• 한국정밀공학회지
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• 제18권2호
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• pp.177-185
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• 2001

This study shows the process design and forming analysis of permalloy shielding can that support the automobile multi-display parts to indicate the accurate information of car. This study is particularly important, since the strain and thickness of permalloy shielding can is known to affect the magnetic properties such as coercivity and permeability quite thickness of permalloy shielding can is known to affect the magnetic properties such as coercivity and permeability quite sensitively. The objective functions are strain and thickness deviation. The punch radius, die radius and blank holding force are considered as design parameters. Orthogonal array (OA) table and characteristics are applied to neural network (NN) as train data. After training, the optimal and robust condition of design parameters is selected. This study shows the correlation between the design methodology of NN and the statistical design of experiments (DOE) approach.

• 한국정밀공학회지
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• 제17권1호
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• pp.204-208
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• 2000

An approximate similarity theory has been applied to predict the forming load of non-axisymmetric forging of aluminum alloys through model material tests. The approximate similarity theory is applicable when strain rate sensitivity, geometrical size, and die velocity of model materials are different from those of real materials. Actually, the forming load of yoke, which is an automobile part made of aluminum alloys(Al-6061), is predicted by using this approximate similarity theory. Firstly, upset forging tests are have been carried out to determine the flow curves of three model materials and aluminum alloy(Al-6061), and a suitable model material is selected for model material test of Al-6061. And then hot forging tests of aluminum yokes have been performed to verify the forming load predicted from the model material, which has been selected from above upset forging tests. The forming loads of aluminum yoke forging predicted by this approximate similarity theory are in good agreement with the experimental results of Al-6061 and the results of finite element analysis using DEFORM-3D.

• 한국정밀공학회지
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• 제32권11호
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• pp.977-982
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• 2015

This study uses finite element analysis to evaluate the forming load of tool entrance angle of the cold forward extrusion molding process of helical gear; this can replace the spur gear applied to the Electronic Parking Brake (EPB) system. A cold forging process is often used in the automobile industry as well as in various industrial machines due to its high efficiency. Finite element analysis is frequently used when interpreting results of the forging process. Formality was evaluated by calculating tooth profile filling rate of helical gear. Change in required forming load was investigated when the entrance angle of forward extrusion tool die was changed from $30^{\circ}$ to $60^{\circ}$, also by finite element analysis. We suggest suitable tool entrance angles.

• Design & Manufacturing
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• 제18권1호
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• pp.39-45
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• 2024

The radiator grille has several air intakes. These holes cause the resin flows to divide and merge. As a result, weld lines occur. These weld lines and other problems appear in various forms depending on the grille pattern. To solve these problems, designers use injection molding analysis to proactively identify problems and determine optimal molding conditions. In this study, we conducted research on the effect and optimization of gates on injection molding of automobile radiator grille. The gates used in molding analysis are the side gate and the grape gate. We then compared the effects of each gate on weld line, injection pressure, clamping force, and deflection. As a result of the analysis applying the side gate, weld lines occurred in all major grilles. In contrast, in applying the grape gate, small weld lines occurred in the minor grille, but the weld line in the major grille could be prevented. The maximum injection pressure was reduced by 48.2% in applying the grape gate compared to applying the side gate. Additionally, the maximum clamping force was also reduced by 17.6%. To compare the amount of deformation, deflection values were measured at 20 identical locations. As a result, applying the grape gate showed a deformation improvement of at least 5.2% and up to 77.9%.

• Design & Manufacturing
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• 제18권1호
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• pp.46-52
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• 2024

In this study, in order to minimize the deformation of the end-plate of plastic injection products used as automobile battery parts, we compared and studied the effect on the amount of product deformation by changing the number and position of gates and the glass fiber content of the injection raw material. To compare the amount of deformation, a molding analysis program was used, and 5 points on the main flat surface of the product were selected to compare the amount of product deformation. The amount of product deformation was compared by changing the number and location of gates to 5 types, and the amount of product deformation was compared by changing the glass fiber content of the raw material to 4 levels. The effect of improving the amount of deformation of the product was confirmed by changing the glass fiber content of the gate and raw materials, and it was confirmed that the addition of glass fiber had a significant effect on the amount of deformation of the product. Compared to products that did not contain glass fiber, the amount of deformation in products containing 30% glass fiber was reduced the most, and it was confirmed that the amount was reduced by about 80 to 90%.

• Design & Manufacturing
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• 제17권3호
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• pp.21-27
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• 2023

The mold industry in Japan, an advanced country in the mold industry, is also at a point of great change. The main causes are the Ukraine crisis and the collapse of the global supply chain (parts supply chain) caused by COVID-19. In addition, the prices of overseas products are rising sharply due to rapid exchange rate fluctuations (decrease in the value of the yen). Until now, Japan's monotsukuri industry has been actively pursuing overseas expansion, riding the trend of globalization. However, the trend began to rapidly reverse, and now the monotsukuri industry that had expanded overseas is showing a tendency to return to Japan. Another factor of change is the change in the automobile industry, which is the most demanded product in the mold industry. As the automobile industry evolves from gasoline cars to electric cars, the number of parts that make up a car will drastically decrease. This trend is expected to increase the demand for small-scale production of a variety of products in the mold industry, and furthermore, it is expected that short delivery times will be required in parts development. As in Korea, the production population working in the mold industry is rapidly decreasing in Japan as well. Even if you add up the total population working in manufacturing in Japan, it only accounts for about 15%. Even in Japan, it is judged that it will be difficult to sustain the monotsukuri industry with this small production population. Therefore, since improvement in production efficiency cannot be expected with the same manual dexterity as before, the mold industry is also demanding the development of mold technology at a different level than before to increase productivity. In this paper, I would like to introduce new Japanese mold technology collected through attending the Intermold exhibition. This is an example of applying a dedicated pin (Gastos) to a mold to prevent an increase in internal pressure during plastic injection molding, and a deep drawing press molding technology with an inherent hydraulic function.

