrene and polypropylene grades. The relationship between mold surface topography and linear shrinkage has been investigated with an experimental two-cavity mold producing simple rectangular parts with the nominal dimensions 1 x 25 x 50 mm (see figure 1). The cavities have different surface topographies on one side, but are otherwise identical (see discussion of other contribution factors).

ArlØ, Uffe Rolf; Hansen, Hans NØrgaard

2003-01-01

4

Development of the computer-aided process planning (CAPP) system for polymer injection molds manufacturing  

Directory of Open Access Journals (Sweden)

Full Text Available Beginning of production and selling of polymer products largely depends on mold manufacturing. The costs of mold manufacturing have significant share in the final price of a product. The best way to improve and rationalize polymer injection molds production process is by doing mold design automation and manufacturing process planning automation. This paper reviews development of a dedicated process planning system for manufacturing of the mold for injection molding, which integrates computer-aided design (CAD), computer-aided process planning (CAPP) and computer-aided manufacturing (CAM) technologies.

J. Tepi?; V. Todi?; D. Luki?; M. Miloševi?; S. Borojevi?

2011-01-01

5

RECENT METHODS FOR OPTIMIZATION OF PLASTIC INJECTION MOLDING PROCESS –A RETROSPECTIVE AND LITERATURE REVIEW  

Directory of Open Access Journals (Sweden)

Full Text Available Injection molding has been a challenging process for many manufacturers and researchers to produce products meeting requirements at the lowest cost. Faced with global competition in injection molding industry, using the trialand- error approach to determine the process parameters for injection molding is no longer good enough. Factors that affect the quality of a molded part can be classified into four categories: part design, mold design, machineperformance and processing conditions. The part and mold design are assumed as established and fixed. During production, quality characteristics may deviate due to drifting or shifting of processing conditions caused by machine wear, environmental change or operator fatigue. Determining optimal process parameter settings critically influences productivity, quality, and cost of production in the plastic injection molding (PIM) industry. Previously, production engineers used either trial-and-error method or Taguchi’s parameter design method to determine optimal process parameter settings for PIM. However, these methods are unsuitable in present PIM because of the increasing complexity of product design and the requirement of multi-response quality characteristics. This article aims to review the recent research in designing and determining process parameters of injection molding. A number of research works based on various approaches have been performed in the domain of the parameter setting for injection molding. These approaches, including mathematical models, Taguchi method, Artificial Neural Networks (ANN),Fuzzy logic, Case Based Reasoning (CBR), Genetic Algorithms (GA), Finite Element Method(FEM),Non Linear Modeling, Response Surface Methodology, Linear Regression Analysis ,Grey Rational Analysis and Principle Component Analysis (PCA) are described in this article. The strength and theweakness of individual approaches are discussed. It is then followed by conclusions and discussions of the potential research in determining process parameters for injection molding.

P.K. Bharti; M. I. Khan,; Harbinder Singh

2010-01-01

6

Low-pressure injection molding  

Energy Technology Data Exchange (ETDEWEB)

Ceramic injection molding experienced a revival in the 1970s and 1980s with the application of ceramics for gas turbine components. Concurrently, techniques were being developed for the injection molding of powdered metal compositions into complex shaped articles. The impetus for the development of injection molding as a ceramic fabrication process lay in the potential to produce complex-shaped components to near-net shape. In the ceramic injection molding process, ceramic powders are processed to obtain the desired particle size, distribution and morphology and blended to obtain a homogeneous distribution. These powders are then mixed with the organic binders, generally in a heated, highshear mixer at temperatures above the melting point of the organic binders. The injection molding mix is pelletized, cooled and fed into an injection molding machine. The molding mix is reheated to a fluid state and injected under high pressure (7--70 MPa) into a die cavity. The molded part is removed from the tooling after the molding mix has solidified in the die. The organic binders are then removed from the component at temperatures up to 400 C, generally by some combination of wicking and thermal decomposition. Finally, the component is sintered to obtain its final ceramic properties, using conventional ceramic processes.

Mangels, J.A. (Ceradyne Inc., Costa Mesa, CA (United States))

1994-05-01

7

Injection Molding of High Aspect Ratio Nanostructures  

DEFF Research Database (Denmark)

We present a process for injection molding of 40 nm wide and >100 nm high pillars (pitch: 200 nm). We explored the effects of mold coatings and injection molding conditions on the replication quality of nanostructures in cyclic olefin copolymer. We found that optimization of molding parameters using native nickel molds only lead to slight improvements in replication quality. In contrast, a fluorocarbon based antistiction coating (FDTS) was found to improve the replication quality significantly.

Matschuk, Maria; Larsen, Niels Bent

8

Injection molding of Y-TZP powders prepared by colloidal processing  

International Nuclear Information System (INIS)

TZP powders containing 3mol% Y2O3 were prepared from ZrOCl2 solution via an aqueous colloidal suspension of ZrO2. Processing variables were optimized to obtain powders suitable for injection molding. Wettability of powders with binders, fluidity of melting compound, removal of binder from green body, and properties of sintered body were investigated.

1991-05-02

9

Injection Molding of Plastics from Agricultural Materials  

Energy Technology Data Exchange (ETDEWEB)

The objective of this research was to conduct a systematic study to relate injection molding parameters to properties of blends of starch and synthetic polymer. From this study, we wished to develop a thorough understanding of the injection molding process and gain significant insight into designing molds and aiding in developing products cheaply and efficiently.

Bhattacharya, M.; Ruan, R.

2001-02-22

10

The effects of process parameters on injection-molded PZT ceramics part fabrication- compounding process rheology.  

Energy Technology Data Exchange (ETDEWEB)

Solid solutions of lead-based perovskites are the backbone materials of the piezoelectric components for transducer, actuator, and resonator applications. These components, typically small in size, are fabricated from large sintered ceramic slugs using grinding and lapping processes. These operations increase manufacturing costs and produce a large hazardous waste stream, especially when component size decreases. To reduce costs and hazardous wastes associated with the production of these components, an injection molding technique is being investigated to replace the machining processes. The first step in the new technique is to compound an organic carrier with a ceramic powder. The organic carrier is a thermoplastic based system composed of a main carrier, a binder, and a surfactant. Understanding the rheology of the compounded material is necessary to minimize the creation of defects such as voids or cavities during the injection-molding process. An experiment was performed to model the effects of changes in the composition and processing of the material on the rheological behavior. Factors studied included: the surfactant of the organic carrier system, the solid loading of the compounded material, and compounding time. The effects of these factors on the viscosity of the material were investigated.

Halbleib, Laura L.; Yang, Pin; Mondy, Lisa Ann; Burns, George Robert

2005-05-01

11

Minimization of sink mark defects in injection molding process – Taguchi approach  

Directory of Open Access Journals (Sweden)

Full Text Available Optimal setting up of injection molding process variables plays a very important role in controlling the quality of the injection molded products. It is all the most important to control attribute defects like sink marks. Sink marks are basically a “designed in” problem and hence it is to be attended during designs stages. Owing to certain conditions and constraints, sometimes, it is rather ignored during design stages and it is expected to be handled by molders with only instruction to ‘do the best’. Handling of numerous processing variables to control defects is a mammoth task that costs time, effort and money. This paper presents a simple and efficient way to study the influence of injection molding variables on sink marks using Taguchi approach. Using the Taguchi approach, optimal parameter settings and the respective sink depth were arrived. The sink depth based on the validation trials was compared with the predicted sink depth and they are found to be in good agreement. The results demonstrate the ability of this approach to predict sink depth for various combination of processing variables with in the design space.

D. Mathivanan; M. Nouby; R. Vidhya

2010-01-01

12

Multi-scale filling simulation of micro-injection molding process  

Energy Technology Data Exchange (ETDEWEB)

This work proposes a multi-scale simulation method that can simulate filling during the micro-injection molding process. The multiscale simulation is comprised of two steps. In the first step, the macro-scale flow is analyzed using the conventional method. In the second step, the micro-scale simulation is conducted taking the slip and surface tension into consideration to investigate the filling of microcavity. Moreover, a conservative level set method is employed to accurately track the flow front. First, numerical tests have been done for circular micro-channels. The results show that slip and surface tension play important roles in the micro-regime. Second, to verify the multi-scale method, filling of a thin plate with micro-channel patterns has been simulated. The results show that the proposed multi-scale method is promising for micro-injection molding simulations.

Choi, Sung Joo; Kim, Sun Kyoung [Seoul National University of Science and Technology, Seoul (Korea, Republic of)

2011-01-15

13

Development of a Plastic Injection Molding Processing Laboratory for Freshman Mechanical Engineering Technology Students  

Science.gov (United States)

As is the case with many educational institutions that offer a MET degree, an introductory course in manufacturing materials and processes is required. At Penn State Erie, The Behrend College, we offer first-year Mechanical Engineering Technology (MET) students the introductory manufacturing materials and processes course. The course has both a lecture and laboratory segment. During the lab segment of the course, students have the opportunity to experience: material testing, plant tours, manufacturing processes, statistical process control, and inspection/measurement techniques. With 10 PIM machines, 3 extrusion lines, 2 thermoforming machines, and 2 blow molding machines, Penn State Behrend has the largest educational plastic injection molding (PIM) laboratory in the country. Collaborative efforts were initiated between the Mechanical Engineering Technology and Plastics Engineering Technology departments to enhance the learning experience. Resulting from the collaboration a decision was made to add a PIM laboratory to emphasize the lecture on plastic materials and processes. The PIM laboratory was developed to give the student an introduction to the PIM process, machine, mold and the effects of processing variables on the parts. Also, students would gain knowledge regarding the effects of part design on the process. Prior to the implementation of this lab, the students went on plant tours or were shown videos of the PIM process.

Meckley, Jonathan A.; Nitterright, Fredrick A.

2009-07-27

14

Influence of process parameters on the weld lines of a micro injection molded component  

DEFF Research Database (Denmark)

The insufficient entanglement of the molecular chains and the stress amplification at the v-notch of a weld line compromise the mechanical strength of a plastic product, also in the micro scale. To investigate the influence of process parameters on the weld lines formation, a special micro cavity was designed and manufactured by µEDM (Electro Discharge Machining). Weld lines were quantitatively characterized both in the two-dimensional (direction and position) and three-dimensional range (surface topography characterization). Results showed that shape and position of weld lines are mainly influenced by mold temperature and injection speed.

Tosello, Guido; Gava, Alberto

2007-01-01

15

Relationship between processing and mechanical properties of injection molded high molecular mass polyethylene + hydroxyapatite composites  

Energy Technology Data Exchange (ETDEWEB)

We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinforcement by two procedures: bi-axial rotating drum and twin screw extrusion (TSE). The processing is by conventional injection molding and by Scorim (shear controlled orientation in injection molding) under a wide range of processing windows. Tensile testing is performed and the corresponding performance related to the morphology evaluated by polarized light microscopy and scanning electron microscopy. The control of the processing parameters led to significant improvements of the tensile properties. Compounding by TSE and then processing by Scorim produces the maximum modulus of 7.4 GPa and the ductility as high as 19%, for the HA weight fraction of 30%. These mechanical properties match those of bone, and were obtained with much smaller amounts of HA reinforcement then has been previously reported in literature. Our PE + HA composites present the additional benefit of being ductile even for 50% HA amounts. The use Scorim is a unique way of inducing anisotropy to thick sections and to produce very stiff composites that may be used in biomedical applications with important mechanical loads. This fact, combined with the bioactive behavior of the HA phase, makes our composite usable for orthopedic load-bearing implants. (orig.)

Reis, R.L.; Cunha, A.M.; Oliveira, M.J.; Campos, A.R. [Dept. of Polymer Engineering, University of Minho, Guimaraes (Portugal); Bevis, M.J. [Wolfson Center for Materials Processing, Brunel Univ., Uxbridge (United Kingdom)

2001-04-01

16

Study of soft magnetic iron cobalt based alloys processed by powder injection molding  

International Nuclear Information System (INIS)

As a near net shape process, powder injection molding (PIM) opens new possibilities to process Fe-Co alloys for magnetic applications. Due to the fact that PIM does not involve plastic deformation of the material during processing, we envisioned the possibility of eliminating vanadium (V), which is generally added to Fe-Co alloys to improve the ductility in order to enable its further shaping by conventional processes such as forging and cold rolling. In our investigation we have found out two main futures related to the elimination of V, which lead to a cost-benefit gain in manufacturing small magnetic components where high-saturation induction is needed at low frequencies. Firstly, the elimination of V enables the achievement of much better magnetic properties when alloys are processed by PIM. Secondly, a lower sintering temperature can be used when the alloy is processed starting with elemental Fe and Co powders without the addition of V.

2008-01-01

17

Experimental validation of viscous and viscoelastic simulations of micro injection molding process  

DEFF Research Database (Denmark)

The effects of two different rheological models used in the simulation of the micro injection molding (µIM) process are investigated. The Cross-WLF viscous model and the Giesekus viscoelastic model are selected and their performance evaluated using 3D models implemented on two different commercially available software packages. Simulation results are then compared with the experimental µIM process. Validation parameters for the comparison are the flow front position during filling of the micro cavity. They are respectively obtained by applying the short-shots method and the flow-markers method. The µIM part is a polystyrene tensile bar test weighting 20mg and with three µ-features 300µm wide.

Gava, Alberto; Tosello, Guido

2009-01-01

18

Injection molded superhydrophobic surfaces based on microlithography and black silicon processing  

DEFF Research Database (Denmark)

This work is concerned with the design, development, and testing of nanostructured polymer surfaces with self-cleaning properties that can be manufactured by injection molding. In particular, the superimposed micro- and nanometer length scales of the so-called Lotus effect were investigated in detail with an engineering perspective on choice of materials and manufacturability by injection molding. Microscope slides with superhydrophobic properties were succesfully fabricated. Preliminary results indicate a contact angle increase from 95° for the unstructured polymer to a maximum 150°. The lowest drop roll off angles observed were in the range 1° to 5°.

SØgaard, Emil; Andersen, Nis Korsgaard

2012-01-01

19

Surface microstructure replication in injection molding  

DEFF Research Database (Denmark)

In recent years, polymer components with surface microstructures have been in rising demand for applications such as lab-on-a-chip and optical components. Injection molding has proven to be a feasible and efficient way to manufacture such components. In injection molding, the mold surface topography is transcribed onto the plastic part through complex mechanisms. This replication, however, is not perfect, and the replication quality depends on the plastic material properties, the topography itself, and the process conditions. This paper describes and discusses an investigation of injection molding of surface microstructures. The fundamental problem of surface microstructure replication has been studied. The research is based on specific microstructures as found in lab-on-a-chip products and on rough surfaces generated from EDM (electro discharge machining) mold cavities. Emphasis is put on the ability to replicate surface microstructures under normal injection-molding conditions, i.e., with commodity materials within typical process windows. It was found that within typical process windows the replication quality depends significantly on several process parameters, and especially the mold temperature. For the specific microstructures, evidence suggests that step-height replication quality depends linearly on structure width in a certain range

Theilade, Uffe ArlØ; Hansen, Hans NØrgaard

2006-01-01

20

Dimensional change in complete dentures fabricated by injection molding and microwave processing.  

UK PubMed Central (United Kingdom)

STATEMENT OF PROBLEM: Acrylic resin complete dentures undergo dimensional changes during polymerization. Techniques with injection molding and polymerization and microwave polymerization are reported to reduce these changes and thereby improve clinical fit. These dimensional changes need to be quantified. PURPOSE: The purpose of this study was to compare differences in dimensional changes of simulated maxillary complete dentures during polymerization and storage in water after injection molding and conventional polymerization, or microwave polymerization against a control of conventionally packed and polymerized simulated maxillary complete dentures. MATERIAL AND METHODS: Forty identical maxillary denture bases were prepared in dental wax with anatomic teeth. They were invested and the wax eliminated from the molds. Ten specimens each were randomly assigned to 1 of 4 groups. Group 1 was compression molded and conventionally polymerized; group 2 was injection molded and conventionally polymerized (Success); group 3 was injection molded and microwave polymerized (Acron MC); and group 4 was injection molded and microwave polymerized (Microbase). Intermolar width and changes in vertical dimension of occlusion, were determined after polymerization and after storage in water for 28 days. Measurements in triplicate were made between points scribed on the second molar teeth with a traveling microscope (accurate to 0.005 mm). Vertical dimension of occlusion was measured between points scribed on the upper and lower members of an articulator by use of an internal micrometer (accurate to 0.05 mm). Data were analyzed by use of a 1-way analysis of variance with Tukey post-hoc contrasts (P <.05). RESULTS: Polymerization contractions (intermolar widths) for each group were: group 1, -0.24%; group 2, -0.27%; group 3, -0.35%; and group 4, -0.37%. The Microbase specimens had greater shrinkage than conventionally polymerized specimens, but there were no significant differences between the groups. All injection methods had less postpolymerization increase in vertical dimension of occlusion (0.63 to 0.41 mm) than the conventional Trevalon control (0.74 mm), but only group 4 was significantly different (P<.004). After storage in water for 28 days, all specimens increased in vertical dimension of occlusion (0.10% to 0.16%) from polymerization techniques, but there were no significant differences between groups. CONCLUSION: Within the limitations of this study, injection molding resulted in a slightly less increase of vertical dimension of occlusion than conventional polymerization techniques, the difference being significant for Microbase compared with the conventional Trevalon control.

Keenan PL; Radford DR; Clark RK

2003-01-01

 
 
 
 
21

Process and mold for molding foamed plastic articles  

Energy Technology Data Exchange (ETDEWEB)

A method for forming foamed plastic articles which includes the steps of closing a mold; prepressurizing the mold cavity with gas to prevent premature diffusion of blowing gas from the material injected into the cavity; injecting a short shot of molten synthetic resin material containing a blowing agent into the cavity; venting a portion of the prepressurization gas during the injection step; and venting the remaining prepressurization gas from the mold cavity to a vacuum chamber means to allow expansion of the injected foamable resin material within the mold cavity, the vacuum drawing the resin material throughout the mold cavity. In addition, the vacuum chamber is coupled to the mold cavity through plural spaced passageways so that the vacuum is drawn at various locations throughout the cavity to thereby enhance the complete filling of the cavity with the injected material as it expands. The mold is vented following the injection step automatically at the expiration of a predetermined time following the closing of a nozzle of the injection apparatus. A mold for carrying out the process includes improved gas flow means for delivering gas to and venting gas from the mold cavity. The mold also includes improved sealing means for sealing the mold to maintain it in a pressurized state as desired.

Baumrucker, E.J.

1984-10-30

22

Dynamic Feed Control For Injection Molding  

Energy Technology Data Exchange (ETDEWEB)

The invention provides methods and apparatus in which mold material flows through a gate into a mold cavity that defines the shape of a desired part. An adjustable valve is provided that is operable to change dynamically the effective size of the gate to control the flow of mold material through the gate. The valve is adjustable while the mold material is flowing through the gate into the mold cavity. A sensor is provided for sensing a process condition while the part is being molded. During molding, the valve is adjusted based at least in part on information from the sensor. In the preferred embodiment, the adjustable valve is controlled by a digital computer, which includes circuitry for acquiring data from the sensor, processing circuitry for computing a desired position of the valve based on the data from the sensor and a control data file containing target process conditions, and control circuitry for generating signals to control a valve driver to adjust the position of the valve. More complex embodiments include a plurality of gates, sensors, and controllable valves. Each valve is individually controllable so that process conditions corresponding to each gate can be adjusted independently. This allows for great flexibility in the control of injection molding to produce complex, high-quality parts.

Kazmer, David O. (San Francisco, CA)

1996-09-17

23

From Process Modeling to Elastic Property Prediction for Long-Fiber Injection-Molded Thermoplastics  

International Nuclear Information System (INIS)

This paper presents an experimental-modeling approach to predict the elastic properties of long-fiber injection-molded thermoplastics (LFTs). The approach accounts for fiber length and orientation distributions in LFTs. LFT samples were injection-molded for the study, and fiber length and orientation distributions were measured at different locations for use in the computation of the composite properties. The current fiber orientation model was assessed to determine its capability to predict fiber orientation in LFTs. Predicted fiber orientations for the studied LFT samples were also used in the calculation of the elastic properties of these samples, and the predicted overall moduli were then compared with the experimental results. The elastic property prediction was based on the Eshelby-Mori-Tanaka method combined with the orientation averaging technique. The predictions reasonably agree with the experimental LFT data.

2007-01-01

24

From Process Modeling to Elastic Property Prediction for Long-Fiber Injection-Molded Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper presents an experimental-modeling approach to predict the elastic properties of long-fiber injection-molded thermoplastics (LFTs). The approach accounts for fiber length and orientation distributions in LFTs. LFT samples were injection-molded for the study, and fiber length and orientation distributions were measured at different locations for use in the computation of the composite properties. The current fiber orientation model was assessed to determine its capability to predict fiber orientation in LFTs. Predicted fiber orientations for the studied LFT samples were also used in the calculation of the elastic properties of these samples, and the predicted overall moduli were then compared with the experimental results. The elastic property prediction was based on the Eshelby-Mori-Tanaka method combined with the orientation averaging technique. The predictions reasonably agree with the experimental LFT data

Nguyen, Ba Nghiep; Kunc, Vlastimil; Frame, Barbara J.; Phelps, Jay; Tucker III, Charles L.; Bapanapalli, Satish K.; Holbery, James D.; Smith, Mark T.

2007-09-13

25

Injection-molded PZT actuators  

Science.gov (United States)

Ceramics injection molding technology is being adapted for the fabrication of net shape piezoelectric actuators of lead zirconate titanate (PZT) and lead magnesium niobate (PMN). INjection molding offers low cost, high quality actuator components with a high degree of part-of-part reproducibility. Configurations under investigation include a proprietary high displacement linear element, air acoustic actuators, tube array actuators, benders, and various multilayer designs. Applications include conformable unidirectional patches for active noise and vibration control, high displacement bender actuators for active vortex generators and synthetic jets, high force-high displacement actuators for rotorblade flaps, and air acoustic actuators for active noise reduction.

Near, Craig D.; Schmidt, Gerald; McNeal, Kelley; Gentilman, Richard L.

1998-06-01

26

Dynamic of taking out molding parts at injection molding  

Directory of Open Access Journals (Sweden)

Full Text Available Most plastic parts used in automobile production are manufactured by injection molding. Their quality depends also on taking out molding and on the manipulators for it. Task of this contribution is to theoretically describe a transport of molding at taking out after injection molding in relation on its regulation. The following quantities are derived at it: the transition characteristic of the taking out system, the blocking diagram of taking out molding regulation, the amplitude and phase characteristic and the transition characteristic of action quantity at taking out molding regulation.

E. Ragan; J. Dobránsky; P. Baron; M. Ko?iško; J. Svetlík

2012-01-01

27

Automatic polishing process of plastic injection molds on a 5-axis milling center  

CERN Multimedia

The plastic injection mold manufacturing process includes polishing operations when surface roughness is critical or mirror effect is required to produce transparent parts. This polishing operation is mainly carried out manually by skilled workers of subcontractor companies. In this paper, we propose an automatic polishing technique on a 5-axis milling center in order to use the same means of production from machining to polishing and reduce the costs. We develop special algorithms to compute 5-axis cutter locations on free-form cavities in order to imitate the skills of the workers. These are based on both filling curves and trochoidal curves. The polishing force is ensured by the compliance of the passive tool itself and set-up by calibration between displacement and force based on a force sensor. The compliance of the tool helps to avoid kinematical error effects on the part during 5-axis tool movements. The effectiveness of the method in terms of the surface roughness quality and the simplicity of impleme...

Pessoles, Xavier; 10.1016/j.jmatprotec.2008.08.034

2010-01-01

28

Modeling and Analysis of Process Parameters for Evaluating Shrinkage Problems During Plastic Injection Molding of a DVD-ROM Cover  

Science.gov (United States)

Plastic injection molding plays a key role in the production of high-quality plastic parts. Shrinkage is one of the most significant problems of a plastic part in terms of quality in the plastic injection molding. This article focuses on the study of the modeling and analysis of the effects of process parameters on the shrinkage by evaluating the quality of the plastic part of a DVD-ROM cover made with Acrylonitrile Butadiene Styrene (ABS) polymer material. An effective regression model was developed to determine the mathematical relationship between the process parameters (mold temperature, melt temperature, injection pressure, injection time, and cooling time) and the volumetric shrinkage by utilizing the analysis data. Finite element (FE) analyses designed by Taguchi (L27) orthogonal arrays were run in the Moldflow simulation program. Analysis of variance (ANOVA) was then performed to check the adequacy of the regression model and to determine the effect of the process parameters on the shrinkage. Experiments were conducted to control the accuracy of the regression model with the FE analyses obtained from Moldflow. The results show that the regression model agrees very well with the FE analyses and the experiments. From this, it can be concluded that this study succeeded in modeling the shrinkage problem in our application.

Öktem, H.

2012-01-01

29

Hollow gas injection technology for plastic molding (AGI process). Plastic no chuku shashutsu seikei gijutsu (AGI ho)  

Energy Technology Data Exchange (ETDEWEB)

The whole field of hollow injection molding technology is explained, and the feature of AGI (Asahi gas injection) is described. The principle of hollow injection molding technology is the introduction of pressurized gas into the molding in a metal mold to perform cooling while the gas pressure is maintained. Hollow injection is the most suitable technology for the elimination of drops and mold cavities, and the flexibility in the product design can be markedly improved. Nitrogen which is inert and low-cost is usually used as the pressurized gas. The AGI patent is concerned with a method of injecting gas from the same inlet for the resin flow channel. Molded products with no external flaw can be obtained, and the gas can be recovered. Thermoplastic resin which can be used for injection molding is basically used as the resin for hollow injection molding. There is no fundamental factor which will cause restriction to the applied products. The future aspect for AGI molding technology is discussed. 4 refs., 11 figs.

Hattori, K. (Asahi Chemical Industry Co. Ltd., Osaka (Japan))

1991-11-01

30

Progress in Titanium Metal Powder Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM) that must be simultaneously satisfied—density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

Randall M. German

2013-01-01

31

Influence of different process settings conditions on the accuracy of micro injection molding simulations: an experimental validation  

DEFF Research Database (Denmark)

Currently available software packages exhibit poor results accuracy when performing micro injection molding (µIM) simulations. However, with an appropriate set-up of the processing conditions, the quality of results can be improved. The effects on the simulation results of different and alternative process conditions are investigated, namely the nominal injection speed, as well as the cavity filling time and the evolution of the cavity injection pressure as experimental data. In addition, the sensitivity of the results to the quality of the rheological data is analyzed. Simulated results are compared with experiments in terms of flow front position at part and micro features levels, as well as cavity injection filling time measurements.

Tosello, Guido; Gava, Alberto

2009-01-01

32

Various high functional sintered materials by injection molding process; Shashutsu seikei process wo mochiita kakushu kokino shoketsu zairyo  

Energy Technology Data Exchange (ETDEWEB)

Since the Metal Injection Molding (MIM) process can offer full dense and net shaping of the three dimensional complicated parts regardless of the soft and hard metals, it can be said that it is one of the new metal processing techniques further advanced to the common power metallurgy process. Authors correctly controlled the amount of carbon and structures by using the new MIM process based on the environmental control during the de-binder (during heat-volatilizing after the solvent extraction) and sintering, finally developed a sintered material with extremely high performance, which was difficult to obtain by the common power metallurgy process. In this paper, the ferrous composite materials showing a good sliding characteristic were introduced by only adding a minority of TiN and CaF2 powers into the MIM sintered alloy steel (various stainless steel, high speed steel, maraging steel, 4100 steel, 4600 steel), high performance soft magnetic steel (Fe-Ni, Fe-Si and Sendust), and low alloy steel developed by using the MIM process. 15 refs., 12 figs., 1 tab.

Miura, H. [Kumamoto Univ. (Japan). Faculty of Engineering

1998-05-15

33

Validation of three-dimensional micro injection molding simulation accuracy  

DEFF Research Database (Denmark)

Data analysis and simulations on micro-molding experiments have been conducted. Micro molding simulations have been executed taking into account actual processing conditions implementation in the software. Various aspects of the simulation set-up have been considered in order to improve the simulation accuracy (i.e. decrease deviations from experimental values): injection speed profile, cavity injection pressure, melt and mold temperatures, three-dimensional mesh parameters, and material rheological characterization. Quality factors investigated for the quantitative comparisons were: short shot length, injection pressure profile, molding mass and flow pattern. The importance of calibrated micro molding process monitoring for an accurate implementation strategy of the simulation and its validation has been demonstrated. In fact, inconsistencies and uncertainties in the experimental data must be minimized to avoid introducing uncertainties in the simulation calculations. Simulations of bulky sub-100 milligrams micro molded parts have been validated and a methodology for accurate micro molding simulations was established.

Tosello, Guido Technical University of Denmark,

2011-01-01

34

Modelling and monitoring in injection molding  

DEFF Research Database (Denmark)

This thesis is concerned with the application of statistical methods in quality improvement of injection molded parts. The methods described are illustrated with data from the manufacturing of parts for a medical device. The emphasis has been on the variation between cavities in multi-cavity molds. >From analysis of quality measurements from a longer period of manufacturing, it was found that differences in cavities was that source of variation with greatest influence on the lenght of the molded parts. The other large contribution to the lenght varation was the different machine settings. Samples taken within the same machine set-point did not cause great variation compared to the two preceding sources of variation. A simple graphical approach is suggested for finding patterns in the cavity differences. Applying this method to data from a 16 cavity mold, a clear connection was found between a parts lenght and the producing cavitys position in the mold. In a designed expriment it was possible to isolate the machine parameters contributing to the variation beteeen cavities. Thus, with a proper choice of levels for the machine variables, it was possible to reduce the varation between cavities substantially. Also an alternative model for the shrinkage of parts from a multi-cavity mold is suggested. From applying the model to data from a shringage study, it seemed that the observed part differences were not only due to differences in cavity dimensions. A model for the in-control varation for a multi-cavity molding process was suggested. Based on this model, control charting proceures have been suggested for monitoring the quality of the molded parts. Moreover, a capability index for multi-cavity molds has been suggested. Furthermore an alternative method for in-line quality charting is suggested. The method is for continuous control by attributes, and it is an alternative to the batch oriented approach mostly used. The procedure is especially efficient for quality requirements of very low proportion non-conformities. For the proposed charts the ARL function is derived. It is shown that in the case where a non-conforning unit is only expected very rarely during sampling, a moving sum chart and a CUSUM chart are equivalent. Finally, the correlation structure of 21 process variables has been studied prior to monitoring the process. Is is illustrated how the process can be analysed with multivariate techniques. It was found that two principal components reflected changes in machine set-points. Thus, there seems to be great potential in monitoring the process variables using a multivariate approach.

Thyregod, Peter

2001-01-01

35

Injection molding of high aspect ratio sub-100 nm nanostructures  

DEFF Research Database (Denmark)

We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increasing the replication fidelity. Surface coating of the nickel molds with a fluorocarbon-containing thin film (FDTS) greatly enhanced the quality of replicated features, in particular at transient mold temperatures above Tg. Injection molding using the latter mold temperature regime resulted in a bimodal distribution of pillar heights, corresponding to either full or very poor replication of the individual pillars. The poorly replicated structures on nickel molds with or without FDTS coatings all appeared fractured. We investigated the underlying mechanism in a macroscopic model system and found reduced wetting and strongly decreased adhesion of solidified COC droplets on nickel surfaces after coating with FDTS. Reduced adhesion forces are consistent with lowered friction that reduces the risk of fracturing the nanoscopic pillars during demolding. Optimized mold surface chemistry and associated injection molding conditions permitted the fabrication of square arrays of 40 nm wide and 107 nm high (aspect ratio >2.5) pillars on a 200 nm pitch.

Matschuk, Maria; Larsen, Niels B

2013-01-01

36

Injection molding of high aspect ratio sub-100 nm nanostructures  

Science.gov (United States)

We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increasing the replication fidelity. Surface coating of the nickel molds with a fluorocarbon-containing thin film (FDTS) greatly enhanced the quality of replicated features, in particular at transient mold temperatures above Tg. Injection molding using the latter mold temperature regime resulted in a bimodal distribution of pillar heights, corresponding to either full or very poor replication of the individual pillars. The poorly replicated structures on nickel molds with or without FDTS coatings all appeared fractured. We investigated the underlying mechanism in a macroscopic model system and found reduced wetting and strongly decreased adhesion of solidified COC droplets on nickel surfaces after coating with FDTS. Reduced adhesion forces are consistent with lowered friction that reduces the risk of fracturing the nanoscopic pillars during demolding. Optimized mold surface chemistry and associated injection molding conditions permitted the fabrication of square arrays of 40 nm wide and 107 nm high (aspect ratio >2.5) pillars on a 200 nm pitch.

Matschuk, Maria; Larsen, Niels B.

2013-02-01

37

Injection-molded nanocomposites and materials based on wheat gluten.  

UK PubMed Central (United Kingdom)

This is, to our knowledge, the first study of the injection molding of materials where wheat gluten (WG) is the main component. In addition to a plasticizer (glycerol), 5 wt.% natural montmorillonite clay was added. X-ray indicated intercalated clay and transmission electron microscopy indicated locally good clay platelet dispersion. Prior to feeding into the injection molder, the material was first compression molded into plates and pelletized. The filling of the circular mold via the central gate was characterized by a divergent flow yielding, in general, a stronger and stiffer material in the circumferential direction. It was observed that 20-30 wt.% glycerol yielded the best combination of processability and mechanical properties. The clay yielded improved processability, plate homogeneity and tensile stiffness. IR spectroscopy and protein solubility indicated that the injection molding process yielded a highly aggregated structure. The overall conclusion was that injection molding is a very promising method for producing WG objects.

Cho SW; Gällstedt M; Johansson E; Hedenqvist MS

2011-01-01

38

IMAGE ANALYSIS DEDICATED TO POLYMER INJECTION MOLDING  

Directory of Open Access Journals (Sweden)

Full Text Available This work follows the general framework of polymer injection moulding simulation whose objectives are the mastering of the injection moulding process. The models of numerical simulation make it possible to predict the propagation of the molten polymer during the filling phase from the positioning of one point of injection or more. The objective of this paper is to propose a particular way to optimize the geometry of mold cavity in accordance with physical laws. A direct correlation is pointed out between geometric parameters issued from skeleton transformation and Hausdorff's distance and results provided by implementation of a classical model based on the Hele-Shaw equations which are currently used in the main computer codes of polymer injection.

David Garcia; Guy Courbebaisse; Michel Jourlin

2001-01-01

39

CENTRAL CONVEYING & AUTO FEEDING SYSTEMS FOR AN INJECTION MOLDING SHOP  

Directory of Open Access Journals (Sweden)

Full Text Available Nowadays injection molding is probably the most important method of Processing of consumer and industrial goods, and is performed everywhere in the world. The developing of injection molding becomes a competition from day to day. This Process now integrated with computer control make the production better in quality and Better quantity. The trends of producing a plastics product in injection molding industries are recently changing from traditional method to using the FEA analysis. For injection molding industries, time and cost is very important aspects to consider because these two aspectswill directly related to the profits at a company. The next issue toconsider, to get the best parameter for the injection molding process, plastics has been waste. Through the experiment, operator will use large amount of plastics material to get the possibly parameters to setup the machine.To produce the parts with better quality and quantity these molding defects are the major obstacles in achieving the targets with quality & quantity. Various defects like Short shot, colour streaks and low productivity rates are associated with the material mixing and feeding as molded plastics are often a blend of two or more materials. Colors (master batch) and other additives are often mixed (blended) with the raw plastic material prior to the molding process in molding plants. So it is very necessary to work out auto blending and auto feeding of plasticgranules to the machine hopper. This paper will cover the studyof automatic blending unit & central conveying system for plasticgranule feeding to machine & will help in optimizing the injection molding process.

Sanjeev Kumar; Ashu Yadav; Prof. Mohd. Parvez

2011-01-01

40

Gastroresistant capsular device prepared by injection molding.  

Science.gov (United States)

In the present work, the possibility of manufacturing by injection molding (IM) a gastro-resistant capsular device based on hydroxypropyl methyl cellulose acetate succinate (HPMCAS) was investigated. By performing as an enteric soluble container, such a device may provide a basis for the development of advantageous alternatives to coated dosage forms. Preliminarily, the processability of the selected thermoplastic polymer was evaluated, and the need for a plasticizer (polyethylene glycol 1500) in order to counterbalance the glassy nature of the molded items was assessed. However, some critical issues related to the physical/mechanical stability (shrinkage and warpage) and opening time of the device after the pH change were highlighted. Accordingly, an in-depth formulation study was carried out taking into account differing release modifiers potentially useful for enhancing the dissolution/disintegration rate of the capsular device at intestinal pH values. Capsule prototypes with thickness of 600 and 900 ?m containing Kollicoat(®) IR and/or Explotab(®) CLV could be manufactured, and a promising performance was achieved with appropriate gastric resistance in pH 1.2 medium and break-up in pH 6.8 within 1h. These results would support the design of a dedicated mold for the development of a scalable manufacturing process. PMID:22683648

Zema, Lucia; Loreti, Giulia; Melocchi, Alice; Maroni, Alessandra; Palugan, Luca; Gazzaniga, Andrea

2012-06-05

 
 
 
 
41

Gastroresistant capsular device prepared by injection molding.  

UK PubMed Central (United Kingdom)

In the present work, the possibility of manufacturing by injection molding (IM) a gastro-resistant capsular device based on hydroxypropyl methyl cellulose acetate succinate (HPMCAS) was investigated. By performing as an enteric soluble container, such a device may provide a basis for the development of advantageous alternatives to coated dosage forms. Preliminarily, the processability of the selected thermoplastic polymer was evaluated, and the need for a plasticizer (polyethylene glycol 1500) in order to counterbalance the glassy nature of the molded items was assessed. However, some critical issues related to the physical/mechanical stability (shrinkage and warpage) and opening time of the device after the pH change were highlighted. Accordingly, an in-depth formulation study was carried out taking into account differing release modifiers potentially useful for enhancing the dissolution/disintegration rate of the capsular device at intestinal pH values. Capsule prototypes with thickness of 600 and 900 ?m containing Kollicoat(®) IR and/or Explotab(®) CLV could be manufactured, and a promising performance was achieved with appropriate gastric resistance in pH 1.2 medium and break-up in pH 6.8 within 1h. These results would support the design of a dedicated mold for the development of a scalable manufacturing process.

Zema L; Loreti G; Melocchi A; Maroni A; Palugan L; Gazzaniga A

2013-01-01

42

Polyethylene ionomer-based nano-composite foams prepared by a batch process and MuCell injection molding  

International Nuclear Information System (INIS)

[en] To understand the correlation between foamability and melt rheology of polyethylene-based ionomers having different degrees of the neutralization and corresponding nano-composites, we have conducted the foam processing via a batch process in an autoclave and microcellular foam injection molding (FIM) process using the MuCell technology. We have discussed the obtainable morphological properties in both foaming processes. All cellular structures were investigated by using field emission scanning electron microscopy. The competitive phenomenon between the cell nucleation and the cell growth including the coalescence of cell was discussed in light of the interfacial energy and the relaxation rate as revealed by the modified classical nucleation theory and rheological measurement, respectively. The FIM process led to the opposite behavior in the cell growth and coalescence of cell as compared with that of the batch process, where the ionic cross-linked structure has significant contribution to retard the cell growth and coalescence of cell. The mechanical properties of the structural foams obtained by FIM process were discussed.

2010-01-01

43

Computer-aided injection molding system  

Science.gov (United States)

Achievements are reported in cavity-filling simulation, modeling viscoelastic effects, measuring and predicting frozen-in birefringence in molded parts, measuring residual stresses and associated mechanical properties of molded parts, and developing an interactive mold-assembly design program and an automatic NC maching data generation and verification program. The Cornell Injection Molding Program (CIMP) consortium is discussed as are computer user manuals that have been published by the consortium. Major tasks which should be addressed in future efforts are listed, including: (1) predict and experimentally determine the post-fillin behavior of thermoplastics; (2) simulate and experimentally investigate the injection molding of thermosets and filled materials; and (3) further investigate residual stresses, orientation and mechanical properties.

Wang, K. K.; Shen, S. F.; Cohen, C.; Hieber, C. A.; Isayev, A. I.

1982-10-01

44

Two component micro injection molding for MID fabrication  

DEFF Research Database (Denmark)

Molded Interconnect Devices (MIDs) are plastic substrates with electrical infrastructure. The fabrication of MIDs is usually based on injection molding and different process chains may be identified from this starting point. The use of MIDs has been driven primarily by the automotive sector, but recently the medical sector seems more and more interested. In particular the possibility of miniaturization of 3D components with electrical infrastructure is attractive. The paper describes possible manufacturing routes and challenges of miniaturized MIDs based on two component micro injection molding and subsequent metallization. The technology will be demonstrated by an industrial component.

Islam, Mohammad Aminul; Hansen, Hans NØrgaard

2009-01-01

45

CAE for Injection Molding - Past, Present and the Future  

Science.gov (United States)

It is well known that injection molding is the most effective process for mass-producing discrete plastic parts of complex shape to the highest precision at the lowest cost. However, due to the complex property of polymeric materials undergoing a transient non-isothermal process, it is equally well recognized that the quality of final products is often difficult to be assured. This is particularly true when a new mold or material is encountered. As a result, injection molding has often been viewed as an art than a science. During the past few decades, numerical simulation of injection molding process based on analytic models has become feasible for practical use as computers became faster and cheaper continually. A research effort was initiated at the Cornell Injection Molding Program (CIMP) in 1974 under a grant from the National Science Foundation. Over a quarter of the century, CIMP has established some scientific bases ranging from materials characterization, flow analysis, to prediction of part quality. Use of such CAE tools has become common place today in industry. Present effort has been primarily aimed at refinements of many aspects of the process. Computational efficiency and user-interface have been main thrusts by commercial software developers. Extension to 3-dimensional flow analysis for certain parts has drawn some attention. Research activities are continuing on molding of fiber-filled materials and reactive polymers. Expanded molding processes such as gas-assisted, co-injection, micro-molding and many others are continually being investigated. In the future, improvements in simulation accuracy and efficiency will continue. This will include in-depth studies on materials characterization. Intelligent on-line process control may draw more attention in order to achieve higher degree of automation. As Internet technology continues to evolve, Web-based CAE tools for design, production, remote process monitoring and control can come to path. The CAE tools will eventually be integrated into an Enterprise Resources Planning (ERP) system as the trend of enterprise globalization continues.

Wang, Kuo K.

2004-06-01

46

Numerical simulation of transport processes in injection mold-filling during production of a cylindrical object under isothermal and non-isothermal conditions  

Energy Technology Data Exchange (ETDEWEB)

In this paper, numerical simulation of injection mold-filling during the production of a cylindrical object under isothermal and non-isothermal conditions is presented. The material of the object is low density polyethylene (LDPE) following power-law viscosity model for non-zero shear rate zone. However, where shear rate becomes zero, zero-shear viscosity value has been used. Three cases have been considered, namely (1) Isothermal filling at constant injection pressure, (2) Isothermal filling at constant flow rate, and (3) Non-isothermal filling at constant flow rate. For the case-(3), the viscosity of LDPE is also a function of temperature. The material of the mold is steel. For the non-isothermal filling, the concept of melt-mold thermal contact resistance coefficient has been incorporated in the model. The length and diameter of the body in all three cases have been taken as 0.254 m and 0.00508 m respectively. The finite-difference method has been used to solve the governing differential equations for the processes. The results show excellent agreement with the corresponding equations for the processes. The results show excellent agreement with the corresponding analytical solutions for the first two cases showing the correctness of the numerical method. The simulation results for non-isothermal filling show physically realistic trends and lend insight into various important aspects of mold-filling including frozen skin layer.

Kumar, A.; Ghoshdastidar, P.S.

1999-07-01

47

Stability of FDTS monolayer coating on aluminum injection molding tools  

DEFF Research Database (Denmark)

The injection molding industry often employs prototype molds and mold inserts from melt spun (rapid solidification processing [1,2]) aluminum, especially for applications in optics [3,4], photonics [5] and microfludics. Prototypes are also used for verification of mold filling. The use of aluminum tools has reduced lead time (days instead of weeks) and manufacturing cost (30% of conventional mold). Moreover, for aluminum, a surface roughness (RMS) below 5 nm can be obtained with diamond machining [3,4,6]. Conventional mold coatings add cost and complexity, and coatings with thicknesses of a few microns can obliterate small features. The nanoimprint lithography community extensively uses functional monolayer coatings on silicon/SiO2 lithographic stamps [7–11]. This treatment dramatically reduces stiction, and improves yield and quality of replicated nanostructures. Here we report on a fluorinated trichloro-silane based coating deposited on aluminum or its alloys by molecular vapor deposition. Wehave tested the stability of this coating in challenging conditions of injection molding, an environment with high shear stress from the molten polymer, pressures up to 200 MPa, temperatures up to 250 ?C, and rapid thermal cycling.

Cech, Jiri; Taboryski, Rafael J.

2012-01-01

48

Assessment of Current Process Modeling Approaches to Determine Their Limitations, Applicability and Developments Needed for Long-Fiber Thermoplastic Injection Molded Composites  

Energy Technology Data Exchange (ETDEWEB)

This report describes the status of the current process modeling approaches to predict the behavior and flow of fiber-filled thermoplastics under injection molding conditions. Previously, models have been developed to simulate the injection molding of short-fiber thermoplastics, and an as-formed composite part or component can then be predicted that contains a microstructure resulting from the constituents’ material properties and characteristics as well as the processing parameters. Our objective is to assess these models in order to determine their capabilities and limitations, and the developments needed for long-fiber injection-molded thermoplastics (LFTs). First, the concentration regimes are summarized to facilitate the understanding of different types of fiber-fiber interaction that can occur for a given fiber volume fraction. After the formulation of the fiber suspension flow problem and the simplification leading to the Hele-Shaw approach, the interaction mechanisms are discussed. Next, the establishment of the rheological constitutive equation is presented that reflects the coupled flow/orientation nature. The decoupled flow/orientation approach is also discussed which constitutes a good simplification for many applications involving flows in thin cavities. Finally, before outlining the necessary developments for LFTs, some applications of the current orientation model and the so-called modified Folgar-Tucker model are illustrated through the fiber orientation predictions for selected LFT samples.

Nguyen, Ba Nghiep; Holbery, Jim; Smith, Mark T.; Kunc, Vlastimil; Norris, Robert E.; Phelps, Jay; Tucker III, Charles L.

2006-11-30

49

Respiratory symptoms associated with the use of azodicarbonamide foaming agent in a plastics injection molding facility.  

UK PubMed Central (United Kingdom)

Respiratory health variables were studied cross-sectionally in 227 employees of a plastics molding facility where numerous complaints had been apparently associated with the use of azodicarbonamide foaming agent in injection molding. Pre- and postshift respiratory status measures and azodicarbonamide concentrations were also obtained for 17 employees. Cross-sectional pulmonary function differences by injection molding status were not observed. Modest decrements in pulmonary function measures were observed between start and end of shift but with no dose-effect relationship. A strong association was observed for injection molding workers for eye/nose/throat irritation, cough, and wheezing. Additionally, wheezing, chest tightness, and symptoms of chronic bronchitis were strongly associated with work in injection molding during periods in which azodicarbonamide was in use. These results suggest respiratory symptom causation by some combination of azodicarbonamide itself, reaction products of azodicarbonamide formed during injection molding, or other unidentified agents uniquely associated with the process of injection molding with azodicarbonamide foaming agent.

Whitehead LW; Robins TG; Fine LJ; Hansen DJ

1987-01-01

50

Respiratory symptoms associated with the use of azodicarbonamide foaming agent in a plastics injection molding facility.  

Science.gov (United States)

Respiratory health variables were studied cross-sectionally in 227 employees of a plastics molding facility where numerous complaints had been apparently associated with the use of azodicarbonamide foaming agent in injection molding. Pre- and postshift respiratory status measures and azodicarbonamide concentrations were also obtained for 17 employees. Cross-sectional pulmonary function differences by injection molding status were not observed. Modest decrements in pulmonary function measures were observed between start and end of shift but with no dose-effect relationship. A strong association was observed for injection molding workers for eye/nose/throat irritation, cough, and wheezing. Additionally, wheezing, chest tightness, and symptoms of chronic bronchitis were strongly associated with work in injection molding during periods in which azodicarbonamide was in use. These results suggest respiratory symptom causation by some combination of azodicarbonamide itself, reaction products of azodicarbonamide formed during injection molding, or other unidentified agents uniquely associated with the process of injection molding with azodicarbonamide foaming agent. PMID:3812500

Whitehead, L W; Robins, T G; Fine, L J; Hansen, D J

1987-01-01

51

Long fiber polymer composite property calculation in injection molding simulation  

Science.gov (United States)

Long fiber filled polymer composite materials have attracted a great attention and usage in recent years. However, the injection and compression molded long fiber composite materials possess complex microstructures that include spatial variations in fiber orientation and length. This paper presents the recent implemented anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation distribution[1] and a newly developed fiber breakage model[2] for predicting fiber length distribution in injection and compression molding simulation, and Eshelby-Mori-Tanaka model[3,4] with fiber-matrix de-bonding model[5] have been implemented to calculate the long fiber composite property distribution with predicted fiber orientation and fiber length distributions. A validation study on fiber orientation, fiber breakage and mechanical property distributions are given with injection molding process simulation.

Jin, Xiaoshi; Wang, Jin; Han, Sejin

2013-05-01

52

The use of variable speed drives to retrofit hydraulic injection molding machines  

Energy Technology Data Exchange (ETDEWEB)

Injection molding is a common method of plastic processing in which thermoplastic materials can be molded into arbitrary complex shapes. Most injection molding machines use complicated hydraulic systems to perform the necessary work of the process. Hydraulic system flow and pressure requirements vary throughout the cycle and in many cases, excess fluid that is not required by the process is throttled back to the reservoir, wasting motor energy and producing additional thermal load on the cooling system. Variable speed drives can be used to allow injection molding machine hydraulic systems to vary the amount of fluid being pumped and thus reduce the amount of fluid that is throttled reducing the amount of wasted energy. This article discusses injection molding machine processes and develops a protocol for assessing the efficacy of variable speed drive retrofits for hydraulic injection molding machines.

