• Design & Manufacturing
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• v.6 no.1
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• pp.73-78
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• 2012

The aim of this dissertation is inferring factors controlling the complex strain behavior of the material and the characteristics of the Fine-Blanking in the most narrow area at the shear zone where we are performing the Fine-Blanking. And also this is for inspecting and presenting their uses and the possibilities to make the results data based in order to utilize easily. Therefore, to analyze of shere zone's strain behaviour, the Fine-Blanking process need to be modelled defining the quadratic-nodded and axi-symmetrical elements as the problems of large deformation axi-symmetry and the non-linear contact. For the method of inputting strain-stress values of the material, the piece-wise linear technics were used, the Implicit-Finite Element method also used making balance of forces on each step by the long intervals, calculates and converges many times was done. The materials used for the analysis was the Steel SNCM220 5.5mm respectively. As the result of FEM analysis, we know that shear stress value in the beginning of punch penetration is distributed widely and done high both in the center of the late-thickness and on the both sides centering around shear strain zone as the punch penetration is increasing. Also.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.3
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• pp.217-222
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• 2008

Equal channel angular pressing (ECAP) is one of the effective methods to produce bulk-nano materials by accumulating plastic strain into the workpiece without changing its cross-sectional shape in the multi-pass processing. However, the forming load becomes higher for manufacturing large specimens using conventional solid or split dies because of friction, flash formation, and usage of dummy specimen. In the present investigation, better split die was designed to reduce the forming loads and improve the geometrical accuracy of the specimen in the multi-pass ECAP. The new die exit channel was also designed to reduce the friction effect. Experiments with AA1050 specimens with a square cross-section were carried out to examine the design goal using the proposed split dies for routes A and C up to four passes. The numerical forming simulations were used to determine the effective geometry of various die models in the present work.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.26-35
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• 2003

This study explains the effects of lubricant and surface treatment on hot forging die life. The mechanical and thermal load, and thermal softening which is happened by the high temperature of die, in hot and warm forging, cause die wear, heat checking and plastic deformation, etc. This study is fur the effects of solid lubricants and surface treatment condition for hot forging die. Because cooling effect and low friction are essential to the long life of dies, optimal surface treatment and lubricant are very important to improve die life for hot forging process. The main factors, which affect die hardness and heat transfer, are surface treatments and lubricants, which are related to thermal diffusion coefficient and heat transfer coefficient, etc. For verifying these effects, experiments are performed for hot ring compression test and heat transfer coefficient in various conditions as like different initial billet temperatures and different loads. The effects of lubricant and surface treatment for hot forging die life are explained by their thermal characteristics. The new developed technique in this study for predicting tool life can give more feasible means to improve the tool life in hot forging process.

• Design & Manufacturing
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• v.7 no.1
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• pp.60-63
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• 2013

Recently, Silicone that one of the thermo-sets is used to making optical products such as LED lenses because of excellent thermal properties. LED lenses are required to keep the precise dimensions, so they must be molded to have the minimum deformation. Thermo-sets have the expansion characteristic on the part of thermal property, it is important to optimize the cure condition so that the deformation of the part become minimum. In this study, to investigate the relationship between the shrinkage by the curing and expansion by the thermal properties of the resin, reactive injection experiment was performed by setting the variables such as mold setting temperature, cure time. As a result, it was confirmed that there was a interval while the thermal properties were transferred to more active during the cure process. It is expected to help in determining the reactive injection molding conditions of the thermo-set parts as well as LED lens in order to reduce the amount of deformation.

• Design & Manufacturing
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• v.8 no.2
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• pp.30-36
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• 2014

In this study, surface deformation patterns have been investigated by the rigid-plastic finite element method for friction factor test in solid cylinder compression process. AA1100 and AA6063 aluminum alloys, which show different work hardening characteristics respectively, have been adopted as model materials used for analysis. The main objective of this study is to provide the deformation mechanics in detail in solid cylinder compression process, especially at the die/workpiece interface that is closely related with the frictional conditions. For this reason, solid cylinder compression process has been numerically analyzed. The surface flow patterns at the contact boundary have been analyzed in terms of surface expansion, surface expansion velocity, pressure distributions exerted on the die surface along the die surface. By defining bulge factor, barreling phenomenon also have been examined with calibration curves to verify their effects on the surface flow pattern that is important for evaluating the frictional condition at the interface.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2577-2582
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• 2009

A rivet which can fasten two parts is one of an important mechanical elements. In this study, the process design of a blind revet is implemented using finite element method in order to manufacture it which can resist high vibration and has strong coherence between two parts. Considering plastic flow, ease of manufacture, high strength, material loss, and so forth, an optimal four-stage process is proposed by finite element analysis and process design rules. In addition, the finite element simulation results such as shape of the forged rivet, strain distribution and forging load are investigated for the usefulness of the forging process of the blind rivet. These results will be contributed to the forging process design and the die design of the blind rivet.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1051-1055
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• 1997