• 대한기계학회논문집
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• 제15권1호
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• pp.127-138
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• 1991

본 연구에서는 인벌류트 치형을 갖는 헬리컬 기어압출에 있어서 실제 치형형 상인 인벌류트 곡선을 다이의 형상으로 하여 비대칭 형상의 다이를 몇 개의 대칭영역 으로 분할하고 각 영역에 대하여 각각의 동적가용 속도장을 구한 후 전체 형상으로 확 장시켜 상계해석 하였다. 해석결과의 계산은 위의 동적가용속도장으로 헬리컬 또는 평기어 압출을 해석하는 수치해석 프로그램을 개발하여 수행하였다. 상계해석에서는 기초원 이하의 필렛부분과 이 뿌리 틈새등은 그 형상이 매우 복잡하므로 해석의 간략 화를 위하여 기초원까지만 변형되는 것으로 가정하였으나 실제의 기어압출실험에서는 기어의 모든 조건이 고려되었다. 압출실험은 전기동으로 전극봉을 제조하고, 전극설 계시에 금형과 소재의 탄성변형량, 방전가공시의 과방전량 그리고 래핑 가공여유등을 고려하여 설계한 후 호빙 및 셰이빙가공하여 실제 제조하려는 기어와 유사하게 기어전 극을 제조한 후, 이를 금현본체와 조립하여 3축제어 방전가공기로 금형을 제작하였다.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.86-92
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• 2008

Recently, the use of tubes in the manufacturing of the automobile parts has increased and therefore many automotive manufactures have tried to use hydro-forming technology. The hydro-forming technology may cause many advantages to automotive applications in terms of better structural integrity of the parts, lower cost from fewer part count, material saving, weight reduction, lower spring-back, improved strength and durability and design flexibility. In this study, the whole process of front engine cradle (or front sub-frame) parts development by tube hydro-forming using steel material having tensile strength of 440MPa grade is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Design) to confirm hydro-formability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape on automotive sub-frame by hydro-forming process were carefully investigated. Overall possibility of hydro-formable sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending, preforming and hydro-forming. At the die design stage, all the components of prototyping tools are designed and interference with press is examined from the point of geometry and thinning.

• 한국산학기술학회논문지
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• 제17권11호
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• pp.610-615
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• 2016

자동차의 부속 장비들은 용도에 따라 네비게이션, 전방 및 후방카메라, 스포일러, 선 바이저 등 다양한 것들이 채택되어 사용되고 있다. 이 중에서 선 바이저는 햇빛을 차단시켜 줌으로써 운전자의 시야 확보를 통해 안전운전을 돕는 역할을 한다. 이런 장점으로 많은 차량에 채택되어 사용되고 있는 추세이다. 그러나 대형의 플라스틱 제품들은 사출성형을 통해 생산하기까지는 웰드 라인, 충전부족, 플로우 마크, 미성형 및 변형 등 여러 가지 문제로 인한 어려움이 따른다. 본 연구는 차량용 대형 선바이저에 관한 것으로써 대형 제품을 사출 성형하는 데 발생될 수 있는 문제점을 먼저 파악하기 위해 선(先)행된 결과를 토대로 CAE 시뮬레이션을 수행하였다. 연구를 수행한 결과 첫째, 용융수지가 완전 충전되기까지 유동의 흐름을 파악할 수 있었다. 둘째, 유동선단부의 온도 편차가 $10^{\circ}C$정도로 매우 안정적임을 확인 할 수 있었다. 셋째, 성형품의 콜드 러너 취출(取出) 가능시간(약 70sec)을 구하였다. 넷째, 사출압력 및 형 체결력을 예측하여 사출 성형기의 능력을 구할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.437-438
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• 2006

Generally, the vertical roll process is used to achieve extensive width reduction in hot strip mill. However, it is difficult to avoid the defects such as dog-bone and seam-defect. The sizing press has been developed in response to the defects mentioned above. Especially, this study is carried out to investigate the deformation of slab by two-step sizing press. The deformation behavior in the width sizing process is more favorable than that in conventional vertical rolling edger. The objective of this study is to determine the optimal anvil shape parameters in the sizing press with two-step die from the viewpoint of edge-seam length. In general, the edge-seam defect occurs parallel to the rolling direction at both edges in horizontal rolling process after sizing press. The optimal combination of the parameters is determined by FE-simulation and Artificial Neural Network (ANN). The slab deformation in sizing press with convex anvil is analyzed by FE-simulation. The most suitable profile of the anvil is also discussed fur the improvement of trimming loss because of the side seam defect by FE-simulation and ANN.