Ambs, L.; Frerker, M.M. [Univ. of Massachusetts, Amherst, MA (United States)

1998-06-01

53

A Recurrent Neural Network for Warpage Prediction in Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available Injection molding is classified as one of the most flexible and economical manufacturing processes with high volumeof plastic molded parts. Causes of variations in the process are related to the vast number of factors acting during aregular production run, which directly impacts the quality of final products. A common quality trouble in finishedproducts is the presence of warpage. Thus, this study aimed to design a system based on recurrent neural networksto predict warpage defects in products manufactured through injection molding. Five process parameters areemployed for being considered to be critical and have a great impact on the warpage of plastic components. Thisstudy used the finite element analysis software Moldflow to simulate the injection molding process to collect data inorder to train and test the recurrent neural network. Recurrent neural networks were used to understand the dynamicsof the process and due to their memorization ability, warpage values might be predicted accurately. Results show thedesigned network works well in prediction tasks, overcoming those predictions generated by feedforward neuralnetworks.

A. Alvarado-Iniesta; D.J. Valles-Rosales; J.L. García-Alcaraz; A. Maldonado-Macias

2012-01-01

54

Binder Removal from Powder Injection Molded 316L Stainless Steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study reports the results of preparation of 316L stainless steel polymer based injection molded feed stock, rheology of feed stock and injection molding. The plastic binder was extracted from molded samples. The binder extraction was carried out in two steps: by solvent and thermal techniques. ...

Muhammad Rafi Raza; Faiz Ahmad; M.A. Omar; R.M. German

55

Development of TiAl-type intermetallic compounds by metal powder injection molding process; Kinzoku funmatsu shashutsu seikei ni yoru TiAl kinzokukan kagobutsu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Since a TiAl-type intermetallic compound (TiAl) has an excellent high temperature strength and corrosion resistance, in addition to light weight, it is expected to be applicable to the engine parts. However, it is difficult for TiAl to produce a part with a complex shape, and considerable cost will be required. In this study, it was tried to develop a technology for producing TiAl products with high density and high efficiency by using metal powder injection molding (MIM) process. Several kinds of TiAl alloy powders made by the self-propagating high temperature synthesis process were mixed with an organic binder, kneaded and then injection-molded into tensile specimens. These compacts were subjected to the treatment for removing the binder and sintering, resulted in a relative density as high as 97%. By room and high temperature tensile tests, it was found that, Ti-47.4Al-2.6Cr (at%) has the strength and ductility as those of the conventional processed materials. (author)

Terauchi, S.; Teraoka, T.; Shinkuma, T. [Osakayakin Kogyo Co. Ltd., Osaka (Japan); Sugimoto, T. [Kansai University, Osaka (Japan). Faculty of Engineering

2000-12-15

56

Preparation and Characterization of Copper Feedstock for Metal Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available Powder loading is one of the most critical factors which have important influence on metal injection molding processes. In this study, four different loading feedstocks were prepared from gas atomized copper powder with wax-based binders. Mixes of four feedstocks with 2 Vol. % incremental powders loading from 55% to 61 Vol. % were carried out in a Z-blade mixer. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal from the samples and then the sintering process take place in argon gas at 900°C. It was observed that the feedstock containing 59 Vol. % of copper produce a free defect samples which was selected as the optimum feedstock.

G. Goudah; F. Ahmad; O. Mamat; Mohd. Afian Omar

2010-01-01

57

Microcellular injection-molding of polylactide with chain-extender  

International Nuclear Information System (INIS)

The effects of adding an epoxy-based chain-extender (CE) on the properties of injection-molded solid and microcellular polylactide (PLA) were studied. PLA and PLA with 8 wt.% CE (PLA-CE) were melt-compounded using a twin-screw extruder. Solid and microcellular specimens were produced via a conventional and microcellular injection-molding process, respectively. Various characterization techniques including gel permeation chromatography, tensile testing and dynamic mechanical analysis, scanning electron microscopy and differential scanning calorimetry were applied to study the molecular weight, static and dynamic mechanical properties, cell morphology, and crystallization behavior, respectively. The addition of CE enhanced the molecular weight but decreased the crystallinity of PLA. The addition of CE also reduced the cell size and increased the cell density. Furthermore, the decomposition temperatures and several tensile properties, including specific strength, specific toughness, and strain-at-break of both solid and microcellular PLA specimens, increased with the addition of CE.

2009-05-05

58

Packing parameters effect on injection molding of polypropylene nanostructured surfaces  

DEFF Research Database (Denmark)

In today´s industry, applications involving surface patterning of sub-?m to nanometer scale structures have shown a high growth potential. To investigate the injection molding capability of replicating sub-?m surface texture on a large scale area, a 30x80 mm2 tool insert with surface structures having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing pressure) were investigated. The replicated surface topographies were quantitatively characterized by atomic force microscopy using specific three-dimensional surface parameters and qualitatively inspected by scanning electron microscopy. Results showed that the degree of replication from the tool to the polymer part was mainly influenced by packing pressure level and distance from the gate.

Calaon, Matteo; Tosello, Guido

2012-01-01

59

Development of magnesium semi-solid injection molding; Magnesium han`yoyu shashutsu seikei gijutsu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Magnesium semi-solid injection molding is safety and clean process. We have investigated influence of molding conditions on mechanical properties and dimension accuracy of products by semi-solid injection molding. As a result it was proved that the accuracy of products by this process is superior to die casting. This advantage as well as better mechanical properties can be utilized for net shape molding of some automobile parts. 4 refs., 8 figs., 3 tabs.

Sakamoto, K.; Sakate, N.; Ishida, K.; Yamamoto, Y.; Nishimura, K. [Mazda Motor Corp., Hiroshima (Japan)

1997-10-01

60

Fast prototyping of injection molded polymer microfluidic chips  

DEFF Research Database (Denmark)

We present fast prototyping of injection molding tools by the definition of microfluidic structures in a light-curable epoxy (SU-8) directly on planar nickel mold inserts. Optimized prototype mold structures could withstand injection molding of more than 300 replicas in cyclic olefin copolymer (COC) without any signs of failure or release. The key parameters to avoid mold failure are maximum adhesion strength of the epoxy to the nickel insert and minimum interfacial energy of the epoxy pattern to the molded polymer. Optimal molding of microstructures with vertical sidewalls was found for nickel inserts pre-coated by silicon oxide before applying the structured epoxy, followed by coating of the epoxy by a fluorocarbon layer prior to injection molding. Further improvements in the mold stability were observed after homogeneous coating of the patterned epoxy by a second reflowed layer of epoxy, likely due to the resulting reduction in sidewall steepness. We employed the latter method for injection molding bondable polymer microfluidic chips with integrated conducting polymer electrode arrays that permitted the culture and on-chip analysis of cell spreading by impedance spectroscopy.

Hansen, Thomas Steen; Selmeczi, David

2010-01-01

 
 
 
 
61

Performance of powder-injection-molded W-4.9Ni-2.1Fe components  

Science.gov (United States)

A 93 wt% W heavy alloy was injection molded into standard tensile test specimens and kinetic energy penetrators. Due to the relatively high activation energy of flow (124 kJ/mol), the rheological behavior of the molten feedstock was very susceptible to temperature variation. Using die sets with constant-volume die cavities, the tensile test specimens could be formed within a wide working window, whereas the penetrator could not be molded without defects because of different jetting phenomena during molding. The penetrator could be molded successfully using a die set whose die cavity progressively expanded during molding. The parts thus formed could subsequently be processed into intact components with full density and low carbon contents (<100 ppm). Their mechanical properties were comparable to or better than those of conventionally processed tungsten heavy alloys. Additional penetration test results indicated that powder injection molding was a viable route for processing high-performance tungsten heavy alloys.

Zu, Y. S.; Chiou, Y. H.; Lin, S. T.

1996-10-01

62

Injection-molded capsular device for oral pulsatile release: development of a novel mold.  

UK PubMed Central (United Kingdom)

The development of a purposely devised mold and a newly set up injection molding (IM) manufacturing process was undertaken to prepare swellable/erodible hydroxypropyl cellulose-based capsular containers. When orally administered, such devices would be intended to achieve pulsatile and/or colonic time-dependent delivery of drugs. An in-depth evaluation of thermal, rheological, and mechanical characteristics of melt formulations/molded items made of the selected polymer (Klucel® LF) with increasing amounts of plasticizer (polyethylene glycol 1500, 5%-15% by weight) was preliminarily carried out. On the basis of the results obtained, a new mold was designed that allowed, through an automatic manufacturing cycle of 5 s duration, matching cap and body items to be prepared. These were subsequently filled and coupled to give a closed device of constant 600 ?m thickness. As compared with previous IM systems having the same composition, such capsules showed improved closure mechanism, technological properties, especially in terms of reproducibility of the shell thickness, and release performance. Moreover, the ability of the capsular container to impart a constant lag phase before the liberation of the contents was demonstrated irrespective of the conveyed formulation.

Zema L; Loreti G; Macchi E; Foppoli A; Maroni A; Gazzaniga A

2013-02-01

63

Comparative Thermal Analysis of Circular and Profiled Cooling Channels for Injection Mold Tools  

Directory of Open Access Journals (Sweden)

Full Text Available Injection Mold Thermal Management is a critical issue in plastic injection molding process and has major effects on production cycle times that is directly linked with cost and also has effects on part quality. For this reason, cooling system design has great significance for plastic products industry by injection molding. It is crucial not only to reduce molding cycle time but also it considerably affects the productivity and quality of the product. The cooling channels in injection molding have circular cross section due to the conventional manufacturing technique of drilling. In Rapid Prototyping and Tooling techniques of fabricating conformal cooling channels, the channel cross section is again circular. In circular channel, there can be a problem that the distance from the edges of channel to the cavity is not constant and it is variable even for conformal channels. This can give problem of not having even heat dissipation. In this study, injection mold designing and thermal simulations were performed and comparison is presented between molds having cooling channels of circular cross section with mold with profiled cross section channels. Thermal analysis and simulations can effectively predict the performance of circular channels as compared to profiled channels. Some concepts are also presented for the manufacturing of molds with circular and profiled channels with the use of metal filled epoxies.

K. Altaf; V.R. Raghavan; A.M.A. Rani

2011-01-01

64

Binder Removal from Powder Injection Molded 316L Stainless Steel  

Directory of Open Access Journals (Sweden)

Full Text Available This study reports the results of preparation of 316L stainless steel polymer based injection molded feed stock, rheology of feed stock and injection molding. The plastic binder was extracted from molded samples. The binder extraction was carried out in two steps: by solvent and thermal techniques. The results showed that feed stock prepared was suitable for injection molding and this was confirmed by rheology data measured by using capillary rheometer. The test samples were injection molded without physical defects. Paraffin Wax (major binder) was extracted by using solvent extraction for 300 min. The thermal debinding was performed four different heating rates rage 1-7C min-1. The SEM results showed that the PW was completely extracted from the test samples after 300 min.

Muhammad Rafi Raza; Faiz Ahmad; M.A. Omar; R.M. German

2011-01-01

65

Optimizing the Filling Time and Gate of the Injection Mold on Plastic Air Intake Manifold of Engines  

Directory of Open Access Journals (Sweden)

Full Text Available In order to acquire the best filling time, Mold trial is made by setting different injection time, or Mold flow software is used to analyze data recorded by computer. Whether doing successive trials or being simulated point by point, is very tedious. A new method is put forward-seeking the minimum of curve being simulated by Lagrange interpolation. The minimum of the curve is the best filling time. This method can improve the efficiency of the simulation analysis. The software Mold flow provides the possibility to simulate the flow processes of plastic air intake manifold with different gate location and number of injection mold and to predict the position of air traps and weld lines. The location and number of the gate in injection mold are determined by comparing analysis results and avoid mold adjustment and mold repairing. Finished injection mold of plastic air intake manifold on basis of simulation is perfect.

Shiqiang Zhang

2013-01-01

66

The use of stereolithography rapid tools in the manufacturing of metal powder injection molding parts  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The utilization of stereolithography molds in the manufacture pre-series for injection molded plastic parts aims to reduce costs throughout the product life-time, but mainly during design and manufacturing phases. The use of this Rapid Tooling technique in powder metal injection molding is evaluated in this work. One of the greatest differences between traditional and stereolithography tools is related to the heat conductivity of the materials employed. For example, steel (more) molds have a heat conductivity coefficient 300 times higher than molds made with the photosensitive resin used in the stereolithography process. The discrepancy regarding the cooling rate of the molded parts during the injection cycle must be compensated with adjustments in the injection molding parameters, such as temperature, pressure and speed. The optimization of these parameters made it possible to eject green parts from the mold without causing defects which would become evident in debinding and sintering stages. The dimensional analysis performed at the end of each case study showed that the shrinking factor of the component after the sintering had the same value obtained for components using traditional metallic molds. Moreover, the dimensional error remains under 2% which can be considered low for a pre-series of components (or prototype series).

Beal, V. E.; Ahrens, C. H.; Wendhausen, P. A.

2004-03-01

67

The use of stereolithography rapid tools in the manufacturing of metal powder injection molding parts  

Directory of Open Access Journals (Sweden)

Full Text Available The utilization of stereolithography molds in the manufacture pre-series for injection molded plastic parts aims to reduce costs throughout the product life-time, but mainly during design and manufacturing phases. The use of this Rapid Tooling technique in powder metal injection molding is evaluated in this work. One of the greatest differences between traditional and stereolithography tools is related to the heat conductivity of the materials employed. For example, steel molds have a heat conductivity coefficient 300 times higher than molds made with the photosensitive resin used in the stereolithography process. The discrepancy regarding the cooling rate of the molded parts during the injection cycle must be compensated with adjustments in the injection molding parameters, such as temperature, pressure and speed. The optimization of these parameters made it possible to eject green parts from the mold without causing defects which would become evident in debinding and sintering stages. The dimensional analysis performed at the end of each case study showed that the shrinking factor of the component after the sintering had the same value obtained for components using traditional metallic molds. Moreover, the dimensional error remains under 2% which can be considered low for a pre-series of components (or prototype series).

Beal V. E.; Ahrens C. H.; Wendhausen P. A.

2004-01-01

68

A Review of Effects of Molding Methods, Mold Thickness and Other Processing Parameters on Fiber Orientation in Polymer Composites  

Directory of Open Access Journals (Sweden)

Full Text Available In injection molded fiber reinforced composites, the mechanical and physical properties of the final product are highly dependent on the patterns of fibers alignment. The orientation of the fibers can be influenced by many factors such as molding methods, materials used, geometry of the part and other processing parameters. Thus, there is considerable interest in studying the factors that affect the fiber orientation, hence the properties of the final product. This study presented a general review on the effects of these factors on fiber orientation in injection molded fiber-reinforced polymer composites. The fiber orientation of a part made by conventional injection molding is compared with those produced by injection-compression and push-pull injection techniques. Effects of injection speed, type of flow and mold thickness on fiber orientation are also discussed. Hence, this review could assist in decisions regarding the design of composite products.

Ahmed N. Oumer; Othman Mamat

2013-01-01

69

Dental molding process  

UK PubMed Central (United Kingdom)

A procedure is disclosed for ensuring a uniform thickness in a wax sheet (18) placed over the contoured surface of a preliminary plaster cast (10) in the process of manufacturing dental prosthetics. The sheet (18) has a plurality of uniform diameter spheres (22) distributed throughout the sheet to provide tactile and visual confirmation of uniform thickness. The advantages can also be applied in the manufacture of a custom impression tray (24) or trial denture base or orthopontic retainer (25) of an acrylic material by putting particles of uniform diameter into the acrylic mix. The particles can be precured acrylic which reduces the shrinkage of the acrylic in the tray as it hardens, and maintains the structural and chemical integrity of the finished product as the filler particles chemically incorporate with the powder and liquid mix.

ELIASZ MICHAEL R

70

Aplicação das técnicas de planejamento e análise de experimentos no processo de injeção plástica Application design of experiments in the injection molding process  

Directory of Open Access Journals (Sweden)

Full Text Available Experimentos industriais são realizados pelas empresas com o intuito de melhorar o desempenho dos produtos e os processos de fabricação. Nesse sentido, este trabalho tem por objetivo estudar e aplicar as técnicas de planejamento e análise de experimentos na melhoria da qualidade industrial. Especificamente são aplicadas as técnicas de planejamento Fatorial Fracionado 2k-p, Metodologia de Superfície de Resposta e Análise de Variância, em um processo de moldagem por injeção plástica. Com essa pesquisa experimental foi possível identificar os níveis ótimos de regulagem e os parâmetros mais importantes da injeção plástica: temperatura da máquina e pressão de injeção. Para finalizar é avaliado o procedimento de implementação das técnicas de experimentação e as dificuldades práticas encontradas na empresa.Industrial experiments are made by companies in order to improve the quality characteristics of products and production processes. In this sense, the objective of this paper is to study and apply the design of experiments in the industrial quality improvement. In addition, as a part of the objective, an application of the techniques of design Fractional Factorial 2k-p, Analysis of Variance and Response Surface Methodology is done. It is focused in an injection molding process applied by a company, that makes and trades plastic products for the civil construction. Using this experimental study, the most important parameters of plastic injection are identified: machine temperature and injection pressure. At the same time, the optimal levels of adjustment of these parameters are determined. From this study, it is evaluated both the implantation procedures of the designs of experiments as well as the difficulties faced. Also, this study tries to contribute to the university-company relationship.

Edwin V. Cardoza Galdamez; Luiz C. Ribeiro Carpinetti

2004-01-01

71

Injection molding of bushes made of tribological PEEK composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polyetheretherketone (PEEK) composites have been extensively studied because of the excellent tribological behavior among plastics. However, laboratory specimens and tests are generally discussed, whereas application studies on industrial components are infrequent. In this paper, an injection molded...

72

Powder Injection Molding of Al-(Steel and Magnet) Hybrid Components  

Science.gov (United States)

A powder injection molding (PIM) process was developed to prepare aluminum hybrid components incorporating low carbon steel, AlNiCo, or BaFeO magnetic inserts. The inserts were securely bound within the powder injection molded aluminum due to sintering shrinkage and physical reaction at the interface. The low sintering temperature of the aluminum alloy ensured a minimal level of interfacial reaction and limited the degradation of the properties of the inserts.

Liu, Z. Y.; Kent, D.; Schaffer, G. B.

2009-12-01

73

New Design and Injection Molding Analysis of a Low Smoke Zero Halogen Cable Trunk  

Directory of Open Access Journals (Sweden)

Full Text Available The traditional production process of a cable trunk is plastic extrusion with PVC or other halogen containing materials. However, they have many disadvantages such as easy burning, producing toxic gases and smokes. A low smoke zero halogen (LSZH) cable trunk was designed and developed in the present study and the injection molding process was adopted to produce the LSZH cable trunk. Numerical simulations were applied to investigate the effects of the important process parameters on the warpage of the cable trunk. Comparing the simulation results under different process conditions and consideration both of the volumetric shrinkage and the total warpage displacement, it is found that the process parameters, including mold temperature 75°C, melt temperature 265°C, injection pressure 190 MPa, packing pressure 152 MPa, cooling water temperature 50°C and injection time 3 s, are the optimal process conditions for the injection molding process of the new designed cable trunk.

Xiaoxun Zhang; Fang Ma; Xia Li

2012-01-01

74

Fabrication of microstructures with extreme structural heights by vacuum reaction injection molding and electroforming  

International Nuclear Information System (INIS)

Development work has resulted in a vacuum reaction injection molding (RIM) process which allows to fabricate plastic microstructures having minimum lateral dimensions in the micrometer range and structural heights of several hundred micrometers. The plastic structures generated by this method on an electrically conductive gate plate can be used directly as templates for the production of metallic microstructures through electroforming. The mold inserts for the molding tools used in the RIM process are fabricated by synchrotron radiation lithography and electroforming on an electrically conductive base plate. Particularly stable mold inserts made of one single material with extremely plane surfaces are obtained by electrodeposition of metal such that it stands by several millimeters over the resist structures generated by lithography. The mold insert produced in this way is separated from the base plate and the resist structures are subsequently removed. The molding tests were performed at a purpose developed vacuum RIM apparatus. Methacrylate base casting resins were used with an internal mold release agent added in order to reduce the adhesion of the produced part on the mold insert. By the example of fabrication of separation nozzle structures with minimum lateral dimensions of about 3 ?m and a maximum structural height of 310 ?m it has been demonstrated that molding can be performed at 100% yield and that service he mold inserts can be achieved which are adequate for mass production. (orig./HP).

1987-01-01

75

Evaluation of stability for monolayer injection molding tools coating  

DEFF Research Database (Denmark)

We tested and characterized molecular coating of Aluminium and Nickel prototype molds and mold inserts for polymer replication via injection molding (IM). X-Ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energy and roughness data have been collected and used to predict coating lifetimes. Samples have been characterized immediately after coating, after 500+ IM cycles to test durability and after 7 months to test temporal stability. Sessile drop contact angle was measured for multiple fluids, namely water, di-iodomethane and benzylacohol. Detectable coating presence was indicated by an increased angle on all post IM samples. To conclude, we present mold coating evaluation method, which is well suited for ultrathin, controlable, covalently bonded coating, that is reasonably durable, affordable, scalable to production, detectable on surface and especially suitable for rapid prototyping and mold geometry testing.

Cech, Jiri; Taboryski, Rafael J.

2012-01-01

76

CREEP MODELING FOR INJECTION-MOLDED LONG-FIBER THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a model to predict the creep response of injection-molded long-fiber thermoplastics (LFTs). The model accounts for elastic fibers embedded in a thermoplastic resin that exhibits the nonlinear viscoelastic behavior described by the Schapery’s model. It also accounts for fiber length and orientation distributions in the composite formed by the injection-molding process. Fiber length and orientation distributions were measured and used in the analysis that applies the Eshelby’s equivalent inclusion method, the Mori-Tanaka assumption (termed as the Eshelby-Mori-Tanaka approach) and the fiber orientation averaging technique to compute the overall strain increment resulting from an overall constant applied stress during a given time increment. The creep model for LFTs has been implemented in the ABAQUS finite element code via user-subroutines and has been validated against the experimental creep data obtained for long-glass-fiber/polypropylene specimens. The effects of fiber orientation and length distributions on the composite creep response are determined and discussed.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.

2008-06-30

77

Feed stock preparation and achievement of shape complexity using powder injection molding (PIM)  

International Nuclear Information System (INIS)

Powder injection molding is one of the near net shape processing (NNSP) techniques used to produce geometrically complex shapes that need very little or no machining. This study presents the comparative study of feedstock preparation for Metal and Ceramic Injection Molding from the view point of achievement of shape complexity. Different variables of feedstock are studied, such as the role of binder, processing temperature, role of additives and the starting powder attributes on shape complexity. In this study, different binder systems; paraffin wax, polyethylene glycol, stearic acid, several thermoplastic resins and powders Fe and Al/sub 2/O/sub 3/ are studied. The differences between metal injection molding and ceramic injection molding are clearly emphasized. A major focus of this study is to attain the requisite engineering properties by a control of microstructure using different dies with increasing shape complexity. Powder is mixed with the binder system, the mix is injection molded into the desired shape cavity, the molded part is de-bound and after debinding it is sintered to produce high density products. (author)

2007-01-01

78

Three dimensional modeling of metal powder injection molding  

International Nuclear Information System (INIS)

In this work, a three-dimensional transient finite element flow analysis code is used to solve powder injection molding problems. Free surface, non-isothermal flow solutions are obtained by solving the momentum, mass and energy equations. An additional transport equation is solved for the front tracking function indicating the flow front position. The flow of 17-4 stainless steel powder with a water-soluble binder is simulated in a thick three-dimensional part with a diaphragm gate. The compound used is very sensitive to thermal effects because of its high thermal diffusivity and highly sensitive temperature dependence of the viscosity. The simulation predicted several unusual experimentally observed flow patterns: bypass flow (flow external and/or internal to the initial annular flow) and nonuniform flow (nonaxisymmetric flow in a preferred direction through the diaphragm gate). The work considers the effect of filling time, melt/mold temperature, inertia, yield stress, and wall slip on flow patterns, in order to identify the processing conditions that separate regions of uniform and nonuniform flow. (author)

2000-01-01

79

Three dimensional modeling of metal powder injection molding  

Energy Technology Data Exchange (ETDEWEB)

In this work, a three-dimensional transient finite element flow analysis code is used to solve powder injection molding problems. Free surface, non-isothermal flow solutions are obtained by solving the momentum, mass and energy equations. An additional transport equation is solved for the front tracking function indicating the flow front position. The flow of 17-4 stainless steel powder with a water-soluble binder is simulated in a thick three-dimensional part with a diaphragm gate. The compound used is very sensitive to thermal effects because of its high thermal diffusivity and highly sensitive temperature dependence of the viscosity. The simulation predicted several unusual experimentally observed flow patterns: bypass flow (flow external and/or internal to the initial annular flow) and nonuniform flow (nonaxisymmetric flow in a preferred direction through the diaphragm gate). The work considers the effect of filling time, melt/mold temperature, inertia, yield stress, and wall slip on flow patterns, in order to identify the processing conditions that separate regions of uniform and nonuniform flow. (author)

Ilinca, F.; Hetu, J-F.; Derdouri, A. [National Research Council of Canada, Industrial Material Inst., Boucherville, Quebec (Canada); Holmes, B. [Columbia Powder Injection Molding, Surrey, British Columbia (Canada); Scott, C.; Stevenson, J. [Honeywell PowerFlo Technologies, Morristown, New Jersey (United States)

2000-07-01

80

Simulation of infrared rapid surface heating for injection molding  

Energy Technology Data Exchange (ETDEWEB)

In this study, a three-dimension ray tracing and transient thermal simulation is developed to evaluate the thermal condition of injection mold surface with infrared surface rapid heating system. Several types of reflectors were applied to study the heating ability of the rapid surface heating system. A commercial available optical analysis program, TracePro, was used to simulate the infrared absorption of the mold surface. The surface temperature of the mold insert was evaluated by 2D and 3D transient thermal analysis with a commercial software, ANSYS. The results from simulation and thermal video measurement system agree well. Besides, the temperature distribution of the mold surface can be better observed via the 3D thermal analysis developed in this article. (author)

Chang, Pei-Chi; Hwang, Sheng-Jye [Room 905, Department of Mechanical Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701 (China)

2006-10-15

 
 
 
 
81

Simulation and measurement of optical aberrations of injection molded progressive addition lenses.  

UK PubMed Central (United Kingdom)

Injection molding is an important mass-production tool in the optical industry. In this research our aim is to develop a process of combining ultraprecision diamond turning and injection molding to create a unique low-cost manufacturing process for progressive addition lenses (PALs). In industry, it is a well-known fact that refractive index variation and geometric deformation of injection molded lenses due to the rheological properties of polymers will distort their optical performance. To address this problem, we developed a method for determining the optical aberrations of the injection molded PALs. This method involves reconstructing the wavefront pattern in the presence of uneven refractive index distribution and surface warpage using a finite element method. In addition to numerical modeling, a measurement system based on a Shack-Hartmann wavefront sensor was used to verify the modeling results. The measured spherocylindrical powers and aberrations of the PALs were in good agreement with the model. Consequently, the optical aberrations of injection molded PALs were successfully predicted by finite element modeling. In summary, it was demonstrated in this study that numerically based optimization for PAL manufacturing is feasible.

Li L; Raasch TW; Yi AY

2013-08-01

82

PHYSICAL PROPERTIES OF EXTRUDED AND INJECTION MOLDED CORN GLUTEN MEAL  

Science.gov (United States)

This study was performed to investigate the compounding of corn gluten meal (CGM) and decanoic acid and to evaluate their mechanical properties. The mixture of CGM and 30% decanoic acid was compounded in a twin screw extruder, followed by injection molding. Scanning electron microscopy (SEM), tens...

83

Injection molding of power-law polymer  

Science.gov (United States)

A polymer in injected with a constant pressure gradient between two parallel plates. The progression of the polymer front is modeled for a power law fluid (typical of a polymer) and compared to results for a Newtonian fluid.

Krane, Matthew J.

2008-10-25

84

Modular injection mold manufacturing in a selective laser sintering machine  

Science.gov (United States)

Reduced time to market places exacting requirements for the speed and quality of the design, manufacture and testing of new plastic parts. Traditionally, the greatest time for getting a new plastic product prototyped and tested is that for the mold fabrication phase. New metal materials for selective laser sintering (SLS) rapid prototyping technology allow direct mold fabrication for prototype plastic parts. Typically these molds are also useable for small scale production runs up to 50,000 parts. Using this technology prototype parts can be manufactured using the same materials and processes as used for the final product allowing testing of the whole manufacturing process for the prototype. This gives a company new opportunities to get a new or modified product to market faster and cheaper than by using traditional mold making processes. In this paper we describe this new technology and discuss how small and mid-size manufacturing companies can benefit from it.

Ikonen, Ilkka; Biles, William E.

1997-12-01

85

Injection molding micro patterns with high aspect ratio using a polymeric flexible stamper  

Directory of Open Access Journals (Sweden)

Full Text Available Poor filling occurs during the injection molding process of micro- or nano- scale patterns mainly because the hot polymer melt rapidly cools and its skin quickly solidifies upon contact with the mold surface. In this study, it is proposed to use Polyethylene terephthalate (PET) film coated with patterned polyurethane acrylate (PUA) as an effective thermal barrier. It can significantly hinder heat transfer into the mold during the molding process and thus may keep the melt viscosity low for longer duration. As a result, the replication would be improved not only during the filling phase but also during the packing phase. In order to verify the validity of the use of polymeric stamper, the melt-film interface temperature was evaluated by numerical simulation. Experimental results indicated that patterns possessing widths within the range of one to tens of micrometers and a height of approximately 10 µm were successfully filled and demolded.

2011-01-01

86

FPGA-Based Multiprocessor System for Injection Molding Control  

Directory of Open Access Journals (Sweden)

Full Text Available The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected.

Benigno Muñoz-Barron; Luis Morales-Velazquez; Rene J. Romero-Troncoso; Carlos Rodriguez-Donate; Miguel Trejo-Hernandez; Juan P. Benitez-Rangel; Roque A. Osornio-Rios

2012-01-01

87

FPGA-based multiprocessor system for injection molding control.  

UK PubMed Central (United Kingdom)

The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected.

Muñoz-Barron B; Morales-Velazquez L; Romero-Troncoso RJ; Rodriguez-Donate C; Trejo-Hernandez M; Benitez-Rangel JP; Osornio-Rios RA

2012-01-01

88

FPGA-based multiprocessor system for injection molding control.  

Science.gov (United States)

The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected. PMID:23202036

Muñoz-Barron, Benigno; Morales-Velazquez, Luis; Romero-Troncoso, Rene J; Rodriguez-Donate, Carlos; Trejo-Hernandez, Miguel; Benitez-Rangel, Juan P; Osornio-Rios, Roque A

2012-10-18

89

Improving energy savings on injection molding machines through microcomputers  

Energy Technology Data Exchange (ETDEWEB)

The need for energy efficiency on plastic injection molding machines has generated an increased awareness of the machine hydraulic system's potential energy losses. First, it must be understood how a particular machine is being used. After this evaluation, an energy efficient hydraulic system can be designed by using a microcomputer to analyze the energy usage for a particular molding operation. The modified, energy saving pumping system is a digital flow system which is controlled by a programmable controller interfaced with the original machine controller. The objective is to apply the most desirable hydraulic system while not losing sight of the other important criteria that the molder must have for overall machine productivity -- molding flexibility or utilization of the overall machine range; durability and low maintenance; quiet operation; and economic payback of the hydraulic system employed.

Moorhead, J.R.

1983-12-01

90

Análise do desenvolvimento morfológico da blenda polimérica PBT/ABS durante as etapas de mistura por extrusão e moldagem por injeção/ Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binária PBT/ABS e desta blenda compatibilizada pela adição de um copolímero acrílico reativo, durante a etapa de mistura por extrusão e de moldagem por injeção. A evolução da morfologia das blendas, durante a etapa de mistura, foi analisada através do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessório especialmente projetado pa (more) ra coleta in line. A morfologia observada nas amostras obtidas por injeção foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extrusão e por moldagem por injeção foram posteriormente preparadas através de crio-ultramicrotomia e observadas através de microscopia eletrônica de transmissão (TEM). Uma "Função Dispersão" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condições de processamento e de compatibilização. A adição de compatibilizante favorece a formação de uma morfologia de domínios de ABS dispersos em PBT, ao longo do canhão da extrusora, e previne satisfatoriamente o fenômeno de coalescência destes domínios durante o processo de moldagem por injeção. A função dispersão foi utilizada principalmente para mostrar a tendência da evolução morfológica e mostrou um bom desempenho para tal. Abstract in english The aim of this work was to observe the development of the phase morphology of the PBT/ABS blends during their extrusion mixing and injection molding steps. The evolution of the blend morphology during the mixing stage was analyzed using a specially designed co-rotational twin-screw extruder with a collecting device located along the barrel. Blend samples were collected in-line along the length of the extruder barrel during the blending process. Blend morphology was also (more) observed from specimens molded through injection molding. All the samples were observed by transmission electron microscopy (TEM). They were prepared by cryo-ultramicrotomy and the rubbery phase of the ABS contained in the blends was stained with osmium tetroxide (OsO4). A special function was established and is proposed to analyze the blend morphology trends through image analysis. In binary blends, the ABS phase showed better dispersion after the mixture passed through the extruder die. However, a coalescence phenomenon was observed during the next molding step. Compatibilized PBT/ABS blends showed better dispersion than binary blends, even after injection molding. The special function used to quantify the dispersion throughout the mixing and molding steps showed an excellent performance.

Ito, Edson N.; Pessan, Luiz A.; Hage Jr., Elias; Covas, José A.

2004-06-01

91

Análise do desenvolvimento morfológico da blenda polimérica PBT/ABS durante as etapas de mistura por extrusão e moldagem por injeção Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes  

Directory of Open Access Journals (Sweden)

Full Text Available O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binária PBT/ABS e desta blenda compatibilizada pela adição de um copolímero acrílico reativo, durante a etapa de mistura por extrusão e de moldagem por injeção. A evolução da morfologia das blendas, durante a etapa de mistura, foi analisada através do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessório especialmente projetado para coleta in line. A morfologia observada nas amostras obtidas por injeção foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extrusão e por moldagem por injeção foram posteriormente preparadas através de crio-ultramicrotomia e observadas através de microscopia eletrônica de transmissão (TEM). Uma "Função Dispersão" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condições de processamento e de compatibilização. A adição de compatibilizante favorece a formação de uma morfologia de domínios de ABS dispersos em PBT, ao longo do canhão da extrusora, e previne satisfatoriamente o fenômeno de coalescência destes domínios durante o processo de moldagem por injeção. A função dispersão foi utilizada principalmente para mostrar a tendência da evolução morfológica e mostrou um bom desempenho para tal.The aim of this work was to observe the development of the phase morphology of the PBT/ABS blends during their extrusion mixing and injection molding steps. The evolution of the blend morphology during the mixing stage was analyzed using a specially designed co-rotational twin-screw extruder with a collecting device located along the barrel. Blend samples were collected in-line along the length of the extruder barrel during the blending process. Blend morphology was also observed from specimens molded through injection molding. All the samples were observed by transmission electron microscopy (TEM). They were prepared by cryo-ultramicrotomy and the rubbery phase of the ABS contained in the blends was stained with osmium tetroxide (OsO4). A special function was established and is proposed to analyze the blend morphology trends through image analysis. In binary blends, the ABS phase showed better dispersion after the mixture passed through the extruder die. However, a coalescence phenomenon was observed during the next molding step. Compatibilized PBT/ABS blends showed better dispersion than binary blends, even after injection molding. The special function used to quantify the dispersion throughout the mixing and molding steps showed an excellent performance.

Edson N. Ito; Luiz A. Pessan; Elias Hage Jr.; José A. Covas

2004-01-01

92

Development and application of FINEMOLD. ; Powder metallurgy precision parts by injection molding. FINEMOLD no tenkai to oyo. ; Shashutsu seikei funmatsu yakin seimitsu buhin  

Energy Technology Data Exchange (ETDEWEB)

FINEMOLD is a trade name, given to powder metallurgy precision parts, produced by Nippon Seisen from metallic micropowder by an injection molding method. That company technically introduced the process from the USA in 1985 and entered the field of powder metallurgy by the injection molding. The production process of FINEMOLD proceeds in order of metallic powder kneading with binder, pelletizing, composing, injection molding, debinding, sintering and post-machining. The present production is, to the utmost, premised to be free from post-machining. However. parts unavoidably needing post-machining are to undergo sizing. That productio is maximally characterized by molding, entirely identical in method with that of plastics by use of injection molding machine. To specify the mold design, it is required to give instructions, specific to the injection molding, while the metallic micropowder is pricewise very expensive. Those points of problem must be engineered to be mitigated. 5 figs., 2 tabs.

Hattori, M. (Nihon Seisen Co. Ltd., Osaka (Japan))

1991-06-05

93

Integrated mold/surface-micromachining process  

Energy Technology Data Exchange (ETDEWEB)

We detail a new monolithically integrated silicon mold/surface-micromachining process which makes possible the fabrication of stiff, high-aspect-ratio micromachined structures integrated with finely detailed, compliant structures. An important example, which we use here as our process demonstration vehicle, is that of an accelerometer with a large proof mass and compliant suspension. The proof mass is formed by etching a mold into the silicon substrate, lining the mold with oxide, filling it with mechanical polysilicon, and then planarizing back to the level of the substrate. The resulting molded structure is recessed into the substrate, forming a planar surface ideal for subsequent processing. We then add surface-micromachined springs and sense contacts. The principal advantage of this new monolithically integrated mold/surface-micromachining process is that it decouples the design of the different sections of the device: In the case of a sensitive accelerometer, it allows us to optimize independently the proof mass, which needs to be as large, stiff, and heavy as possible, and the suspension, which needs to be as delicate and compliant as possible. The fact that the high-aspect-ratio section of the device is embedded in the substrate enables the monolithic integration of high-aspect-ratio parts with surface-micromachined mechanical parts, and, in the future, also electronics. We anticipate that such an integrated mold/surface micromachining/electronics process will offer versatile high-aspect-ratio micromachined structures that can be batch-fabricated and monolithically integrated into complex microelectromechanical systems.

Barron, C.C.; Fleming, J.G.; Montague, S.; Sniegowski, J.J.; Hetherington, D.L.

1996-03-01

94

Micro Machining of Injection Mold Inserts for Fluidic Channel of Polymeric Biochips  

Directory of Open Access Journals (Sweden)

Full Text Available Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip), has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for micro-fluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

Woo-Chul Jung; Young-Moo Heo; Gil-Sang Yoon; Kwang-Ho Shin; Sung-Ho Chang; Gun-Hee Kim; Myeong-Woo Cho

2007-01-01

95

Deflectometric analysis of high volume injection molds for production of occupational eye wear.  

UK PubMed Central (United Kingdom)

PURPOSE: Most of the protective eye wear devices currently on the market are manufactured on simple polycarbonate shields, produced by injection molding techniques. Despite high importance of optical quality, injection molds are rarely inspected for surface quality before or during the manufacturing process. Quality degradation is mainly monitored by optical testing of the molded parts. The purpose of this work was to validate a non-contact deflectometric measurement technique for surface and shape analysis of injection molds to facilitate deterministic surface quality control and to monitor minor conformity of the injection mold with the design data. MATERIAL AND METHODS: The system is based on phase-measuring deflectometry with a operating measurement field of 80×80 mm(2) (±18° slope), a lateral resolution of 60?m and a local sensitivity of some nanometers. The calibration was tested with a calibration normal and a reference sphere. The results were crosschecked against a measurement of the same object with a tactile coordinate measuring machine. Eight injection molds for production of safety goggles with radii of +58mm (convex) and -60mm (concave) were measured in this study. The molds were separated into two groups (cavity 1 and 2 of the tool with different polishing techniques) and measured to test whether the measurement tool could extract differences. The analysis was performed on difference height between the measured surface and the spherical model. RESULTS: The device could derive the surface change due to polishing and discriminate between both polishing techniques, on the basis of the measured data. The concave nozzle sides of the first group (cavity 1) showed good shape conformity. In comparison, the nozzle sides of the second group (cavity 2) showed local deviations from design data up to 14.4?m. Local form variations of about 5?m occurred in the field of view. All convex ejector sides of both groups (cavity 1 and 2) showed rotational symmetric errors and the molds were measured in general flatter than design data. CONCLUSION: We applied a deflectometric system for measuring and evaluating specular reflective injection molding tools to optimize the production process of occupational eye wear. The surface quality could be inline monitored in the production processes for actual spectacle models.

Speck A; Zelzer B; Speich M; Börret R; Langenbucher A; Eppig T

2013-10-01

96

Single Performance Optimization of Micro Metal Injection Molding for the Highest Green Strength by Using Taguchi Method  

Directory of Open Access Journals (Sweden)

Full Text Available Micro metal injection molding is drawing attention recently as one the most cost effective processes in powder metallurgy to produce small-scale intricate part and competitive cost for mass production of micro components where it is greatly influenced by injection parameter. Thus, this paper investigated the optimization of highest green strength which plays an important characteristic in determining the successful of micro MIM. Stainless steel SS 316L was used with composite binder, which consists of PEG and PMMA while SA works as a surfactant. Feedstock with 61.5% with several injection parameters were optimized which highly significant through screening experiment such as injection pressure(A), injection temperature(B), mold temperature(C), injection time(D) and holding time(E). Besides that, interaction effects between injection pressure, injection temperature and mold temperature were also considered to optimize in the Taguchi’s orthogonal array. Analysis of variance (ANOVA) in terms of signal-to-noise ratio (S/N-larger is better) for green strength was also presented in this paper. Result shows that interaction between injection temperature and mold temperature (BxC) give highest significant factor followed by interaction between injection pressure and injection temperature (AxB). Single factor that also contributes to significant optimization are mold temperature(C), injection time (D) and injection pressure (A). Overall, this study shows that Taguchi method would be among the best method to solve the problem with minimum number of trials.

M.H.I Ibrahim; N. Muhamad; A.B Sulong; K.R. Jamaludin; S. Ahmad; N.H.M Nor

2010-01-01

97

Surface Topographic Characterization for Polyamide Composite Injection Molds Made of Aluminum and Copper Alloys.  

UK PubMed Central (United Kingdom)

In order to ensure flexibility and rapid new product development, the mold industry made use of soft materials for cavity inserts in injection molds. However, materials of this kind are prone to wear. This article analyzes the topographic characterization of the surface and wear processes in injection molds cavities. Two materials have been used to produce the cavities: aluminum alloy EN AW-6082 T4 and copper alloy Cu Zn39 Pb3. The surface topography was measured with the use of optical interferometry profiling technology; roughness and surface parameters were determined according to ISO 4287, ISO 25178, and EUR 15178N. In order to complete this research, an experimental part with different thicknesses and shapes was designed, and cavity inserts of aluminum and copper were made. Polyamide PA6, with 30% fiberglass reinforcement, was employed in the experimental procedure. Measurements of cavity mold surfaces were performed after 9,200 cycles on each mold and at different locations on the mold. The surface measurement was made with a white light vertical scanning interferometry, also known as coherence scanning interferometry (ISO DIS 25178-604). The results are analyzed and differences between the two types of cavity inserts materials are discussed. SCANNING 9999:XX-XX, 2013. © 2013 Wiley Periodicals, Inc.

Pereira A; Hernández P; Martinez J; Pérez JA; Mathia TG

2013-02-01

98

Initial verification of an induction heating set-up for injection molding  

DEFF Research Database (Denmark)

Molding of thin and long parts by injection molding leads to special requirements for the mold in order to ensure proper filling and acceptable cycle time. This paper investigates the applicability of embedded induction heating for the improvement of the filling of thin long parts. The object selected for the investigation is a thin spiral. For the complete molding of the component, elevated mold temperatures are required. For this propose a new injection molding set-up was developed, which allows rapid heating of the cavity wall by an induction heating system. The temperature was measured by two thermocouples placed in the die insert. The system was used to heat up the cavity wall with heating rates of up to 10 °C/s. Experiments were carried out with ABS material. The lengths of the object were measured by a suitable measurement set up. The experimental result show that the use of the induction heating system process is an efficient way for improving the filling of the cavity.

Menotti, Stefano; Hansen, Hans NØrgaard

2013-01-01

99

Effects of powder characteristics on injection molding and burnout cracking  

Energy Technology Data Exchange (ETDEWEB)

Silicon nitride particle size and size distributions were varied widely to determine their effects on burnout cracking of injection-molded test parts containing thick and thin sections. Elimination of internal cracking required significant burnout shrinkage, which did not occur by changes of particle size and size distribution. However, isopressing of test parts after burnout provided the dimensional shrinkage necessary for producing crack-free components.

Bandyopadhyay, G.; French, K.W. (GTE Lab. Inc., Waltham, MA (United States))

1994-03-01

100

Powder Injection Molding of Ceria-Stabilized, Zirconia-Toughened Mullite Parts for UAV Engine Components  

Science.gov (United States)

Powder injection molding (PIM) of ceria-stabilized, zirconia-toughened mullite composites were investigated in the present article with the goal of obtaining performance enhancement in complex geometries for energy and transportation applications. A powder-polymer mixture (feedstock) was developed and characterized to determine its suitability for fabricating complex components using the PIM process. Test specimens were injection molded and subsequently debound and sintered. The sintered properties indicated suitable properties for engine component applications used in unmanned aerial vehicles (UAVs). The measured feedstock properties were used in computer simulations to assess the mold-filling behavior for a miniature turbine stator. The results from the measurements of rheological and thermal properties of the feedstock combined with the sintered properties of the ceria-stabilized, zirconia-toughened mullite strongly indicate the potential for enhancing the performance of complex geometries used in demanding operating conditions in UAV engines.

Martin, Renee; Vick, Michael; Enneti, Ravi K.; Atre, Sundar V.

2013-07-01

 
 
 
 
101

A Simulation Study of Conformal Cooling Channels in Plastic Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available In injection molding process, the cooling channel performance is one of the most crucial factors because it has significant effect on both production rate and the quality of the plastic part. In order to reduce the cycle time, and control the uniform distribution of temperature, it is necessary to create conformal cooling channels, which conform to the shape of the mold cavity and core. This paper presents a simulation study of different types of cooling channels in an injection molded plastic part and compares the performance in terms of time to ejectiontemperature, shrinkage, temperature profile, and part warpage to determine which configuration is more appropriate to provide uniform cooling with minimum cycle time. Autodesk Moldflow Insight (AMI) simulation software is used to examine the results of the cooling channels performance.

Omar A. Mohamed, S.H. Masood, Abul Saifullah

2013-01-01

102

Integrally molded dental appliance and process for its manufacture  

UK PubMed Central (United Kingdom)

The invented dental apparatus and method for its manufacture involves an integrally molded, polymeric, unitary, hand piece having fluid conduits formed therein during the molding process for conducting fluid, e.g. air, under pressure from a proximal end having an industry standard couple to a distal end including an integrally molded head piece for housing a rotary, preferably canister-type turbine to which a dental bur may be removably secured. Preferably, an integrally molded venturi chamber fluid-interconnects a pressurized one of the conduits and an inlet to the turbine's impeller and an outlet of the turbine's impeller is fluid-connected at an outlet of the canister to an exhaust one of the conduits. Optionally, one or more chip-air source conduits and a light valve may extend within the elongate interior of the hand piece to provide intra-oral, in-process cleaning, cooling and lighting functions. Preferably, the hand piece is injection molded via a lost-material, e.g. a lost-metal, process similar to investment casting. The invented hand piece, in its preferred embodiment, is autoclavable and disposable.

Nemetz Annette M.; Hoyt Joshua K.; Rux Bruno Rudolf

103

Carbon Nanotubes Reinforced Copper Matrix Nanocomposites via Metal Injection Molding Technique  

Directory of Open Access Journals (Sweden)

Full Text Available New thermal management solutions are required to provide cost-effective means of dissipating heat from next generation microelectronic devices. In this paper, fabrication of heat sink nanocomposite made of copper reinforced by multiwalled carbon nanotubes up to 10 Vol. % using metal injection molding technique is presented. A mixture of Cu-MWNTs was compounded using internal mixer machine for homogenous dispersion of the solid powder in the binder. To ensure a flow able feedstock during injection molding process, different binder systems and their Cu-MWNTs feedstocks were examined using capillary rheometer machine. In order to avoid binder degradation, TGA test was carried out. The TGA results showed that the processing temperature such as mixing and injection molding should be lower than 170°C. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal, and then the samples were isothermally sintered at different sintering temperatures (900-1050°C) in argon atmosphere. The results showed that the sintered samples experienced an isotropic shrinkage around 17% with relatively homogeneous dispersion of MWNTs in the copper matrix which is expected to enhance the physical and mechanical properties of the final product.

Ali S. Muhsan; Faiz Ahmad; Norani M. Mohamed; Putri S.M.BT M. Yusoff; M.R. Raza

2012-01-01

104

DAMAGE MODELING OF INJECTION-MOLDED SHORT- AND LONG-FIBER THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

This article applies the recent anisotropic rotary diffusion – reduced strain closure (ARD-RSC) model for predicting fiber orientation and a new damage model for injection-molded long-fiber thermoplastics (LFTs) to analyze progressive damage leading to total failure of injection-molded long-glass-fiber/polypropylene (PP) specimens. The ARD-RSC model was implemented in a research version of the Autodesk Moldflow Plastics Insight (MPI) processing code, and it has been used to simulate injection-molding of a long-glass-fiber/PP plaque. The damage model combines micromechanical modeling with a continuum damage mechanics description to predict the nonlinear behavior due to plasticity coupled with damage in LFTs. This model has been implemented in the ABAQUS finite element code via user-subroutines and has been used in the damage analyses of tensile specimens removed from the injection-molded long-glass-fiber/PP plaques. Experimental characterization and mechanical testing were performed to provide input data to support and validate both process modeling and damage analyses. The predictions are in agreement with the experimental results.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.; Phelps, Jay; Tucker III, Charles L.