Hot forging is widely used in the manufacturing of automotive component. The mechanical, thermal load and thermal softening which is happened by the high temperature die in hot forging. Tool life of hot forging decreases considerably due to the softening of the surface layer of a tool caused by a high thermal load and long contact time between the tool and workpieces. The service life of tools in hot forging process is to a large extent limited by wear, heat crack, plastic deformation. These are one of the main factors affecting die accuracy and tool life. It is desired to predict tool life by developing life prediction method by FE-simulation. Lots of researches have been done into the life prediction of cold forming die, and the results of those researches were trustworthy, but there have been little applications of hot forming die. That is because hot forming process has many factors influencing tool life, and there was not accurate in-process data. In this research, life prediction of hot forming die by wear analysis and plastic deformation has been carried out. To predict tool life, by experiment of tempering of die, tempering curve was obtained and hardness express a function of main tempering curve.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.55-59
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• 1992

최근 신 연삭 공구인 미세한 지립의 다이아몬드 휠을 이용함으로써 고경도와 취성을 지니는 엔지 니어링 세라믹스등의 신소재및 초경재 등 난삭재류를 대상으로 경면 가공을 추구하고자 노력이 진행중이다. 이는 래핑이나 폴리싱 등의 유리 지립에 의한 경면 창성법에 비하여 가공 능률이나 가공 정도가 높고 곡면이나 홈 등의 복잡 형상부의가공에도적용할 수 있다는 잇점이 있기 때문이다. 따라서 현재 이러한 신 연삭 가공법은 지금까지 연삭 가공후에 연마 가공 공정을 부가함으로써 초정 밀 효과를 지닐 수 있었던 각종 부품들에대한 단일 최종 마무리가공 공정으로의 응용에많은 기대를 걸고 있다. 본 연구는 높은 압축 강도치, 고온경도치와 내마모성, 강성 등을 지님으로써 외부 압력에 대한 변형률이 극히 적어 금형 칫수에가까운 제품을 생산할 수 있다는 특성으로 근래그 사용도가 급증 하고 있는 초경합금 금형재를 대상으로 해그 동안 난삭재에 대한 최적 가공 조건 설정이 정립되어 있지 못했던 관계로 인하여 기존의 숙련자 경험에만 주로 의존 할 수 밖에 없었던 단순한 다이아몬드 연삭 공구의 활용추세로부터 탈피하고 Diamond wheel 및 범용 연삭 공구를 최적으로 활용함으로써 연삭 가공의 초정밀화를 달성하며후 가공을 생략할 수 있는 가공 공정을 창출 해내기위하여, 상관 관계를 연삭 저항 및 가공 표면 품위등의 측면으로분석, 평가해봄으로써 초정밀 가공 차원에서의 최적 가공 조건 설정을 위한 지침을 명확하게 규명하기 위하여 실험적으로 수행하게 된 것이다.

• Journal of Korea Foundry Society
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• v.5 no.3
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• pp.47-51
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• 1985

FMC(FULL MOLD CASTING)법(法)이란 발포 polystyrene모형을 사용하여 조형후, 주형으로부터 모형을 발형치 않은채, 용탕을 주입하여 주물을 제조하는 방법을 말한다. 합성수지 발포체를 주조용(用) 모형의 재료로써 사용하는 방법은 1956년 미국의 슈로이어(H. F. Shroyer)에 의하여 발명되었으나 이것은 실제 주조에 응용하기에는 여러 곤란한 문제가 있어, 단순히 착상에 그치고 공업적으로 적용할 수 있는 기술을 확립치는 못하였다. 그후 서독 아헨대학교수로서 당시 발포폴리스티렌을 포함하는 각종단열재 제조회사 G+H 사(社)의 A. Wittmoser에 의하여 1962년에 처음으로 공업적으로 이용되어, 현재 서독, 미국, 일본등 유럽전역에서 응용되고 있다. 당사(當社)는 1977년6월 5일 첫 가동된 이후, 동(同)그룹 사(社)인 현대자동차로부터 자동차금형 (Press Die)주조를 FMC법(法)으로 생산하여 달라는 요구를 받고, 그해 12月부터 개발시험에 착수하여 이듬해 6월(月)부터 본(本) FM주조를 적용하여왔다. 그러나 1) 폴리스티렌 모형의 주입시(時) 부(不)기화 잔유물에 의한 주물표면결함 2) 도형제 박리 현상에 의한 표면결함 3) 주입시(時) 다량의 매연발생 및 4) 조형시(時) 모형의 변형에 의한 칫수결함 등의 문제가 대두되어 품질면에서는 1982년6월(月)에 와서야 어느정도 정상궤도에 도달하여 본격적인 FM 생산을 해오고 있는 중이다. 여기서 그동안 당사가 경험한 대형주물 (자동차금형:$1{\sim}10$톤/개)에 있어서의 FM 주조법의 적용사례를 본지(本誌)를 통하여 간단히 소개하고자 한다.

• Design & Manufacturing
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• v.10 no.1
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• pp.46-50
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• 2016

Beverage industry is the largest in the domestic packaging market. Usually, beverage is packed in palstic, glass, can and paper bags. However, the cost of these packaging methods are very high and the recycling are not easy to handle. Pouch packaging method is one of the packaging method to solve the drawbacks of former beverage containers. The pouch packaging methods are difficult to control, it requires a number of processes. A vertical form-fill-seal machine which is self-developed is the capable of processing in a single apparatus. In this paper, in order to develop a pouch equipment, the structure analysis was carried out for the main unit. The stress and deformation of feed unit which removes the air inside the pouch while feeding down has been analyzed. It receives the greatest impact from the rolling part. And also, the sealing unit has been analyzed. The analysis result shows that the stress and the deformation was slight to be applicable to the actual system.