• Title, Summary, Keyword: 사출성형 해석

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CAE Simulation Study an Filling Imbalance in Multi-Cavity Injection Molding (다수 캐비티 사출성형에서 충전 불균형 현상에 관한 시뮬레이션)

  • Jeon, Kang-Il;Kim, Dong-Hak
    • Proceedings of the KAIS Fall Conference
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    • pp.678-681
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    • 2009
  • 사출성형은 열가소성수지의 가공법으로써 정밀도나 고품질의 제품을 효과적으로 생산하는데 널리 이용되며 플라스틱은 현재 광범위하게 사용되고 있는 공업재료 중의 하나이다. 과거에는 플라스틱을 일회용품 및 외장재로 사용하였다. 그러나 산업기술이 발전하며 플라스틱은 금속을 대체 할 수 있는 재료로서 사용할 수 있다는 인식의 변화로 점차 기계요소용 재료로 사용되고 있으며 기계요소용 재료로 사용됨에 따라 플라스틱 제품이 정밀한 부품으로 사용되기 위해서는 금형의 가공뿐만 아니라 사출성형 시 용융수지가 금형의 각 캐비티에 균형적으로 충전되는것이 요구된다. 이러한 요구조건을 만족하기 위해서는 각 캐비티의 가공치수는 매우 높은 정밀도를 유지해야 하며, 각 캐비티에서의 충전과 냉각도 동일한 상태를 유지해야 한다. 충전 불균형은 성형품의 품질에 큰 저해 요인으로서 플라스틱 제품의 치수성, 밀도, 외관품질, 강도 등에 불균일한 결과를 가져오는 요인으로 지적되고 있다. 실제로 충전 불균형은 충전 단계에서 런너 내에서 발생하는 불균일한 전단분포에 기인하여 발생되므로 점도변화에 영향을 주는 수지의 물성, 런너의 배열과 같은 외부 요인과 사출압력, 사출속도, 수지온도, 금형온도와 같은 성형공정 조건에 의한 요인에 의한 충전 불균형의 양상이 달라지게 된다. 본 연구는 다수 캐비티 금형에서 충전 불균형 현상에 대한 원인을 검토하고 실제로 사출성형을 실시하기 전 사출성형해석 소프트웨어를 이용하여 시뮬레이션을 하여 다수 캐비티에 대한 충전 패턴을 미리 예측하여 보았다.

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Determined Car Door Latch Injection Molding Process Conditions through the Finite Elements Analysis (유한요소 해석을 통한 차량용 도어 래치 사출성형 공정조건 결정)

  • Lee, Jung-Hyun;Lee, Seon-Bong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.10
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    • pp.499-508
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    • 2016
  • Injection molding is a method for manufacturing many products, wherein a plasticized resin is injected into a mold at high pressure and hardened. According to the method, the product can be manufactured into various forms, and the mass production of up to tens of thousands of products is possible. The purpose of this study was to determine the process conditions for manufacturing a door latch for automobiles, through an analysis of the injection molding method. To calculate an appropriate injection flow for injection molding, a primary analysis for comparing the injection time, pressure, flow pattern, consolidation range, shear stress, shear rate, and weld line, as well as a secondary analysis for determining the conditions for stabilizing the molding temperature, holding pressure, and cooling process, were conducted. The characteristics of injection molding, and their influence on the product quality are discussed. No weld line and pores were observed on the products that had been manufactured based on the process conditions determined above. In addition, there were no flaws regarding the deformation compared to the prototype. Therefore, the manufacture of a product under the conditions determined in this study can reduce the defect rate compared to the existing production, and the process is also more competitive due to reduced production time.

A study on structure analysis system for short fiber reinforced plastics (단섬유강화 플라스틱 복합재료 구조해석 기법연구)

  • Youn, Jee-Young;Kim, Sang-Woo;Park, Bong-Hyun;Lee, Seong-Hoon;Kwon, Tai-Hun;Kim, Ki-Tae
    • Composites Research
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    • v.24 no.4
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    • pp.41-47
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    • 2011
  • This paper deals with anisotropic property and structural analysis for short fiber reinforced plastic composites manufactured by the injection molding process. The common approach for modeling this type of material is the consideration of the material as homogenous and isotropic. However, the common isotropy approach often results in unexpected failure. To overcome this, new structure analysis methodology was developed in order to consider fiber orientation effect using injection mold flow analysis and Halpin-Tsai equations for unidirectional composites and taking an orientation average. The numerical predictions are compared to experimental data for tensile specimen. The predicted mechanical properties agree well with experimental data for fiber orientation and weld line effect. The analysis system was also applied to an automobile part. The proposed anisotropic model predicted different mechanical properties by position of the part and different mechanical performance of the part was changed according to injection gate position.

Numerical study on the effect of the PET bottle thickness difference for blow molding process conditions (블로우 성형 공정 변수가 PET 용기의 두께 편차에 미치는 영향에 관한 수치해석 연구)

  • Kim, Jeong-soon;Kim, Jong-duck
    • 대한공업교육학회지
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    • v.34 no.2
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    • pp.321-330
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    • 2009
  • This study presents the blow molding of injection stretch-blow molding process for PET bottle. The numerical analysis of the blow molding of PET bottle is considered in this paper using CAE with a view to minimize the thickness difference. In order to determine the design parameters and processing conditions in blow molding, it is very important to establish the numerical model with physical phenomenon. In this study, a shell model with thickness has been introduced for the purpose and blow simulations with 3-type blow process condition are carried out. The simulations resulted in the thickness distribution in good agreement with the physical phenomenon. Also, from the result of numerical analysis, we appropriately predicted the thickness distribution along the PET bottle wall and Using the result of numerical analysis we apply the preform design and blow molding process condition for optimization.