2009-10-30

105

Resin Flow Analysis in the Injection Cycle of a Resin Transfer Molded Radome  

Science.gov (United States)

Resin flow analysis in the injection cycle of an RTM process was investigated. Fiberglass and carbon fiber mats were used as reinforcements with EPON 826 epoxy resin. Numerical models were developed in ANSYS finite element software to simulate resin flow behavior into a mold of conical shape. Resin flow into the woven fiber mats is modeled as flow through porous media. The injection time for fiberglass/epoxy composite is found to be 4407 seconds. Required injection time for the carbon/epoxy composite is 27022 seconds. Higher injection time for carbon/epoxy part is due to lower permeability value of the carbon fibers compared to glass fiber mat.

Golestanian, Hossein

2007-04-01

106

Viscosity and powder dispersion in ceramic injection molding mixtures  

Energy Technology Data Exchange (ETDEWEB)

Particle dispersion in ceramic injection molding mixtures is investigated from the shear viscosity data of the mixtures. The degree of agglomeration of the mixture is examined using the Krieger and Dougherty equation on the viscosity for a concentrated suspension. The number of particles in a single agglomerate is evaluated by the shape factor parameter of suspended particles in the Krieger and Dougherty model with the scaling law of fractal analysis on particle agglomerates. The number of particles per agglomerate predicted are four particles for a zirconia sample, and for a alumina sample the particles are in a well dispersed state. These values of agglomeration in the molding mixtures predicted by the viscometric method are almost consistent with those predicted by the visualized technique. (author)

Okada, K.; Nagase, Y. [Kurashiki Univ. of Science and the Arts, Okayama (Japan). Dept. of Chemical Tech.

2000-02-01

107

Process for preparing sand cores and molds  

Energy Technology Data Exchange (ETDEWEB)

An improved process for preparing foundry cores and molds using a foundry aggregate and a binder therefor wherein the aggregate is mixed with an aqueous suspension of cereal flour and then with a core oil, the improvement comprising mixing the aggregate with phosphoric acid or sulfuric acid before mixing with the aqueous suspension of the cereal flour.

Varnum, N.C.; Kraemer, J.F.

1984-11-27

108

Results on powder injection molding of Ni[sub 3]Al and application to other intermetallic compositions  

Energy Technology Data Exchange (ETDEWEB)

Net forming processes are under development to allow affordable production of intermetallic components. Powder injection molding (PIM) mav be employed for the production of complex-shaped intermetallic geometries. Proper choice of powder parameters and processing conditions can lead to the formation of fullv dense structures through pressure-less sintering. In this study, Ni[sub 3]Al with 0.04 wt.-% boron has been successfully injection molded and sintered to full density. A yield strength of 340 MPa, ultimate tensile strength (UTS) of 591 MPa, and 8% elongation were attained for injection molded and sintered tensile bars. Powder characteristics and sintering behavior are given for the nickel aluminide employed in this study to highlight the powder attributes needed for injection molding. Molding parameters, debinding and sintering schedules, along, with mechanical properties are presented to indicate the viability of PIM for intermetallics. This approach based on the understanding of key powder characteristics and use of the reactive synthesis powder process mav be extended to the successful injection molding of other intermetallic systems.

Cooper, R.M.

1992-01-01

109

Fabrication of Composite Material Using Gettou Fiber by Injection Molding  

Science.gov (United States)

This study investigated the mechanical properties of composite using gettou (shell ginger) fiber as reinforcement fabricated from injection molding. Gettou fiber is a natural fiber made from gettou, a subtropical plant that is largely abundant in Okinawa, Japan. We used the stem part of gettou plant and made the gettou fiber by crushing the stem. The composite using gettou fiber contributed to low shrinkage ratio, high bending strength and high flexural modulus. The mechanical strength of composite using long gettou fiber showed higher value than composite using short gettou fiber. Next, because gettou is particularly known for its anti-mold characteristic, we investigated the characteristic in gettou plastic composite. The composite was tested against two molds: aspergillius niger and penicillium funiculosum. The 60% gettou fiber plastic composite was found to satisfy the JISZ2801 criterion. Finally, in order to predict the flexural modulus of composite using gettou fiber by Halpin-Tsai equation, the tensile elastic modulus of single gettou fiber was measured. The tendency of the experimental results of composite using gettou fiber was in good agreement with Halpin-Tsai equation.

Setsuda, Roy; Fukumoto, Isao; Kanda, Yasuyuki

110

SAXS studies of the injection molding effects on the nanostructure of polyesters. I: polybutylene terephthalate (PBT)  

International Nuclear Information System (INIS)

In this work, the nanoperiodicity of some PBT samples, injection molded at different conditions, was evaluated as a function of the thickness of the samples. From the small angle X-ray scattering (SAXS) results, it was possible to observe that, as expected, there is a gradient of the L and lc values found through the thickness of the samples. It was also found that at the center of the PBT sample injection molded at low injection temperature, Ti, the crystallinity degree evaluated previously by wide angle X-Ray diffraction (WAXD) is high. In a previous study it was pointed out that a high orientation process could be present in the center of this sample, increasing the XC evaluated from WAXD. The SAXS results presented here show that this is not the case, because if orientation is high, the value of L at this region of the sample would be smaller. (author)

2005-01-01

111

Finite Element Analysis of Reciprocating Screw for Injection Molding Machine  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with, the solution of problem occurred for reciprocating screw of Injection molding machine. It identifies and solves the problem by using the modeling and simulation techniques. The problem occurred in the reciprocating screw of machine which was wearing of threads due to affect of temperature of mold materials(flow materials) i.e. Nylon, low density polypropylene, polystyrene, PVC etc., The main work was to model the components of machine with dimensions, assemble those components and then simulate the whole assembly for rotation of the screw. The modeling software used is PRO-E wildfire 4.0 for modeling the machine components like body, movable platen, fixed platen, barrel, screw, nozzle, etc. The analysis software ANSYS is used to analyze the reciprocating screws. The objectives involved are:- • To model all the components using modeling software Pro-E 4.0 • To assemble all the components of the machine in the software. • To make the assembly run in Pro-E software.• Analysis of screw of machine using Ansys 11.0 software. • To identify the wearing of threads and to provide the possible solutions.This problem is major for all industrial injection molding machines which the industries are facing and they need the permanent solution, so if the better solution is achieved then the industries will think for implementing it. The industries are having temporary solution but it will affect the life of the screw, because the stresses will be more in machined screw on lathe machine as compared to normal screw. Also if the screw will fail after some years of operation, the new screw available in the market will have the same problem. Also the cost associated with new screw and its mounting is much more as it is the main component of machine.

Nagsen B. Nagrale; Dr.R.N.Baxi

2011-01-01

112

On the Injection Molding of Nanostructured Polymer Surfaces  

DEFF Research Database (Denmark)

Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to form nickelshims. The surface pattern consisted of square pillars repeated equidistantly within the plane of the surface in a perpendicular arrangement. The width and distance between the squares both ranged from 310 to 3100 rim. All the pillars were 220 nm high. The nickel-shim was used as a surface-template during injection molding of polycarbonate. Secondly, a nickel shim, with a surface pattern consisted of a squared sine with a period of 700 nm and amplitude of 450 nm, was mounted on, and it was in good thermal contact with the upper plate in a hot-press. Polycarbonate/polystyrene was melted on the lower plate while the temperature of the shim was kept below the glass transition temperature. The upper plate was lowered until the shim was in contact with the melt. Experiments were carried out with a clean shim and a shim coated with a monolayer of fluorocarbonsilane. As a result of the surface coating, the amplitude of the replicated grating decreased from about 350 nm in polycarbonate and 100 nm in polystyrene to less than 10 nm. The experiments strongly suggest that the possibility to injection mold sub-micrometer surface structures in polymers mainly relates to adhesive energy between polymer and shim.

Pranov, Henrik; Rasmussen, Henrik K.

2006-01-01

113

Development and evaluation of injection-molded sustained-release tablets containing ethylcellulose and polyethylene oxide.  

UK PubMed Central (United Kingdom)

PURPOSE: It was the aim of the present study to develop sustained-release matrix tablets by means of injection molding of ethylcellulose (EC) and polyethylene oxide (PEO) mixtures and to evaluate the influence of process temperature, matrix composition, and viscosity grade of EC and PEO on processability and drug release. METHODS: Formulations consisting of metoprolol tartrate (MPT, concentration: 30%), EC plasticized by dibutyl sebacate, and PEO were extruded and consequently injection molded into tablets. The influence of process temperature (120°C and 140°C), matrix composition, viscosity grade of EC (4, 10, 20, 45, and 100 mPa·s) and PEO (7 × 10(6), 1 × 10(6), and 1 × 10(5) Mw) on processability and drug release was determined. RESULTS: Formulations consisting of 70% EC and 30% MPT showed incomplete drug release, whereas drug release was too fast for formulations without EC. Higher PEO concentrations increased drug release. Formulations containing 30% metoprolol, EC, and different concentrations of PEO showed first-order release rates with limited burst release. Drug release from direct compressed tablets showed faster drug release rates compared to injection-molded formulations. There was no clear relationship between the molecular weight of EC and drug release. The melting endotherm (113.9°C) of MPT observed in the differential scanning calorimeter thermogram of the tablets indicated that a solid dispersion was formed which was confirmed by X-ray diffractogram. X-ray tomography demonstrated a difference in pore structure between tablets processed at 120°C and 140°C. CONCLUSION: It was concluded that injection molding can be applied successfully to develop sustained-release PEO/EC matrix tablets.

Quinten T; De Beer T; Almeida A; Vlassenbroeck J; Van Hoorebeke L; Remon JP; Vervaet C

2011-02-01

114

Replication of continuous-relief diffractive optical elements by conventional compact disc injection-molding techniques.  

UK PubMed Central (United Kingdom)

Continuous-relief diffractive optical elements have been replicated by use of conventional compact disc injection-molding techniques. Two continuous-relief microstructures, a blazed grating and a fan-out element, were chosen to evaluate the replication process. Original elements were fabricated by direct-write electron-beam lithography. Optical measurements and atomic force microscopy were used for investigating the replication fidelity.

Nikolajeff F; Jacobsson S; Hård S; Billman A; Lundbladh L; Lindell C

1997-07-01

115

Improvement Performance of the Filling Step in Injection Mold through Vibration  

Directory of Open Access Journals (Sweden)

Full Text Available This paper shows the flow improvement in the filling step of the polymer injection process due to the polymer excitation though vibration. This process can be split up into three main steps: filling, pocking and cooling. Several mechanical and aesthetic properties of the finished product can be changed in the filling step. The objective of this investigation is to demonstrate the improvement in the filling mold under vibration without adding chemical products. To reach this result, an experimental mold was designed and manufactured in which a vibration device was coupled; it was possible to demonstrate the vibration advantage through this process. Moreover, a heuristic methodology was proposed for the experiment which shows an improvement in the filling process with frequencies close to 3 Hz.

Benítez-Rangel J.P.; Morales-Hernández L.A.; Trejo-Hernández M.

2012-01-01

116

Effect of cross sectional geometry on PDMS micro peristaltic pump performance: comparison of SU-8 replica molding vs. micro injection molding.  

Science.gov (United States)

Two different fabrication methods were employed to fabricate micropumps with different cross-sectional channel geometries. The first was to fabricate rectangular cross-sectional microchannel geometries using the well known fabrication method of replica molding (REM). The second, and far less utilized fabrication technique, was to create microchannel molds using an in-house fabricated handheld micro injection molding apparatus. The injection mold apparatus was designed for use with elastomeric room temperature vulcanization (RTV) polymers, as opposed to most other injection molding machines, which are designed for use with thermoplastic polymers. The injection mold's bottom plate was used as a microchannel molding template. The molding template was created by threading a small-diameter wire (150 ?m or less) through the injection mold's bottom plate, with subsequent adhesion and smoothing of a thin piece of aluminum foil over the wire-raised injection mold template. When molded against, the template produced a rounded/Gaussian-shaped PDMS microchannel. The design of the injection mold will be presented, along with a direct comparison for micropump performance metrics such as flow rate, valving characteristics, and maximum backpressures attainable for each of the respective micropump channel geometries. PMID:23917263

Graf, Neil J; Bowser, Michael T

2013-08-27

117

Effect of cross sectional geometry on PDMS micro peristaltic pump performance: comparison of SU-8 replica molding vs. micro injection molding.  

UK PubMed Central (United Kingdom)

Two different fabrication methods were employed to fabricate micropumps with different cross-sectional channel geometries. The first was to fabricate rectangular cross-sectional microchannel geometries using the well known fabrication method of replica molding (REM). The second, and far less utilized fabrication technique, was to create microchannel molds using an in-house fabricated handheld micro injection molding apparatus. The injection mold apparatus was designed for use with elastomeric room temperature vulcanization (RTV) polymers, as opposed to most other injection molding machines, which are designed for use with thermoplastic polymers. The injection mold's bottom plate was used as a microchannel molding template. The molding template was created by threading a small-diameter wire (150 ?m or less) through the injection mold's bottom plate, with subsequent adhesion and smoothing of a thin piece of aluminum foil over the wire-raised injection mold template. When molded against, the template produced a rounded/Gaussian-shaped PDMS microchannel. The design of the injection mold will be presented, along with a direct comparison for micropump performance metrics such as flow rate, valving characteristics, and maximum backpressures attainable for each of the respective micropump channel geometries.

Graf NJ; Bowser MT

2013-08-01

118

Conformal cooling and rapid thermal cycling in injection molding with 3D printed tools  

Science.gov (United States)

Solid Freeform Fabrication processes such as 3D Printing have demonstrated the potential to produce tools with complex internal geometry. This work explores the application of this capability to improved thermal management for injection molding tooling through: (i)cooling lines which are conformal to the mold surface which provide improved uniformity and stability of mold temperature and (ii)tools with low thermal inertia which, in combination with conformal fluid channels allow for rapid heating and cooling of tooling, thereby facilitating isothermal filling of the mold cavity. This work presents a systematic, modular, approach to the design of conformal cooling channels. Recognizing that the cooling is local to the surface of the tool, the tool is divided up into geometric regions and a channel system is designed for each region. Each channel system is itself modeled as composed of cooling elements, typically the region spanned by two channels. Six criteria are applied including; a transient heat transfer condition which dictates a maximum distance from mold surface to cooling channel, considerations of pressure and temperature drop along the flow channel and considerations of strength of the mold. These criteria are treated as constraints and successful designs are sought which define windows bounded by these constraints. The methodology is demonstrated in application to a complex core and cavity for injection molding. In the area of rapid thermal cycling, this work utilizes the design methods for conformal channels for the heating phases and adds analysis of the packing and cooling phases. A design is created which provides thermal isolation and accommodation of cyclic thermal stresses though an array of bendable support columns which support the molding portion of the tool where the heating/cooling channels are contained. Designed elasticity of the tool is used to aid in packing of the polymer during the cooling phase. Methodology for the design of this structure is presented. A set of tools has been fabricated and subjected to thermal and mechanical tests. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Xu, Xiaorong

119

Non-Polluting Composites Repair and Remanufacturing for Military Applications: Co-Injection Resin Transfer Molding  

Canada Institute for Scientific and Technical Information (Canada)

Vacuum-assisted resin transfer molding (VARTM) processes have been proven to be cost-effective manufacturing techniques for large composite structures. However, their use has been limited to single resin systems. A large variety of composite structures requires multiple resins to serve different purposes while being integrated into a single structure. Significant environmental cost savings are possible by replacing currently practiced sequential repair and manufacturing techniques with reduced-step co-cure processes enabled by the co-injection resin transfer molding (CIRTM) variant of the VARTM process. The CIRIM process was investigated to manufacture two dual-layered structures commonly required in Department of Defense (DoD) structures. The first consists of a vinyl-ester layer for structural integrity and a phenolic layer for flammability, smoke, and toxicity (FST) protection. The second consists of structural epoxy with a polyurethane layer for improved damage tolerance. In each case, the two resins are simultaneously injected into a mold filled with a stationary fiber bed and co-cured. Resin separation is maintained by a 1-mil-thick polysulfone film sandwiched between two layers of 6.5-mil-thick adhesive. Various tests have been performed to demonstrate mechanical, thermal, and rate-dependent performance of the improved structures.

1999-01-01

120

Highly conductive thermoplastic composite blends suitable for injection molding of bipolar plates  

International Nuclear Information System (INIS)

This study aimed at developing highly conductive, lightweight, and low-cost bipolar plates for use in proton exchange membranes (PEM) fuel cells. Injection and compression molding of highly filled polypropylene, PP, and polyphenylene sulfide, PPS, based blends were used as a mean for mass production of bipolar plates. Loadings up to 60-wt% in the form of graphite, conductive carbon black and carbon fibers were investigated. The developed formulations have a combination of properties and processability suitable for bipolar plate manufacturing, such as good chemical resistance, sufficient fluidity, and good electrical and thermal conductivity. Electrical resistivities around 0.15 and 0.09 Ohm-cm were respectively achieved for the PP and PPS-based blends, respectively. Two bipolar plate designs were successfully fabricated by molding the gas flow channels over aluminum plates to form a metallic/polymer composite plate, or simply by direct injection molding of the conductive polymer composite. For the first design, overall plate resistivities of 0.2 and 0.1 Ohm-cm were respectively attained using PP and PPS based blends as conductive skin. A lower volume resistivity of around 0.06 Ohm-cm was attained for the second injected plate design with PPS based blend. (author)

2003-01-01

 
 
 
 
121

An Elastic-Plastic and Strength Prediction Model for Injection-Molded Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper applies a recently developed model to predict the elastic-plastic stress/strain response and strength of injection-molded long-fiber thermoplastics (LFTs). The model combines a micro-macro constitutive modeling approach with experimental characterization and modeling of the composite microstructure to determine the composite stress/strain response and strength. Specifically, it accounts for elastic fibers embedded in a thermoplastic resin that exhibits the elastic-plastic behavior obeying the Ramberg-Osgood relation and J-2 deformation theory of plasticity. It also accounts for fiber length, orientation and volume fraction distributions in the composite formed by the injection-molding process. Injection-molded-long-glass-fiber/polypropylene (PP) specimens were prepared for mechanical characterization and testing. Fiber length, orientation, and volume fraction distributions were then measured at some selected locations for use in the computation. Fiber orientations in these specimens were also predicted using an anisotropic rotary diffusion model developed for LFTs. The stress-strain response of the as-formed composite was computed by an incremental procedure that uses the Eshelby’s equivalent inclusion method, the Mori-Tanaka assumption and a fiber orientation averaging technique. The model has been validated against the experimental stress-strain results obtained for these long-glass-fiber/PP specimens.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Phelps, Jay; Tucker III, Charles L.; Bapanapalli, Satish K.

2008-09-01

122

Electroforming of Tool Inserts for Injection Molding of Optical or Microfluidic Components  

DEFF Research Database (Denmark)

With a rapidly increasing international interest in “Lab-on-a-chip”-systems as well as affordable polymer optics, the combination of electroforming and injection molding offers an attractive fabrication solution. Miniaturized analysis systems can be used for medical, security (anti terror monitoring) and environmental (waste water monitoring) applications. Optical components in polymer materials can be used for consumer electronics and for sensor systems. The presentation will include the complete fabrication scheme for tool inserts based on machining and electroforming. Electroforming processes for nickel and copper will be disclosed. Processing parameters for the different types of tools as well as quality control measures will be presented.

Tang, Peter Torben; Christensen, Thomas R.

2004-01-01

123

Mold temperature measurement for glass-pressing processes  

International Nuclear Information System (INIS)

The largest use of radiation thermometers within Corning Glass Works is for mold temperature measurement for the glass-pressing process. Pressing television panels at today's high quality would be very difficult without a mold temperature measurement system and the computer manipulation of the quality control data to supervise the mold temperature control loop. The most critical part of a television panel is the inside surface curvature. The ideal surface is usually defined as a spherical surface. The tolerance for a normal TV panel is +-0.30 mm (+-0.012 in.). High resolution display panels are more critical, having a dimensional tolerance only one half as large as TV panels. Panel curvature is a direct (but negative) function of mold temperature. Every 10C increase in mold temperature results in the panel center being 0.025 mm (0.001 in.) shorter (flatter). Random dimensional variations within a panel take up most of the dimensional tolerance. The result is that each mold is controlled to its own individual temperature set point, +-10C. Hot panel and cold panel curvature measurements are correlated by a process computer and used to update the mold temperature set points. The same computer adjusts the mold cooling air to maintain the required mold temperatures. From the temperature measurement standpoint, the significant problem is the changing emissivity of the mold surface when the mold is new or reconditioned. The selection of a radiation thermometer with a short wavelength was an obvious choice to minimize the effect of emissivity variations.

1984-05-08

124

Modeling of the injection of loaded thermoplastic mixtures with application in metal injection molding  

Energy Technology Data Exchange (ETDEWEB)

The study is focussed on the modeling and numerical simulation of the loaded thermoplastic mixtures currently used in metal injection molding. Due to the fact that the mixture is highly concentrated in metallic powders, the models based on the homogenization theory and using an equivalent viscosity are no longer suitable. So a biphasic formulation has been developed to describe the flow of such mixtures. An interaction term between powder and thermoplastic fluid polymer accounts for segregation or debinding effects. In this type of the problem, the solid phase fraction is a key fields variable. The associated equations are solved separately for each phase taking into account interactions and coupling effects. A general solver in 2D and 3D has been developed that account propagation of fluid front by the extension to biphasic cases of the VOF method. For solving the velocity/pressure problem the fractional step method has been extended to the biphasic cases. Numerical simulations have been compared to the experimental results obtained by a using multiple cavity with pressure and temperature sensors. Comparisons between numerical simulation results and experiments show good agreements in terms of pressure and temperature evolutions during molding. It is also demonstrated that the numerical results are accurate and sensitive to variation of the injection molding marameters. (author)

Gelin, J.C.; Barriere, Th. [Univ. de Franche-Compte, Lab. de Mecanique Appliquee R. Chaleat, Besancon (France); Liu, B. [Southwest Jiaotong Univ., Inst. of Engineering Science, Chengdu, Sichuan (China)

2000-07-01

125

Modeling of the injection of loaded thermoplastic mixtures with application in metal injection molding  

International Nuclear Information System (INIS)

The study is focussed on the modeling and numerical simulation of the loaded thermoplastic mixtures currently used in metal injection molding. Due to the fact that the mixture is highly concentrated in metallic powders, the models based on the homogenization theory and using an equivalent viscosity are no longer suitable. So a biphasic formulation has been developed to describe the flow of such mixtures. An interaction term between powder and thermoplastic fluid polymer accounts for segregation or debinding effects. In this type of the problem, the solid phase fraction is a key fields variable. The associated equations are solved separately for each phase taking into account interactions and coupling effects. A general solver in 2D and 3D has been developed that account propagation of fluid front by the extension to biphasic cases of the VOF method. For solving the velocity/pressure problem the fractional step method has been extended to the biphasic cases. Numerical simulations have been compared to the experimental results obtained by a using multiple cavity with pressure and temperature sensors. Comparisons between numerical simulation results and experiments show good agreements in terms of pressure and temperature evolutions during molding. It is also demonstrated that the numerical results are accurate and sensitive to variation of the injection molding marameters. (author)

2000-01-01

126

Injection molding simulation to improve the efficiency and quality of metal molding designs. Kanagata no sekkei koritsu ka to hinshitsu kojo wo hakaru shashutsu seikei simulation  

Energy Technology Data Exchange (ETDEWEB)

In order to improve the efficiency and quality of metal molding designs, Sony Corp. has adopted an injection molding simulation system since the first half of 1980s. Since, however, molding materials are thermal fluids, which transit their phase from liquid into solid, and boundary conditions will be changed in the middle of their cycles, their analyzing works are very difficult. Therefore, softwares in this field are still on the way to be developed. Since this corporation has joined to the Cornell Injection Molding Program (CIMP) project in Cornell University, they have added improvements on their programs to be supplied, and have used them with their own programs developed additionally based on transformation processes. They have carried out minimizing of shape of boss root and examining holding pressure control by this simulation system. Since actually input works for CAD process have been carried out by hand now, it takes a time a little, though, they have also considered to make it easy by automating for applications of the full model. 4 refs., 7 figs.

Ito, Y. (Sony Corp., Tokyo (Japan))

1992-01-01

127

Recycling plastic scrap: Injection molding. January 1973-August 1989 (Citations from the Rubber and Plastics Research Association data base). Report for January 1973-August 1989  

Energy Technology Data Exchange (ETDEWEB)

This bibliography contains citations concerning the recycling of scrap plastic produced in the injection-molding process. Plastic pellets made from scrap that are used in the injection-molding process are also discussed. Recycling equipment and automated recycling systems are described. Ways to utilize plastic scrap from used cars, packaging materials, and waste from polyurethane production are presented. (This updated bibliography contains 116 citations, 14 of which are new entries to the previous edition.)

1989-09-01

128

Recycling plastic scrap: injection molding. January 1973-August 1988 (Citations from the Rubber and Plastics Research Association data base). Report for January 1973-August 1988  

Energy Technology Data Exchange (ETDEWEB)

This bibliography contains citations concerning the recycling of scrap plastic produced in the injection-molding process. Plastic pellets made from scrap that are used in the injection-molding process are also discussed. Recycling equipment and automated recycling systems are described. Ways to utilize plastic scrap from used cars, packaging materials, and waste from polyurethane production are presented. (This updated bibliography contains 102 citations, 13 of which are new entries to the previous edition.)

1988-08-01

129

Properties of high density polyethylene – Paulownia wood flour composites via injection molding  

Science.gov (United States)

Paulownia wood (PW) flour is evaluated as a bio-based fiber reinforcement. Composites of high density polyethylene (HDPE), 25% by weight of PW, and either 0% or 5% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding followed by injection molding. Molded test composite...

130

Cytocompatibility of titanium metal injection molding with various anodic oxidation post-treatments  

International Nuclear Information System (INIS)

Metal injection molding (MIM) is a near net shape manufacturing method that allows for the production of components of small to moderate size and complex shape. MIM is a cost-effective and flexible manufacturing technique that provides a large innovative potential over existing methods for the industry of implantable devices. Commercially pure titanium (CP-Ti) samples were machined to the same shape as a composite feedstock with titanium and polyoxymethylene, and these metals were injected, debinded and sintered to assess comparative biological properties. Moreover, we treated MIM-Ti parts with BIOCOAT®, BIODIZE® and BIOCER®, three different anodic oxidation techniques that treat titanium using acid, alkaline and anion enriched electrolytes, respectively. Cytocompatibility as well as morphological and chemical features of surfaces was comparatively assessed on each sample, and the results revealed that MIM-Ti compared to CP-Ti demonstrated a specific surface topography with a higher roughness. MIM-Ti and BIOCER® samples significantly enhanced cell proliferation, cell adhesion and cell differentiation compared to CP-Ti. Interestingly, in the anodization post-treatment established in this study, we demonstrated the ability to improve osseointegration through anionic modification treatment. The excellent biological response we observed with MIM parts using the injection molding process represents a promising manufacturing method for the future implantable devices in direct contact with bones. - Highlights: ? Metal injection molding technique gives titanium a specific surface roughness. It enhances the biological response. ? Anodic oxidation method adds Ca, P, and Mg ions on the surface, promoting the cell adhesion. ? Cytocompatibility analyses show an increased cell adhesion and proliferation on MIM-Ti compared to pure titanium.

2012-10-01

131

Heat pipe cooling of an aerospace foam mold manufacturing process  

Energy Technology Data Exchange (ETDEWEB)

A passive heat pipe cooling system was developed to cool a Bendix foam mold used to manufacture aerospace foam parts. The cooling system consists of ten copper-water heat pipes with cooling fins implanted into the aluminum mold and cooled by a domestic size fan blowing ambient air. The number and location of the heat pipes was determined to provide the most effective cooling and mold isothermalization based on experimental measurements of mold temperatures during the exothermic foaming process and from practical considerations of the mold geometry and use. Performance tests were cnducted on an individual heat pipe and on the ten heat pipes implanted in the mold. Both exothermic foam heating and internal electrical heat input were used in the experiments. The experimental test results indicate that the heat pipe cooling system with a fan is four to six times faster than free convection cooling of the mold with no heat pipes or fan and nearly twice as fast as cooling by the fan only. Similarly fast increases in mold heating time in the cure furnace could be realized if the heat pipes are used during this part of the production process. The heat pipes also cool hot spots in the mold and help isothermalize the mold so that better quality foam parts should be produced.

Hahn, D.R.; Feldman, K.T.; Marjon, P.L.

1980-01-01

132

Experimental Analysis for Factors Affecting the Repeatability of Plastics Injection Molding Tests on the Self-developed Apparatus  

Directory of Open Access Journals (Sweden)

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 To improve the repeatability of the injection molding test result, the affecting factors were investigated by means of experiments. Besides the traditional processing parameter, the factors of test conditions were also considered. In order to focus on the molding process rather than the molded part, the curve measurement of the melt pressure at the entrance to the nozzle was used as the output characteristic. Experiments for polypropylene (PP) showed that the injected volume was the key processing parameter. Within the test conditions, the injection number is the most important factor. According to the analysis the operating procedure was improved effectively. Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Doi: 10.12777/ijse.5.1.6-11 [How to cite this article: Huang, Y., Li, D., Liu, Y. (2013). Experimental Analysis for Factors Affecting the Repeatability of Plastics Injection Molding Tests on the Self-developed Apparatus. International Journal of Science and Engineering, 5(1),6-11. Doi: 10.12777/ijse.5.1.6-11

Yugang Huang; Duxin Li; Yuejun Liu

2013-01-01

133

Linear and volumetric dimensional changes of injection-molded PMMA denture base resins.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The aim of this study was to evaluate the linear and volumetric dimensional changes of six denture base resins processed by their corresponding injection-molding systems at 3 time intervals of water storage. MATERIALS AND METHODS: Two heat-curing (SR Ivocap Hi Impact and Lucitone 199) and four auto-curing (IvoBase Hybrid, IvoBase Hi Impact, PalaXpress, and Futura Gen) acrylic resins were used with their specific injection-molding technique to fabricate 6 specimens of each material. Linear and volumetric dimensional changes were determined by means of a digital caliper and an electronic hydrostatic balance, respectively, after water storage of 1, 30, or 90 days. Means and standard deviations of linear and volumetric dimensional changes were calculated in percentage (%). Statistical analysis was done using Student's and Welch's t tests with Bonferroni-Holm correction for multiple comparisons (?=0.05). RESULTS: Statistically significant differences in linear dimensional changes between resins were demonstrated at all three time intervals of water immersion (p?0.05), with exception of the following comparisons which showed no significant difference: IvoBase Hi Impact/SR Ivocap Hi Impact and PalaXpress/Lucitone 199 after 1 day, Futura Gen/PalaXpress and PalaXpress/Lucitone 199 after 30 days, and IvoBase Hybrid/IvoBase Hi Impact after 90 days. Also, statistically significant differences in volumetric dimensional changes between resins were found at all three time intervals of water immersion (p?0.05), with exception of the comparison between PalaXpress and Futura Gen. SIGNIFICANCE: Denture base resins (IvoBase Hybrid and IvoBase Hi Impact) processed by the new injection-molding system (IvoBase), revealed superior dimensional precision.

El Bahra S; Ludwig K; Samran A; Freitag-Wolf S; Kern M

2013-08-01

134

Reducción del Tiempo de Ciclo de Inyección de Termoplásticos con el uso de Moldes con Tratamiento Superficial por Nitruración Cycle Time Reduction of Thermoplastic Injection using Nitriding Treatment Surface Molds  

Directory of Open Access Journals (Sweden)

Full Text Available Se presenta un estudio sobre la transferencia de calor en un molde, comparando los ensayos de inyección utilizando moldes con y sin tratamiento superficial de nitruración. Simulaciones del proceso se realizaron con el uso de Asistencia Computacional a Ingeniería (CAE) para determinar los parámetros iniciales que se aplicaron en los ensayos reales en moldes instrumentados de acero P20 (con y sin tratamientos), inyectados con el polímero poliestireno cristal. Los resultados indicaron una reducción del tiempo de enfriamiento y del tiempo de proceso en el molde con el tratamiento, debido a una mejora en la conductividad térmica.A study on the heat transfer in a mold, comparing experimental injection tests using a mold with and without surface treatment (nitriding) is presented. Process simulations were carried out using Computer Aided Engineering tools (CAE) for the estimation of the initial parameters to be applied in the tests in instrumented P20 steel injection molds with the polymer crystal polystyrene. Results indicated a reduction of cooling time and of the time of the process in the mold with treatment, due to an increase of the thermal conductivity.

Emerson J Corazza; Carlos M Sacchelli; Cintia Marangoni

2012-01-01

135

Reducción del Tiempo de Ciclo de Inyección de Termoplásticos con el uso de Moldes con Tratamiento Superficial por Nitruración/ Cycle Time Reduction of Thermoplastic Injection using Nitriding Treatment Surface Molds  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Se presenta un estudio sobre la transferencia de calor en un molde, comparando los ensayos de inyección utilizando moldes con y sin tratamiento superficial de nitruración. Simulaciones del proceso se realizaron con el uso de Asistencia Computacional a Ingeniería (CAE) para determinar los parámetros iniciales que se aplicaron en los ensayos reales en moldes instrumentados de acero P20 (con y sin tratamientos), inyectados con el polímero poliestireno cristal. Los resul (more) tados indicaron una reducción del tiempo de enfriamiento y del tiempo de proceso en el molde con el tratamiento, debido a una mejora en la conductividad térmica. Abstract in english A study on the heat transfer in a mold, comparing experimental injection tests using a mold with and without surface treatment (nitriding) is presented. Process simulations were carried out using Computer Aided Engineering tools (CAE) for the estimation of the initial parameters to be applied in the tests in instrumented P20 steel injection molds with the polymer crystal polystyrene. Results indicated a reduction of cooling time and of the time of the process in the mold with treatment, due to an increase of the thermal conductivity.

Corazza, Emerson J; Sacchelli, Carlos M; Marangoni, Cintia

2012-01-01

136

Transcription of Small Surface Structures in Injection Molding - an Experimental Study  

DEFF Research Database (Denmark)

The ability to replicate the surface roughness from mold wall to the plastic part in injection moldning has many functional and cosmetic important implications from medical use to designer products. Generally the understanding of surface transcription i.e the the replication of the surface structure from the mould to plastic part, also relates to micro injection moulding and moulding of parts with specific micro structures on the surface such as optical parts. The present study concerns transcription of surface roughness as a function of process parameters. The study is carried out with a polystyrene part, process parameters at typical levels and a rough spark eroded mould surface with Ra=12.6 micro meters.

ArlØ, Uffe Rolf; Kjær, Erik Michael

2001-01-01

137

Optimization of injection molded parts by using ANN-PSO approach  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of the work was the optimization of injection molded product warpage by using an integrated environment.Design/methodology/approach: The approach implemented took advantages of the Finite Element (FE) Analysis to simulate component fabrication and investigate the main causes of defects. A FE model was initially designed and then reinforced by integrating Artificial Neural Network to predict main filling and packing results and Particle Swarm Approach to optimize injection molding process parameters automatically.Findings: This research has confirmed that the evaluation of the FE simulation results through the Artificial Neural Network system was an efficient method for the assessment of the influence of process parameter variation on part manufacturability, suggesting possible adjustments to improve part quality.Research limitations/implications: Future researches will be addressed to the extension of analysis to large thin components and different classes of materials with the aim to improve the proposed approach.Originality/value: The originality of the work was related to the possibility of analyzing component fabrication at the design stage and use results in the manufacturing stage. In this way, design, fabrication and process control were strictly links.

R. Spina

2006-01-01

138

Mold  

Centers for Disease Control (CDC) Podcasts

This podcast answers a listener's question about the risks associated with mold after a natural disaster or severe weather.  Created: 5/2/2011 by National Center for Environmental Health (NCEH).   Date Released: 5/2/2011.

2011-05-02

139

Efeito do processamento em misturas de alumina/ligantes orgânicos usadas na moldagem por injeção em baixa pressão Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeção em baixa pressão (MIBP) é uma técnica que já vem sendo empregada na produção de peças cerâmicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgânicos e pós cerâmicos é um fator determinante que deve ser controlado para minimizar a formação de imperfeições no processamento de feedstocks para MIBP. Defeitos típicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade nas misturas que, após conformação, possuem poucas possibilidades de remoção. Essas imperfeições comprometem o desempenho dos produtos obtidos por essa técnica. Este trabalho está focado na avaliação dessas heterogeneidades e como elas podem ser correlacionadas com a variação da densidade aparente e com o comportamento reológico dessas misturas. Para tanto, aluminas submicrométricas, como recebida e desaglomerada, foram adicionadas a uma mistura fundida de ligantes a base de parafinas, ceras e aditivos e processada em dois tipos diferentes de misturadores, com e sem o auxílio de vácuo. Foi observada a presença de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinação. Também foi observado que o tipo de misturador e a aplicação ou não de vácuo durante a etapa final do processamento têm grande influência no tempo de mistura necessário para reduzir a viscosidade do feedstock para a injeção.The low-pressure injection molding (LPIM) is a technique already being used in the production of ceramic parts with complex shapes and geometries. The homogeneity of the mixture of organic binder and ceramic powder is a determining factor which must be controlled to minimize defects formation while feedstock processing to LPIM. Typical defects of LPIM processing, such as air bubbles and agglomerates, generate density gradients in the mixtures, which, after shaping, have little possibility of removal. These imperfections compromise the performance of the products obtained by this technique. This work is focused on the evaluation of these inhomogeneities and how they can be correlated with density variation and the rheological behavior of these mixtures. Therefore, submicrometer aluminas, as received and deagglomerated, were added to a molten mixture of paraffin based binders, waxes and additives and processed in two different mixers, with and without vacuum. The presence of alumina agglomerates was observed in the powder as received, possibly generated during the calcination step. It was also observed that the type of mixer and vacuum application or not during the final processing step, has a major influence on the mixing time required to reduce the viscosity of the feedstock for injection.

P . A. Ourique; A. Susin Neto; S. G. Echeverrigaray; R. C. D. Cruz; J. E. Zorzi

2013-01-01

140

Efeito do processamento em misturas de alumina/ligantes orgânicos usadas na moldagem por injeção em baixa pressão/ Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A moldagem por injeção em baixa pressão (MIBP) é uma técnica que já vem sendo empregada na produção de peças cerâmicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgânicos e pós cerâmicos é um fator determinante que deve ser controlado para minimizar a formação de imperfeições no processamento de feedstocks para MIBP. Defeitos típicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade (more) nas misturas que, após conformação, possuem poucas possibilidades de remoção. Essas imperfeições comprometem o desempenho dos produtos obtidos por essa técnica. Este trabalho está focado na avaliação dessas heterogeneidades e como elas podem ser correlacionadas com a variação da densidade aparente e com o comportamento reológico dessas misturas. Para tanto, aluminas submicrométricas, como recebida e desaglomerada, foram adicionadas a uma mistura fundida de ligantes a base de parafinas, ceras e aditivos e processada em dois tipos diferentes de misturadores, com e sem o auxílio de vácuo. Foi observada a presença de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinação. Também foi observado que o tipo de misturador e a aplicação ou não de vácuo durante a etapa final do processamento têm grande influência no tempo de mistura necessário para reduzir a viscosidade do feedstock para a injeção. Abstract in english The low-pressure injection molding (LPIM) is a technique already being used in the production of ceramic parts with complex shapes and geometries. The homogeneity of the mixture of organic binder and ceramic powder is a determining factor which must be controlled to minimize defects formation while feedstock processing to LPIM. Typical defects of LPIM processing, such as air bubbles and agglomerates, generate density gradients in the mixtures, which, after shaping, have l (more) ittle possibility of removal. These imperfections compromise the performance of the products obtained by this technique. This work is focused on the evaluation of these inhomogeneities and how they can be correlated with density variation and the rheological behavior of these mixtures. Therefore, submicrometer aluminas, as received and deagglomerated, were added to a molten mixture of paraffin based binders, waxes and additives and processed in two different mixers, with and without vacuum. The presence of alumina agglomerates was observed in the powder as received, possibly generated during the calcination step. It was also observed that the type of mixer and vacuum application or not during the final processing step, has a major influence on the mixing time required to reduce the viscosity of the feedstock for injection.

Ourique, P . A.; Susin Neto, A.; Echeverrigaray, S. G.; Cruz, R. C. D.; Zorzi, J. E.

2013-03-01

 
 
 
 
141

Crystallization kinetics and morphology of PBT/MMT and PTT/MMT nanocomposites during injection molding  

International Nuclear Information System (INIS)

This work had as main objective to study the crystallization of nanocomposites of poly(butylene terephthalate) (PBT) and poly(trimethylene terephthalate) (PTT) with a montmorillonite nanoclay (MMT) using an on-line optical monitoring system during the injection molding and to characterize the morphologies of the injection samples by polarized light optical microscopy (PLOM), wide angle X-ray diffraction (WAXS) and differential scanning calorimetry (DSC). The optical system allowed to analyze the crystallization process by the changes of the optical properties during the solidification of the materials. It was concluded that the MMT lamellae accelerated the overall crystallization of the polymers. By PLOM, it was observed that the nanoclay caused qualitative changes on the morphology of the PTT (polymer with slow crystallization kinetics). The crystallinity indexes were not affected by the addition of the MMT; however, by WAXS it was shown that the nanocomposites had a higher orientation degree. (author)

2009-01-01

142

Design and development of an injection-molded demultiplexer for optical communication systems in the visible range.  

UK PubMed Central (United Kingdom)

Optical simulation software based on the ray-tracing method offers easy and fast results in imaging optics. This method can also be applied in other fields of light propagation. For short distance communications, polymer optical fibers (POFs) are gradually gaining importance. This kind of fiber offers a larger core diameter, e.g., the step index POF features a core diameter of 980 ?m. Consequently, POFs have a large number of modes (>3 million modes) in the visible range, and ray tracing could be used to simulate the propagation of light. This simulation method is applicable not only for the fiber itself but also for the key components of a complete POF network, e.g., couplers or other key elements of the transmission line. In this paper a demultiplexer designed and developed by means of ray tracing is presented. Compared to the classical optical design, requirements for optimal design differ particularly with regard to minimizing the insertion loss (IL). The basis of the presented key element is a WDM device using a Rowland spectrometer setup. In this approach the input fiber carries multiple wavelengths, which will be divided into multiple output fibers that transmit only one wavelength. To adapt the basic setup to POF, the guidance of light in this element has to be changed fundamentally. Here, a monolithic approach is presented with a blazed grating using an aspheric mirror to minimize most of the aberrations. In the simulations the POF is represented by an area light source, while the grating is analyzed for different orders and the highest possible efficiency. In general, the element should be designed in a way that it can be produced with a mass production technology like injection molding in order to offer a reasonable price. However, designing the elements with regard to injection molding leads to some inherent challenges. The microstructure of an optical grating and the thick-walled 3D molded parts both result in high demands on the injection molding process. This also requires complex machining of the molding tool. Therefore, different experiments are done to optimize the process parameter, find the best molding material, and find a suitable machining method for the molding tool. The paper will describe the development of the demultiplexer by means of ray-tracing simulations step by step. Also, the process steps and the realized solutions for the injection molding are described.

Höll S; Haupt M; Fischer UH

2013-06-01

143

Design and development of an injection-molded demultiplexer for optical communication systems in the visible range.  

Science.gov (United States)

Optical simulation software based on the ray-tracing method offers easy and fast results in imaging optics. This method can also be applied in other fields of light propagation. For short distance communications, polymer optical fibers (POFs) are gradually gaining importance. This kind of fiber offers a larger core diameter, e.g., the step index POF features a core diameter of 980 ?m. Consequently, POFs have a large number of modes (>3 million modes) in the visible range, and ray tracing could be used to simulate the propagation of light. This simulation method is applicable not only for the fiber itself but also for the key components of a complete POF network, e.g., couplers or other key elements of the transmission line. In this paper a demultiplexer designed and developed by means of ray tracing is presented. Compared to the classical optical design, requirements for optimal design differ particularly with regard to minimizing the insertion loss (IL). The basis of the presented key element is a WDM device using a Rowland spectrometer setup. In this approach the input fiber carries multiple wavelengths, which will be divided into multiple output fibers that transmit only one wavelength. To adapt the basic setup to POF, the guidance of light in this element has to be changed fundamentally. Here, a monolithic approach is presented with a blazed grating using an aspheric mirror to minimize most of the aberrations. In the simulations the POF is represented by an area light source, while the grating is analyzed for different orders and the highest possible efficiency. In general, the element should be designed in a way that it can be produced with a mass production technology like injection molding in order to offer a reasonable price. However, designing the elements with regard to injection molding leads to some inherent challenges. The microstructure of an optical grating and the thick-walled 3D molded parts both result in high demands on the injection molding process. This also requires complex machining of the molding tool. Therefore, different experiments are done to optimize the process parameter, find the best molding material, and find a suitable machining method for the molding tool. The paper will describe the development of the demultiplexer by means of ray-tracing simulations step by step. Also, the process steps and the realized solutions for the injection molding are described. PMID:23842150

Höll, S; Haupt, M; Fischer, U H P

2013-06-20

144

Nanoimprint Molds with Circumferentially Aligned Patterns Fabricated by Liftoff Process  

Science.gov (United States)

A liftoff process was used to fabricate nanoimprint molds with dense patterns below 50 nm pitch. Circumferentially aligned patterns were defined by electron-beam lithography (EBL) using an electron-beam recorder with a rotary stage. Undercut profiles suitable for liftoff were fabricated by etching multilayered resist systems that use a hydrogen silsesquioxane (HSQ) layer as an etching mask for the underlying resin, and liftoff was performed by dissolving the HSQ layer on an insoluble resin layer. By using an undercut profile that was formed in a trilayered stack after EBL, a mold with high-density (42 nm pitch) and large-area (2.5 in.) pillar patterns was fabricated. Quartz replica molds were also fabricated by the liftoff process combined with UV nanoimprint. It was possible to fabricate molds with both a positive tone and a negative tone, and the fabrication of a replica mold with pillar patterns (49 nm pitch) was demonstrated.

Okada, Takeru; Fujimori, Jiro; Iida, Tetsuya

2011-12-01

145

[Application of microwave for dental technique. 5. Injection molding system for resin base denture].  

Science.gov (United States)

An injector and FRP denture flask were developed for injection molding and the fit of the denture base constructed with this injection molding system was evaluated. In addition, the flow and pressure of the dough, that is polymer-monomer mixture, in the mold space were investigated. The monomer of 10 mg/cm2 in the dough vaporized during the 5 minutes it took for the flash to be removed. When pressure of more than 55 kgf/cm2 was exerted to the dough, the dough was completely packed in the mold space. Fastening of the sprue with a bolt within 2 minutes after injection of the dough made the pressure of the dough increase to about 30 kgf/cm2. The dough in the mold space was maintained at a pressure of above 20 kgf/cm2 for microwave heating time. The adaptability of the resin base denture constructed with a combination of injection molding and microwave polymerization was 2 or 3 times greater than that of the denture constructed with microwave heating from the tissue side of the denture base. PMID:2134815

Kimura, H; Teraoka, F; Sugita, M

1990-01-01

146

Bulk and Surface Molecular Orientation Distribution in Injection-molded Liquid Crystalline Polymers: Experiment and Simulation  

Energy Technology Data Exchange (ETDEWEB)

Bulk and surface distributions of molecular orientation in injection-molded plaques of thermotropic liquid crystalline polymers (TLCPs) have been studied using a combination of techniques, coordinated with process simulations using the Larson-Doi 'polydomain' model. Wide-angle X-ray scattering was used to map out the bulk orientation distribution. Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) were utilized to probe the molecular orientation states to within about {approx}5 {micro}m and {approx}2 nm, respectively, of the sample surface. These noninvasive, surface-sensitive techniques yield reasonable self-consistency, providing complementary validation of the robustness of these methods. An analogy between Larson-Doi and fiber orientation models has allowed the first simulations of TLCP injection molding. The simulations capture many fine details in the bulk orientation distribution across the sample plaque. Direct simulation of surface orientation at the level probed by FTIR-ATR and NEXAFS was not possible due to the limited spatial resolution of the simulations. However, simulation results extracted from the shear-dominant skin region are found to provide a qualitatively accurate indicator of surface orientation. Finally, simulations capture the relation between bulk and surface orientation states across the different regions of the sample plaque.

