• 한국정밀공학회지
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• 제28권3호
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• pp.301-307
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• 2011

In this paper, effects of major design parameters of cold forging dies on die mechanics are quantitatively investigated with emphasis on shrink fit using a thermoelastic finite element method. A ball-stud cold forging process found in a cold forging company is selected as a test process and the effects of die insert material, magnitude of shrink fit, dimension of shrink ring, number of shrink rings, partition of die insert and clamping force on effective stress and circumferential stress are analyzed. It has shown that the number of shrink rings, magnitude of shrink fit, and Young's modulus of die insert material have strong influence on compressive circumferential stress in die insert but that the influence of the other design parameters is relatively weak.

• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.14-17
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• 2007

The slot-die coating & calcination process was adopted to fabricate the long YBCO precursor films on the buffered metal tape for the $2^{nd}$ generation coated conductors. To obtain the smooth and crack-free surface of long YBCO precursor films, the parameters of slot-die coating and the process variables of calcination step must be optimized simultaneously in reel-to-reel method. Among the parameter of slot-die coating process, the viscosities of the precursor solution was controlled from 60cP to 200cP to obtain the thicker films from on single coating. The slot-die gap, the injection rate of precursor solution, the moving speed of buffered metal tape etc. are controlled lot the full coverage and smooth surface of YBCO precursor films. The slot-die coated films are moved through the tube furnace with predetermined heating profiles in humid oxygen ambient The YBCO precursor films was identifed with $Y_2O_3,\;BaF_2$, and CuO phase by XRD and consisted of fine grains of about 20nm size observed by FE-SEM. The YBCO films show the critical current density over $MA/cm^2$ using the precursor films formed by the continuous slot-die coating & calcination process.

• Design & Manufacturing
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• 제9권3호
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• pp.41-44
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• 2015

The progressive die is processing methods that can improve the productivity for sequentially transferring while continuously producing in multiple processes. In this study was carried out the die analysis through the load analysis acting on the terminal die and sheet metal forming also the study was carried out with respect to optimized die design for the terminal die and progressive die manufacturing using the CimatronE Die Design.

• 대한기계학회논문집
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• 제8권1호
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• pp.57-64
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• 1984

Forward extrusion of sintered porous metal through conical converging die is analyzed using slab method on the basis of plasticity theory for porous metal. It is taken into consideration in the analysis that the material in the container is continuously recompressed on densified until the process reaches steady state. Extrusion pressure and distribution of relative density from the die inlet to the outlet are calculated under various process variables. The results are useful in finding initial relative density of the billet, reduction of area and cone angle of the die in order to get required final products. Experiments are done for porous copper and then compared with the computed results.

• 소성∙가공
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• 제9권3호
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• pp.284-292
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• 2000

Optimization of the process parameters is carried out for process design in sheet metal forming processes. The scheme incorporates with a rigid-plastic finite element method for the deformation analysis and response surface methodology for the optimum searching of process parameters. The algorithm developed is applied to design of the draw bead force and the die radius in deep drawing processes of rectangular cups. The present algorithm shows the capability of designing process parameters which enable the prevention of the weak part of fracture during processes.

• 한국주조공학회지
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• 제24권6호
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• pp.347-355
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• 2004

In the die casting process, the flow of liquid metal has significant influence on the quality of casting products and die life. For the optimal process design of automobile gear housing, various analyses were performed in this study by using computer simulation code, MAGMAsoft. The simulation has been focused on the molten metal behaviors during the mold filling and solidification stages for the sound casting products. Also the internal defects were predicted by application of air pressure and feeding criteria.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.316-319
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• 2008

The L-bending of inner-structure bonded sandwich sheet metal is examined by using a bending die attached to the material testing machine. The specimen is composed of top and bottom layers and a middle layer of pyramid-core structure and each layer is bonded by brazing. The variables chosen for experiments were clearance between punch and die, location of bend line on the specimen surface and clamping type of specimen during L-bending. Effects of these variables on deformation of specimen around die-corner radius were investigated. It was shown that the irregular shapes of recess are formed in the inner layer of bended parts and they greatly depend on working conditions.

• 한국광학회지
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• 제24권6호
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• pp.342-346
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• 2013

고출력 LED 패키지의 방열 특성 향상을 위하여, 다이 접합부에 실리콘 접착제와 금속 패턴의 병렬 접합 구조를 적용하여 열 유동 해석을 수행하였다. 그 결과, LED 칩에서 발생한 열은 주로 금속 패턴 구조물을 통해 기판으로 효과적으로 전달되고 있으나, 패턴 구조물의 크기에 따라 효율의 차이가 있음을 확인하였고, 그 효과를 정량화하기 위해 정규화 길이를 도입하여 칩과 금속 패턴 구조물의 면적에 따른 열 저항을 비교하였다. 정규화 길이가 길어지면 금속 패턴 구조물에 의한 열 우회 경로가 칩에 고르게 분포하여 열 저항이 감소하였으며, 그 값은 단순 병렬 열 저항 이론 값보다 다소 큰 수치로 수렴하지만, 충분한 열 저항 개선 효과를 얻을 수 있었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.86-91
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• 2002

The production part requiring multiple processes such as piecing, blanking and notching, are performed with a high production rates in progressive die. In order to prevent the dejects of process result, the optimum of strip process layout design, die design, die making, and tryout with inspection etc. are needed. According to these factors of die development process, they required theory and practice of metal working process and its phenomena, die structure, machining conditions for die making, die materials, heat treatment of die camponents, know-how and so on. In this study, we designed and analyzed die camponents also simulated the strip process layout of multiple stage drawing by DEFORM. Especially the result of tryout and its analysis become to the feature of this study.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.76-79
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• 1999

The study has been performed for the relation between die and product in forward extrusion by the experiment. Strains of the die have been given by the simple experiment using the strain gauge located at the outer surface of the die and the history of the deformation of the die and product is given by the experiment and Lame's formula. The inner pressure of the die causes the deformation of die that affects the accuracy of dimension and shape of product. The product with accurate dimension and shape can be obtained by analysing elastic deformation of the die during process. The deformation of the die during metal forming process has been usually predicted by the experience of industrial engineer or finite element analysis. But it is difficult to predict the dimension of product at unloading and ejected states. The study has given useful results for the deformation history of the die and product through the experiment and Lame's formula at forward extrusion for solid cylinder and can be applied to the die design for product with accurate dimension.