• 한국기계가공학회지
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• 제14권4호
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• pp.14-20
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• 2015

Molding technologies for plastic microstructures have been extensively investigated during the last two decades, and theoretical and numerical studies on the micro molding process have provided efficient tools for the development of such molding technologies. In this paper, we present a review of numerical simulation methods for the micro molding process. Basic models for a description of the material property, governing equations of the flow and heat transfer during the molding process, and numerical methods will be described. Particularly, numerical simulations for micro injection molding and hot embossing processes will be presented, and their main features noted and compared to those for conventional molding processes.

• 한국정밀공학회지
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• 제25권5호
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• pp.43-51
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• 2008

Generally a plastic injection molding is a manufacturing process used to produce the various parts of complicated shape at low cost. The objective of this study is to implement a new plastic injection molding process with inserted Aluminum sheet, which is highly durable, light and luminous. Moldflow analysis and simulation of plastic injection molding process with inserted Aluminum sheet were carried out in order to predict optimal molding operation conditions. The experimental results in the Al-inserted plastic injection molding process were compared with the simulation results by Moldflow. Durability and reliability test results for trial products were satisfied to adopt the Al-inserted plastic injection molding process developed as manufacturing of automobile interior parts.

• 세라미스트
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• 제21권4호
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• pp.427-432
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• 2018

In this study, the aspherical lens for optical communications produced not with an one-step pneumatic type of external pressurization system (existed GMP process) but a constant weight of self-loaded mold put up to upper core. So the lens is molding with self-loaded weight molding and it calls Weight Molding process. In self-loaded molding process, we measured changes of center thickness molding lenses with each variable molding temperatures and time to find the effect of center of lens thickness to search key factors. As experimental results, the center thickness reach to targeted lenses step time value was changed drastically and it depends by molding temperature. If the molding temperature gets higher, the targeted lens that is reaching to the center thickness step time value was decreased. To find the effect of life improvement on mold core by imposing the self-loaded molding process we molded with GMP(Glass molding press) method and self-loaded molding method for 9,000 times and measured the lenses shape accuracy and surface roughness to evaluate the core life. As a result the self-loaded molding method core has 2,000 times longer that GMP (Glass molding press) method. If we adopt self-loaded molding method of the optical aspherical lens molding in the future, we expect that it would reduce the expense of changing the molds by molding core life improvements.

• Design & Manufacturing
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• 제1권1호
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• pp.1-5
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• 2007

Double injection molding process is very efficient molding-method for molding the products which is consist of multi-materials. Fuel-tube holder which is necessary for automobil power train and circulation systems is composed of plastic and rubber materials to minimize the vibration and pulsation noises. In existing process, fuel-tube holder was made by the insert molding process or assembly process after molding. If fuel-tube holder is manufactured by double injection molding process, it may be realize to improve the product quality, efficiency of molding-process and retrenchment of manufacturing cost. In this study, for manufacturing fuel-tube holder by double injection molding process, the analysis of joining characteristics between PA6(polyamide 6) and TPE(thermoplastic elastomer) was executed and the double injectin mold for molding fuel-tube holder with core toggle mechanism was fabricated. Finally, fuel-tube holder was molding using fabricated double injection mold.

• 정보저장시스템학회논문집
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• 제2권4호
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• pp.236-239
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• 2006

Glass micro molding process is the most suitable process for fabricating high precision glass microlens amy at low cost. A new glass micro molding process was proposed. Tungsten carbide mold was fabricated by imprinting and sintering process to overcome the difficulties of the conventional process. In the glass micro molding process, process conditions such as processing temperature and compression force were changed. Geometrical properties of the replicated glass microlens array were measured and compared at variety process conditions. The condition of glass micro molding process was optimized. The experimental result showed that developed process was effective to produce a glass microlens array.

• 한국지능시스템학회논문지
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• 제11권6호
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• pp.465-469
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• 2001

In injection molding short shot is one of the frequent and fatal defects. Experts of Injection molding usually adjust process conditions such as injection time, mold temperature, and melt temperature because it is most economic way in time and cost. However, it is difficult task to find appropriate process conditions for troubleshooting of short shot as injection molding process is a highly nonlinear system and process conditions are coupled. In this paper, a modular fuzzy neural network (MFNN) has been applied to injection molding process to shorten troubleshooting time of short shot. Based on melt temperature and fill time, a reasonable initial mo이 temperature is recommenced by the NFNN, and then the mold temperature is inputted to injection molding process. Depending on injection molding result, specifically the insufficient quantity of an injection molded part. and appropriate mold temperature is recommend repeatedly through the NFNN.

• 한국기계가공학회지
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• 제12권5호
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• pp.94-101
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• 2013

Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. The objective of this study is to implement the best plastic injection molding process for LED TV speaker frame. Moldflow analysis and simulation of plastic injection molding process were carried out in order to predict optimal modeling operation conditions and then injection molded part was produced various type of resin temperature, filling time and injection pressure variation. the result was that the best injection molding condition is set as 60bar pressure, 2sec filling time and $310^{\circ}C$ degree. The study result would be useful to variety of plastic injection molding process.

• 한국공작기계학회논문집
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• 제11권4호
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• pp.44-53
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• 2002

Injection molding process factors such as molding temperature, injection pressure, flow rate and flow velocity, must be controlled properly in filling and packing phases in the injection molding process. In this study, effects of these factors on the injection molding were investigated through the flow analysis for the filling and packing phases. Molding troubles like flow mark weld line, sink ma가 short shot and warpage car be caused by these injection molding process factors. Among them the short shot was caused by the fact that the packing pressure could not reach properly to the filling end part in the packing phase and hence the flow rate could not be supplied to the full. In addition as the flow rate for the volumetric shrinkage during the f개zen phase could not be supplied Properly by the packing pressure, the short shot appeared. Here, the volumetric shrinkage reduced with increasing the packing pressure and also the warpage of molded part increased with increasing the packing Pressure.

• 한국주조공학회지
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• 제25권4호
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• pp.173-178
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• 2005

The vacuum molding process is one of the clean-foundry molding-processes that can recycle molding sands repeatedly, because molding can be accomplished by introducing vacuum only among dry molding sands in flask. The effects of molding conditions such as sand grain fineness, vacuum pressure and coating thickness on the fluidity of A356 Al alloy were studied and the results was obtained that the fluidity length was decreased as the sand grain fineness number and coating thikness were decreased and the vacuum pressure was increased. A large amount of heat removal from the molten metal resulting from the vacuum suction during the vacuum molding process was the principal cause of this decrease in fluidity.

• Design & Manufacturing
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• 제2권5호
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• pp.30-33
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• 2008

Injection Molding is the most effective process for mass production of plastic parts. The injection molding process is composed with several steps such as Filling, Packing, Holding, Cooling, Ejecting. Among them, filling and packing process should be considered carefully to improve accuracy of dimension, surface quality of plastic parts. Usually the quality above-mentioned is managed with weight of part after molding on the field. In this paper, a series of experiment for molding automotive front bumper was conducted with cavitity temperature sensor to optimize switch-over time(V-P switching), hot runner vale gate sequence time during filling and packing step for the purpose of uniform quality, weight at every molding. As a result, it was found that it is effective method to use temperature sensor in injection molding for quality control of plastic molding.