Fang, J.; Burghardt, W; Bubeck, R; Burgard, S; Fischer, D

2010-01-01

147

Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: > PP/CNFs and PP/TiO{sub 2} composites with relative high loading fractions (10, 20, 30 and 35 wt%) were fabricated by inner melt mixing process. Micro tensile test samples were formed by injection molding combined with variotherm process for all composites. > The morphological properties of all nano composites were characterized by WXRD, whose results imply the adding nano fillers did not change the crystal form of PP, but the crystallites size and distance between lattices of crystals were changed with various nano fillers and loading fractions. > DSC analysis show that due to the nucleating function of nano fillers, the peak temperature of crystallization was increased and the peak temperature of crystallization melting was decreased by adding the nanofillers. > The flow ability of nano composites was tested by high pressure single capillary rheometer and the results demonstrate that nano fillers increased the viscosity of PP matrix. > Based on these significant information and analysis foundation of the nano filled composites, the micro weld line samples were formed by injection molding process and characterized by tensile test method. From the achieved results, it can be found that in general, for functional nano filled polymer composites, the mechanical property of micro weld lines were obviously influenced by nano fillers' shape and loading fractions. > The E modulus of micro weld line was increased due to loading CNFs in PP matrix, while the elongation of the micro tensile samples with weld line is considerably decreased comparing with those of unfilled PP samples. The detrimental tensile strength of micro weld lines were observed when CNFs contents increasing, except for at a 10 wt%. > For TiO{sub 2} nano particles filled PP, due to the poor dispersion of nano particles, at low loading fraction of 10 wt%, the E modulus and tensile strength of micro weld lines were decreased by filling nano particles, but when the loading fraction is increased to 30%, the E modulus and tensile strength of micro weld line were increased again compared with the low loading level. > Finally, an empirical prediction equation for micro injection molded weld line strength of nano PP composites was proposed for higher nano filler loading fraction than 10 wt%. - Abstract: The nano filled functional polymer materials have been widely processed with micro injection molding technology for micro electromechanical systems (MEMS) fabrication. As the unfavorable defect in micro injection molding parts, weld line brings reduced mechanical and physical properties, especially for nano filled composites. In this study, polypropylene (PP) was compounded respectively with carbon nano fibers (CNFs) and TiO{sub 2} nano particles at various weight fractions (10, 20, 30, 35 wt%) through co-screws internal mixing. The morphological, thermal and rheological properties of nano composites were characterized by wider angle X-ray diffraction (WXRD), different scanning calorimeter (DSC) and high pressure capillary rheometer. Additionally, under the constant setting of injection molding process parameters in injection molding machine, micro tensile samples with weld lines for each nano filled PP composite were produced. The tensile tests were served as the characterizing method for weld line mechanical properties. The results show that when the CNFs is filled higher than 10 wt%, the tensile strength of samples with weld lines made of nano composites become lower than neat PP. While the raising CNFs content contributes to the improved E modulus of micro injection molded weld lines. Additionally, with the increasing fraction of CNFs in PP, the weld line area's elongation percent is decreased. Whereas for case of TiO{sub 2}, the 10 wt% is the threshold for micro injection molded weld line tensile strength turning from decrease trend to increase. The same as CNFs, elongation of micro weld line samples were in general lower than neat PP as well, due to the addition of TiO{sub 2} nano particles.

Xie Lei, E-mail: Lei.Xie@tu-clausthal.de [Institute of Polymer Materials and Plastics Engineering, Technology University of Clausthal, Agricola str.6, 38678, Clausthal-Zellerfeld (Germany); Ziegmann, Gerhard [Institute of Polymer Materials and Plastics Engineering, Technology University of Clausthal, Agricola str.6, 38678, Clausthal-Zellerfeld (Germany)

2011-01-12

148

Hot mold casting process of ancient East India and Bangladesh  

Directory of Open Access Journals (Sweden)

Full Text Available Ancient casting process for production of brass or bronze utensils and icons were made in hot molds using clay molded investment casting or piece mold process, as presumed by archaeologists. Piece mold process is still traditionally practiced in many parts of Eastern India and Bangladesh along with investment casting process. Incidentally, Bengal artisans are more accustomed to piece mold process unlike tribal artisans who practiced investment casting process. This piece mold casting process has been reconstructed to get the idea of metal characteristics in order to investigate ancient casting process of Bengal and Bangladesh. The characterization of ancient archaeo-metal products come to a type of cast Cu-Sn-Zn-Pb type quaternary alloy produced by a slow freezing process. Though these alloys physically differ from the traditional cast alloy of binary Cu-Zn type brass, the physical characteristics are similar to the binary cast alloy character. This investigation throws light on the similarity of the production processes by which ancient artisans probably produced cast metal products.

Barnali Mandal; Prasanta Kumar Datta

2010-01-01

149

Injection molded polymer chip for electrochemical and electrophysiological recordings from single cells  

DEFF Research Database (Denmark)

We present a novel method to fabricate an all in polymer injection molded chip for electrochemical cell recordings and lateral cell trapping. The complete device is molded in thermoplastic polymer and it results from assembling two halves. We tested spin-coated conductive polymer poly(3,4-ethylenedioxythiopene) and showed that it can be used as an electrode material for detecting neurotransmitters electrochemically in biosensors.

Tanzi, Simone; Larsen, Simon Tylsgaard

150

A new instrument for statistical process control of thermoset molding  

International Nuclear Information System (INIS)

[en] The recent development of a rugged ceramic mold mounted dielectric sensor and high speed dielectric instrumentation now enables monitoring and statistical process control of production molding over thousands of runs. In this work special instrumentation and software (ICAM-1000) was utilized that automatically extracts critical point during the molding process including flow point, viscosity minimum gel inflection, and reaction endpoint. In addition, other sensors were incorporated to measure temperature and pressure. The critical point as well as temperature and pressure were then recorded during normal production and then plotted in the form of statistical process control (SPC) charts. Experiments have been carried out in RIM, SMC, and RTM type molding operations. The influence of temperature, pressure chemistry, and other variables has been investigated. In this paper examples of both RIM and SMC are discussed

1991-01-01

151

Mejora de la etapa de llenado en moldes de inyección de plástico usando vibración/ Improvement Performance of the Filling Step in Injection Mold through Vibration  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish El presente trabajo muestra la mejora de flujo que tiene la etapa de llenado del proceso de inyección de plásticos, debida a la excitación del polímero a través de vibración. Dicho proceso, puede resumirse en tres etapas principales que son: el llenado, el empaquetado y el enfriamiento. El proceso de llenado es el paso en el que se pueden cambiar una gran cantidad de propiedades, tanto mecánicas como estéticas del producto terminado. El objetivo de esta investigac (more) ión es mostrar que el llenado del molde mejora adicionando vibración, sin tener que agregar aditivos químicos. Para ello, se llevó a cabo el diseño y fabricación de un molde experimental, en el cual se acondicionó un mecanismo de vibración que permitió demostrar las ventajas de la vibración en dicho proceso. Además, se propuso una metodología heurística para la elaboración de las pruebas que reveló una mejora en el llenado con frecuencias cercanas a los 3 Hz. Abstract in english This paper shows the flow improvement in the filling step of the polymer injection process due to the polymer excitation though vibration. This process can be split up into three main steps: filling, pocking and cooling. Several mechanical and aesthetic properties of the finished product can be changed in the filling step. The objective of this investigation is to demonstrate the improvement in the filling mold under vibration without adding chemical products. To reach th (more) is result, an experimental mold was designed and manufactured in which a vibration device was coupled; it was possible to demonstrate the vibration advantage through this process. Moreover, a heuristic methodology was proposed for the experiment which shows an improvement in the filling process with frequencies close to 3 Hz.

Benítez-Rangel, J.P.; Morales-Hernández, L.A.; Trejo-Hernández, M.

2012-12-01

152

Fabrication and characterization of injection molded multi level nano and microfluidic systems  

DEFF Research Database (Denmark)

We here present a method for fabrication of multi-level all-polymer chips by means of silicon dry etching, electroplating and injection molding. This method was used for successful fabrication of microfluidic chips for applications in the fields of electrochemistry, cell trapping and DNA elongation. These chips incorporate channel depths in the range between 100nm and 100?m and depth to width aspect ratios between 1/200 and 2. Optimization of the sealing process of all-polymer COC microfluidic chips by means of thermal bonding is also presented. The latter includes comparing the bonding strength of UV-treated foils and presentation of a simple model for estimating the delamination pressure. With UV surface treatments, foils of 100?m thickness were found to withstand pressures up to 9atm in Ø4mm cylindrical inlets when thermally bonded to micropatterned substrates of 2mm thickness.

Matteucci, Marco; Christiansen, Thomas Lehrmann

2013-01-01

153

Improvements in sintered density and dimensional stability of powder injection-molded 316L compacts by adjusting the alloying compositions  

International Nuclear Information System (INIS)

[en] Powder injection molding is a process that provides advantages when making small parts with high density and complicated shapes. However, dimensional control of powder injection-molded stainless steel parts is difficult due to the presence of the liquid phase and the large amount of shrinkage that occurs during sintering. This study examines whether such a problem can be overcome through adjustments in the alloy composition and by making use of Thermo-Calc analysis. The results show that, with an increase in the molybdenum content up to the maximum limit according to existing specifications, a compact can be sintered to high densities without the presence of the liquid phase, while maintaining it in the dual-phase region of ? + ?. In addition, dimensional control is improved. A slower heating rate is also found to be beneficial. These results are explained through dilatometric analysis and phase diagrams that are calculated using the Thermo-Calc program

2006-01-01

154

Microstructure and mechanical behavior of metal injection molded Ti-Nb binary alloys as biomedical material.  

UK PubMed Central (United Kingdom)

The application of titanium (Ti) based biomedical materials which are widely used at present, such as commercially pure titanium (CP-Ti) and Ti-6Al-4V, are limited by the mismatch of Young's modulus between the implant and the bones, the high costs of products, and the difficulty of producing complex shapes of materials by conventional methods. Niobium (Nb) is a non-toxic element with strong ? stabilizing effect in Ti alloys, which makes Ti-Nb based alloys attractive for implant application. Metal injection molding (MIM) is a cost-efficient near-net shape process. Thus, it attracts growing interest for the processing of Ti and Ti alloys as biomaterial. In this investigation, metal injection molding was applied to the fabrication of a series of Ti-Nb binary alloys with niobium content ranging from 10wt% to 22wt%, and CP-Ti for comparison. Specimens were characterized by melt extraction, optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). Titanium carbide formation was observed in all the as-sintered Ti-Nb binary alloys but not in the as-sintered CP-Ti. Selected area electron diffraction (SAED) patterns revealed that the carbides are Ti2C. It was found that with increasing niobium content from 0% to 22%, the porosity increased from about 1.6% to 5.8%, and the carbide area fraction increased from 0% to about 1.8% in the as-sintered samples. The effects of niobium content, porosity and titanium carbides on mechanical properties have been discussed. The as-sintered Ti-Nb specimens exhibited an excellent combination of high tensile strength and low Young's modulus, but relatively low ductility.

Zhao D; Chang K; Ebel T; Qian M; Willumeit R; Yan M; Pyczak F

2013-08-01

155

Fabrication Processes for Capacity-Equalized Mold with Fine Patterns  

Science.gov (United States)

The variation of residual layer thickness (RLT) by the difference of pattern density is a difficult problem in UV nanoimprint lithography (NIL). A capacity-equalized mold was proposed to solve the problem, and the effectiveness of the concept was validated using a mold with various pattern sizes of hundreds of micrometers. However, the effectiveness should be evaluated at nanometer scales to prove the concept. Here the first challenge has been to fabricate and evaluate a two-step-depth mold with tens of nanometer patterns for the capacity-equalized mold. A two-step-depth mold with sub-100 nm patterns was fabricated by a combination of electron beam lithography and laser beam lithography. We succeeded in fabricating a two-step-structure with a width of around 40 nm, and the widths of the deeper grooves were found to have slightly increased during the second RIE process. The differences in widths were found to vary approximately from 10 to 30 nm. UV nanoimprint was carried out using the two-step-depth mold in order to examine its depth modulation, and to judge whether it could be applied to a NIL process, including a residual-layer-removal process. Fine patterns of 40 nm width were successfully transferred onto the underlying Si wafer from two-step-height resin patterns that were fabricated by UV nanoimprint.

Suzuki, Kenta; Youn, Sung-Won; Wang, Qing; Hiroshima, Hiroshi; Nishioka, Yasushiro

2011-06-01

156

All-in-polymer injection molded device for single cell capture using multilevel silicon master fabrication  

DEFF Research Database (Denmark)

This work demonstrates a novel all-in-polymer device for single cell capture applicable for biological recordings. The chip is injection molded and comprises a "cornered" (non planar) aperture. It has been demonstrated how cornered apertures are straightforward to mold in PDMS [1,2]. In this study we demonstrate cornered apertures made in a thermoplastic polymer. One of the advantages of cornered apertures is the ease of microscopy under a standard inverted optical microscope, when using transparent materials. After the part is injection molded, the sealing of the chip is performed by thermal bonding to a polymer foil, so the complete device results from only two parts. It differs from similar devices in the novel material and fabrication platform that enables high reproducibility and inexpensive mass production. Optimization of the fabrication scheme has been carried out in order to avoid defects during demolding. Capturing of single PC12 cells has been demonstrated.

Tanzi, S.; Larsen, S.T.

2012-01-01

157

Microwaves energy in curing process of water glass molding sands  

Directory of Open Access Journals (Sweden)

Full Text Available This work presents the results of investigation of microwave heating on hardening process of water glass molding sands. Essential influence of this heating process on basic properties such as: compression, bending and tensile strength as well as permeability and abrasion resistance has been found. It has been proved, that all investigated sorts of sodium water glass with a module between 2.0 and 3.3 can be used as a binder of molding sands in microwave curing process. It has been found during analysis of research results of sands with 2.5 % water glass addition that they are practically the same as in case of identical molding sands dried for 120 minutes at the temperature of 110°C, used for comparative purposes. Application of microwave curing of molding sands with water glass, however, guarantees reduction of hardening time (from 120 to 4 minutes) as well as significant reduction of energy consumption. Attempts of two stage hardening of the investigated water glass molding sands have also been carried out, that is after an initial hardening during a classical CO2 process (identical sands have also been tested for comparison after CO2 blowing process) and additional microwave heating. It has been found that application of this kind of treatment for curing sands with 2.5 % sodium water glass content and module from 2.0 up to 3.3 results in the improvement of properties in comparison to classical CO2 process.

Granat K.; Nowak D.; Pigiel M.; Stachowicz M.; Wikiera R.

2007-01-01

158

CO-INJECTION RESIN TRANSFER MOLDING FOR OPTIMIZATION OF INTEGRAL ARMOR  

Science.gov (United States)

To address the cost and performance barriers which hinder the introduction of composite materials for combat ground vehicle applications, Co-Injection Resin Transfer Molding (CIRTM) and Diffusion Enhanced Adhesion (DEA) have been recently invented and developed at the Army Resear...

159

Low Speed Technology for Small Turbine Development Reaction Injection Molded 7.5 Meter Wind Turbine Blade  

Energy Technology Data Exchange (ETDEWEB)

An optimized small turbine blade (7.5m radius) was designed and a partial section molded with the RIM (reaction-injection molded polymer) process for mass production. The intended market is for generic three-bladed wind turbines, 100 kilowatts or less, for grid-assist end users with rural and semi-rural sites, such as the farm/ranch market, having low to moderate IEC Class 3-4 wind regimes. This blade will have substantial performance improvements over, and be cheaper than, present-day 7.5m blades. This is made possible by the injection-molding process, which yields high repeatability, accurate geometry and weights, and low cost in production quantities. No wind turbine blade in the 7.5m or greater size has used this process. The blade design chosen uses a RIM skin bonded to a braided infused carbon fiber/epoxy spar. This approach is attractive to present users of wind turbine blades in the 5-10m sizes. These include rebladeing California wind farms, refurbishing used turbines for the Midwest farm market, and other manufacturers introducing new turbines in this size range.

David M. Wright; DOE Project Officer - Keith Bennett

2007-07-31

160

EXTRUDED AND INJECTION MOLDED BIOPOLYMERS: PROPERTIES OF POLYLACTIC ACID PLA/SUGAR-BEET PULP BLENDS, AND WHEY PROTEIN/CORN GLUTEN MEAL (CGM)  

Science.gov (United States)

In this study, processing techniques for extruded foods and non-foods using new and novel ingredients, to create unique bio-polymer blends, are emphasized. Our team in the Center of Excellence for Extrusion and Polymer Rheology (CEEPR) has recently used extrusion processing and injection molding (I...

 
 
 
 
161

Computing flow-induced stresses of injection molding based on PTT model  

Science.gov (United States)

A numerical approach is introduced to solve the viscoelastic flow problem of filling and post-filling in injection molding. The governing equations are in terms of compressible, non-isothermal fluid, and the constitutive equation is based on the PTT model. By introducing some hypotheses according to the characteristics of injection molding, a quasi-Poisson type equation about pressure is derived with part integration. Besides, an analytical form of flow-induced stress is also generalized by using Undermined Coefficient Method. The conventional Galerkin approach is employed to solve the derived pressure equation, and the 'upwind' difference scheme is used to discrete the energy equation. Coupling is achieved between velocity and stress by Super Relax Iteration Method. The flow in the test mold is investigated by comparing the numerical results and photoelastic photos for polystyrene, showing flow-induced stresses are closely related to melt temperatures. The filling of a two-cavity box is also studied to investigate the viscoelastic effects on real injection molding.

Cao, Wei; Gan, Shufeng; Li, Qian; Shen, Changyu

2010-06-01

162

Experimental Study of Fiber Length and Orientation in Injection Molded Natural Fiber/Starch Acetate Composites  

DEFF Research Database (Denmark)

Composite compounds based on triethyl citrate plasticized starch acetate and hemp and flax fibers were prepared by melt processing. Plasticizer contents from 20 to 35 wt% and fiber contents of 10 and 40 wt% were used. The compounded composites were injection molded to tensile test specimens. The effect of processing, melt viscosity and fiber type on the fiber length was investigated. The lengths of fully processed fibers were determined by dissolving the matrix and measuring the length of the remaining fibers by microscope analysis. A clear reductive effect of the processing on the fiber length was noticed. A reduction of fiber length along the increasing fiber content and the decreasing plasticizer content was also detected. This reduction originated from the increasing shear forces during compounding, which again depended on the increased viscosity of the material. Hemp fibers were shown to remain longer and fibrillate more than flax fibers, leading to higher aspect ratio. Thus, the reinforcement efficiencyof hemp fibers by the processing was improved, in contrast with flax fibers. In addition, the analysis of fiber dispersion and orientation showed a good dispersion of fibers in the matrix, and a predominant orientation of the fibers in the melt flow direction.

Peltola, Heidi; Madsen, Bo

2011-01-01

163

SAXS studies of the injection molding effects on the nanostructure of polyesters. II: polytrimetylene terephthalate (PTT)  

International Nuclear Information System (INIS)

In this work, the nanoperiodicity of some PTT samples, injection molded at different conditions, was evaluated as a function of the thickness of the samples. From the small angle X-ray scattering (SAXS) results, it was possible to observe that, as expected, there is a gradient of the L and lc values found through the thickness of the PTT samples. It was also found that at the center of the PTT sample injection molded at low injection temperature, Ti, the crystallinity degree evaluated previously by wide angle X-ray diffraction (WAXD) is high and the orientation in this region must be also high, because smaller values of L and lC were found at this region of the sample. The opposite trend was found to PBT.(author)

2005-01-01

164

SAXS studies of the injection molding effects on the nanostructure of polyesters. II: polytrimetylene terephthalate (PTT)  

Energy Technology Data Exchange (ETDEWEB)

In this work, the nanoperiodicity of some PTT samples, injection molded at different conditions, was evaluated as a function of the thickness of the samples. From the small angle X-ray scattering (SAXS) results, it was possible to observe that, as expected, there is a gradient of the L and lc values found through the thickness of the PTT samples. It was also found that at the center of the PTT sample injection molded at low injection temperature, Ti, the crystallinity degree evaluated previously by wide angle X-ray diffraction (WAXD) is high and the orientation in this region must be also high, because smaller values of L and l{sub C} were found at this region of the sample. The opposite trend was found to PBT.(author)

Marinelli, Alessandra L. [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil). Centro de Caracterizacao e Desenvolvimento de Materiais]. E-mail: alucas@ccdm.ufscar.br; Farah, Marcelo [Braskem S.A., Sao Paulo, SP (Brazil)]. E-mail: marcelo.farah@braskem.com.br; Plivelic, Tomas; Torriani, Iris [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas (Brazil)]. E-mail: tomas@lnls.br; torriani@lnls.br; Bretas, Rosario E.S. [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil). Dept. de Engenharia de Materiais. Nucleo de Reologia e Processamento de Polimeros]. E-mail: bretas@power.ufscar.br

2005-07-01

165

Determination of Optimal Manufacturing Parameters for Injection Mold by Inverse Model Basing on MANFIS  

Directory of Open Access Journals (Sweden)

Full Text Available Since plastic products are with the features as light, anticorrosive and low cost etc., that are generally used in several of tools or components. Consequently, the requirements on the quality and effectiveness in production are increasingly serious. However, there are many factors affecting the yield rate of injection products such as material characteristic, mold design, and manufacturing parameters etc. involved with injection machine and the whole manufacturing process. Traditionally, these factors can only be designed and adjusted by many times of trial-and-error tests. It is not only waste of time and resource, but also lack of methodology for referring. Although there are some methods as Taguchi method or neural network etc. proposed for serving and optimizing this problem, they are still insufficient for the needs. For the reasons, a method for determining the optimal parameters by the inverse model of manufacturing platform is proposed in this paper. Through the integration of inverse model basing on MANFIS and Taguchi method, inversely, the optimal manufacturing parameters can be found by using the product requirements. The effectiveness and feasibility of this proposal is confirmed through numerical studies on a real case example.

Chung-Neng Huang; Chong-Ching Chang

2010-01-01

166

The manufactoring of a two–layered injection mold by welding  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents the technology of deposit cladding different materials, using the injection molds for thermoplastic as a case study. The aim of the study is to surface weld to the working surface of the mold a different material with corresponding physical properties. Steel (1.1141) and a copper alloy were used as the base, onto which different materials were surface-welded. Tungsten inert gas (TIG) welding was employed to make molds inserts. An analysis of cross-sectioned specimens was made by optical microscopy, and chemical and hardness profiles were measured too. The thermal conductivity of base and cladded layer was also tested. Finally, a thermal fatigue test was employed to investigate the thermal fatigue properties of such surfaces.

A. Košnik; J. Tušek; L. Kosec; T. Muhi?

2011-01-01

167

Evolução da morfologia de fases de blendas PA6/AES em extrusora de dupla rosca e moldagem por injeção/ Evolution of phase morphology of PA6/AES blends during the twin screw extrusion and injection molding processes  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A evolução da morfologia de fases em blendas não reativas e reativas de poliamida-6 com copolímero de acrilonitrila/EPDM/estireno (AES) em uma extrusora de rosca dupla co-rotacional foi investigada. A evolução da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada através da coleta de pequenas amostras em válvulas no barril da extrusora e caracterização por microscopia eletrônica de transmissão (MET). Foram utilizados como compatibilizantes (more) reativos os copolímeros metacrilato de metila-co-anidrido maleico (MMA-MA) e metacrilato de metila-co-metacrilato de glicidila (MMA-GMA). Os grupos anidrido maleico e epóxi nos copolímeros podem reagir com os grupos finais de cadeia da poliamida durante o processamento no estado fundido e melhorar a interação na interfase do sistema PA6/AES. A blenda PA6/AES não compatibilizada apresentou uma morfologia grosseira de fases onde a fase AES não está bem dispersa na matriz de PA6 devido à falta de interações adequadas entre os componentes da blenda. A adição do compatibilizante MMA-GMA não proporcionou boa dispersão de fases e não melhorou as propriedades mecânicas da blenda, provavelmente porque as possíveis reações no sistema são lentas e podem não ocorrer na extrusora. Por outro lado, a blenda compatibilizada com o copolímero MMA-MA apresentou uma excelente resistência ao impacto à temperatura ambiente e uma diminuição na temperatura de transição dúctil-frágil. As partículas de AES apresentam-se muito mais refinadas e sofrem uma redução significativa em seu tamanho já no início do processo de extrusão. A morfologia observada nas amostras injetadas apresentou uma boa correlação com as propriedades mecânicas obtidas. Abstract in english The evolution of phase morphology in non-reactive vs reactive blends with polyamide and ethylene-propylene-diene elastomer grafted with styrene-acrylonitrile copolymer (AES) in a co-rotating twin-screw extruder was investigated. The morphological evolution of these blends along a twin-screw extruder was monitored by quickly collecting small samples from the melt at specific extruder barrel locations and characterizing them with a transmission electron microscope (TEM). Th (more) e copolymers methyl methacrylate-co-maleic anhydride (MMA-MA) and methyl methacrylate-co-glycidyl methacrylate (MMA-GMA) were used as compatibilizing agents. The maleic anhydride and the epoxy groups of the copolymers can react with the polyamide end groups during melt processing and improve the interphase interaction in the PA6/AES system. The uncompatibilized blends showed a coarse phase morphology where the AES phase is not well dispersed in the PA6 matrix due to lack of adequate interaction between the components. The addition of MMA-GMA compatibilizer neither promoted good phase dispersion or improved the mechanical properties of the blends, probably because the possible reactions are very slow and may not occur inside the extruder. On the other hand, the addition of the MMA-MA copolymer promotes better impact strength and good phase dispersion in the blend. The AES particles undergo significant reduction in the first stages of the mixture inside the extruder. The morphology observed for the injection molded specimens was correlated with the mechanical properties.

Bassani, Adriane; Hage Jr, Elias; Pessan, Luiz A.; Machado, Ana V; Covas, José A.

2005-07-01

168

Evolução da morfologia de fases de blendas PA6/AES em extrusora de dupla rosca e moldagem por injeção Evolution of phase morphology of PA6/AES blends during the twin screw extrusion and injection molding processes  

Directory of Open Access Journals (Sweden)

Full Text Available A evolução da morfologia de fases em blendas não reativas e reativas de poliamida-6 com copolímero de acrilonitrila/EPDM/estireno (AES) em uma extrusora de rosca dupla co-rotacional foi investigada. A evolução da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada através da coleta de pequenas amostras em válvulas no barril da extrusora e caracterização por microscopia eletrônica de transmissão (MET). Foram utilizados como compatibilizantes reativos os copolímeros metacrilato de metila-co-anidrido maleico (MMA-MA) e metacrilato de metila-co-metacrilato de glicidila (MMA-GMA). Os grupos anidrido maleico e epóxi nos copolímeros podem reagir com os grupos finais de cadeia da poliamida durante o processamento no estado fundido e melhorar a interação na interfase do sistema PA6/AES. A blenda PA6/AES não compatibilizada apresentou uma morfologia grosseira de fases onde a fase AES não está bem dispersa na matriz de PA6 devido à falta de interações adequadas entre os componentes da blenda. A adição do compatibilizante MMA-GMA não proporcionou boa dispersão de fases e não melhorou as propriedades mecânicas da blenda, provavelmente porque as possíveis reações no sistema são lentas e podem não ocorrer na extrusora. Por outro lado, a blenda compatibilizada com o copolímero MMA-MA apresentou uma excelente resistência ao impacto à temperatura ambiente e uma diminuição na temperatura de transição dúctil-frágil. As partículas de AES apresentam-se muito mais refinadas e sofrem uma redução significativa em seu tamanho já no início do processo de extrusão. A morfologia observada nas amostras injetadas apresentou uma boa correlação com as propriedades mecânicas obtidas.The evolution of phase morphology in non-reactive vs reactive blends with polyamide and ethylene-propylene-diene elastomer grafted with styrene-acrylonitrile copolymer (AES) in a co-rotating twin-screw extruder was investigated. The morphological evolution of these blends along a twin-screw extruder was monitored by quickly collecting small samples from the melt at specific extruder barrel locations and characterizing them with a transmission electron microscope (TEM). The copolymers methyl methacrylate-co-maleic anhydride (MMA-MA) and methyl methacrylate-co-glycidyl methacrylate (MMA-GMA) were used as compatibilizing agents. The maleic anhydride and the epoxy groups of the copolymers can react with the polyamide end groups during melt processing and improve the interphase interaction in the PA6/AES system. The uncompatibilized blends showed a coarse phase morphology where the AES phase is not well dispersed in the PA6 matrix due to lack of adequate interaction between the components. The addition of MMA-GMA compatibilizer neither promoted good phase dispersion or improved the mechanical properties of the blends, probably because the possible reactions are very slow and may not occur inside the extruder. On the other hand, the addition of the MMA-MA copolymer promotes better impact strength and good phase dispersion in the blend. The AES particles undergo significant reduction in the first stages of the mixture inside the extruder. The morphology observed for the injection molded specimens was correlated with the mechanical properties.

Adriane Bassani; Elias Hage Jr; Luiz A. Pessan; Ana V Machado; José A. Covas

2005-01-01

169

Unique opportunities in powder injection molding of refractory and hard materials  

International Nuclear Information System (INIS)

Powder injection molding (PIM) is a relatively new manufacturing process for the creation of complicated net-shapes outside the range usually possible via powder metallurgy technologies. This new process is now in production at more than 550 sites around the world. Although a small industry, PIM will soon pass $1 billion dollars (USA) in annual sales. This presentation overviews the PIM process, some of the new developments and some of the successes that have occurred with both refractory metals and hard metals. Example applications are seen in medical and dental devices, industrial components, wristwatches, jet engines, firearms, automotive components, and even hand tools. To help establish the novel growth opportunities, PIM is compared to other fabrication routes to better understand the design features arising with this new approach, providing a compelling case for substantial opportunities in the refractory and hard materials. Illustrations are provided of several components in production. New opportunities abound for the technology, since it eliminates the shape complexity barrier associated with die compaction and the cost of machining associated with complicated or dimensionally precise components. Further, a relative cost advantage exists for refractory and hard materials because PIM can use the same powders at the same prices as employed in alternative processes. Future successes will occur by early identification of candidate materials and designs. Early examples include tungsten heavy alloy components now reaching production rates of six million per month. (author)

2001-01-01

170

Implementation of Molding Constraints in Topology Optimization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In many cases the topology optimization method yield inadmissible solutions in respect to a particular manufacturing process, e.g. injection molding. In the present work it is chosen to focus on the most common injection molding parameters/factors determining the quality of the mold geometry, i.e. u...

Marx, S.; Kristensen, Anders Schmidt

171

Development of step for light duty truck by using injection molding of long-fiber reinforced thermoplastics; Chosen`i kyoka jushi no shashutsu keisei ni yoru truck yo step no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

The new step for light duty truck was developed by injection molding of glass long-fiber reinforced polypropylene. Feature of the step is good surface appearance and no post processings, compared with the conventional one press molded with a glass fiber reinforced polypropylene sheet (Stampable sheet). 3 refs., 14 figs., 6 tabs.

Togo, A.; Yamamura, H.; Yamaguchi, M. [Mitsubishi Motor Corp., Tokyo (Japan); Yoshino, K. [Kawasaki Steel Corp. Tokyo (Japan)

1997-10-01

172

Research cooperation project on the development of easy injection molding control technology for engineering plastics; Engineering plastic no seikei joken kan`i settei gijutsu ni kansuru kenkyu kyoryoku jigyo seika hokokusho  

Energy Technology Data Exchange (ETDEWEB)

In order to enhance the industries which supply assembly parts to Japan`s assembly industries in Thailand, research cooperation project on the plastic parts production technology has started. For the research cooperation, the mold design is effectively conducted using simulation technique of CAE (computer aided engineering), and an international easy injection molding control system is made using the molding support software for injection molding machines. In FY 1996, actual situations of plastic parts and assembly industries in Thailand have been investigated through the cooperation with the counterpart of Thailand. Demand and supply of engineering plastics, receive and inspection of parts, and current circumstances of molding processing makers in Thailand have been grasped. Based on the results of this investigation, proposal of basic plan, time schedule, and delivery plan of molding machines and testing equipment have been discussed, to make the basic plan. 18 refs., 4 figs., 23 tabs.

NONE

1997-03-01

173

A X-ray study of ?-phase and molecular orientation in nucleated and non-nucleated injection molded polypropylene resins  

Directory of Open Access Journals (Sweden)

Full Text Available The development of ? and ?-phases and the molecular orientation of injection molded disks of two isotactic polypropylene (i-PP) resins were studied by wide angle X-ray diffraction (WAXD) and pole figures. A nucleated (NPP) and non-nucleated (HPP) polymers were analyzed. The main proposal of this article was the comprehensive study of the interrelations between the processing conditions, phase contents and PP ?-phase molecular orientation of injection molded PP resins. In both resins, it was observed that the ?-phase was present in all regions along the thickness while the ?-phase was present mainly in the external layers, decreasing from the surface to the core; however this last phase was present in a very small amount in the NPP resin. For both polymers, the orientation of the macromolecules c-axis was higher along the flow direction (RD) than along the transverse direction (TD). The b-axis of the PP ?-phase molecules was oriented to the thickness direction (ND). The orientation of the c-axis along RD and b-axis along ND of the NPP samples was considerably higher than of the HPP samples, due to the NPP faster crystallization kinetics. For both polymers, the most influential processing parameters on the molecular orientation were the mold temperature and flow rate. The results indicate that, as the mold temperature increased, the characteristic molecular orientation of PP ?-phase, with c-axis along RD and b-axis along ND, decreased. With increase in the flow rate an increase of the c-axis molecular orientation of the samples along RD was observed.

Marcia Maria Favaro; Marcia Cristina Branciforti; Rosario Elida Suman Bretas

2009-01-01

174

Moldagem por injeção da PA 6.6 em moldes de estereolitografia metalizados com Ni-P pelo processo electroless/ Injection molding of PA 6.6 in stereolithography moulds coated with electroless Ni-P  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A fabricação de moldes por técnicas de prototipagem rápida, como a estereolitografia (SL), é considerada uma importante tecnologia no auxílio ao desenvolvimento de produtos de plástico moldados por injeção. Embora esta tecnologia se mostre vantajosa, a vida útil dos moldes pode ser bastante reduzida em decorrência, por exemplo, de forte adesão entre o polímero injetado e o material do molde SL. Neste trabalho é investigado o uso da técnica de recobrimento m (more) etálico com Ni-P por deposição electroless sobre moldes de injeção, fabricados por SL com a resina DSM SOMOS 7110®. Foram comparados resultados de moldagem de PA6.6 em moldes fabricados com e sem recobrimento metálico evidenciando a possibilidade de utilizar a técnica de metalização como alternativa para a moldagem deste material em moldes SL, uma vez que a vida útil foi superior. Abstract in english Manufacturing of moulds by rapid prototyping processes, such as stereolithography (SL), is considered an important technology to aid the development of injection moulding plastic products. Although this technology shows significant advantages, the lifetime of moulds may be drastically be reduced due to strong adhesion between the injected polymer and the material of the SL mould. This work investigates the use of Ni-P metal coating obtained by electroless deposition on SL (more) moulds manufactured with the resin DSM SOMOS 7110. Specimens of PA6.6 have been injected into SL moulds manufactured with and without metal coating. The results showed that the electroless metal coating process can be an appropriate alternative to allow moulding of small series of PA6.6 parts in SL moulds.

Lencina, Diovani C.; Ahrens, Carlos H.; Salmoria, Gean V.; Lafratta, Fernando H.

2007-06-01

175

Moldagem por injeção da PA 6.6 em moldes de estereolitografia metalizados com Ni-P pelo processo electroless Injection molding of PA 6.6 in stereolithography moulds coated with electroless Ni-P  

Directory of Open Access Journals (Sweden)

Full Text Available A fabricação de moldes por técnicas de prototipagem rápida, como a estereolitografia (SL), é considerada uma importante tecnologia no auxílio ao desenvolvimento de produtos de plástico moldados por injeção. Embora esta tecnologia se mostre vantajosa, a vida útil dos moldes pode ser bastante reduzida em decorrência, por exemplo, de forte adesão entre o polímero injetado e o material do molde SL. Neste trabalho é investigado o uso da técnica de recobrimento metálico com Ni-P por deposição electroless sobre moldes de injeção, fabricados por SL com a resina DSM SOMOS 7110®. Foram comparados resultados de moldagem de PA6.6 em moldes fabricados com e sem recobrimento metálico evidenciando a possibilidade de utilizar a técnica de metalização como alternativa para a moldagem deste material em moldes SL, uma vez que a vida útil foi superior.Manufacturing of moulds by rapid prototyping processes, such as stereolithography (SL), is considered an important technology to aid the development of injection moulding plastic products. Although this technology shows significant advantages, the lifetime of moulds may be drastically be reduced due to strong adhesion between the injected polymer and the material of the SL mould. This work investigates the use of Ni-P metal coating obtained by electroless deposition on SL moulds manufactured with the resin DSM SOMOS 7110. Specimens of PA6.6 have been injected into SL moulds manufactured with and without metal coating. The results showed that the electroless metal coating process can be an appropriate alternative to allow moulding of small series of PA6.6 parts in SL moulds.

Diovani C. Lencina; Carlos H. Ahrens; Gean V. Salmoria; Fernando H. Lafratta

2007-01-01

176

Forehead Augmentation with a Methyl Methacrylate Onlay Implant Using an Injection-Molding Technique.  

UK PubMed Central (United Kingdom)

BACKGROUND: The forehead, which occupies about one third of the face, is one of the major determinants of a feminine or masculine look. Various methods have been used for the augmentation of the forehead using autologous fat grafts or alloplastic materials. Methylmethacrylate (MMA) is the most appropriate material for augmentation of the forehead, and we have used an injection-molding technique with MMA to achieve satisfactory results. METHODS: Under local anesthesia with intravenous (IV) sedation, an incision was made on the scalp and a meticulous and delicate subperiosteal dissection was then performed. MMA monomers and polymers were mixed, the dough was injected into the space created, and manual molding was performed along with direct inspection. This surgery was indicated for patients who wanted to correct an unattractive appearance by forehead augmentation. Every patient in this study visited our clinics 3 months after surgery to evaluate the results. We judged the postoperative results in terms of re-operation rates caused by the dissatisfaction of the patients and complications. RESULTS: During a 13-year period, 516 patients underwent forehead augmentation with MMA. With the injection-molding technique, the inner surface of the MMA implant is positioned close to the underlying frontal bone, which minimizes the gap between the implant and bone. The borders of the implant should be tapered sufficiently until no longer palpable or visible. Only 28 patients (5.4%) underwent a re-operation due to an undesirable postoperative appearance. CONCLUSIONS: The injection-molding technique using MMA is a simple, safe, and ideal method for the augmentation of the forehead.

Park DK; Song I; Lee JH; You YJ

2013-09-01

177

Forehead Augmentation with a Methyl Methacrylate Onlay Implant Using an Injection-Molding Technique  

Science.gov (United States)

Background The forehead, which occupies about one third of the face, is one of the major determinants of a feminine or masculine look. Various methods have been used for the augmentation of the forehead using autologous fat grafts or alloplastic materials. Methylmethacrylate (MMA) is the most appropriate material for augmentation of the forehead, and we have used an injection-molding technique with MMA to achieve satisfactory results. Methods Under local anesthesia with intravenous (IV) sedation, an incision was made on the scalp and a meticulous and delicate subperiosteal dissection was then performed. MMA monomers and polymers were mixed, the dough was injected into the space created, and manual molding was performed along with direct inspection. This surgery was indicated for patients who wanted to correct an unattractive appearance by forehead augmentation. Every patient in this study visited our clinics 3 months after surgery to evaluate the results. We judged the postoperative results in terms of re-operation rates caused by the dissatisfaction of the patients and complications. Results During a 13-year period, 516 patients underwent forehead augmentation with MMA. With the injection-molding technique, the inner surface of the MMA implant is positioned close to the underlying frontal bone, which minimizes the gap between the implant and bone. The borders of the implant should be tapered sufficiently until no longer palpable or visible. Only 28 patients (5.4%) underwent a re-operation due to an undesirable postoperative appearance. Conclusions The injection-molding technique using MMA is a simple, safe, and ideal method for the augmentation of the forehead.

Park, Dong Kwon; Song, Ingook; Lee, Jin Hyo

2013-01-01

178

Solidification process and infrared image characteristics of permanent mold castings  

Science.gov (United States)

Interdependence between the development of temperature gradients at the solid-liquid interface during solidification of metals and the formation of local defects demands for thermal investigation. In foundry practice thermocouples are used to control the die's overall cooling-rate, but fluctuations in product quality still occur. Capturing FIR- thermograms after opening the die visualizes the state, when most thermal throughput has already flattened the temperature gradients in the mold. Rapid dissipation of heat from liquid metal to the mold during solidification forces further approach of the process investigation by slowing down the heat flux or the use of transparent mold material. Aluminum gravity casting experiments under technical vacuum conditions lead to decelerated solidification by suppression of convection and image sequences containing explicit characteristics that could be assigned to local shrinkage of the casting. Hence relevant clusters are extracted and thermal profiles are drawn from image series, pointing out correlations between feeding performance from the sink heads and the appearance of local defects. Tracing thermal processes in vacuum casting can scarcely be transferred to image data in foundry practice, since only little analogies exist between atmospheric and vacuum casting. The diagnosis of the casting process requires detection of the still closed mold using a transparent silica- aerogel sheet as part of the die. Hereby thermograms of the initial heat input are recorded by adapting a NIR-camera in addition to the FIR-unit. Thus the entire thermal compensation at the joint face for each casting is visualized. This experimental set-up is used for image sequence analysis related to the intermediate casting phases of mold filling, body formation and solidification shrinkage.

Viets, Roman; Breuer, Markus; Haferkamp, Heinz; Kruessel, Thomas; Niemeyer, Matthias

1999-03-01

179

Thermal and mechanical behavior of injection molded Poly(3-hydroxybutyrate)/Poly(epsilon-caprolactone) blends  

Directory of Open Access Journals (Sweden)

Full Text Available Aiming the development of high-performance biodegradable polymer materials, the properties and the processing behavior of poly(3-hydroxybutyrate), P(3HB), and their blends with poly(epsilon-caprolactone), PCL, have been investigated. The P(3HB) sample, obtained from sugarcane, had a molecular weight of 3.0 x 10(5) g.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg), at - 0.8 °C, and a melting temperature at 171 °C. The molecular weight of PCL was 0.8 x 10(5) g.mol-1. Specimens of 70/30 wt. (%) P(3HB)/PCL blends obtained by injection molding showed tensile strength of 21.9 (± 0.4) MPa, modulus of 2.2 (± 0.3) GPa, and a relatively high elongation at break, 87 (± 20)%. DSC analyses of this blend showed two Tg´s, at - 10.6 °C for the P(3HB) matrix, and at - 62.9 °C for the PCL domains. The significant decrease on the Tg of P(3HB) evidences a partial miscibility of PCL in P(3HB). According to the Fox equation, the new Tg corresponds to a 92/8 wt. (%) P(3HB)/PCL composition.

Marcia Adriana Tomaz Duarte; Roberson Goulart Hugen; Eduardo Sant'Anna Martins; Ana Paula Testa Pezzin; Sérgio Henrique Pezzin

2006-01-01

180

Thermal and mechanical behavior of injection molded Poly(3-hydroxybutyrate)/Poly(epsilon-caprolactone) blends  

Directory of Open Access Journals (Sweden)

Full Text Available Aiming the development of high-performance biodegradable polymer materials, the properties and the processing behavior of poly(3-hydroxybutyrate), P(3HB), and their blends with poly(epsilon-caprolactone), PCL, have been investigated. The P(3HB) sample, obtained from sugarcane, had a molecular weight of 3.0 x 10(5) g.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg), at - 0.8 degreesC, and a melting temperature at 171 degreesC. The molecular weight of PCL was 0.8 x 10(5) g.mol-1. Specimens of 70/30 wt. (%) P(3HB)/PCL blends obtained by injection molding showed tensile strength of 21.9 (? 0.4) MPa, modulus of 2.2 (? 0.3) GPa, and a relatively high elongation at break, 87 (? 20)%. DSC analyses of this blend showed two Tgs, at - 10.6 degreesC for the P(3HB) matrix, and at - 62.9 degreesC for the PCL domains. The significant decrease on the Tg of P(3HB) evidences a partial miscibility of PCL in P(3HB). According to the Fox equation, the new Tg corresponds to a 92/8 wt. (%) P(3HB)/PCL composition.

Duarte Marcia Adriana Tomaz; Hugen Roberson Goulart; Martins Eduardo Sant'Anna; Pezzin Ana Paula Testa; Pezzin Sérgio Henrique

2006-01-01

 
 
 
 
181

Thermal and mechanical behavior of injection molded Poly(3-hydroxybutyrate)/Poly(epsilon-caprolactone) blends  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Aiming the development of high-performance biodegradable polymer materials, the properties and the processing behavior of poly(3-hydroxybutyrate), P(3HB), and their blends with poly(epsilon-caprolactone), PCL, have been investigated. The P(3HB) sample, obtained from sugarcane, had a molecular weight of 3.0 x 10(5) g.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg), at - 0.8 °C, and a melting temperature at 171 °C. The molecular weight of P (more) CL was 0.8 x 10(5) g.mol-1. Specimens of 70/30 wt. (%) P(3HB)/PCL blends obtained by injection molding showed tensile strength of 21.9 (± 0.4) MPa, modulus of 2.2 (± 0.3) GPa, and a relatively high elongation at break, 87 (± 20)%. DSC analyses of this blend showed two Tg´s, at - 10.6 °C for the P(3HB) matrix, and at - 62.9 °C for the PCL domains. The significant decrease on the Tg of P(3HB) evidences a partial miscibility of PCL in P(3HB). According to the Fox equation, the new Tg corresponds to a 92/8 wt. (%) P(3HB)/PCL composition.

Duarte, Marcia Adriana Tomaz; Hugen, Roberson Goulart; Martins, Eduardo Sant'Anna; Pezzin, Ana Paula Testa; Pezzin, Sérgio Henrique

2006-03-01

182

Surface Hardening of Powder Injection Molded 316L Stainless Steels Through Low-Temperature Carburization  

Science.gov (United States)

The surface hardness of powder injection molded (PIM) 316L is generally low due to the inherited austenitic structure and large grains induced during high-temperature sintering. To increase the surface hardness and the wear resistance, low-temperature carburization (LTC) was applied to PIM 316L. With carburization at 773 K (500 °C) for 24 hours, the resulting hardness at the surface increases from 160 to 810 HV due to the "colossal" supersaturation of interstitial carbon and M5C2 carbide, and the corrosion resistance is not deteriorated. The carburized depth is about 40 ?m, and the carbon content in this layer is about 3.25 wt pct or 13.5 at. pct, which causes lattice expansion of the austenite. When the carburization temperature increases to 823 K (550 °C), or the carburization time increases to 72 hours, chromium carbides are observed and the corrosion resistance is impaired. One distinct advantage of applying LTC to PIM 316L is that no acid cleaning process is required, unlike for wrought counterparts, because of the clean surface of the sintered materials.

Cheng, Li-Hui; Hwang, Kuen-Shyang

2013-02-01

183

Minimum Amount of Binder Removal Required during Solvent Debinding of Powder-Injection-Molded Compacts  

Science.gov (United States)

Unsatisfactory dimensional control, distortion, and defects are frequently observed in powder-injection-molded parts, particularly after the solvent and thermal-debinding processing steps. One of the reasons is that the amount of soluble binder removed during the first step, solvent debinding, is not great enough to form interconnected pores throughout the compact, particularly in the core region. Thus, blistering, cracking, and bubbles can form easily during the subsequent thermal debinding. To determine the minimum debinding fraction required for solvent debinding, at which point interconnected pore channels are formed at the center, modeling of the distribution of the remaining soluble binder in the compact was established. The actual distribution, which was obtained by measuring the binder content layer by layer with the soxhelt extraction method, is in good agreement with the model. The modeling, bubble test, and fluorescence dye-penetration analysis show that, regardless of the compact thickness, the minimum bulk debinding fraction needed is consistently approximately 59 pct, yielding a local debinding fraction of 37 pct and a porosity of 8.5 pct at the center. This porosity is close to the value at which pores in a sintered compact transform from open to closed at the beginning of the final stage of sintering.

Fan, Yang-Liang; Hwang, Kuen-Shyang; Wu, Shiau-Han; Liau, Yau-Ching

2009-04-01

184

The effect of injection molding conditions on the near-surface rubber morphology, surface chemistry, and adhesion performance of semi-crystalline and amorphous polymers  

Science.gov (United States)

This thesis investigated the effect of injection molding processing variables, resin formulation and mold material on the resulting morphology and properties of semi-crystalline and amorphous polymers in parts molded on large presses with fully developed flow. Five different polymer resins and two different coating types were investigated, and the near-surface morphology was found to be dependent on material formulation, processing parameters, and geometry. For painted TPO, changes in the near-surface rubber morphology and surface chemistry based on material and processing conditions had no significant effect on the adhesion performance. For metal plated ABS, the adhesion performance was found to be heavily dependent on the rubber surface morphology, which varied with material formulation and processing conditions. One of the most significant findings was that forged aluminum injection molding tooling had little effect on the surface morphology or adhesion performance of either polypropylene or the two TPO formulations examined, despite the five-fold increase in thermal conductivity over traditional tool steel. Surface chemistry, however, was found to be affected by cooling rate, depending on material formulation. A UV stabilizer additive was found concentrated at 2.5 atomic percent on the surface of the aluminum molded part, but not the steel molded part, demonstrating a possible opportunity for using additives and aluminum tooling to create "designer surfaces". Processing conditions were found to have a competing role in metal plated ABS, where conditions that lowered surface stress and improved adhesion by a factor of 15 also increased the amount of bulk molded-in stress by nearly 7%. Both factors were found to play an important role in adhesion performance due to the effect of surface stress on the quality of the resulting etch structure. The bulk stress must be minimized to due to the large mechanical and thermal mismatch between the polymer and metal layers. This work provides a more in-depth understanding of the effect of processing and material composition on morphology, surface chemistry, molded-in stress and adhesion. This will establish guidelines for future injection molded part designs to alleviate delamination failures and minimize warp, as well as contribute to modeling predictions of shrink and mechanical behavior.

