• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.118-121
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• 2004

Manufacturing process for milli components has recently gained researcher's focus with the increasing tendency toward highly integrated and micro-scaled parts for electronic devices. The milli-components cannot be formed by the conventional manufacturing process since the parts require higher dimensional accuracy than the conventional ones. In order to enhance the forming accuracy and productivity, various forming procedures proposed and studied by many researchers. In this paper, forming analysis of milli-components has been studied with a new micro-former. In modeling of progressive dies, multi-stage forming sequence has been analyzed with finite element analysis by LS-DYNA3D. The analysis proposes the sequential die and part shapes with the corresponding punch force and dimensional accuracy. The analysis also considers the effect of elastic dies on the dimensional accuracy of the formed parts. The analysis result demonstrates that the elastic analysis in the milli-forming process is indispensable fur accurate forming analysis. The analysis procedure in the paper will provide good information in design of a new micro-former and milli-component.

• Transactions of Materials Processing
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• v.13 no.5
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• pp.429-434
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• 2004

Manufacturing process for milli components has recently gained researcher's focus with the increasing tendency toward highly integrated and micro-scaled parts for electronic devices. The milli-components need more precise manufacturing process than the conventional manufacturing process since the parts require higher dimensional accuracy than the conventional ones. In order to enhance the forming accuracy and productivity, various forming procedures proposed and studied by many researchers. In this paper, forming analysis of milli-components has been studied with a new micro-former. In modeling of progressive dies, multi-stage forming sequence has been analyzed with finite element analysis by LS-DYNA3D. The analysis proposes the sequential die and part shapes with the corresponding punch force and dimensional accuracy. The analysis also considers the effect of elastic dies on the dimensional accuracy of the formed parts. The analysis result demonstrates that the elastic analysis in the milli-forming process is indispensable for accurate forming analysis. The analysis procedure in the paper will provide good information in design of a new micro-former and milli-component

• Design & Manufacturing
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• v.15 no.3
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• pp.45-49
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• 2021

In this study, during the injection molding process, a device was manufactured and evaluated that calculates a cooling time by measuring a vibration signal generated from a mold using an acceleration. The last two parts, one of which has a large magnitude change in the measured vibration signal of a mold, were divided into a cooling start section (paking end section) and a mold opening section, and the time difference at the relevant points was calculated as the cooling time. The cooling time was monitored on a 5-inch light guide plate mold by applying the method. The manufactured device was attached to a fixed base of mold to measure the cooling time, and data was obtained remotely using Bluetooth technology. Then, the measured cooling time was compared with the cooling time set in the injection molding machine to evaluate the accuracy. As a result of the experiment, the cooling times measured by the devices were 15.675±0.024 sec, 20.637±0.014 sec and 25.623±0.079 sec of each conditions. Also, the measurement results were shown with errors of 0.655±0.044 sec, 0.637±0.014 sec, and 0.662±0.013 sec, respectively.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.286-293
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• 2004

Recently, hot processing using the heat source like laser machining and RFS was developed and spreaded gradually. In order to generate tool-path for the proper hot tool, a new tool-path linking algorithm is needed because tool-path linking algorithm for machining can't be applied. In this paper, zigzag tool-path liking algorithm was proposed to generate tool-path automatically for RFS. The algorithm is composed of three steps: 1) Generating valid tool-path element, 2) Storing tool-path elements and creating sub-groups, 3) linking sub-groups. Using the proposed algorithm, CAD/CAM software for the tool-path generation of hot tool was developed. The proposed algorithm was applied and verified for Venus's face and die of cellular phone case.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.592-597
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• 2001

An automobile lower arm has been fabricated in a prototype form by hydroforming with the aids of numerical analysis and experiments. For the numerical process design, a program called HydroFORM-3D developed here on the basis of a rigid-plastic model, has been applied to the lower arm hydroforming. The friction calculation between die and workpiece has been dealt carefully by introducing a new scheme in three-dimensional surface integration. To accomplish successful hydroforming process design, thorough investigation on proper combination of process parameters such as internal hydraulic pressure, axial feeding, and tool geometry has been performed. Results obtained from numerical simulation for a lower arm in hydroforming process are compared with a series of experiments. The comparison shows that the numerical analysis successfully provides the manufacturing information on the lower arm hydroforming, and it predicts the geometrical deformation and the thinning.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.85-90
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• 1997

The study presents a computer-aided analysis and its design for the forming process of .OMEGA. -type bellows tubes. Finite element analysis was carried out to perform the process simulation. Bsed on the analytic results of various conditions, the forming conditions used for angled U-type bellows tubes were determined. The 3-D modeling was constructed by I-DEAS and the process simulation was constructed by PAM- STAMP. It is concluded that the difference of height between die and bellows during the forming process causes a non-uniform shape of the bellows and also influences .OMEGA. -shape. These results can be utilized for the process design.

