• 한국기계가공학회지
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• 제14권4호
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• pp.92-99
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• 2015

The deformation of injection molding is seriously affected by injection molding conditions, such as melt and mold temperature and injection and holding pressure. In these conditions, the mold temperature is controlled by flowing coolant, which can be classified by the Reynolds number in the mold-cooling channel. In this study, the deformation of the automotive side molding according to the variation of the Reynolds number in the coolant was simulated by Moldflow. In the results, as the Reynolds number was increased, the mold cooling was also increased. However, when the Reynolds number exceeded a certain range, the mold cooling was not increased further. In addition to the Moldflow verification, the mold cooling by the coolant was simulated by CFX. The CFX results confirmed that the Reynolds number significantly influenced the mold cooling. The coolant, which has a high Reynolds number value, quickly cooled the mold. However, the coolant, which has a low Reynolds number value, such as 0 points, hardly cooled the mold. In an injection molding experiment, as the Reynolds number was high, the deformation of the moldings was reduced. The declining tendency of the deformation was similar to the Moldflow results.

• Design & Manufacturing
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• 제6권2호
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• pp.12-16
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• 2012

In this study, an injection mold is made to produce polymer line post insulators. FRP (fiber reinforced plastics) is covered by silicone housing. In injection molding process, chances for offcenter are 60 percent. Given the structure of the product, offcenter occurs owing to the imbalances in positions of gates and improper -designs of cores and jigs. This study focuses on mold modifications and improvements.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.297-300
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• 2008

High pressure is involved during injection molding operation specially packing phase. Cracks in the mold are often occurred by high cavity pressure. In this study, structural analysis of mold has been performed using commercial softwares, Abaqus and Ansys, to investigate cause of crack in the injection mold. Structural analysis contains four cases: stress distribution according to the cavity pressure, stress concentration according to the boundary conditions, stress concentration for inter-locking design of mold, and stress concentration for distributed cavity pressure. Through this study it was observed that the locations of stress concentrations were coincident with locations of crack. Robust mold design is being required to withstand high cavity pressure.

• 소성∙가공
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• 제20권1호
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• pp.29-35
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• 2011

In the design of the injection molding process, various parameters including mold design parameters and molding conditions should be investigated to improve part quality. The mold temperature is one of important processing parameters that affect the flow characteristics, surface appearance, part deformation, mechanical properties, etc. Numerical analyses have been used to predict the temperature distribution of the mold under the given cooling or heating conditions. However, conventional analyses have been performed by assuming that the mold material is a single solid even though a number of plates are assembled to construct an injection mold. In the present study, a numerical approach considering the thermal contact resistance is proposed to provide more reliable prediction of the mold temperature distribution by reflecting the heat-resistance between assembled mold plates.

• Design & Manufacturing
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• 제2권2호
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• pp.43-47
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• 2008

This paper is concerned with the analysis of material flow characteristics of stepped rod forming. The analysis in this paper concentrated on the evaluation of the design parameters for deformation patterns of tube forming, load characteristics, extruded length, and die pressure. The design factors such as punch nose radius, die corner radius, friction factor, and punch face angle are involved in the simulation. The stepped rod forming is analyzed by using a commercial finite element code. This simulation makes use of stepped rod material and punch geometry on the basis of punch geometry recommended by International Cold Forging Group. As radius ratio is large, forming load was reduced but extruded length ratio was increased.

• Design & Manufacturing
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• 제6권2호
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• pp.84-89
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• 2012

In recent years, technology of press plastic working having made remarkable progress. We can say this because it facilitates mass production and have superior performances in machining speed and equivalency of quality than other processing methods. In characteristics of press plastic working, mold manufacturing according to characteristics of each product should be preceded before processing and it has a great influence on machining speed and quality of products and etc according to manufacturing method. Therefore, mold design technology is a critical technology in press plastic working. There are lots of variables in press plastic working according to worked material, mold materials, conditions of heat treatment, clearance and so on. Abrasion of mold depends on these kind of conditions and sheared surface which is crucial for quality of product also depends on them. In this study, we conduct research on abrasion loss of mold according to 8, 10 and 12% of clearance for thickness of 1.0mm of worked material out of mold design variables of the products whose worked materials are high carbon steel and carbon tool steel by a practical experiment.

• 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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• 제2권5호
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• pp.21-24
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• 2008

On this study, injection molding product of rectangular tray structure with thickness 0.25mm and aspect ratio(length/thickness) approximately 150 conducted. Technical aspects were reviewed on mold-die design and injection molding conditions. To have a thin-membraned plastic part, short-shot, shrinkage, twist, whitening and flash problems were considered and resolved. After measuring products, validity of this study and future improvement were discussed.

• Design & Manufacturing
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• 제8권1호
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• pp.14-18
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• 2014

Even though 3D press die design gains more attention everyday in Korea, there are shortages of infrastructure and proper environments for it. What is most needed is human resources development and 3D die design standardization, on which the pace of 3D die design adoption depends. This study focuses on 3D press die design process by looking into an instance in which 3D die design system had been used to sell dies to a company "S" in Japan.

• 한국산학기술학회논문지
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• 제2권2호
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• pp.101-106
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• 2001

사출성형 제품 및 금형설계를 위한 통합형 CAD시스템이 연구되었다. 현존하는 CAD시스템은 주로 기하학적 모델링 기능만을 제공하고 있으나 본 연구에서는 제품설계, 금형설계, 몰드베이스 선정, 공정설계를 통합하여 설계할 수 있도록 CAD/CAPP/CAE를 연계한 설계시스템을 구성하였다. 특징형상 기법을 비롯하여 다양한 방법론이 시스템 구성을 위해 연구되었다. 이러한 통한형 설계시스템은 동시설계를 위해 유용하게 사용될 수 있는 진전된 개념의 설계시스템이다.