Weakley-Bollin, Shannon Christine

185

Injection Molding of Titanium Alloy Implant For Biomedical Application Using Novel Binder System Based on Palm Oil Derivatives  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Titanium alloy (Ti6Al4V) has been widely used as an implant for biomedical application. In this study, the implant had been fabricated using high technology of Powder Injection Molding (PIM) process due to the cost effective technique for producing small, complex and precision parts in high volume compared with conventional method through machining. Approach: Through PIM, the binder system is one of the most important criteria in order to successfully fabricate the implants. Even though, the binder system is a temporary, but failure in the selection and removal of the binder system will affect on the final properties of the sintered parts. Therefore, the binder system based on palm oil derivative which is palm stearin had been formulated and developed to replace the conventional binder system. Results: The rheological studies of the mixture between the powder and binders system had been determined properly in order to be successful during injection into injection molding machine. After molding, the binder held the particles in place. The binder system had to be removed completely through debinding step. During debinding step, solvent debinding and thermal pyrolysis had been used to remove completely of the binder system. The debound part was then sintered to give the required physical and mechanical properties. The in vitro biocompatibility also was tested using Neutral Red (NR) and mouse fibroblast cell lines L-929 for the direct contact assay. Conclusion: The results showed that the properties of the final sintered parts fulfill the Standard Metal Powder Industries Federation (MPIF) 35 for PIM parts except for tensile strength and elongation due to the formation of titanium carbide. The in vitro biocompatibility on the extraction using mouse fibroblast cell line L-929 by means of NR assays showed non toxic for the sintered specimen titanium alloy parts.

R. Ibrahim; M. Azmirruddin; M. Jabir; M. R. Ismail; M. Muhamad; R. Awang; S. Muhamad

2010-01-01

186

An examination of assumptions underlying the state of the art in injection molding modeling  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to place the modeling assumptions involved in injection molding filling simulation software in context by estimating and comparing the various errors associated with predicting the melt pressure within the cavity during filling. This is achieved by identifying specific sources of modeling, material property, and numerical errors and computing their relative magnitudes through simple scaling, or back-of-an-envelope, calculations. Thereby, the users of such software are provided with useful information for evaluating the expected accuracy of the solutions and for interpreting the output generated. The results presented shed additional light into the black box that mold filling simulations sometimes seem, much in the spirit as have previous examinations of issues such as convergence criteria and mesh density.

Guell, D.C.; Lovalenti, P.M.

1994-12-01

187

Feature-based non-manifold modeling system to integrate design and analysis of injection molding products  

International Nuclear Information System (INIS)

Current CAE systems used for both the simulation of the injection molding process and the structural analysis of plastic parts accept solid models as geometric input. However, abstract models composed of sheets and wireframes are still used by CAE systems to carry out more analyses more efficiently. Therefore, to obtain an adequate abstract model, designers often have to simplify and idealize a detailed model of a part to a specific level of detail and/or abstraction. For such a process, we developed a feature-based design system based on a non-manifold modeling kernel supporting feature-based multi-resolution and multi-abstraction modeling capabilities. In this system, the geometric models for the CAD and CAE systems are merged into a single master model in a non-manifold topological representation, and then, for a given level of detail and abstraction, a simplified solid or non-manifold model is extracted immediately for an analysis. For a design change, the design and analysis models are modified simultaneously. As a result, this feature based design system is able to provide a more integrated environment for the design and analysis of plastic injection molding parts

2009-01-01

188

Influência do desempenho térmico de moldes fabricados com compósito epóxi/alumínio nas propriedades de pp moldado por injeção/ Thermal behavior of epoxy/aluminum rapid tooling composite during injection molding of polypropylene  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O surgimento das tecnologias de prototipagem rápida (RP) e de ferramental rápido (RT) tem despertado interesse da indústria de moldes de injeção. O vazamento de termofixos com cargas metálicas possibilita a construção de moldes usando materiais compósitos, os quais apresentam maior resistência que os utilizados por outras técnicas RT. Neste trabalho foi estudado o comportamento térmico de moldes fabricados em epóxi/alumínio durante a injeção de polipropile (more) no através de avaliações da estrutura e de propriedades mecânicas utilizando difração de raio X e ensaios de dureza e de tração. Os corpos-de-prova injetados no molde em compósito epóxi/alumínio apresentaram pequenas diferenças no grau de cristalinidade das superfícies analisadas e propriedades mecânicas semelhantes aos corpos-de-prova injetados em molde de aço. O estudo mostrou um razoável desempenho térmico do molde compósito durante a injeção de polipropileno evidenciando a viabilidade de utilização destes moldes na produção de pequenas séries de protótipos e de produtos neste termoplástico. Abstract in english rapid prototyping (RP) and rapid tooling (RT) technologies are gaining increasing importance in the injection molding industry. Casting of resin/metal composites allows the construction of molds with greater resistance than those manufactured by other RT techniques such as Stereolithography. In this work, the thermal behavior of molds manufactured in epoxy/aluminum during the injection molding of polypropylene specimens was investigated. Structural and mechanical characte (more) rization of the molded specimens included X ray analysis, hardness and tensile testing. The samples presented small differences in the degree of crystallinity and similar mechanical properties in comparison with samples injected into steel molds. This study showed a reasonable thermal performance of the epoxy/aluminum mold during the injection molding of polypropylene, thus demonstrating the viability of using these molds to produce a few number of prototypes or products with this thermoplastic.

Salmoria, Gean V.; Ahrens, Carlos H.; Villamizar, Felix A. Y.; Sabino Netto, Aurélio da C.

2008-09-01

189

Influência do desempenho térmico de moldes fabricados com compósito epóxi/alumínio nas propriedades de pp moldado por injeção Thermal behavior of epoxy/aluminum rapid tooling composite during injection molding of polypropylene  

Directory of Open Access Journals (Sweden)

Full Text Available O surgimento das tecnologias de prototipagem rápida (RP) e de ferramental rápido (RT) tem despertado interesse da indústria de moldes de injeção. O vazamento de termofixos com cargas metálicas possibilita a construção de moldes usando materiais compósitos, os quais apresentam maior resistência que os utilizados por outras técnicas RT. Neste trabalho foi estudado o comportamento térmico de moldes fabricados em epóxi/alumínio durante a injeção de polipropileno através de avaliações da estrutura e de propriedades mecânicas utilizando difração de raio X e ensaios de dureza e de tração. Os corpos-de-prova injetados no molde em compósito epóxi/alumínio apresentaram pequenas diferenças no grau de cristalinidade das superfícies analisadas e propriedades mecânicas semelhantes aos corpos-de-prova injetados em molde de aço. O estudo mostrou um razoável desempenho térmico do molde compósito durante a injeção de polipropileno evidenciando a viabilidade de utilização destes moldes na produção de pequenas séries de protótipos e de produtos neste termoplástico.rapid prototyping (RP) and rapid tooling (RT) technologies are gaining increasing importance in the injection molding industry. Casting of resin/metal composites allows the construction of molds with greater resistance than those manufactured by other RT techniques such as Stereolithography. In this work, the thermal behavior of molds manufactured in epoxy/aluminum during the injection molding of polypropylene specimens was investigated. Structural and mechanical characterization of the molded specimens included X ray analysis, hardness and tensile testing. The samples presented small differences in the degree of crystallinity and similar mechanical properties in comparison with samples injected into steel molds. This study showed a reasonable thermal performance of the epoxy/aluminum mold during the injection molding of polypropylene, thus demonstrating the viability of using these molds to produce a few number of prototypes or products with this thermoplastic.

Gean V. Salmoria; Carlos H. Ahrens; Felix A. Y. Villamizar; Aurélio da C. Sabino Netto

2008-01-01

190

Implementation of Molding Constraints in Topology Optimization  

DEFF Research Database (Denmark)

In many cases the topology optimization method yield inadmissible solutions in respect to a particular manufacturing process, e.g. injection molding. In the present work it is chosen to focus on the most common injection molding parameters/factors determining the quality of the mold geometry, i.e. uniform thickness, filling of the die and ejection of the molded item, i.e. extrusion. The mentioned injection mold parameters/factors are introduced in the topology optimization by defining a centerline of the initial domain and then penalize elements in respect to the distance to the defined centerline of the domain.

Marx, S.; Kristensen, Anders Schmidt

2009-01-01

191

Analysis of residual layer thickness of resin in an imprinting process using a soft mold  

Science.gov (United States)

The selection of proper mold material for an imprinting process is important with respect to the manufacturing cost of the mold as well as the interfacial material mechanics between the resin and the mold. Among the various material characteristics of the mold, its rigidity is an influential factor for the distribution shape of the residual layer thickness (RLT) of the resin, and is therefore an important consideration for subsequent etching processes (window open processes) that remove the residual resin layer. In this work, variations in the RLT for a rectangular mold structure are simulated using thin film lubrication theory and compared with experimental results from an imprinting process.

Jang, Siyoul; Lee, Taek Kyoung; Lee, Jae Gab

2013-09-01

192

Estudo de caso de peça moldada pelo processo de injeção-compressão para termoplásticos utilizando análise computacional Study of injection-compression molded part using CAE analysis  

Directory of Open Access Journals (Sweden)

Full Text Available O processamento de termoplásticos através do processo de injeção representa o principal método de fabricação de peças plásticas. Limitações do processo de injeção convencional, principalmente quanto à matéria-prima e configuração e funcionamento das máquinas disponíveis, tornam inviável a produção de produtos com grande área projetada e pequena espessura, como janelas automotivas e alguns tipos de lentes. Paralelamente, o processo de injeção evolui continuamente e há uma série de novas tecnologias geradas a partir do processo original, dentre elas o processo de injeção-compressão. No presente trabalho, utilizando análise computacional, estudou-se a produção de lentes de policarbonato através de dois processos distintos: injeção convencional e processo de injeção-compressão. A seqüência de estudos envolveu basicamente os seguintes pontos: estudo do padrão de preenchimento com conseqüente otimização do processo de injeção-compressão quanto à formação de linha de emenda; estudo da janela de processo para ambos os casos e comparação de alguns parâmetros principalmente tensão de cisalhamento e força de fechamento, por se tratarem de fatores limitantes na produção de peças com grande área projetada. Os resultados para o caso estudado comprovam grande vantagem na utilização do processo de injeção-compressão.The injection-molding of thermoplastics is the main process used in the production of plastics parts. There are some limitations in the conventional injection process, specially related to raw materials, machines configuration and operation, which hamper fabrication of thin parts with large areas such as car windows and lenses. On the other hand, the process has been improved continuously with several new technologies, going beyond the conventional injection molding process, including the "injection-compression" process. In this paper, using CAE (computer aided engineering) technology, the author studied the production of PC lens by both processes: conventional injection molding and injection-compression molding. The studies were basically conducted in the following sequence: flow pattern study and optimization of the injection-compression process focusing on the weld line size, molding window study for both cases and comparison of several parameters, particularly shear stress and clamp force - as they are key parameters for the production of large-area parts. The results confirm the advantages of the injection-compression process.

Thyago M. Kiam; Nilson C. Pereira

2007-01-01

193

Interfacial crystalline structures in injection over-molded polypropylene and bond strength.  

UK PubMed Central (United Kingdom)

This paper describes interfacial crystalline structures found in injection overmolded polypropylene components and the relationship of these structures to bond strength between the components. The combined effects of the development of hierarchical gradient structures and the particular thermomechanical environment near the interface on the interfacial crystalline structures were investigated in detail by PLM, SEM, DSC, WAXD, and infrared dichroism spectroscopy. The experimental results showed that during molding there was competitive formation of interfacial crystalline structures consisted of "shish-kebab" layer (SKL) and a transcrystalline layers (TCL). Variation in shear stress (controlled by injection pressure and injection speed) plays an important role in the formation of the SKL. The formation of TCL is influenced by the thermal environment, namely melt temperature and mold temperature. Increasing within certain limits, interfacial temperature and the thermal gradient near the interface promotes ?-iPP growth. The relationship between interfacial crystalline structures and interfacial bond strength was established by lap shear measurement. The interfacial bond strength is improved by enhancing the formation of TCL, but reduced if SKL predominates.

Yan B; Wu H; Jiang G; Guo S; Huang J

2010-11-01

194

Prediction of the Elastic-Plastic Stress/Strain Response for Injection-Molded Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a model to predict the elastic-plastic response of injection-molded long-fiber thermoplastics (LFTs). The model accounts for elastic fibers embedded in a thermoplastic resin that exhibits the elastic-plastic behavior obeying the Ramberg-Osgood relation and J-2 deformation theory of plasticity. It also accounts for fiber length and orientation distributions in the composite formed by the injection-molding process. Fiber orientation was predicted using the anisotropic rotary diffusion model recently developed by Phelps and Tucker for LFTs. An incremental procedure using the Eshelby’s equivalent inclusion method and the Mori-Tanaka model is proposed to compute the overall stress increment resulting from an overall strain increment for an aligned fiber composite that contains the same fiber volume fraction and length distribution as the actual composite. The incremental response of the later is then obtained from the solution for the aligned fiber composite that is averaged over all possible fiber orientations using the orientation averaging method. Failure during incremental loading is predicted using the Van Hattum-Bernado model. The elastic-plastic and strength prediction model for LFTs was validated against the experimental stress-strain results obtained for long glass fiber/polypropylene specimens.

Nguyen, Ba Nghiep; Bapanapalli, Satish K.; Kunc, Vlastimil; Phelps, Jay; Tucker III, Charles L.

2009-01-26

195

Estudo de caso de peça moldada pelo processo de injeção-compressão para termoplásticos utilizando análise computacional/ Study of injection-compression molded part using CAE analysis  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O processamento de termoplásticos através do processo de injeção representa o principal método de fabricação de peças plásticas. Limitações do processo de injeção convencional, principalmente quanto à matéria-prima e configuração e funcionamento das máquinas disponíveis, tornam inviável a produção de produtos com grande área projetada e pequena espessura, como janelas automotivas e alguns tipos de lentes. Paralelamente, o processo de injeção evolu (more) i continuamente e há uma série de novas tecnologias geradas a partir do processo original, dentre elas o processo de injeção-compressão. No presente trabalho, utilizando análise computacional, estudou-se a produção de lentes de policarbonato através de dois processos distintos: injeção convencional e processo de injeção-compressão. A seqüência de estudos envolveu basicamente os seguintes pontos: estudo do padrão de preenchimento com conseqüente otimização do processo de injeção-compressão quanto à formação de linha de emenda; estudo da janela de processo para ambos os casos e comparação de alguns parâmetros principalmente tensão de cisalhamento e força de fechamento, por se tratarem de fatores limitantes na produção de peças com grande área projetada. Os resultados para o caso estudado comprovam grande vantagem na utilização do processo de injeção-compressão. Abstract in english The injection-molding of thermoplastics is the main process used in the production of plastics parts. There are some limitations in the conventional injection process, specially related to raw materials, machines configuration and operation, which hamper fabrication of thin parts with large areas such as car windows and lenses. On the other hand, the process has been improved continuously with several new technologies, going beyond the conventional injection molding proce (more) ss, including the "injection-compression" process. In this paper, using CAE (computer aided engineering) technology, the author studied the production of PC lens by both processes: conventional injection molding and injection-compression molding. The studies were basically conducted in the following sequence: flow pattern study and optimization of the injection-compression process focusing on the weld line size, molding window study for both cases and comparison of several parameters, particularly shear stress and clamp force - as they are key parameters for the production of large-area parts. The results confirm the advantages of the injection-compression process.

Kiam, Thyago M.; Pereira, Nilson C.

2007-03-01

196

Characteristics and infl uence factors of mold fi lling process in permanent mold with a slot gating system  

Directory of Open Access Journals (Sweden)

Full Text Available The main problems caused by improper gating are entrained aluminum oxide fi lms and entrapped gas. In this study, the slot gating system is employed to improve mold fi lling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum fl owing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to observe the fl ow pattern through a number of vertically oriented gating systems. The investigation discovers that there are many infl uencing factors on the mold fi lling process. This paper focuses its research on some of the factors, such as the dimensions of the vertical riser and slot thickness, as well as roughness of the coating layer. The results indicate that molten metal can smoothly fi ll into casting cavity with a proper slot gating system. A bigger vertical riser, proper slot thickness and rougher coating can provide not only a better mold fi lling pattern, but also hot melt into the top of the cavity. A proper temperature gradient is obtainable, higher at the bottom and lower at the top of the casting cavity, which is in favor of feeding during casting solidifi cation.

Chang Qingming; Chen Xia; Chen Changjun

2009-01-01

197

Biocompatibility of metal injection molded versus wrought ASTM F562 (MP35N) and ASTM F1537 (CCM) cobalt alloys.  

UK PubMed Central (United Kingdom)

We present a comparative analysis between biocompatibility test results of wrought and Metal Injection Molded (MIM) ASTM F562-02 UNS R30035 (MP35N) and F1537 UNS R31538 (CCM) alloy samples that have undergone the same generic orthopedic implant's mechanical, chemical surface pre-treatment, and a designed pre-testing sample preparation method. Because the biocompatibility properties resulting from this new MIM cobalt alloy process are not well understood, we conducted tests to evaluate cytotoxicity (in vitro), hemolysis (in vitro), toxicity effects (in vivo), tissue irritation level (in vivo), and pyrogenicity count (in vitro) on such samples. We show that our developed MIM MP35N and CCM materials and treatment processes are biocompatible, and that both the MIM and wrought samples, although somewhat different in microstructure and surface, do not show significant differences in biocompatibility.

Chen H; Sago A; West S; Farina J; Eckert J; Broadley M

2011-01-01

198

Biocompatibility of metal injection molded versus wrought ASTM F562 (MP35N) and ASTM F1537 (CCM) cobalt alloys.  

Science.gov (United States)

We present a comparative analysis between biocompatibility test results of wrought and Metal Injection Molded (MIM) ASTM F562-02 UNS R30035 (MP35N) and F1537 UNS R31538 (CCM) alloy samples that have undergone the same generic orthopedic implant's mechanical, chemical surface pre-treatment, and a designed pre-testing sample preparation method. Because the biocompatibility properties resulting from this new MIM cobalt alloy process are not well understood, we conducted tests to evaluate cytotoxicity (in vitro), hemolysis (in vitro), toxicity effects (in vivo), tissue irritation level (in vivo), and pyrogenicity count (in vitro) on such samples. We show that our developed MIM MP35N and CCM materials and treatment processes are biocompatible, and that both the MIM and wrought samples, although somewhat different in microstructure and surface, do not show significant differences in biocompatibility. PMID:21537059

Chen, Hao; Sago, Alan; West, Shari; Farina, Jeff; Eckert, John; Broadley, Mark

2011-01-01

199

Analysis of the PUR specific material behavior for improving the simulation of the molding process; Analyse des PUR-spezifischen Materialverhaltens zur Verbesserung der Simulation des Formteilbildungsprozesses  

Energy Technology Data Exchange (ETDEWEB)

3D mold filling studies are carried out to optimize the injection molding of solid PUR components via RIM and RRIM, as well as the PUR foaming process. Ultrasonic measurements are used for characterizing the early states of the foaming process of a PUR rigid foam, and the polymer formation in solid PUR systems. Furthermore, rheokinetic methods for materials characterizing and viscosity field simulations of crosslinking PURs are described.

Zabold, J. [Solvay Fluor und Derivate GmbH, Hannover (Germany). SFD-AS; Kleba, I.; Haberstroh, E. [Institut fuer Kunststoffverarbeitung, Aachen (Germany)

2000-07-01

200

Heat transfer at the polymer-metal interface -- A method of analysis and its application to injection molding  

Energy Technology Data Exchange (ETDEWEB)

Heat transfer at the polymer-metal interface constitutes a key point to interpret shrinkage and warpage during injection molding. In heat transfer, the interface conditions are modelized by a thermal contact resistance (TCR). An apparatus was built and a new method was used to determine the TCR variation and simultaneously the temperature field in the polymer, in a real situation of injection molding. The experimental device consists in an instrumented injection mold. A specific heat flux sensor has been developed in order to determine simultaneously the metal surface temperature and the heat flux crossing the interface. The polymer surface temperature is obtained by solving numerically the heat conduction equation in the polymer. The boundary conditions are the experimental heat flux densities. The initial condition is evaluated by an inverse method based on the energy conservation and the heat flux history. Two thermal models are necessary to take into account the packing and the cooling phases. Some experimental results will be shown.

Quilliet, S.; Le Bot, P.; Delaunay, D.; Jarny, Y.

1997-07-01

 
 
 
 
201

Fabrication of a polyurethane acrylate/polyimide-based polymer mold for a hot embossing process.  

Science.gov (United States)

A high-thermal-resistance polymer-based flexible imprint mold was developed to be used in a hot embossing process. This mold was readily replicated in a UV curing imprint process and can be used as a mold for hot embossing and thermally curing imprint processes. The nano-sized pattern of this mold was not degraded by soaking at 350 degrees C for 10 min and the pattern fidelity was maintained after 10 separate cyclic heating tests between 0 degrees C and 350 degrees C. The substrate of this flexible mold was PI film, and a UV-cured polyurethane acrylate (PUA) layer was used to form the nano-scale patterns. The durability of this polymeric mold was tested by repetitive hot embossing processes. Nano-scale patterns of the mold were readily transferred to a PMMA layer coated onto a Si substrate by hot embossing lithography at 180 degrees C. After 10 cycles of hot embossing processes, no damage or degradation was observed in the flexible polymer mold. Using this polymer mold, patterns as small as 50 nm were successfully transferred to a Si substrate. Due to the flexibility of the polymer mold, nano-scale patterns were successfully transferred to a non-flat acryl substrate by hot embossing lithography. PMID:22849136

Kim, Kang-In; Han, Kang-Soo; Yang, Ki-Yeon; Kim, Hyeong-Seok; Lee, Heon

2012-04-01

202

Fabrication of a polyurethane acrylate/polyimide-based polymer mold for a hot embossing process.  

UK PubMed Central (United Kingdom)

A high-thermal-resistance polymer-based flexible imprint mold was developed to be used in a hot embossing process. This mold was readily replicated in a UV curing imprint process and can be used as a mold for hot embossing and thermally curing imprint processes. The nano-sized pattern of this mold was not degraded by soaking at 350 degrees C for 10 min and the pattern fidelity was maintained after 10 separate cyclic heating tests between 0 degrees C and 350 degrees C. The substrate of this flexible mold was PI film, and a UV-cured polyurethane acrylate (PUA) layer was used to form the nano-scale patterns. The durability of this polymeric mold was tested by repetitive hot embossing processes. Nano-scale patterns of the mold were readily transferred to a PMMA layer coated onto a Si substrate by hot embossing lithography at 180 degrees C. After 10 cycles of hot embossing processes, no damage or degradation was observed in the flexible polymer mold. Using this polymer mold, patterns as small as 50 nm were successfully transferred to a Si substrate. Due to the flexibility of the polymer mold, nano-scale patterns were successfully transferred to a non-flat acryl substrate by hot embossing lithography.

Kim KI; Han KS; Yang KY; Kim HS; Lee H

2012-04-01

203

DNA barcoding via counterstaining with AT/GC sensitive ligands in injection-molded all-polymer nanochannel devices  

DEFF Research Database (Denmark)

Nanochannel technology, coupled with a suitable DNA labeling chemistry, is a powerful approach for performing high-throughput single-molecule mapping of genomes. Yet so far nanochannel technology has remained inaccessible to the broader research community due to high fabrication cost and/or requirement of specialized facilities/skill-sets. In this article we show that nanochannel-based mapping can be performed in all polymer chips fabricated via injection molding: a fabrication process so inexpensive that the devices can be considered disposable. Fluorescent intensity variations can be obtained from molecules extended in the polymer nanochannels via chemical counterstaining against YOYO-1. In particular, we demonstrate that the counterstaining induced fluorescent intensity variations to a large degree appear to be proportional to the theoretically computed sequence-maps of both local AT and GC variation along DNA sequences.

Østergaard, Peter Friis; Matteucci, Marco

2012-01-01

204

Development of injection molding used kucha-ceramics. Kucha nendo wo mochiita shashutsu seikei gijutsu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Properties of Kucha-clay were studied as material for injection molding. After the mixtures of the clay and binders were heated at 423 K for 6 hours, those were crushed to prepare pellets for injection molding, and after injection molding and degreasing, the molded pellets were sintered in temperature range of 1,273-1,448 K for 1-2 hours. As a result, polyethylene (PE) offered excellent properties as binder, and the mixed binder composed of PE, ethylene vinylacetate copolymer (EVA), paraffin wax and zinc stearin allowed to keep the molded pellets in shape. Linear low-density PE (LLDPE) could also reduce a binder content by 15wt% as compared with other binders. The hardness of products increased with sintering temperature, in particular, sharply at 1,373 K or more, accompanying shrinkage at 1,373 K or less and expansion at 1,373 K or more. The bending strength was higher in LLDPE than LDPE showing the maximum value of 108 MPa at 1,373 K. 5 refs., 15 figs., 3 tabs.

Fukumoto, I.; Mekaru, S.; Koja, M. (University of The Ryukyus, Okinawa (Japan). Faculty of Engineering); Teruya, Z. (Industrial Research Institute of Okinawa Prefecture, Okinawa (Japan))

1993-09-01

205

Process for producing a flexible plastic gel molding with a plurality of catheters embedded equidistantly therein  

UK PubMed Central (United Kingdom)

A process for producing a flexible plastic molding with one or more catheters or tubes embedded equidistantly therein which comprises firmly clamping the catheters or tubes in a liquid or semi-gelled paste comprising a precursor of the plastic material of the molding, in a gelling or hardening mold, and then carrying out complete gelling or hardening, and a product made by the process.

ANDERS CHRISTINE; BRATHUN REINHOLD

206

Injection-molded Sm-Fe-N anisotropic magnets using unsaturated polyester resin  

Energy Technology Data Exchange (ETDEWEB)

New injection-molding technology has been developed using an unsaturated polyester (UP) resin in order to produce bonded Sm-Fe-N anisotropic magnets. Sheet magnets of 50 mm x 20 mm x 0.36 mm are successfully made within a cycle time of 90 s. Magnetic properties obtained are almost the same as those obtained in column magnets of {phi}10 mm x 7 mm. Typical data of magnetic properties are as follows: B {sub r} = 0.72 T, H {sub CJ} = 796 kA/m and (BH){sub max} 94.7 kJ/m{sup 3}. The density is 4.79 Mg/m{sup 3}. The degree of orientation of (0 0 6) is 5.31 calculated using the Wilson formula from X-ray diffraction result. Ring magnets of 7.4 mm x 3.2 mm x 0.3 mm are easily made from sheet magnets.

Ohmori, K. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan)]. E-mail: k_omori@adch.smm.co.jp; Hayashi, S. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan); Yoshizawa, S. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan)

2006-02-09

207

Injection-molded Sm-Fe-N anisotropic magnets using unsaturated polyester resin  

International Nuclear Information System (INIS)

New injection-molding technology has been developed using an unsaturated polyester (UP) resin in order to produce bonded Sm-Fe-N anisotropic magnets. Sheet magnets of 50 mm x 20 mm x 0.36 mm are successfully made within a cycle time of 90 s. Magnetic properties obtained are almost the same as those obtained in column magnets of ?10 mm x 7 mm. Typical data of magnetic properties are as follows: B r = 0.72 T, H CJ = 796 kA/m and (BH)max 94.7 kJ/m3. The density is 4.79 Mg/m3. The degree of orientation of (0 0 6) is 5.31 calculated using the Wilson formula from X-ray diffraction result. Ring magnets of 7.4 mm x 3.2 mm x 0.3 mm are easily made from sheet magnets.

2006-02-09

208

Biodegradability of injection molded bioplastic pots containing polylactic acid and poultry feather fiber.  

UK PubMed Central (United Kingdom)

The biodegradability of three types of bioplastic pots was evaluated by measuring carbon dioxide produced from lab-scale compost reactors containing mixtures of pot fragments and compost inoculum held at 58 °C for 60 days. Biodegradability of pot type A (composed of 100% polylactic acid (PLA)) was very low (13 ± 3%) compared to literature values for other PLA materials. Near infrared spectroscopy (NIRS) results suggest that the PLA undergoes chemical structural changes during polymer extrusion and injection molding. These changes may be the basis of the low biodegradability value. Biodegradability of pot types B (containing 5% poultry feather, 80% PLA, 15% starch), and C (containing 50% poultry feather, 25% urea, 25% glycerol), were 53 ± 2% and 39 ± 3%, respectively. More than 85% of the total biodegradation of these bioplastics occurred within 38 days. NIRS results revealed that poultry feather was not degraded during composting.

Ahn HK; Huda MS; Smith MC; Mulbry W; Schmidt WF; Reeves JB 3rd

2011-04-01

209

Shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins.  

Science.gov (United States)

Abstract Objective. This study investigated the shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins. Materials and methods. Four injection-molded thermoplastic resins (two polyamides, a polyethylene terephthalate copolymer and a polycarbonate) were used in this study. The specimens were divided into eight groups according to the type of surface treatment given: (1) no treatment, (2) air abrasion with alumina, (3) dichloromethane, (4) ethyl acetate, (5) 4-META/MMA-TBB resin, (6) alumina and 4-META/MMA-TBB resin, (7) tribochemical silica coating or (8) tribochemical silica coating and 4-META/MMA-TBB resin. Half of the specimens in groups 1, 5, 6 and 8 were thermocycled for 10,000 cycles in water between 5-55°C with a dwell time of 1 min at each temperature. The shear bond strengths were determined. Results. The shear bond strengths to the two polyamides treated with alumina, dichloromethane and ethyl acetate and no treatment were very low. The greatest post-thermocycling bond strengths to polyamides were recorded for the specimens treated with tribochemical silica coating and 4-META/MMA-TBB resin (PA12: 16.4 MPa, PACM12: 17.5 MPa). The greatest post-thermocycling bond strengths to polyethylene terephthalate copolymer and polycarbonate were recorded for the treatment with alumina and 4-META/MMA-TBB resin (22.7 MPa, 20.8 MPa). Conclusion. Polyamide was exceedingly difficult to bond to an autopolymerizing repair resin; the shear bond strength improved using tribochemical silica coating followed by the application of 4-META/MMA-TBB resin. Both polyethylene terephthalate copolymer and polycarbonate were originally easy to bond to an autopolymerizing repair resin. However, with 4-META/MMA-TBB resin, the bond was more secure. PMID:23339746

Hamanaka, Ippei; Shimizu, Hiroshi; Takahashi, Yutaka

2013-01-23

210

Shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins.  

UK PubMed Central (United Kingdom)

OBJECTIVE: This study investigated the shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins. MATERIALS AND METHODS: Four injection-molded thermoplastic resins (two polyamides, a polyethylene terephthalate copolymer and a polycarbonate) were used in this study. The specimens were divided into eight groups according to the type of surface treatment given: (1) no treatment, (2) air abrasion with alumina, (3) dichloromethane, (4) ethyl acetate, (5) 4-META/MMA-TBB resin, (6) alumina and 4-META/MMA-TBB resin, (7) tribochemical silica coating or (8) tribochemical silica coating and 4-META/MMA-TBB resin. Half of the specimens in groups 1, 5, 6 and 8 were thermocycled for 10,000 cycles in water between 5-55°C with a dwell time of 1 min at each temperature. The shear bond strengths were determined. RESULTS: The shear bond strengths to the two polyamides treated with alumina, dichloromethane and ethyl acetate and no treatment were very low. The greatest post-thermocycling bond strengths to polyamides were recorded for the specimens treated with tribochemical silica coating and 4-META/MMA-TBB resin (PA12: 16.4 MPa, PACM12: 17.5 MPa). The greatest post-thermocycling bond strengths to polyethylene terephthalate copolymer and polycarbonate were recorded for the treatment with alumina and 4-META/MMA-TBB resin (22.7 MPa, 20.8 MPa). CONCLUSION: Polyamide was exceedingly difficult to bond to an autopolymerizing repair resin; the shear bond strength improved using tribochemical silica coating followed by the application of 4-META/MMA-TBB resin. Both polyethylene terephthalate copolymer and polycarbonate were originally easy to bond to an autopolymerizing repair resin. However, with 4-META/MMA-TBB resin, the bond was more secure.

Hamanaka I; Shimizu H; Takahashi Y

2013-09-01

211

An opto-chemical assay for mold detection in processing tomatoes  

Science.gov (United States)

Fungal (mold) contamination is an important indicator of low quality raw product or unsanitary processing conditions in the food industry. A quantitative lectin assay was developed that was less expensive, faster, and more precise than the industry standard Howard mold count. This assay, based on a fluorescent-labeled lectin isolated from wheat germ, has a selective affinity for the chitin in fungal cell walls. Assay values had high linear correlations (from r 2 = .72 to r2 = .99) with fungal biomass for ten fungal species of greatest importance to the California processing tomato industry. One hundred raw tomato juice samples with natural mold infections were collected, as part of the normal California processing tomato inspection program, from commercial processing tomato loads. The raw juice samples were sent to four processor quality control laboratories, where an industry standard Howard mold count was conducted on blind triplicates of each of the samples. The lectin assay was also conducted on blind replicates of the raw juice samples. The correlation between the lectin assay and the Howard mold count (r = .85) was as strong as the correlation between the Howard mold counts for two facilities. The assay had significantly better (alpha = .01) precision than the Howard mold count, with an average coefficient of variation of 8%, compared with 38% for the Howard mold count. The assay is objective, can be conducted in under six minutes, and has the potential to replace mold testing in both raw and processed products.

Potts, Steven James

212

Hybrid tooling technologies and standardization for the manufacturing of inserts for micro injection molding  

DEFF Research Database (Denmark)

This paper is based on the European Platform’s activities within the 4M Network of Excellence “Multi-Material Micro Manufacturing”. To overpass limitations of the current existing micro tooling capabilities, a new generation of micro hybrid tooling technologies for micro replication was developed. A metrological approach was applied to standardize the employed tooling processes (micro milling, µEDM, laser micromachining, electrochemical µ-milling). The micro tools were then tested with different polymers (PP, PP + nano fillers, PC, COC). The paper provides a comparison of these technologies concerning obtainable feature sizes, surface finish, and aspect ratios of both micro tools and micro molded parts.

Tosello, Guido; Fillon, Bertrand

2007-01-01

213

CONVERSION OF WIND POWER TO HYDROGEN FUEL: DESIGN OF AN ALTERNATIVE ENERGY SYSTEM FOR AN INJECTION MOLDING FACILITY  

Science.gov (United States)

Injection molding plants are large consumers of electricity. At its current level of operations, Harbec Plastics (Ontario, NY) uses about 2,000,000 kilowatt-hours of electricity per year. Based on the US average fuel mix, approximately 1.5 pounds of CO2...

214

Thermal Properties of Extruded Injection-Molded Polycaprolactone/Gluten Bioblends Characterized by TGA, DSC, SEM and Infrared Photoacoustic Spectroscopy  

Science.gov (United States)

In order to determine the degree of compatibility between Polycaprolactone resin (PCL) and vital wheat gluten (VG), PCL was compounded with VG at 90:10, 80:20, 70:30, 60:40, 50:50, and 30:70. The composites were blended by extrusion followed by injection molding. Thermal, morphological, and struct...

215

MECHANICAL PROPERTIES OF INJECTION-MOLDED FOAMED WHEAT STRAW FILLED HDPE BIOCOMPOSITES: THE EFFECTS OF FILLER LOADING AND COUPLING AGENT CONTENTS  

Directory of Open Access Journals (Sweden)

Full Text Available This study investigated the effect of filler loading and coupling agent contents on the densities and mechanical properties of injection-molded foamed biocomposites. Biocomposite pellets were manufactured using wheat straw flour, maleic anhydrite grafted polyethylene (MAPE), paraffin wax, and high-density polyethylene (HDPE) with an extrusion process. Pellets and the chemical foaming agent (azodicarbonamide) were dry-mixed and foamed in an injection-molding machine. Densities and mechanical properties of the foamed biocomposites samples were measured and analyzed using central composite design (CCD). The results showed that both filler loading and coupling agent contents affected the density and mechanical properties of foamed biocomposites. Densities in the range of 0.57 to 0.81 gr cm-3 were achieved. Best results were obtained when less than 20% wheat straw flour and 1% coupling agent content were used. The flexural modulus and tensile modulus of foamed biocomposites were improved with increasing filler loading. However, flexural strength, tensile strength, elongation at break, and impact strength values were diminished. The tensile strength of the biocomposites was positively affected by CA contents, but other mechanical properties were not affected by it. Overall, injection molded foamed biocomposites with moderate mechanical properties were produced.

Fatih Mengeloglu,; Kadir Karaku?

2012-01-01

216

Metal injection molding of Ti-Mo-Al mixed powder. Ti-Mo-Al kongofun no idashi seikei  

Energy Technology Data Exchange (ETDEWEB)

Metal injection molding of Ti-15Mo-3Al alloys was studied by use of the Ti-Mo-Al compound composed of Ti powder with an average diameter of 38 [mu]m, Mo powder of 1.24 [mu]m, TiAl alloy powder of 9.4 [mu]m and two types of wax-polymer binders. Since oxidation of the compound in the air was depressed by using TiAl alloy powder substituted for Al powder, kneading, molding and debinding of the compound were successfully conducted in the air. The relative density of the sintered compacts approached as high as 97% or more through debinding at 210[degree]C in the air and at 500-550[degree]C in vacuum, and sintering at 1296[degree]C in vacuum for 3 hours. A large amount of precipitated Ti oxide particles were observed in sintered microstructures of die pressed compacts, however, in the case of injection molded compacts, since residual C derived from the binder reduced Ti oxides, TiC particles were observed instead of Ti oxide ones. Such precipitated TiC probably enhanced densification of the injection molded sintered compacts depressing crystal grain growth in them. 2 refs., 7 figs.

Takekawa, J. (Ishinomaki Senshu University, Miyagi (Japan))

1994-03-13

217

Determinação da redução da resistência à tração em corpos de prova com Weld Line/ Determination of reduction of the weld line strength in injection molded  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Neste trabalho objetivou-se determinar a redução da resistência à tração de corpos de prova com linhas de solda. Os corpos de prova ASTM foram moldados pelo processo de injeção com diferentes temperaturas de plastificação (180 ºC a 280 ºC). O material utilizado foi o polímero termoplástico Polystyrol 158 K da Basf. Este estudo relaciona as linhas de solda em produtos moldados por injeção com a redução da resistência mecânica devido a fragilização na (more) região da linha de solda. Para o desenvolvimento deste trabalho foi projetado e desenvolvido um molde de injeção com uma cavidade em forma de corpo de prova com canal de ataque pelas extremidades. Desta forma no momento da junção dos fluxos obtêm-se uma linha de solda no centro do corpo de prova. Os parâmetros do processo de injeção foram determinados a partir de um aplicativo comercial. A temperatura do molde e o tempo de injeção permaneceram constantes. O tempo de solidificação do material foi determinado analiticamente, considerando-se o centro do corpo de prova como referência. Foram injetados dez corpos de prova em cada uma das temperaturas. Foi observada de forma clara a existência de linhas de junção no centro da peça e as condições de processo utilizadas não permitiram a formação de linha de solda fria. Após a realização dos ensaios de tração, foi determinado que a tensão de ruptura decresce nas seguintes condições: com a diminuição da temperatura de injeção e do tempo de solidificação e com o aumento da trinca. A ruptura sempre ocorreu na linha de solda. Abstract in english In this paper, the purpose is to determine the weld line strength in injection molded samples. The ASTM standard dogbone-shaped samples were molded over a range of melt temperatures (180 ºC up to 280 ºC). The plastic used was a commercial grade of polystyrene (PS), BASF Polystyrol 158K. This study links weld lines in parts by injection molding with mechanical strength reduction due to embrittling effect in weld-line region. A single-cavity mold double-gated was used to (more) generate ASTM D638 Type I tensile specimens. The double-gated and runner allow the parts to be molded with weld line. The injection process parameters were determined by imputing resin, machine and geometry information into a CAE software package. The mold temperature and fill time were maintaining the same. The frozen time was determined by analytic equation, which considers the center of the thickness as reference. For each melt temperature 10 samples were tested. The weld line was clearly noted in the centre of the samples and the process condition set avoided the cold weld line. By the strength tests were possible to realize that lower the injection temperature lower the frozen time and higher the length of the crack. Then low injection temperature leads to low maximum strength. The fracture always occurs in the weld line.

Bom, R.P.; Kalin, A.F.

2008-06-01

218

OXYGEN-PERMEABLE MOLDING AND PROCESS FOR ITS PRODUCTION  

UK PubMed Central (United Kingdom)

The invention provides a transparent oxygen-permeable molding showing a high oxygen permeability in a specific direction, which comprises either (a) a block copolymer of polyalkyl methacrylate segments with silicon polymethacrylate segments, or (b) a block copolymer or (c) a graft copolymer containing polyorganosiloxane as one component in a specific higher order structure. The molding offers a high oxygen permeability at a relatively low silicon content, and hence it forms an oxygen-permeable product with high tear strength and surface hardness.

TONE Seiji; MORI Hiroshi; YAMAMOTO Naoki; TAKEDA Haruko; SUGIMORI Masahiro

219

Fabrication and characterization of injection molded poly ({epsilon}-caprolactone) and poly ({epsilon}-caprolactone)/hydroxyapatite scaffolds for tissue engineering  

Energy Technology Data Exchange (ETDEWEB)

In this study, poly({epsilon}-caprolactone) (PCL)/sodium chloride (NaCl), PCL/poly(ethylene oxide) (PEO)/NaCl and PCL/PEO/NaCl/hydroxyapatite (HA) composites were injection molded and characterized. The water soluble and sacrificial polymer, PEO, and NaCl particulates in the composites were leached by deionized water to produce porous and interconnected microstructures. The effect of leaching time on porosity, and residual contents of NaCl and NaCl/HA, as well as the effect of HA addition on mechanical properties was investigated. In addition, the biocompatibility was observed via seeding human mesenchymal stem cells (hMSCs) on PCL and PCL/HA scaffolds. The results showed that the leaching time depends on the spatial distribution of sacrificial PEO phase and NaCl particulates. The addition of HA has significantly improved the elastic (E Prime ) and loss moduli (E Double-Prime ) of PCL/HA scaffolds. Human MSCs were observed to have attached and proliferated on both PCL and PCL/HA scaffolds. Taken together, the molded PCL and PCL/HA scaffolds could be good candidates as tissue engineering scaffolds. Additionally, injection molding would be a potential and high throughput technology to fabricate tissue scaffolds. - Highlights: Black-Right-Pointing-Pointer PCL/NaCl, PCL/PEO/NaCl and PCL/PEO/NaCl/HA composites were injection molded. Black-Right-Pointing-Pointer Leaching time depends on the distribution of PEO phase and NaCl particulates. Black-Right-Pointing-Pointer The elastic and loss moduli of PCL/HA scaffolds have significantly improved. Black-Right-Pointing-Pointer Human hMSCs have attached, survived and proliferated well on PCL and PCL/HA scaffolds. Black-Right-Pointing-Pointer Molded PCL and PCL/HA scaffolds could be good candidates for tissue engineering.

Cui Zhixiang [Zhengzhou University, Henan (China); Nelson, Brenton; Peng, YiYan [University of Wisconsin-Madison, Wisconsin (United States); Li Ke [South China University of Technology, Guangzhou (China); Pilla, Srikanth; Li Wanju [University of Wisconsin-Madison, Wisconsin (United States); Turng, Lih-Sheng, E-mail: turng@engr.wisc.edu [University of Wisconsin-Madison, Wisconsin (United States); South China University of Technology, Guangzhou (China); Huazhong University of Science of Technology, Wuhan (China); Shen Changyu, E-mail: shency@zzu.edu.cn [Zhengzhou University, Henan (China)

2012-08-01

220

Fabrication and characterization of injection molded poly (?-caprolactone) and poly (?-caprolactone)/hydroxyapatite scaffolds for tissue engineering  

International Nuclear Information System (INIS)

In this study, poly(?-caprolactone) (PCL)/sodium chloride (NaCl), PCL/poly(ethylene oxide) (PEO)/NaCl and PCL/PEO/NaCl/hydroxyapatite (HA) composites were injection molded and characterized. The water soluble and sacrificial polymer, PEO, and NaCl particulates in the composites were leached by deionized water to produce porous and interconnected microstructures. The effect of leaching time on porosity, and residual contents of NaCl and NaCl/HA, as well as the effect of HA addition on mechanical properties was investigated. In addition, the biocompatibility was observed via seeding human mesenchymal stem cells (hMSCs) on PCL and PCL/HA scaffolds. The results showed that the leaching time depends on the spatial distribution of sacrificial PEO phase and NaCl particulates. The addition of HA has significantly improved the elastic (E?) and loss moduli (E?) of PCL/HA scaffolds. Human MSCs were observed to have attached and proliferated on both PCL and PCL/HA scaffolds. Taken together, the molded PCL and PCL/HA scaffolds could be good candidates as tissue engineering scaffolds. Additionally, injection molding would be a potential and high throughput technology to fabricate tissue scaffolds. - Highlights: ?PCL/NaCl, PCL/PEO/NaCl and PCL/PEO/NaCl/HA composites were injection molded. ?Leaching time depends on the distribution of PEO phase and NaCl particulates. ?The elastic and loss moduli of PCL/HA scaffolds have significantly improved. ?Human hMSCs have attached, survived and proliferated well on PCL and PCL/HA scaffolds. ?Molded PCL and PCL/HA scaffolds could be good candidates for tissue engineering.

2012-08-01

 
 
 
 
221

Trial production of titanium orthodontic brackets fabricated by metal injection molding (MIM) with sintering.  

UK PubMed Central (United Kingdom)

Safety and esthetics are two indispensable factors to consider when fabricating orthodontic brackets. However, these factors are not easily achieved when conventional techniques (including forging and casting) are used in the mass production of titanium brackets, albeit the brackets exhibit excellent biocompatibility. In the present study, orthodontic brackets were manufactured by metal powder injection molding with sintering. Brackets with three different base designs were made and subjected to compression shear tests for evaluation of their bonding strength to enamel substrate. The shapes given to the dimple of the base were spherical, oval, and grooved. The maximum shear forces for each type were 11.1 kgf, 7.6 kgf, and 18.5 kgf, respectively. The bonding strengths of the titanium bracket were equivalent to those obtained with conventional stainless steel brackets. Moreover, uniform distribution of Vickers hardness values (average, 240 +/- 40 Hv) measured at three locations indicated that the titanium bracket was uniformly sintered. Accordingly, titanium brackets thus fabricated exhibit a potential for clinical application.

Deguchi T; Ito M; Obata A; Koh Y; Yamagishi T; Oshida Y

1996-07-01

222

Model and simulation for melt flow in micro-injection molding based on the PTT model  

Science.gov (United States)

Unsteady viscoelastic flows were studied using the finite element method in this work. The Phan-Thien-Tanner (PTT) model was used to represent the rheological behavior of viscoelastic fluids. To effectively describe the microscale effects, the slip boundary condition and surface tension were added to the mathematical model for melt flow in micro-injection molding. The new variational equation of pressure, including the viscoelastic parameters and slip boundary condition, was generalized using integration by parts. A computer code based on the finite element method and finite difference method was developed to solve the melt flow problem. Numerical simulation revealed that the melt viscoelasticity plays an important role in the prediction of melt pressure, temperature at the gate and the succeeding melt front advancement in the cavity. Using the viscoelastic model one can also control the rapid increase in simulated pressure, temperature, and reduce the filling difference among different cavities. The short shot experiments of micro-motor shaft showed that the predicted melt front from the viscoelastic model is in fair agreement with the corresponding experimental results.

Cao, Wei; Kong, Lingchao; Li, Qian; Ying, Jin; Shen, Changyu

2011-12-01

223

Quality Prediction Model of Injection-Molded Rib Design using Back-Propagation Network  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, an analytical model of a rectangular thermoplastic ABS (Acrylonitrile Butadiene Styrene) plastic cover with rib of a given thickness (2.8 mm) was introduced and the dimensions as well as width of the rib were selected as the control factors for simulation. Additionally, the deflection under a constant force of 150 Newton at the back centre of the cover was defined as quality characteristic. Moreover, the L9(34) orthogonal array for four factors and three levels from Taguchi method was additionally considered to layout the 34 = 81 sets of full simulations. By commencing the BPN (Back-Propagation Network) to learn the selected 45 sets of simulated results. The remaining 36 sets of simulated results are then employed to verify and construct a quality predictor of rib design. Considering the learning rate as 1 and momentum factor as 0.5, the results of 20000 times of BPN training through a hidden layer indicated that the accuracy of deflection prediction reached 95.87%. In this study, the full FEM (Finite Element Method) simulated results from the 81 sets of combinations layout by Taguchi method are learned and verified by BPN for the design of injection-molded rib. It is shown that the quality of a plastic rib can surely be effectively found with the proposed economic and prospective BPN. This study exactly contributes an economical technique to the quality prediction of rib design for plastic injection industry in minimizing the development period of a new product.

Tian-Syung Lan; Ming-Yung Wang

2009-01-01

224

Development of a low cost permanent mold casting process for TiAl automotive valves  

Energy Technology Data Exchange (ETDEWEB)

This paper reviews progress made in the development of a low cost permanent mold casting process for TiAl automotive valves. The issues studied include mold life, mold/metal reaction, shrinkage void control, dimensional control, and post casting processes. More than 800 Ti-47Al-2Nb-1.75 Cr (at%) valves were produced by gravity, centrifugal, and pressure assisted casting methods on a laboratory scale. Microstructures, tensile, creep, and fatigue properties of as-HIP and as-heat treated valves are described. Process scale up challenges identified in this work are also discussed.