• Design & Manufacturing
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• v.17 no.3
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• pp.55-60
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• 2023

The fiber-reinforced plastics and cellular injection molding process can be used to efficiently reduce the weight of battery housing components of mild hybrid electronic vehicles(MHEV) made of metal. However, the fiber orientation of fiber-reinforced plastics and the growth of foaming cells are intertwined during the injection molding process, so it is difficult to predict the mechanical properties of products in the design process. Therefore, it is necessary to evaluate the mechanical properties of the materials prior to the efficient stiffness design of the target product. In this study, a study was conducted to evaluated the mechanical properties of fiber reinforced cellular injection-molded specimens. Two types of fiber-reinforced plastics that can be used in the target product were evaluated for changes in tensile properties of cellular injection-molded specimens depending on the foaming ratio and position from the injection gate. The PP and PA66 specimens showed a decrease of tensile modulus and strength of approximately 30% and 17% depending on the foaming ratio, respectively. Also, the tensile strength decreased approximately 26% and 17% depending on the position from the injection gate, respectively. As a result, it was confirmed that the PP specimens have a significantly mechanical property degradation compared to the PA66 specimens depending on the foaming ratio and position.

• CDE review
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• v.8 no.2
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• pp.47-52
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• 2002

레이저를 이용한 직접금속성형기술(영문명 : DMT: Direct Metal Tooling)은 고 부가가치의 기능성 소재(금속, 합금, 세라믹 등)의 미세한 분말을 원하는 3차원 공간상에 주사함과 동시에 이를 레이저로 직접, 순간 용착시키며 이것이 공간상에서 축적되가면서 미리 정해진 3차원 파트형상이 자동적으로 빌드업 되도록 하는 고도의 정밀제어 기술을 요하는 신기술이다. 이는 컴퓨터에 저장된 3차원 디지털 형상정보(digital data of 3D subjects)만 갖고 있으면 이로부터 그에 해당하는 금속파트형상을 적절히 소재분말을 이용하여 곧바로 실물로 재현하여 얻을 수 있게 됨을 의미하며 이로서 기존에 절삭기계를 이용한 가공 공법보다 손쉽고 빠르면서도 반면 기계적 성질은 종전기술보다 월등히 우수한 B차원 금속 파트나 금형 형상을 소재의 낭비가 전혀 없는 환경 친화적인 방법으로 제작할 수 있는, 소위 밀레니엄시대를 대표하는 최첨단 미래형 기술의 구현이다.

• Korean Journal of Computational Design and Engineering
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• v.5 no.3
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• pp.255-262
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• 2000

A computer-aided process planning (CAPP) system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has not been reported yet. Therefore, this study investigates process sequence design in deep drawing process and constructs an expert system of process planning for non-axisymmetric motor frame products with elliptical shape. The system developed consists of four modules. The first one is recognition of shape module to recognize the products. The second one is a 3-D modeling module to calculate surface area for non-axisymmetric products. The third one is a blank design module that creates an oval-shaped blank with the identical surface area. The forth one is a process planning module based on production rules that play the best important role in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers. The constructed system using AutoLISP language under the AutoCAD environment is baled on the knowledge base system which is involved a lot of expert's technology. Results of this system will be provide effective aids to the designer and engineer in this field.

• Korean Journal of Computational Design and Engineering
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• v.7 no.1
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• pp.9-17
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• 2002

The study is insufficient on process planning of the elliptical deep drawing product. Thus, in this present study, the expert system for elliptical deep drawing products was constructed by using process sequence design. The expert system was developed to be based on the general concept of each entity. The system was developed in this work consists of sixth modules. The first one is a shape recognition module to recognize non-axisymmetric products and to generate Entity_list. The second one is three dimensional (3-D) modeling module to calculate the surface area for non-axisymmetric products. The third one is a blank design module to create suggested blanks of three shapes with the identical surface area. The fourth one is shape design module based on the production rules that play the most important role in an expert system for manufacturing. The production rules are generated and upgraded by inter- viewing field engineers, plastic theory and experiments. The fifth and sixth ones are a graphic module to visualize results of the expert system and a post module to rise user's convenience, respectively. According to constructed the expert system for process sequence design, it was possible to reduce the lead time.