• 한국정밀공학회지
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• 제12권10호
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• pp.32-39
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• 1995

The design of injection molded polymeric parts has been done empirically, since it requires profound knowledge about the moldability and causal effects on the properties of the part, which are not available to designers through current CAD systems. An interactive computer-based design system is developed in order to realize the concept of rational design for the productivity and quality of mold making. The knowledge-based CAD system is constructed by adding the knowledge -base module for mold feature synthesis and appropriate CAE programs for mold design analysis in order to provide designers, at the initial design stage, with comprehensive process knowledge for feature synthesis, performance analysis and feature-based geometric modeling. A knowledge-based CAD system is a new tool which enables the concurrent design with integrated and balanced design decisions at the initial design stage of injection molding.

• Design & Manufacturing
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• 제8권1호
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• pp.1-4
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• 2014

Large injection molds commonly have molding defects such as flashes and variation of product thickness. In this study, we conducted injection molding CAE analysis to find out the cavity pressure and structural analysis to find out mold deflection as input load conditions injection pressure obtained from injection molding analysis. As the results from CAE analysis, we found which element is the most effective on the mold deflection and we suggested a mold design to minimize the mold deflection.

• 한국정밀공학회지
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• 제10권3호
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• pp.231-238
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• 1993

Mold-marking industries currently demands to reduce the tooling costs and time in mold making and to improve the productivity and quality in injection molding process. These problems can be easily solved by the laminated injection mold which is made by laser cutting metal sheets and bonding them by the brazing. Comparing with the conventional mold making technology which mainly depends on the machining, the new thchnology enables an arvitary design of cooling circuit whithout any restrictions of geometry. Therefore, it will offer high production tata of the injection molding processes. This paper evaluates the conventional and laminated injection mold making processes with a simple molding geometry, and also the cooling efficienty of the kinds of mold with the filling and cooling analyses. The results show that the laminated injection mold process takes much shorter time in tooling and cooling, and distributes temperatures more uniformly than the conventional one.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.329-332
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• 2008

Flow imbalance among the cavities was often observed in multi-cavity mold. The flow imbalance affects on the dimensions and physical properties of melded articles. First of all, the origin of flow imbalance is geometrical imbalance of delivery system. However, even the geometry of delivery system is balanced the cavity imbalance is being developed. This comes from the temperature distribution in the cross-section of runner, which is affected by the operational conditions. In this study, experimental study of flow imbalance has been conducted for various injection speeds. This study also suggests new runner design to eliminate flow imbalance in multi-cavity injection mold. Simulation and experimental results showed suggested new designed runner could eliminate or reduce flow imbalance in multi-cavity injection mold.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1601-1604
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• 2003

This paper describes a split operation for generation of core and cavity plates of an injection mold for a pseudo-solid model of a plastic part. Here, a pseudo-solid model means a sheet model that looks like a solid model. but whose boundary is not closed. When a solid model created in a different CAD system is imported through standard data exchange format, a pseudo-solid model is created in most cases as tolerance or some other problems make sewing operation failed. As most existing mold design system based on solid modeling kernels require a complete part solid model, mold designers have to do time-consuming healing operations to convert a pseudo-solid to solid. The essential capability of mold design system is the split operation for generation of core and cavity plates. Thus. we developed a split operation for pseudo-solid part model to eliminate or reduce healing preprocessing for mold design.

• Design & Manufacturing
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• 제15권1호
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• pp.32-40
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• 2021

Mold design for in-mold coating was carried out to achieve simultaneous injection molding and two-color coating for car gas cap cover. The developed mold includes one core and three cavities which are composed of a substrate cavity and two coating cavities. To provide a sealing edge for complete seal during the second coating, the first coated material was used at the boundary between the first coating and the second one, and injection molded substrate was used at the parting line. The materials used were PC/ABS for substrate and 2-component Polyurea for coating. Through experiments, it was found that the suggested sealing edges were effective for complete seal during the second coating. In cavity pressure traces, there were three peaks caused by mold closing, coating-material injection and cleaning-piston advancement inside the mixing head. The cavity pressure increased with decreasing coating thickness.

• 한국생산제조학회지
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• 제21권6호
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• pp.1008-1012
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• 2012

Injection molds are fabricated by assembling a number of plates in which mold core and cavity components are inserted. The assembled structure causes a number of contact interfaces between each component where the heat transfer is affected by the thermal contact resistance. However, the mold assembly has been treated as a one body in numerical analyses of injection molding, which has a limitation in predicting the mold temperature distribution during the molding cycle. In this study, a numerical approach that considers the thermal contact effect is proposed to predict the heat transfer characteristics of an injection mold assembly. To find the thermal contact conductance between the mold core and plate, a number of finite element (FE) simulations were performed with the design of experiment (DOE) and statistical analysis. Thus, the heat transfer analyses using the obtained conductance values can provide more reliable results than conventional one-body simulations.

• 한국기계가공학회지
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• 제21권4호
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• pp.100-106
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• 2022

Topology optimization is applied for the optimal design of various products to ensure weight reduction and productivity improvement. Reducing the weight of the mold while maintaining its rigidity can ensure shortening of the production cycle, stabilization of the mold temperature, and reduction of mold material costs. In this study, a topology optimization technique was applied to the optimal design of the injection mold, and a topology-optimized model of the mold was obtained. First, the injection mold for the square specimens was modeled. Subsequently, a structural analysis was performed by implementing a load condition generated during the injection molding process. Topology optimization was performed based on the structural analysis results, and the models of the initial and topology-optimized designs were manufactured at 1/4 magnification using a 3D printer. Consequently, compared with the existing model, the weight of the topology-optimized model decreased by 9.8%, and the manufacturing time decreased by 7.61%.

• 한국금형공학회:학술대회논문집
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• 한국금형공학회 2008년도 하계 학술대회
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• pp.99-102
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• 2008

Large injection molds commonly have molding defects such as flashes and variation of product thickness. In this study, we conducted injection molding CAE analysis to find out the cavity pressure and structural analysis to find out mold deflection as input load conditions injection pressure obtained from injection molding analysis. As the results from CAE analysis, we found which element is the most effective on the mold deflection and we suggested a mold design to minimize the mold deflection.

• Design & Manufacturing
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• 제9권3호
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• pp.9-13
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• 2015

Plastic material has been applied to many automobile parts with the automotive lightweighting trend. In this study, a passenger air bag(PAB) housing which is produced by steel material in the present were molded using a plastics material. Before design and making of a mold for the PAB housing molding, it was carried out injection molding analysis. By analyzing the deformation results, the correction dimension for mold designing was determined. The design and manufacturing the mold applied the correction dimension were conducted. It was performed actual injection molding. The warpage value of the PAB housing was similar to the warpage of the injection molding analysis.