Jones, P.E.; Porter, W.J. III; Eylon, D. [Univ. of Dayton, OH (United States); Colvin, G. [Howmet Corp., Whitehall, MI (United States)

1995-12-31

225

Characteristics of thermoplastics containing electrically conducting asymmetric particles - anisotropic electrical conductivity of injection molded parts and extrusion behavior  

Energy Technology Data Exchange (ETDEWEB)

The characteristics of compounds of acrylonitrile-butadiene-styrene and high impact polystyrene resins filled with carbon fibers, steel fibers, carbon black, and aluminum flakes have been investigated with special emphasis on electrical conductivity and flow behavior in a capillary rheometer. Compression- and injection-molded compounds were found to be highly electrically anisotropic. The components of the electrical conductivity tensor, were measured. Generally, kappa-11, the flow direction conductivity, has the highest value and the thickness direction, and kappa-33 has the lowest. The injection-molded parts were usually electrically heterogeneous, with the conductivities highest at the greatest distances from the gate. The flow of these compounds through dies was investigated. Examination of material from the die entrance indicated streamline flow without entrance vortices. Extrudates were found to contain oriented particles. 25 references.

Martinsson, J.; White, J.L.

1986-10-01

226

Constante de mola de molas cerâmicas injetadas a baixa pressão/ Spring constant of low-pressure injection molded ceramic springs  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A dificuldade de usinagem de peças cerâmicas já sinterizadas é muito grande, principalmente devido à dureza e fragilidade destes materiais, o que implica em altos custos de produção. Por isso, grandes esforços tem sido feitos no sentido de melhorar os processos de conformação a verde existentes, ou criar novos processos que permitam a obtenção de peças cada vez mais próximas do formato final desejado. Produzir peças cerâmicas com formatos complexos, livres (more) de defeitos, é uma tarefa que implica em grandes dificuldades. Molas cerâmicas possuem formatos extremamente difíceis de serem moldados e, conseqüentemente, atualmente são produzidas comercialmente molas cerâmicas pelo processo de usinagem, geralmente a um custo elevado. Uma alternativa para a produção de molas cerâmicas é a moldagem por injeção em baixa pressão. Para o desenvolvimento de molas cerâmicas para aplicações tecnológicas, é necessário, além de obter peças íntegras e livres de defeitos, aferir algumas de suas propriedades, como a constante de mola. Uma vez que estas molas encontram aplicação em altas temperaturas, torna-se imprescindível realizar a medida da resistência imposta pela mola à deformação elástica em diferentes temperaturas. Para tanto, este trabalho propõem a montagem de um sistema para a medição da constante de mola de molas cerâmicas injetadas a baixa pressão, tanto à temperatura ambiente como em altas temperaturas, usando o método dinâmico da excitação por impulso para medir a frequência de vibração da mola suspensa no interior de um forno. Para ilustrar a aplicação desta técnica são apresentados resultados obtidos para uma mola helicoidal de alumina, da temperatura ambiente até 1100 ºC. Abstract in english The machining of sintered ceramic parts is a difficult process, mainly due to the hardness and brittleness of these materials, which implies in high production costs. Therefore, great efforts have been made to improve the forming processes of green ceramics, or create new processes to obtain the near net shape parts. The production of ceramic parts with complex shapes, free of defects, is a task that involves great difficulties. Ceramic springs exhibits shapes extremely d (more) ifficult to be molded and therefore are currently commercially produced mainly by machining, a process which is difficult and expensive. An alternative for the production of ceramic springs is by low-pressure injection molding. For the development of ceramic springs for technological applications, it is required in addition to getting parts intact and free of defects, to measure some of its properties, including the spring constant. Since these springs are usually applied at high temperatures, it becomes important to carry out the measurement of resistance imposed by the spring to elastic deformation at different temperatures. Accordingly, in this work we describe the assembly of an experiment for the measurement of the spring constant of low-pressure injection molded ceramic springs, both at ambient temperature and at high temperatures, using the dynamic impulse excitation method to measure the frequency of vibration of a suspended spring inside a furnace. Results are presented for a helical spring of alumina from room temperature to1100 ºC to illustrate the application of this technique.

Barbieri, R. A.; Zorzi, J. E.

2011-12-01

227

Unique crystal morphology and tensile properties of injection-molded bar of LLDPE by adding HDPE with different molecular weights  

International Nuclear Information System (INIS)

In this research, a linear low density polyethylene (LLDPE) was first melt blended with a series of high density polyethylenes (HDPE) with different molecular weights at a fixed ratio of LLDPE/HDPE = 90/10 (w/w). The prepared HDPE/LLDPE blends were then injection-molded into specimen bars through a dynamic packing injection molding (DPIM) technique, in which an oscillating shear field was imposed on the melt by two pistons that move reversibly with the same frequency during the packing stage. The crystal morphology, orientation and tensile properties were characterized by scanning electron microscopy, two-dimensional wide-angle X-ray scattering and Instron, respectively. Compared with conventional injection molding, DPIM caused an obvious increase in tensile strength in the injection-molded bars. Interestingly, LLDPE blended with low molecular weight HDPE (LMW-PE) was found to possess much higher tensile strength than that blended with high molecular weight HDPE (HMW-PE). Shish-kebab morphology was observed for all blends obtained, regardless of the molecular weight of the HDPE. However, thicker but shorter lamellae were observed for the LLDPE/LMW-PE blend, corresponding to a higher melting temperature; while thinner but longer lamellae were seen for the LLDPE/HMW-PE blend, corresponding to a lower melting temperature. Furthermore, the phase miscibility between HDPE and LLDPE was found to increase with increasing HDPE molecular weight, which would affect the sensitivity of molecular chains for response to external shear. The changed miscibility, together with the changed entanglement density in different HDPE was responsible for the change in tensile strength and unique crystal morphology of LLDPE induced by adding HDPE.

2008-01-01

228

Unique crystal morphology and tensile properties of injection-molded bar of LLDPE by adding HDPE with different molecular weights  

Energy Technology Data Exchange (ETDEWEB)

In this research, a linear low density polyethylene (LLDPE) was first melt blended with a series of high density polyethylenes (HDPE) with different molecular weights at a fixed ratio of LLDPE/HDPE = 90/10 (w/w). The prepared HDPE/LLDPE blends were then injection-molded into specimen bars through a dynamic packing injection molding (DPIM) technique, in which an oscillating shear field was imposed on the melt by two pistons that move reversibly with the same frequency during the packing stage. The crystal morphology, orientation and tensile properties were characterized by scanning electron microscopy, two-dimensional wide-angle X-ray scattering and Instron, respectively. Compared with conventional injection molding, DPIM caused an obvious increase in tensile strength in the injection-molded bars. Interestingly, LLDPE blended with low molecular weight HDPE (LMW-PE) was found to possess much higher tensile strength than that blended with high molecular weight HDPE (HMW-PE). Shish-kebab morphology was observed for all blends obtained, regardless of the molecular weight of the HDPE. However, thicker but shorter lamellae were observed for the LLDPE/LMW-PE blend, corresponding to a higher melting temperature; while thinner but longer lamellae were seen for the LLDPE/HMW-PE blend, corresponding to a lower melting temperature. Furthermore, the phase miscibility between HDPE and LLDPE was found to increase with increasing HDPE molecular weight, which would affect the sensitivity of molecular chains for response to external shear. The changed miscibility, together with the changed entanglement density in different HDPE was responsible for the change in tensile strength and unique crystal morphology of LLDPE induced by adding HDPE.

Liang, S.; Yang, H.; Wang, K.; Zhang, Q.; Du, R. [Department of Polymer Science and Materials, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065 (China); Fu, Q. [Department of Polymer Science and Materials, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065 (China)], E-mail: qiangfu@scu.edu.cn

2008-01-15

229

Continuous carbon and glass fiber reinforced polypropylene: Optimization of the compression molding process  

Energy Technology Data Exchange (ETDEWEB)

The objective of this work was to optimize the processing conditions of polypropylene/carbon, PP/C, and polypropylene/glass, PP/G, composites. Investigation of the effects of molding parameters such as molding temperature and residence time and cooling rate on the tensile performance of PP/C and PP/G was undertaken. It is well known that the mechanical performance of composite based on thermoplastic matrix such as polypropylene is closely related to crystalline morphology which is dependent on the thermal history. Since the compression molding process involves kinetic behavior of systems undergoing phase transformations under non-isothermal conditions, the crystallization behavior of PP matrix in the presence of carbon and glass fibers was investigated under non-isothermal conditions. The effects of processing temperature, residence time and cooling rate on the crystallization temperature, degree of crystallinity, crystallization rate and kinetics of crystallization were analyzed. The tensile behavior of the {+-}45{degrees} laminate of PP/C and PP/G and their interfacial properties were evaluated as a function of molding parameters. The variation in the tensile strength of the {+-}45{degrees} laminates as a function of molding temperature was found to show three distinct regions: the tensile strength first increases with molding temperature, attains a plateau region, and finally decreases at high molding temperature. DSC analysis done in order to simulate phase transformation under non-isothermal conditions also revealed similar behavior suggesting a close relationship between mechanical performance and matrix properties.

Denault, J.; Guillemenet, J. [Industrial Materials Institute, Boucherville, Quebec (Canada)

1996-12-31

230

Tool steel quality and surface finishing of plastic molds  

Directory of Open Access Journals (Sweden)

Full Text Available Plastic industry is today in a constant growth, demanding several products from other segments, which includes the plastic molds, mainly used in the injection molding process. Considering all the requirements of plastic molds, the surface finishing is of special interest, as the injected plastic part is able to reproduce any details (and also defects) from the mold surface. Therefore, several aspects on mold finishing are important, mainly related to manufacturing conditions - machining, grinding, polishing and texturing, and also related to the tool steel quality, in relation to microstructure homogeneity and non-metallic inclusions (cleanliness). The present paper is then focused on this interrelationship between steel quality and manufacturing process, which are both related to the final quality of plastic mold surfaces. Examples are discussed in terms of surface finishing of plastic molds and the properties or the microstructure of mold steels.

Rafael Agnelli Mesquita; Reinhold Schneider

2010-01-01

231

Effect of mixing on the rheology and particle characteristics of tungsten-based powder injection molding feedstock  

International Nuclear Information System (INIS)

[en] This study investigates the effect of mixing technique and particle characteristics on the rheology and agglomerate dispersion of tungsten-based powder injection molding (PIM) feedstock. Experiments were conducted with as-received (agglomerated) and rod-milled (deagglomerated) tungsten powder mixed in a paraffin wax-polypropylene binder. Increase in the mixing shear rate decreased the agglomerate size of the agglomerated tungsten powder, decreased the viscosity, and improved the flow stability of the feedstock, interpreted as increased homogeneity of the feedstock. Higher solids volume fraction, lower mixing torques, and improved homogeneity were observed with deagglomerated tungsten powder, emphasizing the importance of particle characteristics and mixing procedures in the PIM process. Hydrodynamic stress due to mixing and the cohesive strength of the tungsten agglomerate were calculated to understand the mechanism of deagglomeration and quantify the effect of mixing. It was concluded that deagglomeration occurs due to a combination of rupture and erosion with the local hydrodynamic stresses exceeding the cohesive strength of the agglomerate

2003-09-15

232

Diseño de un molde de inyección con un sistema de cavidades intercambiables y deslizantes/ DESIGN OF INJECTION MOULD WITH A SYSTEM OF INTERCHANGEABLE AND SLIDING CAVITIES  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish El presente trabajo tuvo como objetivo principal diseñar un molde de inyección de probetas normalizadas, destinadas a ensayos mecánicos, utilizando un sistema novedoso de cavidades intercambiables y deslizantes. El diseño que se propone se basa en el uso de insertos o postizos, para el moldeo individualizado de diferentes probetas. Actualmente, existe la tendencia a diseñar moldes con postizos intercambiables que ofrecen facilidades para la obtención de probetas div (more) ersas, con la característica de fijarse al sistema de placas mediante tornillos. Al estar sujetos de esa forma, presentan dificultades importantes al momento de montarlos y desmontarlos, para un cambio rápido de cavidades de moldeo. Para ello se requiere de un gran esfuerzo manual e inversión de tiempo. Partiendo de esa experiencia y de las tendencias recientes en la industria a usar moldes con sistemas de cambio rápido, el presente trabajo plantea el diseño con un sistema de postizos intercambiables y deslizantes, bajo las especificaciones de las normas ASTM 6141 e ISO 294-1. Con tal fin, se han diseñado dos postizos, uno para la inyección de probetas tipo halterio y otro para barras rectangulares, las cuales pueden usarse en múltiples ensayos mecánicos (tracción, flexión e impacto). Para modelar y validar el molde diseñado y los postizos propuestos se usaron los programas Pro/ENGINEER y C-MOLD. Se formularon dos propuestas preliminares, considerando los dos movimientos posibles de los postizos en el sistema de placas de la máquina de inyección: vertical y horizontal. La evaluación comparativa de los pros y los contras de cada molde favoreció al sistema horizontal, debido a sus facilidades de manipulación y garantías para inmovilizar los postizos Abstract in english The main aim of this work was the design of an injection mould with the purpose of preparing test specimens, using a new system of interchangeable and sliding cavities. The proposed mould is able to hold inserts able to, manufacture the individualized test specimen by injection moulding. Nowadays, the trend toward the design of moulds with interchangeable cavities intended for easing the process of obtaining diverse plastic parts in the same mould, present the characteris (more) tic of fixing the system of plates by means of several screws. This system presents important drawback, at the moment of a rapid change of them, like the trend of having to make a great manual effort and to spend considerable amount of time. The present work presents the design of a mould with sliding and interchangeable cavities, under ASTM 6141 and ISO 294-1 norms. The design of two interchangeable and sliding cavities is developed: one with the purpose of producing tensile test specimen and the other for manufacturing rectangular bars (for flexion or impact tests). In order to shape and validate the designed mold and the proposed cavities, the Pro/ENGINEER and C-MOLD software were used. Two preliminary designs were formulated considering horizontal or vertical possible movements of the interchangeable cavities in the system of plates of the injection mould. The comparative evaluation of the advantages and disadvantages of every mould favoured the horizontal system, due to its operational facility associated with the guaranty of an easy manipulation and immobilization of cavities

Candal, María V; Hernández, María I

2011-03-01

233

Die-sinking electrical discharge machining of a high-strength copper-based alloy for injection molds  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english High-strength copper alloys are used as materials for injection molding tools or as cores and inserts in steel molds because of their high thermal conductivity, corrosion and wear resistance. Unfortunately, there is little technological knowledge on the electrical discharge machining (EDM) of copper-beryllium ASTM C17200 alloy. In this work, rough and finish machining conditions were tested using copper and tungsten-copper as materials for the electrodes. Cross-sectional (more) micrographic and hardness examinations as well as surface roughness measurements were also carried out on workpieces after machining in order to study the thermally affected zones. Appropriate parameters settings for EDM of the investigated alloy are suggested.

Amorim, F. L.; Weingaertner, W. L.

2004-06-01

234

Die-sinking electrical discharge machining of a high-strength copper-based alloy for injection molds  

Directory of Open Access Journals (Sweden)

Full Text Available High-strength copper alloys are used as materials for injection molding tools or as cores and inserts in steel molds because of their high thermal conductivity, corrosion and wear resistance. Unfortunately, there is little technological knowledge on the electrical discharge machining (EDM) of copper-beryllium ASTM C17200 alloy. In this work, rough and finish machining conditions were tested using copper and tungsten-copper as materials for the electrodes. Cross-sectional micrographic and hardness examinations as well as surface roughness measurements were also carried out on workpieces after machining in order to study the thermally affected zones. Appropriate parameters settings for EDM of the investigated alloy are suggested.

F. L. Amorim; W. L. Weingaertner

2004-01-01

235

Paste based component molding process involves deep drawing a paste-coated membrane and hardening  

UK PubMed Central (United Kingdom)

The paste material(5) is applied onto a expandable membrane(3) covering a first deep drawing mold(1) and the membrane is then formed into the cavity using either positive pressure and/or vacuum.. After hardening the paste on the shaped membrane the final product is demolded. An Independent claim is made for the process equipment including a mold(1) and an expandable membrane.

HERMANN MICHAEL; KOSCHIKOWSKI JOACHIM

236

Moldagem por injeção de pós cerâmicos: remoção da parafina e do polipropileno utilizados como veículo orgânico Ceramic injection molding: removal of pafafin and polypropylene used as organic binder  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeção de pós cerâmicos tem se tornado um processo altamente atrativo por aliar a versatilidade e a produtividade da moldagem por injeção convencional às propriedades inerentes aos materiais cerâmicos. A remoção do ligante, usado como veículo orgânico nesse processo, é uma das etapas críticas para a produção de peças cerâmicas sem defeitos. Neste trabalho avaliou-se a influência da geometria das peças injetadas na remoção do ligante, tanto por imersão em solvente como por decomposição térmica. Alumina em pó foi misturada fisicamente a um ligante composto por polipropileno [PP], parafina [PW] e ácido esteárico [AE]. As peças com diferentes geometrias foram mantidas imersas em hexano, secas sob vácuo e acompanhada a variação de massa devido à solubilização do PW e AE. A determinação da porosidade das peças, realizada por meio das isotermas de adsorção/desorção de nitrogênio, mostrou um aumento de porosidade de 0,5% volume para aproximadamente 20% volume após a imersão em solvente. A remoção térmica do PP remanescente produziu hidrocarbonetos alifáticos e compostos insaturados, determinados e quantificados por espectroscopia de infravermelho, que permearam a estrutura porosa da peça. A geometria das peças tem grande influência na remoção do ligante, podendo afetar não só a qualidade do produto final, mas também as etapas subseqüentes do processo.Powder injection molding [PIM] has become highly attractive as it combines the versatility and productivity of conventional injection molding processes with the intrinsic properties of metallic and ceramic materials. The removal of organic binder, used as vehicles during the process, is one of the most critical stages in the production of ceramic devices in this process. In this work, the influence from the geometry of the injected part on the removal of the organic binder was evaluated for both solvent immersion and thermal degradation processes. Alumina powder was mixed with an organic binder, comprising polypropylene [PP], paraffin wax [PW] and stearic acid [SA], and injection molded in different geometries. Immersion of ceramic parts in hexane induced the solubilization of PW and SA, confirmed by weight variation. Parts porosity, determined through nitrogen adsorption isotherm, showed an increase from 0.5 v% before immersion to ca. 20 v% after immersion. PP burnout produced aliphatic hydrocarbons and unsaturated compounds that flow through a porous structure produced in early stages of this process. Parts geometry plays an important role in binder removal, affecting the quality of the sintered part as well as the remaining stages of the process.

Ricardo V. B. Oliveira; Eduardo A. Pinheiro; Valdir Soldi; Alfredo T. N. Pires; Márcio C. Fredel

2004-01-01

237

Fabrication of high performance sintered alloy steels by metal injection molding. Koseino shoketsu gokinko no kinzoku funmatsu shashutsu seikeiho ni yoru sakusei  

Energy Technology Data Exchange (ETDEWEB)

To fabricate high performance sintered alloy steels, discussions were given on application of the metal injection molding process to a powder mixed to the composition of the 4600 b steel and the A4600V alloy powder, both the powder forging steel species. This paper describes the following matters on the result therefrom: A de-binder method that performs heating and evaporation of wax after extracting it using solvents is suitable for the case where wax-based binders are used: to make carbon amount in the sinters to about 0.4% (a target value), an N2 gas mixture with H2 concentration made to 40% plus may be used as an atmosphere during the heating and evaporation; on the injection molding material using the powder mixture, dense and microfine sintered structure can be formed if the sintering temperature (1573 K) and the atmosphere are controlled adequately; and a sinter with mechanical properties comparable with those for powder forging alloy steel can be obtained if a densifying treatment is given using the Ceracon process. 30 refs., 17 figs., 2 tabs.

Miura, H. (Kumamoto University, Kumamoto (Japan). Faculty of Engineering)

1992-08-20

238

Vacuum-assisted resin transfer molding (VARTM) model development, verification, and process analysis  

Science.gov (United States)

Vacuum-Assisted Resin Transfer Molding (VARTM) processes are becoming promising technologies in the manufacturing of primary composite structures in the aircraft industry as well as infrastructure. A great deal of work still needs to be done on efforts to reduce the costly trial-and-error methods of VARTM processing that are currently in practice today. A computer simulation model of the VARTM process would provide a cost-effective tool in the manufacturing of composites utilizing this technique. Therefore, the objective of this research was to modify an existing three-dimensional, Resin Film Infusion (RFI)/Resin Transfer Molding (RTM) model to include VARTM simulation capabilities and to verify this model with the fabrication of aircraft structural composites. An additional objective was to use the VARTM model as a process analysis tool, where this tool would enable the user to configure the best process for manufacturing quality composites. Experimental verification of the model was performed by processing several flat composite panels. The parameters verified included flow front patterns and infiltration times. The flow front patterns were determined to be qualitatively accurate, while the simulated infiltration times over predicted experimental times by 8 to 10%. Capillary and gravitational forces were incorporated into the existing RFI/RTM model in order to simulate VARTM processing physics more accurately. The theoretical capillary pressure showed the capability to reduce the simulated infiltration times by as great as 6%. The gravity, on the other hand, was found to be negligible for all cases. Finally, the VARTM model was used as a process analysis tool. This enabled the user to determine such important process constraints as the location and type of injection ports and the permeability and location of the high-permeable media. A process for a three-stiffener composite panel was proposed. This configuration evolved from the variation of the process constraints in the modeling of several different composite panels. The configuration was proposed by considering such factors as: infiltration time, the number of vacuum ports, and possible areas of void entrapment.

Sayre, Jay Randall

239

Moldes de ABS construídos pelo processo de modelagem por fusão e deposição para injeção de PP e PEBD PP and LDPE injection in ABS molds built with fused deposition modeling  

Directory of Open Access Journals (Sweden)

Full Text Available Os processos de prototipagem rápida (Rapid Prototyping - RP) e ferramental rápido (Rapid Tooling - RT) surgiram para reduzir os tempos de desenvolvimento de produtos na fase de projeto diminuindo a necessidade de retrabalhos e, conseqüentemente, antecipando a entrada de novos produtos no mercado. Neste trabalho foi utilizada uma das tecnologias de prototipagem rápida, denominada Modelagem por Fusão e Deposição (FDM), na construção de moldes em ABS com o objetivo de investigar sua aplicação na moldagem por injeção de termoplásticos. Amostras das peças injetadas foram submetidas a ensaios de difração de raios X, dureza Shore D e tração. Os resultados mostraram a viabilidade de fabricar pequenos lotes de peças em PEBD e PP com propriedades mecânicas bastante similares às encontradas em peças moldadas em moldes metálicos.Rapid Prototyping and Rapid Tooling are aimed at reducing the development time of products in the design phase by minimizing re-workings and, consequently, reducing the time to launch new products. In this work one of the technologies of rapid prototyping, called Fused Deposition Modeling (FDM), was used in the construction of ABS molds with the objective of investigating its application in the injection molding of thermoplastics. Specimens of the molded parts were characterized with X-ray diffraction, Shore D hardness and tensile tests. The results demonstrated the viability to manufacture small batches of LDPE and PP parts with mechanical properties similar to those molded parts in metallic molds.

José A. Foggiatto; Carlos H. Ahrens; Gean V. Salmoria; Alfredo T. N. Pires

2004-01-01

240

Fabrication Process for Large Size Mold and Alignment Method for Nanoimprint System  

Science.gov (United States)

Nanoimprint technology is considered one of the mass production methods of the display for cellular phone or notebook computer, with Anti-Reflection Structures (ARS) pattern and so on. In this case, the large size mold with nanometer order pattern is very important. Then, we describe the fabrication process for large size mold, and the alignment method for UV nanoimprint system. We developed the original mold fabrication process using nanoimprint method and etching techniques. In 66 × 45 mm2 area, 200nm period seamless patterns were formed using this process. And, we constructed original alignment system that consists of the CCD-camera system, X-Y-? table, method of moiré fringe, and image processing system, because the accuracy of pattern connection depends on the alignment method. This alignment system accuracy was within 20nm.

Ishibashi, Kentaro; Kokubo, Mitsunori; Goto, Hiroshi; Mizuno, Jun; Shoji, Shuichi

 
 
 
 
241

Fiber Length and Orientation in Long-Fiber Injection-Molded Thermoplastics. Part I: Modeling of Microstructure and Elastic Properties  

Energy Technology Data Exchange (ETDEWEB)

This paper investigates the effects of fiber length and orientation distributions on the elastic properties of long-fiber injection-molded thermoplastics (LFTs). The corrected experimental fiber length distribution and the predicted and experimental orientation distributions were used in modeling to compute the elastic properties of the composite. First, from the fiber length distribution (FLD) data in terms of number of fibers versus fiber length, the probability density functions were built and used in the computation. Also, it has been shown that the two-parameter Weibull’s distribution can be used to represent the actual FLD. Next, the Mori-Tanaka model that employs the Eshelby’s equivalent inclusion method was applied to calculate the stiffness matrix of the aligned fiber composite containing the established FLD. The stiffness of the actual as-formed composite was then determined from the stiffness of the computed aligned fiber composite that was averaged over all possible orientations using the orientation averaging method. The methodology to predict the elastic properties of LFTs was validated via experimental verification of the longitudinal and transverse moduli determined for long glass fiber injection-molded polypropylene specimens. Finally, a sensitivity analysis was conducted to determine the effect of a variation of FLD on the composite elastic properties.

Nguyen, Ba Nghiep; Bapanapalli, Satish K.; Holbery, James D.; Smith, Mark T.; Kunc, Vlastimil; Frame, Barbara J.; Phelps, Jay; Tucker III, Charles L.

2008-05-01

242

In-Situ Real Time Monitoring and Control of Mold Making and Filling Processes: Final Report  

Energy Technology Data Exchange (ETDEWEB)

This project presents a model for addressing several objectives envisioned by the metal casting industries through the integration of research and educational components. It provides an innovative approach to introduce technologies for real time characterization of sand molds, lost foam patterns and monitoring of the mold filling process. The technology developed will enable better control over the casting process. It is expected to reduce scrap and variance in the casting quality. A strong educational component is integrated into the research plan to utilize increased awareness of the industry professional, the potential benefits of the developed technology, and the potential benefits of cross cutting technologies.

Mohamed Abdelrahman; Kenneth Currie

2010-12-22

243

Organic germanium injection and preparation process thereof  

UK PubMed Central (United Kingdom)

The invention relates to an organic germanium injection and its preparing process, wherein the injection is prepared from organic germanium, compound of organic germanium, polysaccharides and organic germanium polysaccharide through mixing with water for injection, heating, stirring for complete dissolving, filtering, adjusting pH, keeping constant volume, encapsulating, sterilizing and packaging.

PAN WEIXIN

244

Peri-implant bone formation and surface characteristics of rough surface zirconia implants manufactured by powder injection molding technique in rabbit tibiae.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To evaluate osseointegration in rabbit tibiae and to investigate surface characteristics of novel zirconia implants made by powder injection molding (PIM) technique, using molds with and without roughened inner surfaces. MATERIAL AND METHODS: A total of 20 rabbits received three types of external hex implants with identical geometry on the tibiae: machined titanium implants, PIM zirconia implants without mold etching, and PIM zirconia implants with mold etching. Surface characteristics of the three types of implant were evaluated. Removal torque tests and histomorphometric analyses were performed. RESULTS: The roughness of PIM zirconia implants was higher than that of machined titanium implants. The PIM zirconia implants exhibited significantly higher bone-implant contact and removal torque values than the machined titanium implants (P < 0.001). The PIM zirconia implants using roughened mold showed significantly higher removal torque values than PIM zirconia implants without using roughened mold (P < 0.001). CONCLUSIONS: It is concluded that the osseointegration of PIM zirconia implant is promising and PIM using roughened mold etching technique can produce substantially rough surfaces on zirconia implants.

Park YS; Chung SH; Shon WJ

2013-05-01

245

Mold with porous cavity vent  

Science.gov (United States)

A mold for injection molding of long thin walled articles has precisely balanced high-volume venting of a narrow cavity space surrounding a long slender cantilevered core and minimized flash. The venting is provided by closing an end of the female mold cavity with a sintered metal plug and forming an end of the mold cavity in an end face of the plug.

1979-08-21

246

Molecular weight dependence of hybrid shish kebab structure in injection molded bar of polyethylene/inorganic whisker composites.  

UK PubMed Central (United Kingdom)

In our previous work, a hybrid shish kebab structure, with polyethylene (PE) crystal lamellae periodically decorated on the surface of an inorganic whisker (SMCW) and aligned approximately perpendicular to the long axis of the whisker, has been observed in the injection molded bar of PE/SMCW composites. To investigate the effect of the molecular weight of the PE matrix on the formation of the hybrid shish kebab structure and the corresponding physical properties of HDPE/SMCW composites, in this work, three types of PE with different molecular weights were used to prepare the composites. They were first melt blended and then subjected to dynamic packing injection molding (DPIM), in which the prolonged shear was exerted on the melt during the solidification stage. An obvious hybrid shish kebab (HSK) structure, with PE crystal lamellae closely packed on the surface of the SMCW, was found in the samples with a low molecular weight PE (LMW-PE) matrix and a medium molecular weight PE (MMW-PE) matrix. However, in samples with a high molecular weight PE (HMW-PE) matrix, an incomplete HSK structure with PE crystal lamellae loosely decorated on the surface of the SMCW was observed. Furthermore, DSC results indicated that SMCW served as a good nucleating agent only for the composite with a LMW-PE matrix and the nucleation efficiency decreased with increasing PE molecular weight. Correspondingly, the tensile strength of the PE/SMCW composites was significantly improved by adding SMCW for the samples with a LMW-PE or MMW-PE matrix. Especially for samples with a LMW-PE matrix, the tensile strength was remarkably enhanced by the presence of only 1 wt % SMCW. For the composites with a HMW-PE matrix, the addition of SMCW had almost no reinforcing effect on the composites. The molecular weight dependence of the formation of HSK and property enhancement was discussed on the basis of the chain mobility and crystallization capability of the PE matrix.

Ning N; Luo F; Wang K; Zhang Q; Chen F; Du R; An C; Pan B; Fu Q

2008-11-01

247

Molecular weight dependence of hybrid shish kebab structure in injection molded bar of polyethylene/inorganic whisker composites.  

Science.gov (United States)

In our previous work, a hybrid shish kebab structure, with polyethylene (PE) crystal lamellae periodically decorated on the surface of an inorganic whisker (SMCW) and aligned approximately perpendicular to the long axis of the whisker, has been observed in the injection molded bar of PE/SMCW composites. To investigate the effect of the molecular weight of the PE matrix on the formation of the hybrid shish kebab structure and the corresponding physical properties of HDPE/SMCW composites, in this work, three types of PE with different molecular weights were used to prepare the composites. They were first melt blended and then subjected to dynamic packing injection molding (DPIM), in which the prolonged shear was exerted on the melt during the solidification stage. An obvious hybrid shish kebab (HSK) structure, with PE crystal lamellae closely packed on the surface of the SMCW, was found in the samples with a low molecular weight PE (LMW-PE) matrix and a medium molecular weight PE (MMW-PE) matrix. However, in samples with a high molecular weight PE (HMW-PE) matrix, an incomplete HSK structure with PE crystal lamellae loosely decorated on the surface of the SMCW was observed. Furthermore, DSC results indicated that SMCW served as a good nucleating agent only for the composite with a LMW-PE matrix and the nucleation efficiency decreased with increasing PE molecular weight. Correspondingly, the tensile strength of the PE/SMCW composites was significantly improved by adding SMCW for the samples with a LMW-PE or MMW-PE matrix. Especially for samples with a LMW-PE matrix, the tensile strength was remarkably enhanced by the presence of only 1 wt % SMCW. For the composites with a HMW-PE matrix, the addition of SMCW had almost no reinforcing effect on the composites. The molecular weight dependence of the formation of HSK and property enhancement was discussed on the basis of the chain mobility and crystallization capability of the PE matrix. PMID:18925778

Ning, Nanying; Luo, Feng; Wang, Ke; Zhang, Qin; Chen, Feng; Du, Rongni; An, Chunyang; Pan, Baofeng; Fu, Qiang

2008-10-17

248

Optimisation de l'Injection des Thermoplastiques Thermostables Peek Renforces de Fibres Courtes de Carbone (Optimization of the Injection Process for Thermostatic Polyether-Ether-Ketone (Peek) Thermoplastics Reinforced with Short Carbon Fibers).  

Science.gov (United States)

The injection parameters of polyether-ether-ketone (PEEK) reinforced with 30% carbon fibers were studied, to determine the effects on the characteristics of molded products. Injection pressure, injection velocity, mold temperature and hold pressure were e...

P. Hornet K. Stocklin J. P. Spigolis

1984-01-01

249

Effects of ultrasonic vibration on the micro-molding processing of polylactide.  

Science.gov (United States)

A new ultrasonic micro-molding system was used to process polylactide (PLA) and fabricate reduced dimension specimens. Plasticization and molding of PLA were achieved by applying ultrasonic waves after feeding the polymer into a plasticizing chamber. Chemical and physical characteristics of processed PLA varied depending on the processing window (i.e. changes in ultrasonic wave amplitude between 14.2 and 48.1?m and molding pressure between 0.5 in 6bars). In terms of chemical effects, the application of ultrasound can lead to lower molecular weights (e.g. decreases of more than 45% in the weight average molecular weight), revealing partial degradation of the material. Also, the processed materials exhibited slightly higher thermal degradability than pure PLA because ultrasonic vibrations break molecular linkages and worsen the polymer structure. Finally, the processing conditions for the preparation of PLA specimens could be optimized without causing degradation and preserving structural characteristics and mechanical properties. Specifically, the use of an amplitude of 48.1?m and a pressure of 3bars gave samples with the same molecular weight as the raw material (i.e. 117,500g/mol as opposed to 117,300g/mol for Mw). PMID:23932811

Sacristán, Matías; Plantá, Xavier; Morell, Mireia; Puiggalí, Jordi

2013-07-25

250

Effects of ultrasonic vibration on the micro-molding processing of polylactide.  

UK PubMed Central (United Kingdom)

A new ultrasonic micro-molding system was used to process polylactide (PLA) and fabricate reduced dimension specimens. Plasticization and molding of PLA were achieved by applying ultrasonic waves after feeding the polymer into a plasticizing chamber. Chemical and physical characteristics of processed PLA varied depending on the processing window (i.e. changes in ultrasonic wave amplitude between 14.2 and 48.1?m and molding pressure between 0.5 in 6bars). In terms of chemical effects, the application of ultrasound can lead to lower molecular weights (e.g. decreases of more than 45% in the weight average molecular weight), revealing partial degradation of the material. Also, the processed materials exhibited slightly higher thermal degradability than pure PLA because ultrasonic vibrations break molecular linkages and worsen the polymer structure. Finally, the processing conditions for the preparation of PLA specimens could be optimized without causing degradation and preserving structural characteristics and mechanical properties. Specifically, the use of an amplitude of 48.1?m and a pressure of 3bars gave samples with the same molecular weight as the raw material (i.e. 117,500g/mol as opposed to 117,300g/mol for Mw).

Sacristán M; Plantá X; Morell M; Puiggalí J

2014-01-01

251

Acoustic emission signals from gypsum-bonded dental casting molds during thermal processing.  

UK PubMed Central (United Kingdom)

To develop a suitable heating program for the investments which affect the casting accuracy/defects of prostheses, a probable microstructural change of the gypsum-bonded investments related to the transition of refractory particles during thermal processing was inspected by the measurement of acoustic emission (AE) signals. Gypsum-bonded cristobalite and quartz investment molds were used. AE measurements were carried out for the specimens in an electric furnace that was heated/cooled at a constant rate. For the heating process of the cristobalite investment, high AE activities were detected in the temperature range where the cristobalite was transformed. However, the AE signals detected were low for the second run of the heating and cooling processes. Even in the heating process, significant AE signals were not detected for the quartz investment. For cristobalite investment molds, micro-cracks are initiated and developed in relation to the transition of cristobalite particles in the mold. This leads to deterioration of the mechanical properties of the cristobalite investment at high temperatures (melt-pouring), and may affect the fitness of cast prostheses.

Kim KH; Asaoka K; Yoshida K

1998-03-01

252

An Approach to Rib Design of Injection Molded Product Using Finite Element and Taguchi Method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, not only Taguchi Method but also ANSYS in providing an economical and effective advance to the optimum design of the rib for a plastic injected product are introduced. The analytical model of a rectangular thermoplastic Acrylonitrile Butadiene Styrene (ABS) plastic cover with rib of g...

Tian-Syung Lan; Min-Chie Chiu; Long-Jyi Yeh

253

Artificial leaves via reproduction of hierarchical structures by a fast molding and curing process.  

UK PubMed Central (United Kingdom)

In this work, we have developed a practical approach for the replication of hierarchical structures on a native leaf surface via a fast two-step molding process combining both the fast curability to prevent shrinkage of cells and the strong resistance to chemical compounds for further applications. The negative replica of the leaf was produced from perfluoropolyether (PFPE) by precise molding followed by a fast curing with UV. A liquid ceramic precursor material (polyvinylsilazane, PVSZ) was used to fabricate the positive leaf structure through the same process as applied for the negative imprint of the surface yielding a highly detailed replica of the native leaf surface structure. Static water contact angle measurements show that the biomimetic surfaces exhibit a wettability similar to the native leaves.

Park S; van Rijn P; Böker A

2012-08-01

254

Artificial leaves via reproduction of hierarchical structures by a fast molding and curing process.  

Science.gov (United States)

In this work, we have developed a practical approach for the replication of hierarchical structures on a native leaf surface via a fast two-step molding process combining both the fast curability to prevent shrinkage of cells and the strong resistance to chemical compounds for further applications. The negative replica of the leaf was produced from perfluoropolyether (PFPE) by precise molding followed by a fast curing with UV. A liquid ceramic precursor material (polyvinylsilazane, PVSZ) was used to fabricate the positive leaf structure through the same process as applied for the negative imprint of the surface yielding a highly detailed replica of the native leaf surface structure. Static water contact angle measurements show that the biomimetic surfaces exhibit a wettability similar to the native leaves. PMID:22576668

Park, Sungjune; van Rijn, Patrick; Böker, Alexander

2012-05-11

255

Mutational processes molding the genomes of 21 breast cancers.  

UK PubMed Central (United Kingdom)

All cancers carry somatic mutations. The patterns of mutation in cancer genomes reflect the DNA damage and repair processes to which cancer cells and their precursors have been exposed. To explore these mechanisms further, we generated catalogs of somatic mutation from 21 breast cancers and applied mathematical methods to extract mutational signatures of the underlying processes. Multiple distinct single- and double-nucleotide substitution signatures were discernible. Cancers with BRCA1 or BRCA2 mutations exhibited a characteristic combination of substitution mutation signatures and a distinctive profile of deletions. Complex relationships between somatic mutation prevalence and transcription were detected. A remarkable phenomenon of localized hypermutation, termed "kataegis," was observed. Regions of kataegis differed between cancers but usually colocalized with somatic rearrangements. Base substitutions in these regions were almost exclusively of cytosine at TpC dinucleotides. The mechanisms underlying most of these mutational signatures are unknown. However, a role for the APOBEC family of cytidine deaminases is proposed.

Nik-Zainal S; Alexandrov LB; Wedge DC; Van Loo P; Greenman CD; Raine K; Jones D; Hinton J; Marshall J; Stebbings LA; Menzies A; Martin S; Leung K; Chen L; Leroy C; Ramakrishna M; Rance R; Lau KW; Mudie LJ; Varela I; McBride DJ; Bignell GR; Cooke SL; Shlien A; Gamble J; Whitmore I; Maddison M; Tarpey PS; Davies HR; Papaemmanuil E; Stephens PJ; McLaren S; Butler AP; Teague JW; Jönsson G; Garber JE; Silver D; Miron P; Fatima A; Boyault S; Langerød A; Tutt A; Martens JW; Aparicio SA; Borg Å; Salomon AV; Thomas G; Børresen-Dale AL; Richardson AL; Neuberger MS; Futreal PA; Campbell PJ; Stratton MR

2012-05-01

256

Fabrication and characterization of poly(propylene fumarate) scaffolds with controlled pore structures using 3-dimensional printing and injection molding.  

UK PubMed Central (United Kingdom)

Poly(propylene fumarate) (PPF) is an injectable, biodegradable polymer that has been used for fabricating preformed scaffolds in tissue engineering applications because of in situ crosslinking characteristics. Aiming for understanding the effects of pore structure parameters on bone tissue ingrowth, 3-dimensional (3D) PPF scaffolds with controlled pore architecture have been produced in this study from computer-aided design (CAD) models. We have created original scaffold models with 3 pore sizes (300, 600, and 900 microm) and randomly closed 0%, 10%, 20%, or 30% of total pores from the original models in 3 planes. PPF scaffolds were fabricated by a series steps involving 3D printing of support/build constructs, dissolving build materials, injecting PPF, and dissolving support materials. To investigate the effects of controlled pore size and interconnectivity on scaffolds, we compared the porosities between the models and PPF scaffolds fabricated thereby, examined pore morphologies in surface and cross-section using scanning electron microscopy, and measured permeability using the falling head conductivity test. The thermal properties of the resulting scaffolds as well as uncrosslinked PPF were determined by differential scanning calorimetry and thermogravimetric analysis. Average pore sizes and pore shapes of PPF scaffolds with 600- and 900-microm pores were similar to those of CAD models, but they depended on directions in those with 300-microm pores. Porosity and permeability of PPF scaffolds decreased as the number of closed pores in original models increased, particularly when the pore size was 300 microm as the result of low porosity and pore occlusion. These results show that 3D printing and injection molding technique can be applied to crosslinkable polymers to fabricate 3D porous scaffolds with controlled pore structures, porosity, and permeability using their CAD models.

Lee KW; Wang S; Lu L; Jabbari E; Currier BL; Yaszemski MJ

2006-10-01

257

An Approach to Rib Design of Injection Molded Product Using Finite Element and Taguchi Method  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, not only Taguchi Method but also ANSYS in providing an economical and effective advance to the optimum design of the rib for a plastic injected product are introduced. The analytical model of a rectangular thermoplastic Acrylonitrile Butadiene Styrene (ABS) plastic cover with rib of given thickness (2.8 mm) was selected and constructed based on design experiences and the dimensions as well as the width of the rib were selected as the control factors for Taguchi Method. The deflection under a constant force of 150 Newton at the back centre of the cover was defined as quality characteristic. Additionally, the deformation experiment on a fixed thin beam was compared with the analytical result from ANSYS to verify the reliability of structure analysis from associated parameter setup and boundary condition operation. The L9(34) orthogonal array from Taguchi Method was moreover arranged to establish nine sets of finite element analysis models. Through Taguchi Method, the optimum design parameters were furthermore received from minimum deformation at back centre of the plastic cover analyzed by ANSYS. It is shown that the optimum structural parameters of a plastic rib can surely be effectively found with the integration of both Taguchi Method and ANSYS. Therefore, an Expert System of optimum design for various shapes of ribs can then be constructed through this study. This study exactly contributes a novel technique to the rib design for plastic injection industry in minimizing the development period of a new product.

Tian-Syung Lan; Min-Chie Chiu; Long-Jyi Yeh

2008-01-01

258

Improvement of the Dimensional Stability of Powder Injection Molded Compacts by Adding Swelling Inhibitor into the Debinding Solvent  

Science.gov (United States)

Defects are frequently found in powder injection molded (PIM) compacts during solvent debinding due to the swelling of the binders. This problem can be alleviated by adjusting the composition of the debinding solvent. In this study, 10 vol pct swelling inhibitors were added into heptane, and the in-situ amounts of swelling and sagging of the specimen in the solvent were recorded using a noncontacting laser dilatometer. The results show that the addition of ethanol, 2-propanol, 1-butanol, and 1-pentanol reduced the amounts of swelling by 31, 21, 17, and 11 pct, respectively. This was because the small molecule alcohols, which do not dissolve paraffin wax (PW) or stearic acid (SA) in the binder system, could diffuse easily into the specimen and increased the portion of the swelling inhibitor inside. The amount of the extracted PW and SA also decreased, but only by 8.3, 6.1, 4.3, and 2.4 pct, respectively. The solubility parameters of 1-bromopropane (n-PB) and ethyl acetate (EA) are between those of heptane and alcohols, and they also yielded a slight reduction in the amounts of swelling by 6 and 11 pct, respectively. These results suggest that to reduce defects caused by binder swelling during solvent debinding, alcohols with high solubility parameters can be added into heptane without sacrificing significantly on the debinding rate.

Fan, Yang-Liang; Hwang, Kuen-Shyang; Su, Shao-Chin

2008-02-01

259

Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.  

UK PubMed Central (United Kingdom)

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications.

Mi HY; Salick MR; Jing X; Jacques BR; Crone WC; Peng XF; Turng LS

2013-12-01

260

Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.  

Science.gov (United States)

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. PMID:24094186

Mi, Hao-Yang; Salick, Max R; Jing, Xin; Jacques, Brianna R; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

2013-08-02

 
 
 
 
261

Mold for forming a medical balloon  

UK PubMed Central (United Kingdom)

A mold for forming medical balloons and the balloons formed therefrom are disclosed. The mold has a generally cylindrical inner molding surface for forming a working length of the balloon, and generally cylindrical outer molding surfaces at either end of the mold for forming shafts of the balloon. Joining these outer and inner molding surfaces are taper molding regions composed of two generally conical molding surfaces oriented at two different angles from a longitudinal axis of the mold. A balloon resulting from a manufacturing process using a mold according to the present invention reflects the geometry of the mold and has a unique concave taper profile and a well-defined working length.

MURRAY ROBERT J; MURRAY III ROBERT J

262

DATA MINING BASED KNOWLEDGE DISCOVERY FOR QUALITY PREDICTION AND CONTROL OF EXTRUSION BLOW MOLDING PROCESS  

Directory of Open Access Journals (Sweden)

Full Text Available In practice, when quality of products fall below the expected level, causal relationships between process variables and product defects are investigated. Quality improvement and control activities in product manufacturing include identifying the factors that significantly affect quality, modeling relationships between input attributes and target attribute (yield, quality, performance index etc) and predicting quality levels of given input attributes. Data mining tools have created new ways of extracting useful knowledge from existing manufacturing process databases. This paper proposed data mining based knowledge discovery approach from Extrusion Blow Molding process database making use of Microsoft Clustering, Naïve Bayes and Decision Trees algorithms available in SQL Server 2008. Data mining models have been created using these algorithms from extrusion blow molding process data set of a typical product (Gum Bottle). These models were trained based on database containing historical process data. The objective of this study was to apply the discovered process knowledge to set optimum process parameters resulting in high quality products, increased output and reduction of scrap.

E.V.Ramana; P. Ravinder Reddy

2013-01-01

263

Method for protecting a pre-formed projecting appendage during plastic molding  

UK PubMed Central (United Kingdom)

Method and apparatus are disclosed for injection molding a generally cylindrical sleeve-like penile prosthesis from a thermoplastic or thermosetting material utilizing a male mold core and a pair of female mold halves in which the molded prosthesis has encased in a wall therein a portion of a pre-formed length of resilient tubing, the remaining length and free end of the tubing extending from the molded prosthesis as a length of free tubing projecting therefrom. The apparatus includes a mandrel for carrying the mold core and is adapted for mounting between the female mold halves, and means for anchoring one end of the preformed tubing at a selected position on the mold core. The apparatus further includes a first portion of the tubing after the anchored one end positioned adjacent at least a portion of the mold core, a box-like member on the mandrel and positionable adjacent the mold core surface for accepting and isolating the remaining length and free end of the tubing extending past a predetermined location for the tubing to exit the molded prosthesis. The box-like member is carried in a recess between the female mold halves, the member having a cavity therein for storing and protecting the remaining length and free end of the tubing during the injection molding process.

GEROW FRANK J

264

Plastic baby bottles, other blow molded articles, and processes for their manufacture  

UK PubMed Central (United Kingdom)

The invention is generally directed to baby bottles and other articles produced by blow molding from polymeric materials having glass transition temperatures ranging from 100 DEG C to 130 DEG C, as well as to processes for producing them. These articles can be exposed to boiling water and can be produced by using a suitable combination of a stretch ratio of less than 3 and a preform temperature at least 20 DEG C greater than the glass transition temperature (Tg) of the polymeric material.

KEITH PHILLIPS ALAN; ALLEN GILLIAM SPENCER; JOSEPH PECORINI THOMAS

265

PLASTIC BABY BOTTLES, OTHER BLOW MOLDED ARTICLES, AND PROCESSES FOR THEIR MANUFACTURE  

UK PubMed Central (United Kingdom)

The invention is generally directed to baby bottles and other articles produced by blow molding from polymeric materials having glass transition temperatures ranging from 100 DEG C. to 130 DEG C., as well as to processes for producing them. These articles can be exposed to boiling water and can be produced by using a suitable combination of a stretch ratio of less than 3 and a preform temperature at least 20 DEG C. greater than the glass transition temperature (Tg) of the polymeric material.

PECORINI THOMAS JOSEPH; GILLIAM SPENCER ALLEN; PHILLIPS ALAN KEITH

266

MOLD FOR FORMING MEDICAL BALLOON  

UK PubMed Central (United Kingdom)

A mold for forming medical balloons and the balloons formed therefrom are disclosed. The mold has a generally cylindrical inner molding surface (116) for forming a working length of the balloon, and generally cylindrical outer molding surfaces (118, 124) at either end of the mold for forming shafts of the balloon. Joining these outer and inner molding surfaces are taper molding regions composed of two generally conical molding surfaces (120) oriented at two different angles from a longitudinal axis of the mold. A balloon resulting from a manufacturing process using a mold according to the present invention reflects the geometry of the mold and has a unique concave taper profile and a well-defined working length.

MURRAY Robert III

267

PLASTIC MOLDING FOR OSTOMY DEVICE  

UK PubMed Central (United Kingdom)

A method and apparatus for forming an ostomy device component, for attaching a preformed first portion of the component to a second portion. The second portion is formed by being blow molded into intimate bonding contact with the preformed first portion. The preformed first portion may be injection molded. An ostomy device component formed by this technique may comprise first and second portions, at least one of which is a blow molded part integrally molded to the other part.

