• 대한기계학회논문집A
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• 제38권7호
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• pp.771-777
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• 2014

자동차용 도어그립을 대상으로 하여 3 차원 엠보 패턴이 인쇄된 필름을 적용한 인서트성형을 구현하기 위하여 사출압축성형을 사용하였다. 진공금형을 제작하여 필름 열성형을 하였으며, 필름인서트성형을 위하여 사출압축금형을 개발하였다. 3 개의 압력센서를 설치하여 금형 캐비티압력을 측정하였으며, 다양한 압축스트로크와 토글속도에 대한 사출압축성형 실험을 수행하여, 공정조건이 캐비티 압력과 엠보 패턴의 높이에 미치는 영향을 고찰하였다. 압축스트로크 0.9mm와 느린 토글속도에서 엠보 패턴의 유지율이 높게 나타났다. 또한 엠보패턴이 최대 높이를 갖기 위한 공정조건은 캐비티 압력의 적분값이 최소가 되는 조건과 거의 동일하였다. 사출압축성형을 사용하여 엠보 패턴이 인쇄된 소프트한 촉감을 갖는 플라스틱 제품을 구현할 수 있다.

• Design & Manufacturing
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• 제14권4호
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• pp.11-16
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• 2020

In this study, forming of carbon composite parts was performed using an injection/compression molding process. An impregnation of matrix is determined by ability of wet and flow rate between the matrix and reinforcement. The flow rate of matrix passing through the reinforcements is a function of permeability of reinforcement, a viscosity of matrix and pressure gradient on molding, and the viscosity of the matrix depends on the mold temperature, molding pressure and shear strain of matrix. Therefore, compression molding experiment was conducted using a heating mold in order to confirm the possibility of matrix impregnation. The impregnation of the matrix through the porosities between the woven yarns was confirmed by the cross-sectional SEM image of compression molded parts. An injection molding process was also performed at a short cycle time, high molding pressure and low mold temperature than those of compression experiment conditions. Deterioration of impregnation on the surface of molded parts were caused by these injection conditions and it could be the reason of decreasing the maximum tensile strength. In order to improve impregnation of matrix on the surface, injection/compression molding and insert-over molding were applied. As a result of applying injection/compression molding and insert-over molding, it was shown that the improvement of impregnation on the surface and the maximum tensile strength was increased about 2.8 times than the virgin matrix.

• Design & Manufacturing
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• 제17권4호
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• pp.72-78
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• 2023

Injection molding is a process widely used in various industries because of its high production speed and ease of mass production during the plastic manufacturing process, and the product is molded by injecting molten plastic into the mold at high speed and pressure. Since process conditions such as resin and mold temperature mutually affect the process and the quality of the molded product, it is difficult to accurately predict quality through mathematical or statistical methods. Recently, studies to predict the quality of injection molded products by applying artificial neural networks, which are known to be very useful for analyzing nonlinear types of problems, are actively underway. In this study, structural optimization of neural networks was conducted by applying multi-task learning techniques according to the characteristics of the input and output parameters of the artificial neural network. A structure reflecting the characteristics of each process step was applied to the input parameters, and a structure reflecting the quality characteristics of the injection molded part was applied to the output parameters using multi-tasking learning. Building an artificial neural network to predict the three qualities (mass, diameter, height) of injection-molded product under six process conditions (melt temperature, mold temperature, injection speed, packing pressure, pacing time, cooling time) and comparing its performance with the existing neural network, we observed enhancements in prediction accuracy for mass, diameter, and height by approximately 69.38%, 24.87%, and 39.87%, respectively.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.267-270
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• 2004

In Micro injection process, it is needed to the technique of making micro die, Rapid Thermal Pressing (RTP) and other techniques. Those techniques are independent. But the mutual connected system of techniques is needed. The target of this paper is the design of micro mold and the development of the entire micro injection techniques for functional polymer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1354-1357
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• 2003

Mold Analysis is crucial factors in the design of injection molding process. Since the qualify of products depends on filing, shrinkage and etc, the procedure of prediction through analysis in the design of injection molding process is needed. In many cases, this kind of analysis makes it possible to predict pressure pattern which determines the condition of injection molding process. Crystallinity is the factor that determines the shrinkage of products. The studies showed the factors that had been related to the degree of crystallinity, which were mostly Weight Reduction, mold temperature and melt temperature. Therefore, the objective of this study is to see the differences of the degree of crystallinity depending on the positions of foamed plastics. The procedure of this study is as the following. First, Simulate the pressure gradient in mold cavity that can produces specimen by using Moldflow. Secondly, produce specimen and measure the degree or crystallinity of each part of specimen by using XRD. Lastly, identify the sensitivity of conventional plastic and foamed plastic on pressure gradient by comparing the simulation and the results of measurement.

