• Title, Summary, Keyword: Injection Molding

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Finite Element Analysis of Injection/Compression Molding Process (사출압축성형 공정에 대한 유한요소 해석)

  • 이호상
    • Transactions of Materials Processing
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    • v.13 no.2
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    • pp.180-187
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    • 2004
  • A computer code was developed to simulate the filling stage of the injection/compression molding process by a finite element method. The constitutive equation used here was the compressible Leonov model. The PVT relationship was assumed to follow the Tait equation. The flow-induced birefringence was related to the calculated flow stresses through the linear stress-optical law. Simulations of a disk part under different process conditions including the variation of compression stroke and compression speed were carried out to understand their effects on birefringence variation. The simulated results were also compared with those by conventional injection molding.

A study on carbon composite fabrication using injection/compression molding and insert-over molding (사출/압축 공정과 인서트 오버몰딩을 이용한 탄소복합소재 성형에 대한 연구)

  • Jeong, Eui-Chul;Yoon, Kyung-hwan;Hong, Seok-Kwan;Lee, Sang-Yong;Lee, Sung-Hee
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.14 no.4
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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.

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A Study of Injection Mold Manufacturing for Ultra-Thin Walled Plate (초박판 사출성형특성 분석을 위한 금형제작에 관한 연구)

  • Lee, Sung-Hee;Ko, Young-Bae;Lee, Jong-Won;Kim, Sung-Kyu;Yang, Jin-Suk;Heo, Young-Moo
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.2 no.5
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    • pp.11-15
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    • 2008
  • A micro-injection mold for ultra-thin-walled plate was considered in this work. The proposed mold system is for the fabrication of ultra-thin walled plastic plate with micro features by injection molding. As the injection molding of thin-walled plastic, which has the thickness under $400{\mu}m$, itself is not easy, the injection molding of the micro-features in the thin-walled structure is more complicated and difficult. To investigate the basic phenomenon of the ultra-thin walled part during the injection molding process, design of the part and mold system were performed in the present study. The injection molding and structural analysis of the suggested part and mold system were also performed. Consequently, injection molding system for ultra-thin walled plate with micro features were manufactured and presented.

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A Study on the Unified Molding of a Portable Cosmetic Chest Using Gas-Assisted Injection Molding (가스사출성형을 이용한 휴대용 화장품 보관함의 일체화 성형 연구)

  • Lee, Ho-Sang;Ryu, Yeon-Sun
    • Proceedings of the KSME Conference
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    • pp.772-777
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    • 2001
  • The gas-assisted injection molding process is often perceived to be unpredictable, because of the extreme sensitivity of the gas. Since a slight change in design or process parameters can significantly change the resulting gas penetration, few designers and molders have the level of experience with the new gas-assisted injection molding process required for the development of new parts. This paper is concerned with the unified molding for a thick cosmetic chest by using gas-assisted injection molding. CAE analysis was carried out to design the part and the gas channel without inducing sink marks. And based on the part weight measurement, the processing parameters to control gas penetration percentage were chosen through the method of design of experiments. A thick cosmetic chest was successfully produced using the gas assist technology. The sink mark issue associated with the conventional injection molded parts was resolved. Weight savings and cycle-time reduction were also achieved.

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The Effect of Filling Imbalances on the Molding Quality in the Multy-Cavity Injection Mold (다수캐비티 사출금형에서 충전 불균형이 성형 품질에 미치는 영향)

  • Han, Dong-Yeop;Jeong, Yeong-Deug
    • 한국금형공학회:학술대회논문집
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    • pp.89-94
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    • 2008
  • The injection molding process is a predominant method for producing plastic parts. In order to maximize productivity and molding quality in a injection mold, it is important that each cavity in a multi-cavity injection mold is identical. This requires that cavity dimensions should be identical and delivery system of melt to each cavity have to be the same. Despite the geometrically balanced layout in multi-cavity injection mold more than 4 cavities, it has been observed that the filling in each cavity results in imbalances. Most of cases, this phenomenon of filling imbalances have a bad effect on dimension accuracy, warpage, molding appearance and strength of molding parts. In this study, experiment were conducted to investigate the effect of filling imbalances on the molding quality(surface gloss, shrinkage, tensile strength) in the multy-cavity injection mold.