BLUM JOHN L

268

Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography  

Science.gov (United States)

Superalloy airfoils are produced by investment casting (IC), which uses ceramic cores and wax patterns with ceramic shell molds. Hollow cored superalloy airfoils in a gas turbine engine are an example of complex IC parts. The complex internal hollow cavities of the airfoil are designed to conduct cooling air through one or more passageways. These complex internal passageways have been fabricated by a lost wax process requiring several processing steps; core preparation, injection molding for wax pattern, and dipping process for ceramic shell molds. Several steps generate problems such as high cost and decreased accuracy of the ceramic mold. For example, costly tooling and production delay are required to produce mold dies for complex cores and wax patterns used in injection molding, resulting in a big obstacle for prototypes and smaller production runs. Rather than using separate cores, patterns, and shell molds, it would be advantageous to directly produce a mold that has the casting cavity and the ceramic core by one process. Ceramic stereolithography (CerSLA) can be used to directly fabricate the integrally cored ceramic casting mold (ICCM). CerSLA builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This dissertation addresses the integrally cored casting ceramic mold (ICCM), the ceramic core with a ceramic mold shell in a single patternless construction, fabricated by ceramic stereolithography (CerSLA). CerSLA is considered as an alternative method to replace lost wax processes, for small production runs or designs too complex for conventional cores and patterns. The main topic is the development of methods to successfully fabricate an ICCM by CerSLA from refractory silica, as well as related issues. The related issues are the segregation of coarse fused silica powders in a layer, the degree of segregation parameter to prevent segregation, and sintering and cristobalite transformation in fused silica compacts.

Bae, Chang-Jun

269

The effect of process parameters on the thermal conditions during moving mold ESR  

Energy Technology Data Exchange (ETDEWEB)

Several experimental melts were conducted using a moving mold electroslag remelting furnace. The conditions of electrode immersion depth, slag cap thickness, and melt current were varied. Mold wall temperatures and slag pool temperatures were measured and the heat flux through the mold wall was calculated. The relationships between varying ESR melt parameters and the resultant thermal conditions were examined. The thermal profile of the mold, the heat transfer to the mold coolant total and fractional, and the formation of a slag skin were studied.

Heilman, J.E. [Carpenter Technology Corp., Reading, PA (United States); Damkroger, B.K. [Sandia National Labs., Albuquerque, NM (United States)

1994-09-01

270

Method for forming a molded confection  

UK PubMed Central (United Kingdom)

A microwaveable confection mold for use in a conventional microwave oven. The mold permits solid confection capable of melting when exposed to microwave energy to be introduced into the mold. The mold comprises a clear microwave transparent plastic material to facilitate observation of the confection melting process with subsequent settling in the mold sections. A pigment in the mold changes the colour to indicate to the user when the liquified confection has hardened and the mold cooled.

SEGAL ERIC

271

High-Throughput UV Nanoimprint Process Using Flexible Resin Mold for High-Brightness Light-Emitting Diodes  

Science.gov (United States)

This paper demonstrated a high-throughput fabrication process of resin mold and nanostructures for high-brightness light-emitting diodes (LED). The fabrication process includes roll-to-roll (RtR) UV imprinting for resin mold fabrication and perpendicular UV imprinting on wafers. The measurement results of pattern sizes in UV imprinted sample indicate that the resin mold was uniform enough to use for subsequent UV imprinting, and highly uniform UV imprinting was achieved by means of developed high-throughput UV imprinting equipment. Thickness of the residual layer was highly uniform and repeatable. This fabrication process is expected to be applied to fabricate nanostructures for actual high-brightness LEDs.

Shinohara, Hidetoshi; Tashiro, Takaharu; Ookawa, Takafumi; Nishihara, Hiromi

272

Simulation of the Two Stages Stretch-Blow Molding Process: Infrared Heating and Blowing Modeling  

International Nuclear Information System (INIS)

In the Stretch-Blow Molding (SBM) process, the temperature distribution of the reheated perform affects drastically the blowing kinematic, the bottle thickness distribution, as well as the orientation induced by stretching. Consequently, mechanical and optical properties of the final bottle are closely related to heating conditions. In order to predict the 3D temperature distribution of a rotating preform, numerical software using control-volume method has been developed. Since PET behaves like a semi-transparent medium, the radiative flux absorption was computed using Beer Lambert law. In a second step, 2D axi-symmetric simulations of the SBM have been developed using the finite element package ABAQUS registered . Temperature profiles through the preform wall thickness and along its length were computed and applied as initial condition. Air pressure inside the preform was not considered as an input variable, but was automatically computed using a thermodynamic model. The heat transfer coefficient applied between the mold and the polymer was also measured. Finally, the G'sell law was used for modeling PET behavior. For both heating and blowing stage simulations, a good agreement has been observed with experimental measurements. This work is part of the European project ''APTPACK'' (Advanced knowledge of Polymer deformation for Tomorrow's PACKaging).

2007-05-17

273

Crystallization kinetics and morphology of PBT/MMT and PTT/MMT nanocomposites during injection molding;Cinetica de cristalizacao e morfologia de nanocompositos de PBT/MMT e PTT/MMT durante a moldagem por injecao  

Energy Technology Data Exchange (ETDEWEB)

This work had as main objective to study the crystallization of nanocomposites of poly(butylene terephthalate) (PBT) and poly(trimethylene terephthalate) (PTT) with a montmorillonite nanoclay (MMT) using an on-line optical monitoring system during the injection molding and to characterize the morphologies of the injection samples by polarized light optical microscopy (PLOM), wide angle X-ray diffraction (WAXS) and differential scanning calorimetry (DSC). The optical system allowed to analyze the crystallization process by the changes of the optical properties during the solidification of the materials. It was concluded that the MMT lamellae accelerated the overall crystallization of the polymers. By PLOM, it was observed that the nanoclay caused qualitative changes on the morphology of the PTT (polymer with slow crystallization kinetics). The crystallinity indexes were not affected by the addition of the MMT; however, by WAXS it was shown that the nanocomposites had a higher orientation degree. (author)

Favaro, Marcia M.; Branciforti, Marcia C.; Bretas, Rosario E.S., E-mail: mmfavaro@gmail.co [Universidade Federal de Sao Carlos (DEM/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

2009-07-01

274

Fluoropolymer synthesis and its application as a mold material in UV-nano-imprint lithography process.  

Science.gov (United States)

In our present work, we report the synthesis of a novel, highly photosensitive photocurable methacrylate functionalized perfluoropolyether (fluoropolymer) by grafting methacrylate functional group onto the backbone of perfluoropolyether chain. Reaction mechanism for the synthesis of the oligomer has been clearly described in this article. Dihydroxy terminated perfluoropolyether (PFPE-diol) monomer was made photocurable by carrying out its reaction with ethyl isocyanato methacrylate (EIM) by a simple addition reaction. The product was characterized by NMR and FT-IR analysis. The synthesized polymeric material has potential application in soft lithographic process, as a viable option for PDMS (polydimethylsiloxane). Mold materials made from fluoropolymer have higher modulus, when compared to PDMS and posses better pattern relief property than rigid materials such as, quartz. In particular this fluoropolymer can be used as stamping material in nano fabrication, especially in UV-based Nano-imprinting lithographic (NIL) process. PMID:19198451

Perumal, Jayakumar; Kim, Dong-Pyo; Lee, Jae-Jong

2008-10-01

275

CARRIER MOLD  

UK PubMed Central (United Kingdom)

A carrier mold having prongs that produces shaped tampons is provided. When subjected to pressure by a pushrod the prongs of the carrier mold flex to substantially or partially open one end of the carrier mold. A method of forming a shaped tampon using the carrier mold is also provided.

HUBBARD WADE MONROE JR; STRONG KEVIN CHARLES; MERS-KELLY MICHAEL JOHN; WIEGELE DANIEL RAYMOND

276

Resin Flow Behavior Simulation of Grooved Foam Sandwich Composites with the Vacuum Assisted Resin Infusion (VARI) Molding Process  

Directory of Open Access Journals (Sweden)

Full Text Available The resin flow behavior in the vacuum assisted resin infusion molding process (VARI) of foam sandwich composites was studied by both visualization flow experiments and computer simulation. Both experimental and simulation results show that: the distribution medium (DM) leads to a shorter molding filling time in grooved foam sandwich composites via the VARI process, and the mold filling time is linearly reduced with the increase of the ratio of DM/Preform. Patterns of the resin sources have a significant influence on the resin filling time. The filling time of center source is shorter than that of edge pattern. Point pattern results in longer filling time than of linear source. Short edge/center patterns need a longer time to fill the mould compared with Long edge/center sources.

Chenhui Zhao; Guangcheng Zhang; Yibo Wu

2012-01-01

277

Method for molding ceramic powders using a water-based gel casting process  

Energy Technology Data Exchange (ETDEWEB)

A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant, and a monomer solution. The monomer solution includes at least one monofunctional monomer and at least one difunctional monomer, a free-radical initiator, and a aqueous solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

Jenny, Mark A. (Knoxville, TN); Omalete, Ogbemi O. (Lagos, NG)

1992-09-08

278

Void Prediction During Liquid Composite Molding Processes: Wetting and Capillary Phenomena  

CERN Multimedia

The aim of this work is to contribute in improving fibrous preforms impregnation for Liquid Composite Molding (LCM) processes. The void prediction in LCM sparks off interest within the Composite Material elaboration because it represents a significant issue to keep the expected mechanical properties of the final product. The liquid properties, the preform geometry and the flow conditions impact the void or bubble entrapped inside and outside the yarns. Nevertheless, due to the complex geometry of the reinforcement, experimental characterization of bubble formation remains delicate. Thus, our study deals with two simple model networks representing connected pores so called "Pore Doublet Model". A first is considering two capillaries converging on a node (T-junction) and a second is representing two capillaries interconnected with a supplying principle. In this paper, we emphasize on microfluidic and millifluidic approaches where wetting and capillary forces are significant during bubble formation mechanism.

Abdelwahed, Mohamed Amine Ben; Bizet, Laurent; Bréard, Joël

2012-01-01

279

Heat-radiation combination for control of mold infection in harvested fruits and processed cereal foods  

International Nuclear Information System (INIS)

[en] A combination of mild heat and low dose irradiation was found to extend the shelf-life of fresh fruits and processed cereal foods by controlling mold infection. Chapaties (Indian unleavened bread) and bread slices packed in polycell pouches, subjected to 50 krad followed by dry heat (650C) were free from mold and shelf-stable for 10 weeks at ambient temperature (28-320C). Inoculated pack studies confirmed the efficiency of the treatment. No immediate changes in organoleptic attributes were discernible even after exposure to 100 krad. The quality deterioration in sliced bread stored for 2 1/2 months has been attributed to natural staling rather than radiation. Hot water dip (500C for 5 min) followed by 150 krad irradiation extended the shelf-life of fresh figs by 3-4 days at 28-320C and 8-10 days at 150C. Regardless of the sequence of treatments, combination of heat and 100 krad extended the shelf-life of grapes both at ambinet and refrigerated storage. In mangoes, heat followed by 50 krad was effective in controlling anthracnose and stem-end rot whereas in bananas irradiated for delayed ripening, hot water treatment can be used as a supplementary process to control stem-end rot. Quality of combination treated fruits was comparable to normally ripened fruits. In vitro studies with fungal pathogens isolated from the above fruits and cereal foods revealed that the synergistic effect of heat-radiation combination depends on the sequence of treatments which varied with respect to different pathogens studied. Some biochemical aspects of combination treated fruits is discussed. (F.J.)

1972-09-18

280

Improvement of Moldability for Ultra Thin-Wall Molding with Micro-Patterns  

Energy Technology Data Exchange (ETDEWEB)

The Rapid Thermal Response(RTR) molding is a novel process developed to raise the temperature of mold surface rapidly in the injection stage and then cool rapidly to the ejection temperature by air or water. The objectives of this paper are to investigate the effect of mold temperature, pressure and thickness of micro pattern molding and to provide a optimization of RTR injection molding for micro pattern from Moldflow simulation. Optimal minimum temperature and pressure was found without shortcut according to thickness. Filling percentage was influenced by glass transition temperature with the kinds of resin. Optimal temperature is slightly higher than glass transition temperature irrespectively of pressure, thickness, the kinds of resin in the micro pattern molding.

Kwon, Oh Kyung; Yun, Jae Ho [Korea Institute of Industrial Technology, Cheonan (Korea, Republic of); Park, Keun [Seoul National Univ. of Technology, Seoul (Korea, Republic of)

2007-05-15

 
 
 
 
281

Energy saving by changing hydraulically driven injection molding machine into electric motor driven. Chunyu seikeiki Yuatsu kudo no dendo kudoka ni yoru sho energy  

Energy Technology Data Exchange (ETDEWEB)

An attempt was made on saving energy by changing the driving source of an automotive parts injection molding machine from hydraulic power to electric motor power. In the hydraulic system, a drive source pump is operated continuously, whereas 74.3% of the total energy is not used directly to make products, but wasted as a loss in idle operation. A hydraulic system has a structural difficulty to remarkably reduce this loss, and therefore, it was planned to change the system to electric motor driven, and a new injection molding machine was fabricated using a 4.4 kW AC servo motor as the drive source. As a result, the driving energy cost was reduced from 72,274 yen/year to 5,927 yen/year, a reduction to a one-twelfth level. Elimination of oil leakage measures and hydraulic fluid replacement contributed to enhancing the maintenance requirement, and improving the working environment as a result of reduced noise. However, an increase in the investment from 1.83 million yen per machine to 2.63 million yen leaves a problem of future cost reduction by means of reviewing the drive motor types, and reducing the motor capacity. 5 figs., 2 tabs.

Nakamura, I. (Toyoda Gosei Co. Ltd., Aichi (Japan))

1991-02-04

282

Tension-Compression Fatigue Behavior of a Carbon Fiber/Epoxy (IM7/EPON 862) Composite Fabricated Using Vacuum Assisted Resin Transfer Molding Process.  

Science.gov (United States)

New composite materials and processing methods are continually being developed for use in high performance aerospace systems. One of these new processing methods is the vacuum assisted resin transfer molding (VARTM) process, which shows promise in produci...

D. W. Katwyk

2007-01-01

283

Efecto del proceso de transformación sobre el coeficiente de endurecimiento por deformación en polímeros/ Effect of the molding process on the strain hardening index by deformation in polymers  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish El objetivo principal de este trabajo fue analizar el comportamiento del coeficiente de endurecimiento por deformación (Gp) en materiales plásticos, para diferentes condiciones de inyección y velocidades de deformación durante el ensayo mecánico. Se inyectaron probetas tipo I de Polietileno de Alta Densidad (PEAD 2811) modificando las variables del proceso de inyección (presión, velocidad y temperatura de inyección). Se evaluaron las propiedades tensiles y se dete (more) rminaron los parámetros mecánicos (Módulo de Young, Esfuerzo y Deformación a la fluencia y Gp). Se encontró que el Gp disminuye con la presión de inyección y se mantiene constante al incrementar la temperatura de inyección, sin embargo, con la velocidad de inyección presenta una dualidad de comportamientos, es decir a bajas velocidades de ensayo aumenta, mientras que a altas velocidades disminuye el coeficiente. También se obtuvo que a medida que la velocidad de deformación aumenta el Gp disminuye Abstract in english The main objective of this study was to analyze the behavior of the strain hardening coefficient (Gp) in plastic materials, for different injection molding conditions and the strain rate during a mechanical test. Test specimen type I of High Density Polyethylene (HDPE 2811) was injected under different process conditions (injection pressure, injection temperature and injection velocity). The tensile properties were evaluated and the mechanical parameters (Young modulus, y (more) ield stress, yield strain and Gp) were determined. Gp decreases with injection pressure, and remains constant by increasing injection temperature; however, with injection velocity, it presents a mixed behaviour. A low velocity generated an increase of the Gp and a high velocity decreases the Gp. Also, the Gp decreases with an increase in the strain rate

Morales, Rosa; Candal, María; Robles, Jennifer

2009-12-01

284

Processamento de placa espessa de compósito através de moldagem por transferência de resina/ Processing of thick composite plate by resin transfer molding process  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Devido às suas elevadas propriedades mecânicas específicas, os materiais compósitos estão enfrentando demandas novas, onde a capacidade de produção em massa a um custo mais acessível se tornou indispensável. A Moldagem por Transferência de Resina ou RTM (Resin Transfer Molding) constitui um promissor processo de fabricação de materiais compósitos. O objetivo deste trabalho é o estudo experimental do processo de infusão durante a fabricação de placa espess (more) a por RTM. Os materiais usados nos experimentos foram: tecido de fibra de vidro e resina éster-vinílica com catalisador Butanox e acelerador CoNaP. As placas de material compósito eram constituídas de 32 camadas de fibra de vidro com espessura de 25,4 mm. Dois tipos de experimentos foram realizados: o primeiro para medir a influência do sistema de injeção de resina no processamento e o segundo para medir a influência da quantidade de resina presente no reservatório de injeção. Nos processamentos realizados, o sistema de injeção de resina alterou o tempo de preenchimento da preforma. A variação na quantidade de resina no reservatório não só alterou os tempos de preenchimento como impediu o preenchimento da preforma em um dos processamentos realizados. Não foi possível impedir o fenômeno de race-tracking. Baseando-se nos experimentos realizados, pode-se concluir que: o sistema de injeção de resina é importante no real entendimento do processamento por RTM e que a quantidade de resina no reservatório de injeção pode influenciar o processamento por RTM. Abstract in english Because of their high specific mechanical properties, composite materials are facing new demands, where the large scale production capacity with low cost became important. Resin Transfer Molding (RTM) constitutes a promising process of composite materials manufacturing. The objective of this work is an experimental study of the infusion process during the manufacture of thick plate by RTM.The materials used in the experiments were: fiber glass fabric and vinylester resin (more) with Butanox initiator and CoNaP accelerator. The preform had 32 layers of fiber glass reinforcements whose dimension was approximately 25,4 mm thick. Two types of experiments were carried out: the first one, to measure the influence of the resin injection system on the processing and the second one, to measure the influence of the amount of resin in the reservoir on the injection processing. By the experiments, we could conclude that the resin injection system and the variation of the amount of resin modified the fulfilling time of the preform and prevented the fulfilling of the preform in the experiments. It was not possible to prevent the phenomenon of race-tracking. The resin injection system and the variation of the amount of resin in the reservoir of injection influence RTM processes.

Amorim Júnior, Wanderley F. de; Chaves, Gustavo Queiroz; Calado, Verônica M. A.; Bastian, Fernando Luiz

2006-09-01

285

Selected methods of modelling of polymer during the injection moulding process  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The purpose of present paper was presenting chosen results of investigations on polymer flow during mould cavity filling phase of injection process. Advancement in the simulation software make possible to model more phenomena occurring during polymer flow in injection molding process.Design/methodology/approach: The results of computer simulations of injection process have been compared with the results of video recording for the plastic flow during filling phase. For the simulating investigations a professional computer software Moldflow Plastics Insight ver. 6.1. has been employed. A specialized injection mould which enables observation and registration of the plastic flow during processing has been employed. The mould enables direct monitoring of the course of phenomena inside the mould cavity in two planes. To record the flow, a digital video camera has been employed. As an example the issue of stream flow (jeting) have been described.Findings: The results of the investigations enabled documenting of specific phenomena which occur during plastics or their composites injection process. The registered video sequences have been compared with the results of numerical calculations and then it was estimated to what degree the computer simulation of injection process may be useful in practice.Research limitations/implications: The camera enabled to register the flows with the rate of 25 fps. This reduced the scope of the investigations, since at higher plastic flow speeds the registered image became less clear. The investigations were performed on a wide scale, however, only chosen results have been presented.Practical implications: Deep understanding of the phenomena which occur during filling the injection mould may lead to more effective design of the processing tools and shortening of the time for implementation and production time.Originality/value: The transparent sight-glasses have been used, made of a material called Zerodur® which is characterized by the coefficient of thermal expansion close to zero.

J. Koszkul; J. Nabia?ek

2007-01-01

286

Process for the production of prismatic graphite molded articles for high temperature fuel elements  

International Nuclear Information System (INIS)

[en] Prismatic graphite molded objects for high temperature fuel elements are prepared by producing the outer geometry and the holes for cooling channels and for receiving fuel and fertile materials in the formation of the carbon object

1976-01-01

287

Nanopatterning planar and non-planar mold surfaces for a polymer replication  

DEFF Research Database (Denmark)

We present a novel process to create nanopatterns on planar and non-planar polymer replication tools, such as metallic molds for an injection molding. Such tools with nanopatterned cavities then allow affordable mass production of nanopatterned polymer parts with inherent advanced functionalities such as low reflectivity or color effects, self cleaning, superhydrofobicity, antifouling, etc, all created in a single injection molding cycle. Presented process is based on the classic cleanroom microfabrication of micro/nano patterns, nickel electroplating and template removal to form a flexible, freestanding nickel foil with a reversed pattern. This foil is then used either as a direct master for polymer replication or as a master for an extremely high pressure embossing of such master onto a metallic injection mold cavity surface coated with special coating, which, when cured, forms robust and hard, glass-like material. We have demonstrated nanopattern transfer on both planar and non-planar geometries and our nanopatterned mold coating can sustain more than 10.000 injection molding cycles. We can coat our nanopatterned mold surfaces with a monolayer of perfluorosilane to further reduce surface energy and sticktion and to facilitate de-molding of plastic parts.1 This allows forming of affordable plastic parts with advanced functionality.

Cech, Jiri; Pranov, Henrik

2013-01-01

288

Research on the Process of Biofuel Injection  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this research was to examine penetration peculiarities of rapeseed oil injected into the combustion chamber of a diesel engine. For conducting tests, a stand imitating conditions (air density) for the engine combustion chamber was designed. The analysis of pictures obtained using a fast recording camera determined fuel injection into the chamber volume and calculated the velocity of spray head. It was established that fuel spray of injected rapeseed oil proceeds deeper into the combustion chamber than that of mineral diesel fuel. The parameters of fuel spray are mainly influenced by injection pressure rather than by the density of compressed gases.

Birut? Skukauskait?; Tomas Mickevi?ius

2012-01-01

289

Problems with injection facilities for process additives or wash water  

Energy Technology Data Exchange (ETDEWEB)

Process additives or wash water have been used during the past years to control corrosion and fouling in various refinery process streams. Various problems with injection facilities for process additives or wash water are reviewed and appropriate solutions suggested. Topics covered include reasons for injecting process additives or wash water into refinery process streams, process considerations, location and design of injection nozzles, dilution methods, and temperature and velocity limitations for streams being treated. Corrosion, fouling, and contamination problems downstream of injection points are also covered.

Gutzeit, J. [Gutzeit (Joerg), Naperville, IL (United States)

1996-08-01

290

Plastics injection molding tool core has a coolant outlet in a coaxial inner tube and transverse coolant grooves in the core inner wall  

UK PubMed Central (United Kingdom)

The hollow shell core(1) houses an internal cooling tube(5) which forms a gap with the inner surface(4) of the core and is coaxial with the latter over its entire length. At the front end there is an outlet(9) for coolant. Cooling grooves(11) on the inner surface of the core run transverse to the central axis of the core. Cooling grooves(11) have a pointed and/or rounded cross-section and form a helical path along the inside of the core. The grooves extend over the surface area of the core on which a plastic molding is injected. The cooling tube outlet(9) has one or more cut-outs(13) extending along the central axis.

PLASS WERNER; LAUSENHAMMER MANFRED

291

A process for co-molding a visible-wavelength photonic crystal and microfluidic channel for biosensing applications  

Science.gov (United States)

Rapid DNA analysis systems show promise for reduced DNA analysis times and can be used by untrained operators in point-of-use applications. Throughput improvements can be gained by reducing the polymerase chain reaction (PCR) cycle count, which is used in conventional DNA processing to amplify the DNA to an easily measurable amount. A Photonic Crystal (PhC) can be integrated within a microfluidic channel to enhance fluorescence emission, enabling a reduction in PCR cycling. Most PhCs are fabricated using serial top-down fabrication techniques, resulting in a structure that is challenging to integrate with microfluidic system components. Here, we present a co-integration process for fabricating a Silicon master mold consisting of a visible range PhC lattice and a microfluidic channel. This process can be used to co-fabricate microscale channel and nanoscale lattice structures in polymer or thermoplastic materials. Two dimensional visible range PhCs are fabricated by patterning electron beam resist via E-Beam Lithography (EBL). The patterned features (100-300nm features with 200-450nm pitch) are cured to a glass-like material that is used as a direct etch mask for Reactive Ion Etching. A 200?m wide and 25?m high ridge "strip" is fabricated around the PhC region using Photolithography and Deep RIE etching to form the completed channel and lattice mold. Results indicating the quality of nanoscale features resulting from the molding process in Polydimethylsiloxane (PDMS) will be discussed.

Srungarapu, Maurya; Snyder, Chloe E.; Kadiyala, Anand; Hamza, Bashar; Liu, Yuxin; Dawson, Jeremy M.

2013-05-01

292

Silicon micro-mold  

Energy Technology Data Exchange (ETDEWEB)

The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

Morales, Alfredo M. (Livermore, CA)

2006-10-24

293

FORMING MOLD FOR BREAD  

UK PubMed Central (United Kingdom)

The present invention relates to a mold for making bread that easily achieves the smooth supply of air, temperature and moisture for gentle generation of gas during the fermentation process and easily separates the molded bread from the mold. The mold for making bread includes: a cylindrical body having a hollow interior so as to allow a material to be molded (dough) to be fermented therein, the body being opened at both side ends thereof; a flange portion 11 formed integrally with the body 10 in such a manner as to extend outwardly from each of the opened both side ends of the body 10; and an opening and closing cover 20 adapted to be detachably mounted to the flange portion 11 and having a folding portion 21 formed at one side thereof so as to conduct a folding operation about a hinge shaft 22.

CHO EUN JUNG

294

Graphene-coated Si mold for precision glass optics molding.  

UK PubMed Central (United Kingdom)

Despite many attractive properties and well-developed micro/nano manufacturing technologies based on silicon (Si) wafers, severe adhesions between Si and glass at high temperature have limited its application as a mold material in precision glass molding. In this Letter, a coating using carbide-bonded graphene is introduced to build nonstick Si molds for glass molding. The coating has extraordinary mechanical properties and can effectively prevent Si-glass adhesion under high temperature. We demonstrated fabrications of a Fresnel lens and glass parts with micrometer pillars using graphene-coated Si molds. This newly developed process enables the use of Si as a mold material to fabricate sophisticated structures with high-precision dimensions that was not previously available. This technology will greatly improve precision glass molding process and allow high-precision low-cost glass optics to be manufactured in large quantity.

He P; Li L; Yu J; Huang W; Yen YC; Lee LJ; Yi AY

2013-07-01

295

Molded optics design and manufacture  

CERN Multimedia

While several available texts discuss molded plastic optics, none provide information on all classes of molded optics. Filling this gap, Molded Optics: Design and Manufacture presents detailed descriptions of molded plastic, glass, and infrared optics. Since an understanding of the manufacturing process is necessary to develop cost-effective, producible designs, the book extensively covers various manufacturing methods, design guidelines, trade-offs, best practices, and testing of critical parameters. It also discusses topics that often arise when designing systems with molded optics, such as

Schaub, Michael

2007-01-01

296

Inhibitory activity of phosphates on molds isolated from foods and food processing plants.  

Science.gov (United States)

Six commercial phosphates were evaluated for inhibition of the growth of 17 molds isolated from food sources. The assays were performed at neutral and natural (without pH adjustment) pH values, and the molds were streaked on plate count agar with added phosphates. Phosphate concentrations of 0.1, 0.3, 0.5, 1.0, and 1.5% (wt/vol) were used, and the MIC was determined. The resistance of molds to phosphates depended on the species. At a neutral pH, Aspergillus ochraceus and Fusarium proliferatum were resistant to all phosphates at all concentrations assayed, and Byssochlamys nivea, Aureobasidium pullulans, and Penicillium glabrum were most sensitive. The most inhibitory phosphates were those with chain lengths greater than 15 phosphate units and the highest sequestering power. At natural pH values (resulting from dissolving the phosphate in the medium), inhibitory activity changed dramatically for phosphates that produced alkaline or acidic pH in the medium. Phosphates with alkaline pH values (sodium tripolyphosphate of high solubility, sodium tripolyphosphate, and sodium neutral pyrophosphate) were much more inhibitory than phosphates at a neutral pH, but sodium acid pyrophosphate (acidic pH) had decreased inhibitory activity. The results indicate that some phosphates could be used in the food industry to inhibit molds linked to food spoilage. PMID:16300093

Suárez, V B; Frisón, L; de Basílico, M Z; Rivera, M; Reinheimer, J A

2005-11-01

297

EFFECTS OF PROCESSING CONDITIONS ON VACUUM ASSISTED RESIN TRANSFER MOLDING PROCESS (VARTM)  

Science.gov (United States)

The continued growth of vacuum-based processes has warranted the development of both models and experimental studies designed to capture the unique aspects associated with this manufacturing technique. To that end, this report summarizes an initial set of experiments that charact...

298

Mold Charlatans.  

Science.gov (United States)

|Offers a primer on toxic mold and its removal, warning against ignorant or unethical mold remediation companies and offering five considerations (checking references, considering the big picture, sampling more than the air, considering release, and considering the source) when hiring such services. (EV)|

Woody, Daniel

2002-01-01

299

Mold Heating and Cooling Pump Package Operator Interface Controls Upgrade  

Energy Technology Data Exchange (ETDEWEB)

The modernization of the Mold Heating and Cooling Pump Package Operator Interface (MHC PP OI) consisted of upgrading the antiquated single board computer with a proprietary operating system to off-the-shelf hardware and off-the-shelf software with customizable software options. The pump package is the machine interface between a central heating and cooling system that pumps heat transfer fluid through an injection or compression mold base on a local plastic molding machine. The operator interface provides the intelligent means of controlling this pumping process. Strict temperature control of a mold allows the production of high quality parts with tight tolerances and low residual stresses. The products fabricated are used on multiple programs.

Josh A. Salmond

2009-08-07

300

Process for producing or cleaning high pressure water injection wells  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a process for cleaning a production well. It comprises: stopping the pumping of oil out of the wall; generating an aqueous solution of chlorine dioxide gas under pressure; and injecting under pressure the solution of chlorine dioxide gas into a pumped water injection stream and thereafter under pressure into the well. Also describes is a second process for cleaning a producing well. It comprises: stopping the pumping of oil out of the well; selecting an oxidant reactive with hydrogen sulfide under downhole conditions; and injecting the oxidant under pressure into a pumped water injection stream and thereafter under pressure into a well containing hydrogen sulfide.

Sacco, F.J.

1990-08-07

 
 
 
 
301

PENGEMBANGAN PROSES COMPRESSION MOLDING DALAM PEMBUATAN EDIBLE FILM DARI TEPUNG KORO PEDANG (Canavalia ensiformis L.) [Development of Compression Molding Process for Edible Films Production from Canavalia ensiformis (L.) Flour  

Directory of Open Access Journals (Sweden)

Full Text Available Edible Films based on Canavalia Ensiformis flour could be made using compression molding process. This research was to investigate temperature (120oC, 130oC, 140oC) and pressure ( 0.845 Mpa, 1.690 Mpa, 2.540 Mpa) effect on the properties of the film. The compression-molding pressure significantly affected the film’s thickness, lightness, tensile strength, elongation and Water Vapor Transmition Rate (WVTR). Meanwhile molding temperature only affected film’s elongation (P<0.05) over the range of conditions studied. Increase in compaction pressure resulted in decreased thickness, tensile strength, elongation with increase in lightness (L*) and WVTR. Increasing the molding temperature decreased elongation. Flexible, light-yellow edible films could be produced at a processing temperature of 140oC and compaction pressure of 0.845 Mpa. The films thickness was 0.302 mm; lightness (L*) was 68.557, tensile strength was 4.091 Mpa, elongation was 37.547 % and WVTR was 0.001 mg/m2.det.

Triana Lindriati1)*; Hari Arbiantara2)

2011-01-01

302

Diseño de moldes y tecnología para la fabricación de engranajes plásticos de dientes rectos asimétricos.  

Directory of Open Access Journals (Sweden)

Full Text Available En el presente trabajo se hace un análisis de los procesos de moldeado por inyección de los engranajes, mostrándose las ventajas con respecto al maquinado de los polímeros. Se brinda el procedimiento de cálculo para el diseño y fabricación de ruedas dentadas con dientes rectos asimétricos, así como los métodos de obtención del herramental necesario que permite acabados de alta calidad en piezas fabricadas de materiales termoplásticos. Se usa una metodología de cálculo que incluye diferentes parámetros de un molde, tales como: número de cavidades, tiempo de enfriamiento, longitud de las vías de frío. Por otra parte se sugiere la configuración de los canales de alimentación y puntos de inyección entre otras. Finalmente se muestra el molde diseñado y fabricado para un caso particular destacando la validez del método usado. Se resalta en particular la asimetría en los perfiles logrados mediante la utilización del método de electro-erosión por hilo para fabricar la cavidad del molde.An analysis of the injection molding process of plastic gears, showing its advantages regarding width machining process it is made in this paper. Calculation procedure for designing and molding of spur gears with asymmetric teeth is offer, including necessary tools for obtaining high quality surface finishing of gears made from thermoplastic materials. The procedure includes different molding parameters such as number of cavities, cooling time, injection points, etc. Molded spur gears, tools, machines and molds are showed.

A. R. García Martínez; J. L. Moya Rodríguez

2008-01-01

303

A study on development of the three-dimensional numerical model to analyze the casting process: mold filling and solidification  

Energy Technology Data Exchange (ETDEWEB)

A three dimensional model was developed to analyze the mold filling and solidification in the casting processes. The model uses the VOF method for the calculation of the free surface and the modified equivalent specific heat method for the treatment of the latent heat evolution. The solution procedure is based on the SIMPLER algorithm. The complete model has been validated using the exact solutions for phase change heat transfer and the experimental results of broken water column. The three-dimensional model has been applied to the benchmark test and the results were compared to those from experiment, a two-dimensional analysis, and another three dimensional numerical model.

Mok, Jin Ho [Nano Cast Korea, Incheon (Korea, Republic of)

2005-07-15

304

Interarytenoid botulinum toxin injection for recalcitrant vocal process granuloma.  

UK PubMed Central (United Kingdom)

OBJECTIVES/HYPOTHESIS: This study evaluated the efficacy of botulinum toxin type A injected into the interarytenoid muscle to treat recalcitrant vocal process granulomas. STUDY DESIGN: Retrospective clinical review at a tertiary care center. METHODS: Eight patients with vocal process granulomas refractory to a variety of prior treatments including surgical resection, proton pump inhibitor therapy, and voice therapy underwent percutaneous injection of botulinum toxin type A into the interarytenoid muscle, performed in an office setting. Doses ranged from 5 U to 25 U in one to two injections. RESULTS: One patient demonstrated no improvement, two patients demonstrated partial resolution, and five patients demonstrated complete resolution of their granulomas. Four patients noted transient breathiness. There were no other side effects. All patients tolerated the injections without difficulty. CONCLUSION: Botulinum toxin injection into the interarytenoid muscle appears to be a safe and effective modality for treating recalcitrant vocal process granuloma. Laryngoscope, 2013.

Fink DS; Achkar J; Franco RA; Song PC

2013-09-01

305

Mold Allergy  

Science.gov (United States)

... not share your e-mail address Sign up Definition If you have a mold allergy, your immune ... bathrooms are properly ventilated, and run the ventilation fan during a shower or bath and immediately after ...

306

Diesel injection technology. Mixture processing. 4. enlarged ed. Dieseleinspritztechnik. Gemischaufbereitung  

Energy Technology Data Exchange (ETDEWEB)

This service manual tells everything one needs to know about mixture processing of high-speed small diesel engines and deals with several brands of injection units so as to give a representative market survey. Diesel injection novelhes (electronic controls, comprex-pressure wave superchargers, direct diesel injection for passenger cars) are given special attention. There are also many practical hints for error diagnosis and adjusting. Main subjects: diesel engine, -injectors; distributor injectors, suction,- turbo-, comprex diesel engines; direct injection for passenger cars; tools for inspection and adjustment of diesel aggregates; starter aid. Many illustrations. (HWJ).

Kasedorf, J.

1991-01-01

307

Mold inhibitors  

UK PubMed Central (United Kingdom)

The invention relates to novel mold growth inhibiting products for various foodstuffs, and a method of making and using the same. The mold growth inhibiting product is generally a mixture of various compounds, including: a first compound selected from the group consisting of azodicarbonamide or potassium bromate, a second compound selected from the group consisting of benzoic acid, sodium benzoate, calcium benzoate, potassium benzoate, paraben, acetic acid, lactic acid, fumaric acid, citric acid, potassium sorbate, sodium sorbate, calcium sorbate, sorbic acid, calcium propionate, potassium propionate, sodium propionate, propionic acid or mixtures thereof. In a second embodiment of the invention, a third compound is added which lowers the decomposition temperature of the azodicarbonamide. In a fifth embodiment of the invention, the mold growth inhibiting product is prepared by placing a layer of azodicarbonamide on a substrate means and then covering said layer with a gas permeable separator means. The second compound is then added on top of the separator and then the combination is heated to form the final product. In a seventh embodiment, the second compound is mixed with a gaseous mixture to yield a mold inhibitor product having little or no off-flavor, off-texture, off-color or off-odor. All embodiments of this invention are added to the foodstuff in the same or greater percentages of current day mold inhibitors, yet the resultant foodstuff has no off-flavor, taste or color which is normally imparted by current day mold inhibitors.

KUHN DALE F

308

Design, assembly, and optical bench testing of a high-numerical-aperture miniature injection-molded objective for fiber-optic confocal reflectance microscopy.  

UK PubMed Central (United Kingdom)

The design, analysis, assembly methods, and optical-bench test results for a miniature injection-molded plastic objective lens used in a fiber-optic confocal reflectance microscope are presented. The five-lens plastic objective was tested as a stand-alone optical system before its integration into a confocal microscope for in vivo imaging of cells and tissue. Changing the spacing and rotation of the individual optical elements can compensate for fabrication inaccuracies and improve performance. The system performance of the miniature objective lens is measured by use of an industry-accepted slanted-edge modulation transfer function (MTF) metric. An estimated Strehl ratio of 0.61 and a MTF value of 0.66 at the fiber-optic bundle Nyquist frequency have been obtained. The optical bench testing system is configured to permit interactive optical alignment during testing to optimize performance. These results are part of an effort to demonstrate the manufacturability of low-cost, high-performance biomedical optics for high-resolution in vivo imaging. Disposable endoscopic microscope objectives could help in vivo confocal microscopy technology mature to permit wide-scale clinical screening and detection of early cancers and precancerous lesions.

Chidley MD; Carlson KD; Richards-Kortum RR; Descour MR

2006-04-01

309

Cosintering of Powder Injection Molding Parts Made from Ultrafine WC-Co and 316L Stainless Steel Powders for Fabrication of Novel Composite Structures  

Science.gov (United States)

Sintering response and phase formation during sintering of WC-Co/316L stainless steel composites produced by assembling of powder injection molding (PIM) parts were studied. It is shown that during cosintering a significant mismatch strain (>4 pct) is developed in the temperature range of 1080 °C to 1350 °C. This mismatch strain induces biaxial stresses at the interface, leading to interface delamination. Experimental results revealed that sintering at a heating rate of 20 K/min could be used to decrease the mismatch strain to M6C carbides at 1220 °C. Spreading of the liquid accelerates the reaction, affecting the dimensional stability of the PIM parts. To prevent the reaction, surface oxidation of the cemented carbide followed by hydrogen reduction during sintering was examined. Although the amount of mismatch strain increased, formation of a metallic interface consisting of a W-Co alloy (45 to 50 at. pct Co) and a Co-rich iron alloy (18 at. pct Co) prevented the decomposition of WC and melt formation. It is also shown that the deposition of a thin Ni layer after thermal debinding decreases the mismatch stresses through melt formation, although interlayer diffusion causes pore-band formation close to the steel part.

Simchi, A.; Petzoldt, F.

2010-01-01

310

Influence of the stretch blow molding processing parameters on PET bottles properties / Influence of the stretch blow molding processing parameters on PET bottles properties  

Directory of Open Access Journals (Sweden)

Full Text Available U radu je prikazana analiza utjecajnih faktora u postupku izradbe boca od poli(etilen-tereftalata) za pakiranje jestivog ulja – injekcijskom razvla?nom puhanju. Razmatran je utjecaj pogonski prilagodljivih parametara izradbe na ?imbenike koji su važni za izradbu PET boca za pakiranje jestivog ulja, obujam i naknadno stezanje boca. Primjenom centralno kompozitnog plana pokusa odre?eni su faktori koji utje?u na obujam i naknadno stezanje PET boca. / The paper deals with the analysis of the influencing factors in the procedure of manufacturing poly(ethylene terephthalate) bottles for packaging of table oil - injection stretch blow moulding. The influence of individual manufacturing parameters on the quality guidelines important in the making of PET bottles for table oil packaging, final volume, and post-shrinkage have been studied. The influencing factors have been determined which affect the volume and shrinkage of PET bottles by using the central composite design.

Maja RUJNI?-SOKELE

2008-01-01

311

Process for molding complex beta''-alumina shapes for sodium/sulfur batteries  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a method for manufacturing dimensionally precise, highly contoured green bodies which comprise a sacrificial binder composition densely packed with powdered beta''-alumina precursor particulate solids, by compression molding a mixture of the beta''-alumina precursor particulate solids and the sacrificial binder. The method consists of: 1.) providing a mixture of about 40-60 volume percent sinterable particulate solids consisting essentially of a particle size distribution of powdered beta''-alumina precursor particulate comprising alpha-alumina and about 60-40 volume percent organic sacrificial binder in a mold; 2.) applying heat and pressure to the first and second amounts between the mold member and another mold member; 3.) maintaining the heat and pressure for a time sufficient to knit together portions of the first and second amounts in conformity with the cavity. The binder consists essentially of: (a) a thermoplastic block copolymer component selected from the group consisting of linear, radial and linear and radial block copolymers; (b) two oils having different boiling point ranges selected from the group consisting of oil, at least about 75 percent by weight of which boils in a range between about 285/sup 0/-260/sup 0/C; (c) two waxes having different boiling point ranges and selected from the group consisting of wax which melts at a temperature in a range between about 50/sup 0/C-80/sup 0/C, at least 75 percent by weight of which boils at temperatures in a range between about 315/sup 0/C-490/sup 0/C; (d) a first stiffening thermoplastic polymer which is glassy or crystalline at 20/sup 0/-25/sup 0/C, has a softening point between about 80/sup 0/-250/sup 0/C, and comprises aromatic monomeric units associable with block copolymer (a); and (e) a second stiffening thermoplastic polymer, different from the first polymer and which is glassy or crystalline at 20/sup 0/-25/sup 0/C.

Theodore, N.; Pett, R.A.

1986-02-04

312

Moulded interconnect device fabrication by two shot molding and lasert induced selective activation  

DEFF Research Database (Denmark)

This report on the project “Molded Interconnect Device (MID) by two shot injection molding and laser induced selective activation” has been submitted to fulfil the requirements for the master project at department of Manufacturing Engineering and Management of Technical University of Denmark (IPL-DTU). MID is defined as an injection molded plastic substrate with electrical infrastructures on the surface and integrates both mechanical and electrical functionalities on the single device. This paper describes many aspects of MID such as the background information, manufacturing process chain, comparative process analysis, applications and specially two shot injection molding and laser induced selective activation in the MID area. There is also an experimental part which contains fabrication of a MID demonstrator, selective metallization as well as characterization. The realization of molded interconnect device was achieved with two innovative processes such as two shot injection molding which combines platetableand none-platetable thermoplastics, and laser induced selective activation which uses a laser to draw circuit on the thermoplastic surface containing laser sensitive additive. Different material combinations such as PEI (GE Ultem 1000) +PPO (GTX 810) and PEEK (Victrex 150GL30) +PPO (GTX 810) were investgated which can be selected electroless plating for metallization. Several plastics such as PC (GE Lexan 500R) and PEEK (Victrex 150GL30) were applied to the laser induced activation and reacted differently with the diverse structure.

Sun, Jie

2008-01-01

313

Relationships between processing and mechanical properties of injection molded high molecular mass polyethylene + hydroxyapatite composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinf...

Reis, R. L.; Cunha, A. M.; Oliveira, M. J.; Campos, A. R.; Bevis, M. J.

314

Controlling Flow Orientation in Molding of Short-Fiber Compounds.  

Science.gov (United States)

The degree of fiber orientation produced in transfer or plunger molding of short fiber-filled epoxy molding compounds, and hence their mechanical properties, can be controlled by mold design, processing conditions, and formulation, as well as by part desi...

L. A. Goettler R. Buchdahl

1970-01-01

315

Innovative molding technologies for the fabrication of components for microsystems  

Science.gov (United States)

Economic success of microsystems technology requires a wide range of materials as well as the related manufacturing processes. A suitable technology for medium/large scale production is micro injection molding which actually allows the manufacturing of plastic microstructures with 20 microns minimum thickness, structural details of approximately 0.2 microns or maximum aspect ratios of more than 20. These microstructures are, for example, applied as components in micro optics, micro fluidics or minimally invasive surgery. This is demonstrated by microparts that are currently available or will be available soon. For higher economic efficiency and cost reduction, fully electrical injection modeling machines of higher accuracy have been applied. Also, micro insert injection molding reduces mounting costs. Manufacturing of metal or ceramic microparts by powder injection modeling allows large-scale production of complex shaped microstructures with a wide range of materials. Typical examples are sintered structured like stepped LIGA- gear wheels with minimal dimensions of 50 microns in different metal and ceramic materials. Micro Precision Casting originating from conventional investment casting is a suitable process for small/medium-scale production. Examples are microturbine housings made of precious metal alloys. An approach similar to rapid prototyping applies photocurable reactive resins. Photoinduced molding of low viscous resins under ambient conditions leads to significantly reduced cycle times. Additionally, rapid testing of new composite materials can be performed easily. Microcomponents molded from polymers and different composites like dyes with nonlinear optical properties and nanosized ceramic powders will be presented.

Piotter, Volker; Benzler, Tobias; Hanemann, Thomas; Woellmer, Heinz; Ruprecht, Robert; Hausselt, Juergen H.

1999-03-01

316

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY13 Third Quarterly Report  

Energy Technology Data Exchange (ETDEWEB)

This quarterly report summarizes the status for the project planning to obtain all the approvals required for a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). The CRADA documents have been processed by PNNL Legal Services that is also coordinating the revision effort with the industrial parties to address DOE’s comments.

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-08-06

317

Effect of mold temperature on short and long-term mechanical properties of PBT  

Directory of Open Access Journals (Sweden)

Full Text Available In this work, the effect of mold temperature variation on the short-term mechanical properties obtained from the tensile and Charpy impact tests, and the long-term mechanical properties obtained from dynamic mechanical loading and flexural creep of injection molded polybutylene terepthalate (PBT) are reported. It has been observed that the effect of changing the processing condition viz. mold temperature on the viscoelastic properties are more pronounced when their long-term behavior is tested. The tensile and impact properties showed only a negligible effect to the change in mold temperature. Further, analysis of the creep curves by applying a four-element Burger model presented a comprehensive understanding of their long-term viscoelastic behavior with respect to the change in mold temperature.

2008-01-01

318

Implementation of preform-LCM process chain for the manufacturing of rotor hub shaft combination[Liquid Composite Molding  

Energy Technology Data Exchange (ETDEWEB)

Concept of a waste-free preform-liquid composite molding (LCM) process chain for the production of composite parts is developed and implemented for an integral lightweight construction with improvement in their ecological and economical properties. This also enables new applications for the composite materials. A prototype of rotor hub and shaft combination (HSC) of a horizontal axis wind turbine was designed and manufactured using integral components and composite materials. The aim of this study was to reduce the costs and weight in comparison with individual parts of standard metallic hub and shaft. This approach in the later stage facilitates to reduce the system costs of wind turbines. In this paper, the basic concept of the HSC component and the preform-LCM process chain used for its manufacturing is presented. Major advantageous features of preform and LCM technology for the large structures are described in detail. (au)

NONE

2006-07-01

319

Mold - Glossary of Terms  

Science.gov (United States)

Mold:  A group of organisms that belong to the kingdom Fungi. In this course, the terms fungi and mold are used interchangeably.   From Mold - Glossary of Terms  -  Search all glossaries for terms containing Mold

2012-12-12

320

Molds in the Environment  

Science.gov (United States)

... Digg Google Bookmarks Basic Facts Molds in the Environment What are molds? What are some of the ... molds found? Molds are found in virtually every environment and can be detected, both indoors and outdoors, ...

 
 
 
 
321

Casting process modeling using ProCAST and CAST2D -- Mold filling, solidification and structural response  

Energy Technology Data Exchange (ETDEWEB)

Correctly modeling the fluid flow and heat transfer during the filling of a mold with a molten fluid is important in predicting the quality of a cast part. Determining the dynamics of the flow and the free surface shape during filling are essential in establishing the temperature gradients in the melt and in the mold. After filling the mold, solidification may be greatly affected by natural convection effects. Further, correctly modeling the physics across the solidifying part-mold interface is crucial in predicting the part final shape. Most metals undergo a volume change on solidification (e.g. aluminum-6.6%) and shrinkage on cooling. As the cast metal shrinks, it pulls away from the mold wall creating a gap. This gap affects the thermal contact resistance between the part and mold. The thermal contact resistance increases as the gap widens. This directly affects the cooling rate and ultimately the final cast shape, stress state, and quality of the cast part.

Stein, W.; Shapiro, A.B.