• 대한기계학회논문집A
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• 제39권9호
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• pp.893-899
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• 2015

사출 금형 설계에서 금형 온도 분포와 변형은 사출품의 플래시나 표면 단차에 주요한 영향 인자이다. 금형 온도 분포와 성형면의 압력분포를 예측하기 위하여 먼저 금형을 포함한 사출해석을 수행하였다. 계산된 온도분포와 압력분포는 금형 구조해석의 입력조건으로 사용하였다. 해석의 정확성을 위하여 금형 전체 세트에 대한 구조해석 조건을 도출하였다. 도출된 해석 모델로 성형면의 단차 및 벌어짐 크기에 대하여 금형 열팽창, 성형 중 온도변화의 영향을 분석하였다. 해석 결과를 바탕으로 성형면의 단차 감소 방안을 도출하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.230-233
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• 2006

In this study, the effects of residual stress induced by plastic injection molding process on the tensile behavior of plastic tensile test specimen were investigated. To manufacture plastic tensile test specimens, an injection mold based on the international standard system was designed and made. Cavity pressure and temperature sensors were installed inside of the presented mold to monitor pressure and temperature values during the cycle of injection molding. Injection molding simulation was performed with the same condition of experiment and linear structural tensile analysis was also performed with the initial condition of the residual stress. It was shown that the residual stress induced by injection molding has an effect on the experiment of tensile test and linear structural tensile simulation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.579-580
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• 2006

In this study, an injection mold of tensile test specimen was manufactured by international standard. Pressure and temperature in the cavity of the injection mold was measured by sensors. Simulation of injection molding process was performed with the same condition of experiment and linear structural tensile analysis was also performed with the initial condition of the residual stress induced by injection molding analysis. Normalized elastic coefficient of tensile test was compared with that of structural analysis. It was shown that the residual stress induced by injection molding has an effect on both the experiment of tensile test and linear structural analysis.

• 정보저장시스템학회논문집
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• 제1권2호
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• pp.192-196
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• 2005

In this paper, we investigated the possibility of replicating patterned media by nano-injection molding process with a metallic nano-stamper. The original nano-master was fabricated by E-beam lithography and ICP etching process. The metallic nano-stamper was fabricated using a nanoimprint lithography and nano-electroforming process. The nano-patterned substrate was replicated using a nano-injection molding process without additional etching process. In nano-injection molding process, since the solidified layer, generated during the polymer filling, deteriorates transcribability of nano patterns by preventing the polymer melt from filling the nano cavities, an injection-mold system was constructed to actively control the stamper surface temperature using MEMS heater and sensors. The replicated polymeric patterns using nano-injection molding process were as small as 50 nm in diameter, 150 nm in pitch, and 50 nm in depth. The replicated polymeric patterns can be applied to high density patterned media.

• Journal of Welding and Joining
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• 제32권4호
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• pp.10-14
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• 2014

Laser aided Direct Metal Tooling(DMT) process is a kind of Additive Manufacturing processes (or 3D-Printing processes), which is developed for using various commercial steel powders such as P20, P21, SUS420, H13, D2 and other non-ferrous metal powders, aluminum alloys, titanium alloys, copper alloys and so on. The DMT process is a versatile process which can be applied to various fields like the mold industry, the medical industry, and the defense industry. Among of them, the application of DMT process to the mold industry is one of the most attractive and practical applications since the conformal cooling channel core of injection molds can be fabricated at the slightly expensive cost by using the hybrid fabrication method of DMT technology compared to the part fabricated with the machining technology. The main objectives of this study are to provide various characteristics of the parts made by DMT process compared to the same parts machined from bulk materials and prove the performance of the injection mold equipped with the conformal cooling channel core which is fabricated by the hybrid method of DMT process.