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The Effect of Filling Imbalances on the Molding Quality in the Multy-Cavity Injection Mold (다수캐비티 사출금형에서 충전 불균형이 성형 품질에 미치는 영향)

  • Han, Dong-Yeop;Jeong, Yeong-Deug
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.7 no.1
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    • pp.1-6
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    • 2013
  • The injection molding process is a predominant method for producing plastic parts. In order to maximize productivity and molding quality in a injection mold, it is important that each cavity in a multi-cavity injection mold is identical. This requires that cavity dimensions should be identical and delivery system of melt to each cavity have to be the same. Despite the geometrically balanced layout in multi-cavity injection mold more than 4 cavities, it has been observed that the filling in each cavity results in imbalances. Most of cases, this phenomenon of filling imbalances have a bad effect on dimension accuracy, warpage, molding appearance and strength of molding parts. In this study, experiment were conducted to investigate the effect of filling imbalances on the molding quality(surface gloss, shrinkage, tensile strength) in the multy-cavity injection mold.

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A study on the Injection Molding Process of the Case of Drum Type Washer using Moldflow (Moldflow를 이용한 드럼세탁기 케이스의 사출성형공정에 관한 연구)

  • Park, Chul-Woo
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.1
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    • pp.90-96
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    • 2009
  • Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. Today, injection molded parts have been increased dramatically the demand for high strength and quality applications. This report investigates that the optimum injection molding condition for minimum of shrinkage. Molding shrinkage is occurred by several reasons such as thermal shrinkage, a hardening process and compressibility. This report concentrate on shrinkage by a hardening process. As Change a holding pressure and holding time, checked deflections of X, Y, Z directions by shrinkage based on same condition. In conclusion, it was found that holding pressure is stronger and holding time is longer, the deflection by shrinkage is smaller because injection molding needs enough time for cooling and high density. The FEM Simulation CAE tool. Moldflow, is used for the analysis of injection molding process.

Optimum Injection Molding Condition Search With Process Monitoring System (공정 모니터링 시스템을 이용한 최적 사출 조건 설정)

  • Kang, J.K.;Cho, Y.K.;Chang, H.K.;Rhee, B.O.
    • Transactions of Materials Processing
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    • v.16 no.1
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    • pp.54-60
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    • 2007
  • Optimum injection molding condition for a box mold was searched by the Response Surface Analysis(RSA) with the aid of process monitoring system(PMS). Process variables on the control panel of the injection molding machine such as barrel temperatures, screw speed profile, holding pressures, etc. cannot guarantee the uniformity of the material variables directly related with the state of the product in the mold cavity. In order to make sure the state of the resin in the cavity, pressures and temperatures in the cavity, runner and nozzle were monitored in the experiment with the PMS. To accomplish the consistency of the molding process, dependent variables such as the switchover point and holding time were searched with the PMS. With a proper objective function about deflection of the box-type product, the optimum injection molding condition was obtained.

A Study on the Unified Molding for a Box Shaped Thick Part Using Gas-Assisted Injection Molding (가스사출성형을 이용한 두꺼운 박스형 제품의 일체화 성형 연구)

  • 이호상
    • Transactions of Materials Processing
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    • v.10 no.5
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    • pp.402-410
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    • 2001
  • The gas-assisted injection molding process is often perceived to be unpredictable, because of the extreme sensitivity of the gas. Since a slight change in design or process parameters can significantly change the resulting gas penetration, few designers and molders have the level of experience with the new gas-assisted injection molding process required for the development of new parts. This paper is concerned with the unified molding for a thick cosmetic chest by using gas-assisted injection molding. CAE analysis was carried out to design the part and the gas channel without inducing sink marks. And based on the part weight measurement, the processing parameters to control gas penetration percentage were chosen through the method of design of experiments. A thick cosmetic chest was successfully produced using the gas assist technology. The sink mark issue associated with the conventional injection molded parts was resolved. Weight savings and cycle-time reduction were also achieved.

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Optimizing the Injection Molding Process for Cooling Filter Using Computer Simulation and Taguchi Methods (컴퓨터 시뮬레이션과 다구치 방법을 이용한 냉각 필터 사출성형 공정의 최적화)

  • Lee, Seung-Hoon;Min, Byeong-Hyeon;Kim, Byeong-Gon
    • IE interfaces
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    • v.15 no.3
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    • pp.263-269
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    • 2002
  • The injection molding process is a one of the most efficient techniques for manufacturing plastic parts of complex shape at low cost. In injection molding, molten plastic material is injected into the mold and cooled. Selection of molding conditions greatly affects the quality of molded parts. In this case study, we attempted to optimize the injection molding condition for a cooling filter using Taguchi experimental design methodology. The injection molding experiments were carried out using the Moldflow simulation software.