• 한국정밀공학회지
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• 제20권7호
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• pp.36-43
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• 2003

In this paper, the warm forging process sequence has been determined to manufacture the warm forged product for the precision bevel gear used as the differential gear unit of a commercial automobile. The preform shape of bevel gear influences the dimensional accuracy and stiffness of final product. So, the design parameters related preform shape such as aspect ratio and chamfer length having an influence the formability of forged product are analyzed. Then the optimal conditions of design parameters have been selected by artificial neural network (ANN). Finally, to verify the optimal preform shape, the experiments of the warm forging of the bevel gear have been executed. The proposed method can give more systematic and economically feasible means for designing preform shape in metal forming process.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.199-206
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• 1997

The inner pulley is an automobile component used as air conditioner clutch assembly. In cold forging of inner pulley, the design requirements are to keep the same height of the inner rib and outer one, and to make uniform the hardness distribution in the forged product. In industry, the design of forging processes is performed based on experience-oriented technology, that is, designers experience and expensive trial and error. Using the rigid-plastic finite element simulations. we design the optimal process conditions, which has a preforming operation. Also the final product configuration of forging has to be designed again in view of metal flow involved in the operation, derived from the finite element simulations. The forged pulley is investigated by checking the hardness distribution and it is noted that distribution has improved to be even and high enough for industrial application.

• 한국생산제조학회지
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• 제20권1호
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• pp.67-73
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• 2011

In this study, the manufacturing technology of a folding blind rivet was developed through finite element analysis(FEA). Numerical simulations of the folding blind rivet used to join two components have been performed with the finite element method for the forging process design. To minimize the process and manufacture the folding blind rivet without defects, a variety of design rules were proposed. From the results of FEA applied process design rules, an optimal six-stage process was proposed. The finite element simulation results such as shape of the forged rivet, strain distribution and forging load were investigated for the usefulness of the forging process of the blind rivet. In addition, the experiments have been implemented and their results were compared to the analytic results.

• 소성∙가공
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• 제18권8호
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• pp.589-595
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• 2009

The hot forming process of an exhaust CAM for vessel engine was designed by finite element(FE) simulation and experimental analysis. An aim of process design was to achieve the near-net shaped CAM forgings by hot forging process. Based on the compression test results of the low alloy steel, power dissipation map was generated using the the dynamic materials model(DMM). From the map, the initial heating temperature was determined as 1200oC. FE analysis was simulated to predict the formation of forging defects and deformed shape with different forging designs. Optimum process design suggested in this work was made by comparing with the CAM for vessel engine manufactured by actual forging process.

• 소성∙가공
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• 제6권4호
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• pp.329-337
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• 1997

Forging of an inner pulley for compressor clutch assembly of car air conditioner is investigated in this study. In cold forging of inner pulley, the design requirements are to keep the same height of the inner rib and the outer one, and to make uniform the hardness distribution in the forged product. Using the rigid-plastic finite element simulation. we design the optimal process conditions, which has a performing operation. Also the final product configuration of forging has to be designed again in view of the metal flow involved in the operation, derived from the finite element simulations. The forged pulley is investigated by checking the hardness distribution and it is noted that the distribution has improved to be even and high enough for industrial application.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.184-189
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• 2004

In this paper, the warm forging process sequence has been determined to manufacture the warm forged product for the precision bevel gear used as the differential gear unit of a commercial automobile. The preform shape of bevel gear influences the dimensional accuracy and stiffness of final product. The aspect ratio and chamfer length are considered as design parameters to achieve adequate metal distribution in the finish forging operation. Then the optimal conditions of design parameters have been selected by artificial neural network (ANN). Finally, to verify the optimal preform shape, the experiments of the warm forging of the bevel gear have been executed. The proposed method can give more systematic and economically feasible means for designing the preform shape in metal forming process.

• 한국정밀공학회지
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• 제17권1호
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• pp.209-215
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• 2000

Precision forging technology that can control flow velocity of workpiece have been developed to minimize the amounts of machining. To get the uniform rib length, flow velocity distribution is needed to be estimated and controlled. Computer-aided design is known for very effective to estimate the deformation behavior and design the die for controlling the flow velocity. In this study, die design to control the deformation velocity are investigated using the DEFORM-2D about rib-web shape parts. Also we can get uniform rib length by enforcing the back pressure at end section of rib. The applied load of back pressure farming is lower than that of conventional forging. These results are analysed and confirmed by the experiment.

• Journal of Advanced Marine Engineering and Technology
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• 제39권7호
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• pp.729-734
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• 2015

본 연구는 내경부에 깊은 구멍이 있는 컵형상의 대형단조품을 형단조와 자유단조 공법을 복합하여 성형하기 위한 단조공법 개발에 관한 것이다. 제안된 단조공법은 형단조를 이용하여 예비성형체를 성형하고 코깅 공법을 이용하여 후방압출 형상을 성형하는 방법이다. 유한요소해석에서 제안된 공법이 후방압출공법에 비하여 낮은 성형하중으로 더 높은 유효변형율을 나타내었다. 제안된 공법으로 시제품을 제작하여 내부품질이 양호한 제품을 적은 용량을 프레스로 성형할 수 있음을 확인하여 제안 공법의 타당성을 검증하였다.

• 소성∙가공
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• 제14권9호통권81호
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• pp.798-803
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• 2005

In this paper, the six sigma scheme together with the rigid-viscoplastic finite element method is employed to obtain the optimal metal flow lines of a hot forging according to the six sigma processes, i.e., five steps such as define, measure, analyze, improve and control. Each step is investigated in detail to meet customer's requirements through improvement of product quality. A forging simulator is used for analysis of the metal flow lines of the hot forging, manufactured by a hot press forging machine, under various conditions of major factors determined at each step. The analyzed results are examined in order to reveal the effects of major factors on the metal flow lines and the formed shapes. The effects are then used to find an optimal process and the optimal process with die is devised and tested. The comparison between the required metal flow lines and the experiments shows that the approach is effective for optimal process design in hot forging considering metal flow lines.

• 소성∙가공
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• 제13권7호
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• pp.586-593
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• 2004

A terminal pin, which is a part of high-voltage capacitors, has a plate-shaped head section with thickness of 0.8mm. The current manufacturing process, in which the head section is welded on the body part, has given wide deviations of part qualities such as geometrical accuracy, mechanical strength and electrical stability. In this study, a cold forging process sequence was designed in order to produce the terminal pin as one piece. The plate-shaped head section requires an upsetting in the lateral direction of a cylindrical billet, which is followed by a blanking process. The deformed geometry of the lateral upsetting, however, could not be predicted precisely by intuition since metal flows of an axial and a lateral direction of the cylindrical billet would occur simultaneously. Therefore, in this study, three dimensional finite element analyses were applied to the lateral upsetting process in order to determine a proper diameter and height of the cylindrical billet. Once the geometry of the initial billet was determined, intermediate forging processes were designed by applying cold forging guidelines and the designed process sequence was verified by two dimensional finite element analysis. In addition, cold forging tryouts were conducted by using a die set, which was manufactured based on the designed process and finally we found that the part qualities were improved by the proposed cold forging process.