Numerical Analysis of Mold Deformation Including Plastic Melt Flow During Injection Molding (플라스틱 유동을 고려한 사출성형 충전공정 중 금형의 변형 해석)

  • Jung, Joon Tae;Lee, Bong-Kee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.7
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    • pp.719-725
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    • 2014
  • In the present study, a numerical analysis of an injection molding process was conducted for predicting the mold deformation considering non-Newtonian flow, heat transfer, and structural behavior. The accurate prediction of mold deformation during the filling stage is important to successfully design and manufacture a precision injection mold. While the local mold deformation can be caused by various factors, a pressure induced by the polymer melt is considered to be one of the most significant ones. In this regard, the numerical simulation considering both the melt filling and the mold deformation was carried out. A mold core for a 2D axisymmetric center-gated disk was used for the demonstration of the present study. The flow behavior inside the mold cavity and temperature distribution were analyzed along with the core displacement. Also, a Taguchi method was employed to investigate the influence of the relevant parameters including flow velocity, mold core temperature, and melt temperature.

Optimization of Gate Location Using Computer-Aided Injection Molding Analysis (사출성형 해석을 이용한 게이트 위치 최적화)

  • Moon, Jong-Sin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.10
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    • pp.5968-5973
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    • 2014
  • The gate location in injection molding has a significant influence on the quality and productivity. Therefore, injection molding CAE is used to determine the gate location. With increasing injection molding CAE and the adoption of a 3D mesh, which takes more computation time for analysis, gate location optimization in the shortest time and least resources is the most challenging issue. In this paper, we propose a methodology for optimization based on the flow length to consider the flow balance and weld line. In addition, the flow balance is obtained in the disc-type plate while the weld lines exit the slit-holes to avoid a stress concentration.

Deformation Analysis Considering Thermal Expansion of Injection Mold (사출금형의 열팽창을 고려한 변형 분석)

  • Kim, Jun Hyung;Yi, Dae-Eun;Jang, Jeong Hui;Lee, Min Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.9
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    • pp.893-899
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    • 2015
  • In the design of injection molds, the temperature distribution and deformation of the mold is one of the most important parameters that affect the flow characteristics, flash generation, and surface appearance, etc. Plastic injection analyses have been carried out to predict the temperature distribution of the mold and the pressure distribution on the cavity surface. As the input loads, we transfer the temperature and pressure results to the structural analysis. We compare the structural analysis results with the thermal expansion effect using the actual flash and step size of a smartphone cover part. To reduce the flash problem, we proposed a new mold design, and verified the results by performing simulations.

A study on the runner system for filling balance in multi-cavity injection molds (다수 캐비티 사출금형에서의 균형 충전을 위한 러너 시스템 연구)

  • Jeon, Kang-Il;Noh, Seung-Kyu;Kim, Dong-Hak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.4
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    • pp.1581-1588
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    • 2011
  • In this study, flow characteristics in a multi-cavity injection molding process were investigated. One of main problems occurred in the multi-cavity molding is a flow imbalance among cavities since it affects physical properties and quality of products. Charge imbalance is caused by the uneven shear stress. Therefore, changes in viscosity affect the physical properties of resin and injection conditions differ in the filling imbalance phenomenon. Through, this study focus on experimental studies of flow imbalance for PC and PP resin occurring in a balanced delivery system. Experimental results were compared with CAE results. By experimental and CAE analysis, main cause for the flow imbalance is temperature distribution in cross section of runner. New runner system with a simple change of runner shape was suggested to avoid the flow imbalance. A series of simulation to confirm feasibility of Volume Runner's effects was conducted using injection molding CAE.

The Prediction of Phase Morphology of Injection Molded Polymer Blends (사출성형된 고분자 블렌드의 형태학적 상구조 예측)

  • Son, Young-Gon
    • Elastomers and Composites
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    • v.39 no.3
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    • pp.193-208
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    • 2004
  • Morphology of injection molded polymer blend was investigated by experimental and theoretical approach. In experiments, the effects of injection speed and injection temperature on the morphology of injection molded MPPO/Nylon 6 blend were investigated. The morphology distribution across the part thickness was clearly observed in injection molded blend. We could observe several distinct regions across the thickness of molded part: skin layer, subskin layer and core region. The skin layer where the dispersed phase is fine and highly deformed to the flow direction is observed to be located near the part surface. The subskin layer located at inner region of the skin layer also observed. In the subskin layer, the dispersed phase is coarser than that of skin layer and deforms to the flow direction. Based on the experimental results, the calculation scheme to predict the morphology of injection molded polymer blend was suggested. The morphology of injection molded polymer blend could be predicted in corporation with the result of flow analysis obtained from commercial software for injection molding process and the theory of drop behavior under the flow. The suggested calculation scheme could predict the effect of injection conditions on the morphology of injection molded parts.