1992-04-01

322

Geothermal injection treatment: process chemistry, field experiences, and design options  

Energy Technology Data Exchange (ETDEWEB)

The successful development of geothermal reservoirs to generate electric power will require the injection disposal of approximately 700,000 gal/h (2.6 x 10/sup 6/ 1/h) of heat-depleted brine for every 50,000 kW of generating capacity. To maintain injectability, the spent brine must be compatible with the receiving formation. The factors that influence this brine/formation compatibility and tests to quantify them are discussed in this report. Some form of treatment will be necessary prior to injection for most situations; the process chemistry involved to avoid and/or accelerate the formation of precipitate particles is also discussed. The treatment processes, either avoidance or controlled precipitation approaches, are described in terms of their principles and demonstrated applications in the geothermal field and, when such experience is limited, in other industrial use. Monitoring techniques for tracking particulate growth, the effect of process parameters on corrosion and well injectability are presented. Examples of brine injection, preinjection treatment, and recovery from injectivity loss are examined and related to the aspects listed above.

Kindle, C.H.; Mercer, B.W.; Elmore, R.P.; Blair, S.C.; Myers, D.A.

1984-09-01

323

INGOT MOLD  

Science.gov (United States)

An improved ingot-mold assembly is described, consisting of a body having a cavity and a recess extending through to the bottom of the body from the cavity, and the bottom of the cavity having an internal shoulder extending downward and a plug having an external shoulder. The plug extends above the shoulders and below the bottom of the body.

Mangold, A.J. Jr.; MaHaffey, J.W.; Reese, S.L.

1958-04-29

324

Study on forming method of fine ceramics powder by slip casting and low pressure injection molding. Fine ceramics funtai no slip castter dot teiatsu idashi seikeiho ni kansuru kenkyu  

Energy Technology Data Exchange (ETDEWEB)

Slip casting and low pressure injection molding were tested as forming methods of fine ceramics powder, and the results are described in this report. In the slip casting method, selection of a binder which gives plasticity to the green body is important. In case of slip casting of Si {sub 3} N {sub 4} powder with PVA as a binder, plasticity of the compact increased and higher strength was obtained after sintering. Then, a method to apply high pressure to the slurry was examined in order to shorten the casting time of slip casting. It was found that the casting time was shortened appropriately and drying shrinkage was decreased by applying pressure up to 200kgf/cm {sup 2}. Moreover, strength of the alumina compact was investigated by the low pressure injection molding method with a paraffin wax binder at 80-100 centigrade under the pressure of 3-5 atm. When the slurry prepared by the ball mill was formed in the vertical mold, such good results as mean flexural strength of 46kgf/mm {sup 2} with Weibull constant of 14.5 were obtained. 4 refs., 10 figs.

Miyamoto, H. (Osaka Prefectural Industrial Technology Research Inst., Osaka (Japan))

1990-07-25

325

Injection  

International Nuclear Information System (INIS)

The author presents an introduction to beam injection. Especially considered are single-turn injection, multi-turn injection, H- charge-exchange injection, and injection from a cyclotron into a synchrotron. Finally some novel injection schemes are briefly mentioned. (HSI).

1994-01-26

326

Processamento de laminados de compósitos poliméricos avançados com bordas moldadas/ Processing of advanced structural polymeric composite laminates with molded edges  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Técnicas que contribuem para melhorar a qualidade dos compósitos produzidos por laminação manual e cura em autoclave e/ou visando à redução no custo de processamento têm sido intensamente pesquisadas. Uma das maneiras de se obter esse ganho de produtividade é eliminar operações de usinagem da borda por meio da técnica de fabricação de laminados com bordas moldadas. Neste trabalho é apresentada uma revisão da tecnologia de fabricação de peças estruturais (more) de compósitos poliméricos avançados, com ênfase na produção de laminados com bordas moldadas. Exemplos deste tipo de acabamento são mostrados utilizando laminados cruzados simétricos [(0,90)/0]s e [(0,90)/90]s, fabricados com fita unidirecional contínua e tecido bidirecional de carbono, pré-impregnados com resina epóxi. O arranjo de fibras e resina na região da borda livre de todos os corpos-de-prova foi analisado usando um microscópio óptico. Foi observado que as fibras longitudinais (a 0°) podem se mover lateralmente na direção da borda moldada sob ação da pressão aplicada durante a cura. Bolsas de resina pura podem ser formadas nessa região dependendo da seqüência de empilhamento do laminado. Abstract in english Manufacturing techniques that improve the quality and/or reduce the cost of advanced composites structures produced by vacuum bag and cure in autoclave have been intensely investigated. One way to obtain a gain in productivity is to produce laminates with molded edges. This work presents a literature review of the fabrication process of structural parts of advanced polymeric composites, with emphasis in the manufacturing of laminates with molded edges. As an example of th (more) is type of edge finishing, symmetric cross ply laminates [(0,90)/0]s and [(0,90)/90]s were manufactured with pre-impregnated unidirectional tape and fabric. The arrangement of fibers and resin near the free edge of all specimens were analyzed using an optical microscope. It was observed that longitudinal fibers in the laminate (fibers at 0°) may move laterally towards the molded edge under the action of the pressure applied during cure. Pockets of pure resin may be formed at this region depending on the laminate stacking sequence.

Cândido, Geraldo M.; Almeida, Sérgio F. M.; Rezende, Mirabel C.

2000-03-01

327

Processamento de laminados de compósitos poliméricos avançados com bordas moldadas Processing of advanced structural polymeric composite laminates with molded edges  

Directory of Open Access Journals (Sweden)

Full Text Available Técnicas que contribuem para melhorar a qualidade dos compósitos produzidos por laminação manual e cura em autoclave e/ou visando à redução no custo de processamento têm sido intensamente pesquisadas. Uma das maneiras de se obter esse ganho de produtividade é eliminar operações de usinagem da borda por meio da técnica de fabricação de laminados com bordas moldadas. Neste trabalho é apresentada uma revisão da tecnologia de fabricação de peças estruturais de compósitos poliméricos avançados, com ênfase na produção de laminados com bordas moldadas. Exemplos deste tipo de acabamento são mostrados utilizando laminados cruzados simétricos [(0,90)/0]s e [(0,90)/90]s, fabricados com fita unidirecional contínua e tecido bidirecional de carbono, pré-impregnados com resina epóxi. O arranjo de fibras e resina na região da borda livre de todos os corpos-de-prova foi analisado usando um microscópio óptico. Foi observado que as fibras longitudinais (a 0°) podem se mover lateralmente na direção da borda moldada sob ação da pressão aplicada durante a cura. Bolsas de resina pura podem ser formadas nessa região dependendo da seqüência de empilhamento do laminado.Manufacturing techniques that improve the quality and/or reduce the cost of advanced composites structures produced by vacuum bag and cure in autoclave have been intensely investigated. One way to obtain a gain in productivity is to produce laminates with molded edges. This work presents a literature review of the fabrication process of structural parts of advanced polymeric composites, with emphasis in the manufacturing of laminates with molded edges. As an example of this type of edge finishing, symmetric cross ply laminates [(0,90)/0]s and [(0,90)/90]s were manufactured with pre-impregnated unidirectional tape and fabric. The arrangement of fibers and resin near the free edge of all specimens were analyzed using an optical microscope. It was observed that longitudinal fibers in the laminate (fibers at 0°) may move laterally towards the molded edge under the action of the pressure applied during cure. Pockets of pure resin may be formed at this region depending on the laminate stacking sequence.

Geraldo M. Cândido; Sérgio F. M. Almeida; Mirabel C. Rezende

2000-01-01

328

PROSTHESIS RESTORATION MOLDING APPARATUS  

UK PubMed Central (United Kingdom)

A wax master sprue and gate form used in the investment casting process of dental prosthesis. It has a web (32) between the gates (26, 28, 30) so that the gates are secured together to prevent shifting of the gates during the molding of the casting material around a wax master (52).

BERGER Robert P

329

Compound and its processing technology for compound sulfamonomethoxine sodium injection  

UK PubMed Central (United Kingdom)

The present invention discloses a formula of a daimeton sodium injection and making process thereof, and aims at providing a formula of compound recipe formulation compound recipe daimeton sodium injection capable of preventing and curing mixing infection contamination of a plurality of virus, bacilli, mycoplasma and bloodworm and making process thereof. Said formula and making process are characterized in that the formula is as follows: daimeton sodium of150g, trimethoprim of 30g, ofloxacin of 20g, dexamethasone sodium phosphate of 1g, propylene glycol of 600ml, ethanol amine of right amount, benzenemethanol of 40ml, ethylenediamine tetraacetic acid disodium of 100mg, anhydrous sodium sulfite of 2g, active carbon of 3g, and water for injection of added to 1000ml the organic combination of daimeton sodium, trimethoprim, ofloxacin, dexamethasone sodium phosphate together can effectively exhibits effects of medicament cooperation, synergism and long acting, and improves medicament curative effects, expands antibacterial spectrum, improves medicament side-effects, can achieve the objective of one injection for effect onset and 3-5 injection for healing wrapping material is saved to reduce the cost of products.

CHENG QINGLAN PENG

330

Staged mold for encapsulating hazardous wastes  

Energy Technology Data Exchange (ETDEWEB)

A staged mold for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

Unger, Samuel L. (Los Angeles, CA); Telles, Rodney W. (Alhambra, CA); Lubowitz, Hyman R. (Rolling Hills Estates, CA)

1990-01-01

331

Staged mold for encapsulating hazardous wastes  

Energy Technology Data Exchange (ETDEWEB)

A staged mold for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

Unger, Samuel L. (Los Angeles, CA); Telles, Rodney W. (Alhambra, CA); Lubowitz, Hyman R. (Rolling Hills Estates, CA)

1988-01-01

332

THE PROCESS OF MANUFACTURE OF VARIETY QUAIL EGG PEELED AND A MOLD OF QUAIL EGG TO USING THAT ONE  

UK PubMed Central (United Kingdom)

A method for manufacturing peeled quail egg and a quail egg mold for the same are provided to remove the shells of quail eggs easily and quickly and reduce the amount of waste resulting from the shells. A method for manufacturing peeled quail egg comprises the steps of: blowing hot air of 30~45 C to a quail egg to sterilize and dry it(6), immersing the quail egg in edible acetic acid and peeling the outer shell(1), putting the quail egg with inner shell left in a mold(2), putting the mold containing the quail egg in water of 90~100 C to heat(3), putting the heated mold in cold water to cool(4), and taking out the boiled quail egg from the mold and peeling the inner shell(5).

LIM KI MAN

333

Combined in situ combustion process with chemical injection  

Energy Technology Data Exchange (ETDEWEB)

The paper presents the technology of the combined in situ combustion (ISC) process with chemical injection. Results of physical and computer simulation and pilot tests are considered. Commercial application of ISC is limited due to increase of the corrosivity of produced fluids and formation of stable water-oil emulsions. Developed technology serves to improve oil recovery, to avoid formation of stable water-oil emulsion, and to decrease the corrosion activity of produced fluids. The technology includes injection of the chemical reagent solution slug prior to the ISC process ignition, control of the process state, and injection of the reagent solution at the final stage of ISC, again. Alkali formed as a result of thermo-chemical reaction of the injected reagent in reservoir neutralizes acid products of oil oxidation. The medium reaction change from acid to neutral decreases corrosion activity of production and stability of water-oil emulsion. Improvement of oil recovery is due to the increase of relative mobility of the oil phase. The most effective reagent composition, concentration, and injection volume was determined during the laboratory tests on the linear model and computer simulation of the technology. Pilot tests are ongoing on the Mordovo-Karmalskoe deposit of natural bitumens. A reagent solution slug was injected in January 1993, then the ISC was ignited. Results of chemical analysis of produced gas and of surface surveys of the thermal front movement proved the stability of the process. Corrosion rates of steel in water samples from the pilot unit were much lower than those obtained outside the pilot unit. (1) not be absorbed by the reservoir rocks; (2) not precipitate as a result of mixing with native reservoir water. Two series of experiments were performed. In the first, one efficiency of ISC combustion and neutralization was tested. In the second, adsorption of the reagent was studied.

Diyashev, I.R.; Sattarova, F.M.; Volkov, Y.V. [TatNIPIneft Institute, Tatarstan (Russian Federation)

1995-12-31

334

Embranquecimento do polipropileno isotático injetado contendo TiO2 como pigmento Whitening mechanism in injection molded polypropylene with TiO2 as pigment  

Directory of Open Access Journals (Sweden)

Full Text Available Descrevemos neste trabalho as causas e o mecanismo do embranquecimento de peças de polipropileno isotático injetado. Para isto foram injetados corpos de prova e placas com e sem estabilizantes. As amostras foram envelhecidas por exposição ambiental e em equipamento de envelhecimento acelerado (Weatherometer). Foi feito o acompanhamento visual das peças para que pudessem ser caracterizadas quando começassem a embranquecer. A caracterização foi feita através de espectroscopia FT-IR por reflectância, Microscopia eletrônica de varredura, Microfluorescência de raios-X, Reflectância de luz e Microanálise de energia dispersiva (EDS) da superfície. Os espectros de infravermelho mostraram o aparecimento de diversos produtos de degradação como cetonas, aldeídos, ácidos carboxílicos, ésteres, perésteres e alfa-cetoésteres. Quando as amostras começaram a embranquecer foi verificada a formação de fissuras superficiais e o aumento da reflectância de luz para todos os comprimentos de onda do espectro. Concomitantemente foi verificado que a composição de superfície não é alterada pelo envelhecimento. A superfície não apresenta grande quantidade de partículas de TiO2 expostas. Conclui-se que o embranquecimento das peças é devido ao fissuramento superficial que aumenta a quantidade de luz refletida na superfície e não pela migração do pigmento.We studied in this work the whitening mechanism in injection molded polypropylene (PP), a problem usually manifested in car parts and particularly in car bumpers. For the development of this work we had samples (plaques and test samples) with and without antioxidants and ultraviolet stabilizers. These samples had been already aged by natural and artificial (Weatherometer equipment) exposure. In the natural aging samples were collected when the material started to whiten, after 3190, 4320 and 6190 h of exposure. In the artificial aging samples were collected after 415, 515 and 3000 h of exposure. The samples were characterized by visual observation, infrared spectroscopy, scanning electron microscopy, surface total light reflectance and titanium mapping in the samples cross section by X-ray microfluorescence and X-ray difraction of the TiO2 used in the formulation. When the samples start to whiten we observe the evolution of surface fissures which increase the surface roughness. This is followed by an increase in the total light reflection by the surface for all wavelengths. We observed that titanium is almost homogeneously distributed along samples cross section. In addition, we did not observe high concentration of exposed TiO2 on the surface. We conclude that the whitening phenomenon is a consequence of surface fissures evolution, which provides higher surface roughness and is followed by a higher surface diffuse light reflectance.

Dênison R. J. Maia; Marco-Aurelio De Paoli

2000-01-01

335

Embranquecimento do polipropileno isotático injetado contendo TiO2 como pigmento/ Whitening mechanism in injection molded polypropylene with TiO2 as pigment  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Descrevemos neste trabalho as causas e o mecanismo do embranquecimento de peças de polipropileno isotático injetado. Para isto foram injetados corpos de prova e placas com e sem estabilizantes. As amostras foram envelhecidas por exposição ambiental e em equipamento de envelhecimento acelerado (Weatherometer). Foi feito o acompanhamento visual das peças para que pudessem ser caracterizadas quando começassem a embranquecer. A caracterização foi feita através de esp (more) ectroscopia FT-IR por reflectância, Microscopia eletrônica de varredura, Microfluorescência de raios-X, Reflectância de luz e Microanálise de energia dispersiva (EDS) da superfície. Os espectros de infravermelho mostraram o aparecimento de diversos produtos de degradação como cetonas, aldeídos, ácidos carboxílicos, ésteres, perésteres e alfa-cetoésteres. Quando as amostras começaram a embranquecer foi verificada a formação de fissuras superficiais e o aumento da reflectância de luz para todos os comprimentos de onda do espectro. Concomitantemente foi verificado que a composição de superfície não é alterada pelo envelhecimento. A superfície não apresenta grande quantidade de partículas de TiO2 expostas. Conclui-se que o embranquecimento das peças é devido ao fissuramento superficial que aumenta a quantidade de luz refletida na superfície e não pela migração do pigmento. Abstract in english We studied in this work the whitening mechanism in injection molded polypropylene (PP), a problem usually manifested in car parts and particularly in car bumpers. For the development of this work we had samples (plaques and test samples) with and without antioxidants and ultraviolet stabilizers. These samples had been already aged by natural and artificial (Weatherometer equipment) exposure. In the natural aging samples were collected when the material started to whiten, (more) after 3190, 4320 and 6190 h of exposure. In the artificial aging samples were collected after 415, 515 and 3000 h of exposure. The samples were characterized by visual observation, infrared spectroscopy, scanning electron microscopy, surface total light reflectance and titanium mapping in the samples cross section by X-ray microfluorescence and X-ray difraction of the TiO2 used in the formulation. When the samples start to whiten we observe the evolution of surface fissures which increase the surface roughness. This is followed by an increase in the total light reflection by the surface for all wavelengths. We observed that titanium is almost homogeneously distributed along samples cross section. In addition, we did not observe high concentration of exposed TiO2 on the surface. We conclude that the whitening phenomenon is a consequence of surface fissures evolution, which provides higher surface roughness and is followed by a higher surface diffuse light reflectance.

Maia, Dênison R. J.; De Paoli, Marco-Aurelio

2000-12-01

336

Characterization of corner and edge permeabilities during mold filling in resin transfer molding  

Energy Technology Data Exchange (ETDEWEB)

During the fiber preform lay-up in an RTM mold, air cavities or other regions of high porosity are set up near the edges and corners of the mold and the inserts within the mold. Such high porosity regions offer the injected resin least flow resistance, causing the resin flow front to flow much faster in these regions, this effect is generally known as racetracking. Numerical simulations to model RTM can account for the effects of racetracking once one can specify the permeability or the resistance to flow in these regions. A systematic experimental study was conducted in a 1-dimensional mold to investigate the role of air gap, preform type, volume fraction and process and material parameters on flow. Experimental flow fronts were matched with numerical flow fronts at all times during filling, by adjusting the permeability values for the edge elements in the numerical simulation. This allowed us to construct a phenomenological model for permeability in an air gap, as a function of air gap size, preform fiber volume fraction, and preform material.

Bickerton, S.; Advani, S.G. [Univ. of Delaware, Newark, DE (United States)

1995-12-31

337

Polyamide from lactams by reactive rotational molding via anionic ring-opening polymerization: Optimization of processing parameters  

Directory of Open Access Journals (Sweden)

Full Text Available A reactive rotational molding (RRM) process was developed to obtain a PA6 by activated anionic ring-opening polymerization of epsilon-caprolactam (APA6). Sodium caprolactamate (C10) and caprolactam magnesium bromide (C1) were employed as catalysts, and difunctional hexamethylene-1,6-dicarbamoylcaprolactam (C20) was used as an activator. The kinetics of the anionic polymerization of !-caprolactam into polyamide 6 was monitored through dynamic rheology and differential scanning calorimetry measurements. The effect of the processing parameters, such as the polymerization temperature, different catalyst/activator combinations and concentrations, on the kinetics of polymerization is discussed. A temperature of 150°C was demonstrated to be the most appropriate. It was also found that crystallization may occur during PA6 polymerization and that the combination C1/C20 was well suited as it permitted a suitable induction time. Isoviscosity curves were drawn in order to determine the available processing window for RRM. The properties of the obtained APA6 were compared with those of a conventionally rotomolded PA6. Results pointed at lower cycle times and increased tensile properties at weak deformation.

N. Barhoumi; A. Maazouz; M. Jaziri; R. Abdelhedi

2013-01-01

338

Fabrication of microlenses by combining silicon technology, mechanical micromachining and plastic molding  

Science.gov (United States)

Silicon can be subjected to plasmaless isotropic etching in mixtures of elemental bromine and fluorine. BrF3 is generated in the etching process. This ensures a high etching rate on smooth surfaces. The addition of noble gases, e.g. xenon, allows extremely smooth surfaces to be etched. Thermally oxidized SiO2 layers are applied as the etching mask. Among other applications, this technique can be used to manufacture microlenses. As a consequence of the complete isotropy of the etching process, spherical depressions of 100 to 500 micrometers in diameter are produced in the silicon when small circular holes of 5 to 50 micrometers are underetched in the SiO2 mask. After removal of the SiO2 mask the silicon sample can be used as a mold insert for plastic molding. The molded microlenses have been checked dimensionally and verified optically. The microlenses are planned for technical use in a miniaturized endoscope. This requires further processing of the silicon sample. As no hemispherical recesses but calotte shells are needed, the silicon surface must be machine prior to molding. This is done by microgrinding with variable-grain diamond tools on CNC high- precision machines. To generate adjusting devices, stoppers, and holding structures, the ground silicon sample and a mechanically microstructured perforated plate are combined in a modular multi-level mold insert. The microlenses molded by hot embossing or injection molding are separated mechanically. They can then be integrated in the endoscope with a holding unit manufactured independently.

Koehler, Uwe; Guber, Andreas E.; Bier, W.; Heckele, M.; Schaller, Thomas

1996-03-01

339

A systematic experimental approach to the resin transfer molding of graphite reinforced tubes  

Energy Technology Data Exchange (ETDEWEB)

The aim of this paper is to explore a systematic approach to experimentally quantify process variable in Resin Transfer Molding (RTM) of composite panels. Experience from resulting experiments were then used to aid in the fabrication of graphite/epoxy tubes. Composite Panels were fabricated from 8-Harness graphite weave preform using RTM. The process parameters for individual panels were varied in order to understand their effect on the quality of the panels produced. Three variations of RTM technique were employed for this study. The regular RTM (RRTM), the Vacuum Assist RTM (VARTM) and the Controlled Leak Vacuum Assist RTM (CLVRTM). The mold unit employs a steel cavity and a top plate made of transparent Plexiglass. The resin matrix was Dow Chemical Tactix 123, with Millamine 5260 as the curing agent. The resin flow and void formation mechanism during resin injection, were recorded with a video camera through the transparent mold face. Void and microvoid content were determined using the non-destructive testing of ultrasonic C-scanning. The tube making process employs some of the useful techniques resulting from the fabrication of the panels. The mold unit consist of a single tubular mold, and two end flanges made of steel. Internal pressure was provided through an inflatable silicone rubber bladder and resin injected into the mold with the aid of a peristaltic pump. The tube produced using a vacuum assist RTM were void-free, but there was the problem of non uniform wall thickness.

Senibi, S.; Sadler, R. [North Carolina A and T State Univ., Greensboro, NC (United States)

1995-06-01

340

Microstructured metal molds fabricated via investment casting  

Science.gov (United States)

This paper describes an investment casting process to produce aluminum molds having integrated microstructures. Unlike conventional micromolding tools, the aluminum mold was large and had complex curved surfaces. The aluminum was cast from curved microstructured ceramic molds which were themselves cast from curved microstructured rubber. The aluminum microstructures had an aspect ratio of 1:1 and sizes ranging from 25 to 50 µm. Many structures were successfully cast into the aluminum with excellent replication fidelity, including circular, square and triangular holes. We demonstrate molding of large, curved surfaces having surface microstructures using the aluminum mold.

Cannon, Andrew H.; King, William P.

2010-02-01

 
 
 
 
341

Influence of calcium carbonate and slip agent addition on linear medium density polyethylene processed by rotational molding  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In this paper, the influence of calcium carbonate and slip agent on linear medium density polyethylene (LMDPE) processed by rotational molding was evaluated. LMDPE was dry blended with different CaCO3 masterbatch ratios, erucamide slip agent and then extruded, micronized and rotomolded. The powder samples were characterized using MFI (Melting flow index), dry flow and bulk density. The characterization of rotomolded samples properties was performed by DSC (Differential sc (more) anning calorimetry), microscopy analysis, izod impact and tensile test. The results pointed out that the CaCO3 addition modifies the bulk density compared to neat LMDPE, but did not significantly affect the dry flow and MFI. The erucamide addition decreased the dry flow and increased the bulk densities. The porosity degree data showed that CaCO3 addition in the LMDPE increased the quantity of pores. The DSC results showed no significant difference in the crystallinity degree. The behavior of porosity led to a decrease in the mechanical properties of LMDPE with the CaCO3 addition.

Baumer, Marina I.; Leite, Janaina L.; Becker, Daniela

2013-01-01

342

Influence of reaction chamber shape on cast-iron spheroidization process in-mold  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a results concerning the influence of reaction chamber shape on cast – iron spheroidization process in form. The volume of the tested reaction chambers was about 118000mm3. Reaction chambers in the shape of: rectangular, cylinder and spherical cap were examined. It has been shown that the best graphite spheroidizing process was provided by spherical cap chamber shape. The reaction of cast – iron with magnesium in reaction chamber depends on the flow of cast – iron in the chamber. In rectangular and cylinder shape chambers proceed the impact of diphase stream on flat bottom wall. It causes the creation on its surface film, called: cast – iron “film”, where single grains of magnesium master alloy exist. The largest part of master alloy is drifted by liquid cast – iron to the top and only there graphite spheroidization process proceed. In the spherical cap shape reaction chamber, as a result of rotation movement of liquid cast – iron throughout its volume, graphite spheroidization process proceed. Apart from the reaction chamber shape, applying of mixing chamber ensure full cast – iron spheroidization process.

S. Pietrowski

2010-01-01

343

SILICONE MOLD AND USE THEREOF  

UK PubMed Central (United Kingdom)

A silicone mold comprising and oxidized, patterned surface and a layer of perfluoroether 5 silane release agent is described. The mold enables 2nd generation silicone molds to be replicated, i.e. silicone molds from silicone molds.

ZHANG JUN-YING; PELLERITE MARK J

344

Cavity air flow behavior during filling in microinjection molding  

DEFF Research Database (Denmark)

Process monitoring of microinjection molding (?-IM) is of crucial importance in understanding the effects of different parameter settings on the process, especially on its performance and consistency with regard to parts' quality. Quality factors related to mold cavity air evacuation can provide valuable information about the process dynamics and also about the filling of a cavity by a polymer melt. In this paper, a novel experimental setup is proposed to monitor maximum air flow and air flow work as an integral of the air flow over time by employing a microelectromechanical system gas sensor mounted inside the mold. The influence of four ?IM parameters, melt temperature, mold temperature, injection speed, and resistance to air evacuation, on two air flow-related output parameters is investigated by carrying out a design of experiment study. The results provide empirical evidences about the effects of process parameters on cavity air evacuation, and the influence of air evacuation on the part flow length. © 2011 American Society of Mechanical Engineers.

Griffiths, C.A.; Dimov, S.S.

2011-01-01

345

Characterization of the level fluctuations in a physical model of the steel continuous casting mold through image processing  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In this work is characterized the periodic behavior of the liquid level inside a scaled cold-model of the mold section of a steel continuous casting machine, which uses water as working fluid. The models are designed in order to simulate the dynamic forces acting on the molten steel inside a mold of continuous casting. The force magnitude can induce choppy flow, waves and vortex formation in the mold. The experimental model uses a closed-loop hydraulic configuration. In t (more) he mold, the inlet and the outlet water flow rates are the same. This configuration resembles a perfect control of the liquid level inside the water model. A high-speed video camera was used to get several video clips of the movement of the water level profile. Several techniques were tested in order to obtain the best lighting conditions for recording the water movement. The edge-detection technique of Sobel was used to determine the profile of the liquid level in each one of the images recorded. The analysis of the dynamic behavior of the water profile showed that the fluctuations of the liquid level inside the mold have a complex structure, which is repeated over large time periods.

Miranda-Tello, J.R.; Sánchez-Rangel, F.; Real-Ramírez, C.A.; Khatchatourov, G.; Aragón-Lezama, J.A.; Hoyos-Reyes, L.F.; Andrade-González, E.A.; González-Trejo, J.I.

2012-04-01

346

Rapid tooling for functional prototyping of metal mold processes. CRADA final report  

Energy Technology Data Exchange (ETDEWEB)

The overall scope of this endeavor was to develop an integrated computer system, running on a network of heterogeneous computers, that would allow the rapid development of tool designs, and then use process models to determine whether the initial tooling would have characteristics which produce the prototype parts. The major thrust of this program for ORNL was the definition of the requirements for the development of the integrated die design system with the functional purpose to link part design, tool design, and component fabrication through a seamless software environment. The principal product would be a system control program that would coordinate the various application programs and implement the data transfer so that any networked workstation would be useable. The overall system control architecture was to be required to easily facilitate any changes, upgrades, or replacements of the model from either the manufacturing end or the design criteria standpoint. The initial design of such a program is described in the section labeled ``Control Program Design``. A critical aspect of this research was the design of the system flow chart showing the exact system components and the data to be transferred. All of the major system components would have been configured to ensure data file compatibility and transferability across the Internet. The intent was to use commercially available packages to model the various manufacturing processes for creating the die and die inserts in addition to modeling the processes for which these parts were to be used. In order to meet all of these requirements, investigative research was conducted to determine the system flow features and software components within the various organizations contributing to this project. This research is summarized.

Zacharia, T.; Ludtka, G.M.; Bjerke, M.A.; Gray, W.H.

1997-12-01

347

Rapid tooling for functional prototyping of metal mold processes: Literature review on cast tooling  

Energy Technology Data Exchange (ETDEWEB)

This report is a literature review on cast tooling with the general focus on AISI H13 tool steel. The review includes processing of both wrought and cast H13 steel along with the accompanying microstructures. Also included is the incorporation of new rapid prototyping technologies, such as Stereolithography and Selective Laser Sintering, into the investment casting of tool steel. The limiting property of using wrought or cast tool steel for die casting is heat checking. Heat checking is addressed in terms of testing procedures, theories regarding the mechanism, and microstructural aspects related to the cracking.

Baldwin, M.D. [Sandia National Labs., Albuquerque, NM (United States); Hochanadel, P.W. [Colorado School of Mines, Golden, CO (United States). Dept. of Metallurgical and Materials Engineering

1995-11-01

348

Fine Metal Structure, Process for Producing the Same, Fine Metal Mold and Device  

UK PubMed Central (United Kingdom)

A fine metal structure having its surface furnished with microprojections of high strength, high precision and large aspect ratio and a process for producing the fine metal structure free of defects. There is provided a fine metal structure having its surface furnished with microprojections, characterized in that the microprojections have a minimum thickness or minimum diameter ranging from 10 nanometers to 10 micrometers and that the ratio between minimum thickness or minimum diameter (D) of microprojections and height of microprojections (H), H/D, is greater than 1. There is further provided a process for producing a fine metal structure, characterized by comprising providing a substrate having a fine rugged pattern on its surface, applying a molecular electroless plating catalyst to the surface, thereafter carrying out electroless plating to thereby form a metal layer having the rugged pattern filled, and detaching the metal layer from the substrate to thereby obtain a fine metal structure furnished with a surface having undergone reversal transfer of the above rugged pattern.

YOSHIDA HIROSHI; AKAHOSHI HARUO; MIYAUCHI AKIHIRO; OGINO MASAHIKO

349

Roughness measurement of hole processing surface for mold steel using white light interferometer  

International Nuclear Information System (INIS)

[en] In this study, NIMAX material has been processed using the three dimensional measuring instrument and white light interferometer. They were tested to roundness and surface roughness and results are as follows: As for a cutting characteristic, it indicated that F4 showed a lower result than 2F showed due to the high hardness of the material and showed a good result when spindle rotation speed and tool feed were low. As for the measurement of roundness through 3 Dimensional measuring machine, it indicated that 4F showed a good result like the condition of cutting component and that roundness showed a good result when spindle rotation speed of 1,700 rpm and tool feed speed of 85 mm/min were applied. As for the surface roughness of processing surface, Surface roughness showed better 4F than 2F and conditions of spindle rotation speed 1,700 rpm, tool feed rate 55 mm/min showed good results in the Ra 0.4025 ?m

2013-01-01

350

Analysis of the solidification process of steel ingots in a casting mold  

International Nuclear Information System (INIS)

[en] The quantitative characteristics of the process of solidification of steel ingots in moulds were investigated. Studied were the kinetics of horizontal and vertical solidification and the effect of tapering upon the vertical solidification of a round cross section ingot. It was found that different levels of steel ingots in moulds solidify at different moments of time. A combined factor representing the effect of the distance from the cross section to the base of the ingot, the ratio of side dimensions and the tapering upon the kinetics of solidification is the ratio of the volume of an ingot to its heat emitting surface area. The horizontal solidification does not follow the square root law. Its rate is maximum at the beginning of solidification, then drops sharply and at delta approximately 0.6 has a least value. The further solidification proceeds at an accelerated rate toward the centre of the ingot

1977-01-01

351

FLEXIBLE CARRIER MOLD  

UK PubMed Central (United Kingdom)

A carrier mold having prongs that produces shaped tampons is provided. When subjected to pressure the prongs of the carrier mold flex to completely or substantially close one end of the carrier mold. A method of forming a shaped tampon using the carrier mold is also provided.

HUBBARD WADE MONROE JR; STRONG KEVIN CHARLES; MERS-KELLY MICHAEL JOHN; WIEGELE DANIEL RAYMOND

352

Chalcogenide-mold interactions during precision glass molding (PGM) of GeAsSe glasses  

Science.gov (United States)

Five chalcogenide glasses in the GeAsSe ternary glass system were melted, fabricated into flats, and molded between planar, uncoated, binderless WC molds using a laboratory-scale precision glass molding machine. The five glasses originate at the binary arsenic triselenide (As40Se60) and are modified by replacing As with Se in 5 mol% increments, or by locking the As:Se ratio and adding Ge, also in 5 mol% increments. The glasses are separated into two groups, one for the Ge-free compositions and the other for the Ge-containing compositions. This effort analyzes the differences between the Ge-containing and the Ge-free glasses on the post-molded glass and mold surface behavior, as well as the mold lifetime. Fabrication features, such as scratch and/or dig marks were present on the glass and mold surfaces prior to the PGM process. White light interferometry analysis of the surfaces shows an overall reduction in the RMS roughness of the glass after molding, and an increase of the roughness of the molds, after 15 molding cycles. After molding, the quantity of observable defects, primarily deposits and dig marks are increased for both the glass and mold surfaces. Deposits found on the WC molds and glasses were analyzed using Electron Dispersive X-ray Spectroscopy (EDS) and showed no evidence of being due to material transfer between the WC molds and the glass constituents. In general the main observable difference in the analysis of the two post molded sets, despite the changes in chemistry, is the quantity of molding induced defects near the edge of the GeAsSe samples.

Gleason, B.; Wachtel, P.; Musgraves, J. D.; Steinkopf, R.; Eberhardt, R.; Richardson, K.

2013-09-01

353

Finite Element Analysis Of Reciprocating Screw For Injection Moulding Machine  

Directory of Open Access Journals (Sweden)

Full Text Available Injection moulding machine is the most commonly used manufacturing process for the fabrication of plastic parts. The plastic being melted in injection molding machine and then injected into the mould. The barrel contains reciprocating screw for injecting the material into the mould and the material is also melted into the barrel. This project deals with, the solution of problem occurred for reciprocating screw of Injection molding machine. It identifies and solves the problem by using the modeling and analysis techniques. The problem occurred in the reciprocating screw of machine which is wearing of threads due to affect of temperature of mold materials (flow materials) i.e. Nylon, low density polypropylene, polystyrene, PVC etc., The main work was to model the components of machine with dimensions, and perform thermal analysis with modeled component.

VIKAS.R.RAJORIA, PROF.P.K.JADHAO

2013-01-01

354

[Studies on key processes of Fufang Kushen injection].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To study the key processes of Fufang Kushen injection for technical upgrading. METHOD: Total alkaloids (sum of matrine, oxymatrine, sophoridine and oxysophoridine) and macrozamin were selected as quality evaluation markers. The key processes of percolation with acetic acid and discoloration with activated carbon were optimized by orthogonal experiment design, and process of purification with alcohol was investigated by single factor method. RESULT: The optimal condition of percolation process is as follows: the medicinal materials are soaked for 9 h with 4 times water containing 0.8% acetic acid, then percolation starts at flow-rate of 5 mL x min(-1) x kg(-1) and adding 2 times 0.8% acetic acid solution is added at the same velocity. Purification process is that the concentrated solution is precipitated by 60%, 80% and 90% alcohol in turn. Discoloration process is that 6 activated carbon is added into the solution which is heated at 60 degrees C for 20 minutes. CONCLUSION: The optimal extraction process is not only simple, saving the industrial cycle, reducing the potential risk, but also decreasing the acetic acid amount to guarantee the acid-insoluble ash as well as the functional ingredients.

Liu X; Wang J; Tong Y; Wang R; Zhang Y; Wang Z; Zhang Q

2011-03-01

355

Monitoring an underground steam injection process using electrical resistance tomography  

Energy Technology Data Exchange (ETDEWEB)

We used electrical resistance tomography (ERT) to map the subsurface distribution of a steam flood as a function of time as part of a prototype environmental restoration process performed by the Dynamic Underground Stripping Project. We evaluated the capability of ERT to monitor changes in the soil resistivity during the steam injection process using a dipole-dipole measurement technique to measure the bulk electrical resistivity distribution in the soil mass. The injected steam caused changes in the soil's resistivity because the steam displaced some of the native pore water, increased the pore water and soil temperatures and changed the ionic content of the pore water. We could detect the effects of steam invasion by mapping changes in the soil resistivity as a function of space and time. The ERT tomographs are compared with induction well logs, formation temperature logs and lithologic logs. These comparisons suggest that the ERT tomographs mapped the formation regions invaded by the steam flood. The data also suggest that steam invasion was limited in vertical extent to a gravel horizon at depth of approximately 43 m. The tomographs show that with time, the steam invasion zone extended laterally to all areas monitored by the ERT technique.

Ramirez, A.; Daily, W.; Owen, E.; Chesnut, D. (Lawrence Livermore National Lab., CA (United States)); LaBrecque, D. (Univ. of Arizona, Tucson (United States))

1993-01-01

356

Evaluation of wear during the injection process with the use of optical profilometry  

Science.gov (United States)

This article deals with the study of wear of non-conventional materials in the plastic injection industry, particularly in inserts for reusable injection molds. A methodology for the analysis of wear is proposed using new measurement parameters. Superficial parameters like roughness average (Ra) have proven not to be quite effective for this purpose. Therefore new coefficients are suggested, as the Minimum Wear Area (MWA), which takes advantage of the collected data and appears to be a better choice for wear characterization. A Polyamide with 30% load of fiberglass has been injected into two cavities manufactured in different material (aluminum and brass) and with the same geometry, in which the wear at different points has been evaluated. We have used interferometry and an optical microscope as measurement tools. Finite element analysis and simulation software has also been used.

Hernández, P.; Díaz, M.; Covelo, E.; Ares, E.

2012-04-01

357

Mold cleaning with polydimethylsiloxane for nanoimprint lithography.  

UK PubMed Central (United Kingdom)

We present a simple and effective mold cleaning method for nanoimprint lithography. Polydimethylsiloxane (PDMS) prepolymer is spin-coated onto a contaminated imprint mold, thermally cured in an ambient environment, and then peeled off afterwards. Contaminants of 100 s ?m to sub-50 nm sizes are effectively cleaned within one cycle. During the cleaning process, a very thin PDMS film (1-2 nm) is uniformly coated onto the mold surface, serving as a protection and anti-sticking layer.

Lin P; Pi S; Jiang H; Xia Q

2013-08-01

358

Capillarity in metal casting mold filling  

Science.gov (United States)

In metal casting processes, surface tension of the molten metal typically resists filling of the metal into the mold. The effects are greater for smaller mold cavities, and ultimately, the smallest cavities may not be filled. Surface tension forces can be overcome by applying pressure (head) to the molten metal, thus forcing metal into the cavities. However, a pressure-window will exist, too little pressure resulting in non-filled cavities and too much pressure resulting in penetration of the mold, which is itself porous. Filling-pressure windows are investigated for cylindrical-shaped mold cavities on both a theoretical and experimental basis. The lower bound of the filling pressure window is examined by treating cylindrical mold cavities as cylinders lined with packed spheres representing mold particles. The upper bound is examined by treating the mold as a 3-D array of close-packed spheres. The experimental work concerns industrial-scale vacuum investment casting of superalloy IN718 into molds containing various cylindrical mold cavities at various heights (heads). The experimental results are found to be in good agreement with the numerical modeling predictions for filling of rough (sphere-lined) cylindrical mold cavities.

Hilden, Jon L.

359

Measurement of thermal stress in plastic molded IC by image processing. Gazo shori ni yoru IC mold nai no netsuoryoku keisoku  

Energy Technology Data Exchange (ETDEWEB)

Thermal stress remained in a nolded resin which is used to package integrated circuits(ICs) was measured by the photoelastic method using the thermal stress distribution chart. The princple used in this method is the shear difference method, and main experimental apparatuses inchude a polarization microscope, a CCD camera and an image processing unit and ICs used in this experiment are IM and 4M bits DRAM type ones. It was found on the basis of the distribution of the thermal stress and the shearing force that the thermal stress is larger at the upper and lower resin paret of the chip and lead frame and becomes largest at the interface. In addition, the measurement was carried out by changing the package length, but thermal stress and the distribution were not affected by the package length. The failure of an IC is estimated to be caused by the superimposed maximum thermal stress and shearing stress of which location is estimated from their distributions. 7 refs., 12 figs.

Yoshimura, N.; Kawasaki, K.; Shoji, T. (Akita University, Akita (Japan). Mining College); Hatakeyama, K.; Kobayashi, T. (Akita Electronics Co. Ltd. Akita (Japan))

1991-09-30

360

Development of the Resin Infusion between Double Flexible Tooling process : assessment of the viability of in-mold coating and implementation of UV curing.  

Energy Technology Data Exchange (ETDEWEB)

As composites gain wider acceptance in all sectors of the economy, new methodologies must be developed to increase their cost effectiveness in manufacturing. The neoteric Resin Infusion between Double Flexible Tooling (RIDFT) process is undergoing modifications to improve its cost-effectiveness by developing methodologies for in-mold coating and the incorporation of UV curing. In-mold coating is desired by the composites industry since it eliminates the current paint process, which is not only laborious and time consuming, but expensive, and presents safety issues. Two methodologies (paint films and coinfusion) for implementing in-mold coating were investigated. It was demonstrated that thermoformable paint films could be used to produce coated RIDFTed components. Coinfusion was also successfully implemented. This work also investigated the feasibility of designing and incorporating a Cure on Demand system into the RIDFT process, using ultraviolet (UV) light for the curing of composite laminates. The objective was to develop a process for the RIDFT that would eliminate or reduce the inflexibility in the current production process, resulting in shortened production cycle times. UV-cured laminates were produced at a fraction of the time required to produce catalyst-cured laminates. Mechanical and material characterization tests were performed on each of the UV-cured laminates produced. The results were referenced against those obtained for laminates produced using a catalyst curing system to determine their overall quality. The UV-cured laminates, after undergoing tensile and rheological thermal tests, were found to have mechanical and material properties comparable, or in a few instances slightly better, than that of thermally cured laminates.

Okoli, Okenwa I. (. FAMU-FSU College of Engineering, Tallahassee, FL)

2004-12-01

 
 
 
 
361

Amorphous materials molded IR lens progress report  

Science.gov (United States)

Amorphous Materials began in 2000 a joint program with Lockheed Martin in Orlando to develop molding technology required to produce infrared lenses from chalcogenide glasses. Preliminary results were reported at this SPIE meeting by Amy Graham1 in 2003. The program ended in 2004. Since that time, AMI has concentrated on improving results from two low softening glasses, Amtir 4&5. Both glasses have been fully characterized and antireflection coatings have been developed for each. Lenses have been molded from both glasses, from Amtir 6 and from C1 Core glass. A Zygo unit is used to evaluate the results of each molded lens as a guide to improving the molding process. Expansion into a larger building has provided room for five production molding units. Molded lens sizes have ranged from 8 mm to 136 mm in diameter. Recent results will be presented

Hilton, A. R., Sr.; McCord, James; Timm, Ronald; Le Blanc, R. A.

2008-05-01

362

Three-step mold remediation system  

Energy Technology Data Exchange (ETDEWEB)

Although molds exist indoors and outdoors on almost any material without posing any health risks, large concentrations of any mold will usually require remediation. An innovative three-step system for cleaning and removing molds and for protecting against future mold formation is proposed. Step One in this process involves cleaning with a hydrogen peroxide-based cleaner/disinfectant to destroy the mold and other microorganisms, followed by the application of an anti-microbial agent (a fungicide, bactericide and viracide) to provide residual anti-microbial action and prevent recurrence of the contamination, and finally shielding, which involves the application of a shielding compound to coat and bind the anti-microbial agent within the treated surface. The three-step treatment system has been field tested in various types of buildings and surfaces with outstanding results in terms of appearance and mold elimination. 1 photo.

Gaylor, D.

2000-11-01

363

Alumina Depyrogenates F 18 Fludeoxyglucose Injection during Purification Processes.  

UK PubMed Central (United Kingdom)

UNLABELLED: Endotoxin indicators (EIs) and photometric bacterial endotoxin test (BET) assays were used to determine the capacity of alumina (Al(2)O(3)) for removing endotoxin from a parenteral solution. Fludeoxyglucose F 18 (FDG) Injection, USP, a radioactive imaging agent, is made daily at about 150 American sites for same-day administration. Each FDG synthesis unit contains a cartridge of alumina for removing a radiochemical impurity before delivery to the final product vial. Recognizing that alumina is a cationic adsorption medium, its capacity for removing endotoxin was challenged with purified endotoxin. A 2000 EU vial of an EI was reconstituted with water or FDG, vortex-mixed, and passed through a representative final product assembly consisting of an alumina cartridge with connecting tubing, a sterilizing membrane filter, and aseptic collection vial. In addition to sterilization, the filter removed alumina "fines" that are inhibitory to the BET because of adsorption of the positive control. Confirmation of labeled claim for each EI and measurement of endotoxin challenge eluates from a simulated FDG process were analyzed by valid kinetic chromogenic assays using a microplate reader and a cartridge reader. Overkill depyrogenation conditions were achieved, defined as greater than a 3 log endotoxin reduction. In conclusion, alumina was observed to depyrogenate the eluate of a representative FDG synthesis unit. LAY ABSTRACT: A fever-inducing (pyrogenic) bacterial toxin may arise during the complex synthesis of a radioactive imaging agent known as Fludeoxyglucose F 18 (FDG) Injection. One of the purification steps for FDG, a cartridge of aluminum oxide (alumina), removes negatively charged, radioactive impurities. Representative FDG solutions were inoculated with purified bacterial endotoxin to determine if the toxin's negative charge would result in removal by alumina. Alumina's effectiveness for endotoxin removal, a process known as depyrogenation, was measured by endotoxin detection assays. Alumina reduced endotoxin levels by more than a thousand fold in a simulated FDG process. Therefore, an unrecognized benefit of the alumina cartridge is removal of a potentially harmful toxin while purifying the FDG for patient injection.

Cooper JF; Petry NA; Engelbrecht H; Breslow K

2012-05-01

364

Novel bread molding cutter  

UK PubMed Central (United Kingdom)

The utility model relates to a novel flour molding cutter which is characterized in that a blade (10) can be made to be several shapes, and is combined to a plurality of molding knife rolls (8) together with a molding knife roll shaft (9), if the blade is made to be a circular shear blade, the blade can be combined to be a circular molding knife roll (11) together with the molding knife roll shaft (9) if the blade is made to be a semicircle blade, the blade can be combined to be an elliptic molding knife roll (12) together with the molding knife roll shaft (9) if the blade is made to be a straight bar blade, the blade can be combined to be a square or rectangle molding knife roll (13) together with the molding knife roll shaft (9) the blade is made to be a hexagon blade, and can be combined to be a hexagon molding knife roll (14) together with the molding knife roll shaft (9), etc., the molding knife rolls are combined to be any one novel flour molding cutter together with the molding knife roll shaft (9). The novel flour molding cutter can be used as a cutter replacement part of a noodle maker, a dumpling skin maker, a Wonton skin maker and a stewed noodle maker to match with the noodle maker, the dumpling skin maker, the Wonton skin maker and the stewed noodle maker for using. The novel flour molding cutter has the advantages that: firstly, the replacement of the cutter is convenient secondly, the cost is low, and the production cost is saved thirdly, the variety of the cutter is multiple, and the use is wider.

CHAOMIN WANG

365

Incipient flocculation molding: A new ceramic-forming technique  

Science.gov (United States)

Incipient Flocculation Molding (IFM) was conceived as a new near-net-shape forming technique for ceramic components. It was hypothesized that the development of a temperature-dependent deflocculant would result in a forming technique that is flexible, efficient, and capable of producing a superior microstructure with improved mechanical properties from highly reactive, submicron ceramic powders. IFM utilizes a concentrated, nonaqueous, sterically stabilized ceramic powder and/or colloidal suspension which is injected into a non-porous mold. The suspension is then flocculated by destabilizing the suspension by lowering the temperature. Flocculation is both rapid and reversible. Cooling to -20°C produces a green body with sufficient strength for removal from the mold. The solvent is removed from the green body by evaporation. The dried green body is subsequently sintered to form a dense ceramic monolith. This is the first ceramic forming method based upon the manipulation of a sterically-stabilized suspension. To demonstrate IFM, the process of grafting polyethylene glycol (PEG), with molecular weights from 600 to 8000, to alumina powders was investigated. The maximum grafted amounts were achieved by the technique of dispersing the alumina powders in molten polymer at 195°C. The ungrafted PEG was then removed by repeated centrifuging and redispersion in fresh distilled water. The rheological behavior of suspensions of the PEG-grafted powders in water, 2-propanol and 2-butanol were characterized. All of the aqueous suspensions were shear thinning. The PEG 4600-grafted alumina powder aqueous suspensions were the most fluid. Sample rods and bars were molded from 52 vol% PEG-grafted alumina suspensions in 2-butanol. The best results were obtained with a preheated aluminum mold lubricated with a fluorinated oil mold-release. The samples were dried, sintered, and their microstructure and density were compared with sintered samples dry pressed from the same alumi