• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.85-88
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• 2001

Deep drawing process, one of sheet metal forming methods, is used widely. Circular or square shape blanks are currently studied mainly. Especially, circular blank for coating case of chip condenser remains bridges when it is made out of aluminum coil. The bridge reduces Material-withdrawal-rate of aluminum coil to $60\%$. This paper proposes a no-bridge blank instead of circular blank. To get the different values of two cases, comparison circular blank with no-bridge blank is accomplished in the point of thickness strain in the vicinity of flange. In order to find optimal condition in new proposed blank, several process variables - those are blank holder shape, die shape radii, punch shape radii and blank holding force - are changed.

• Transactions of Materials Processing
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• v.3 no.1
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• pp.38-50
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• 1994

Fundamental deformation mechanism and plastic behavior of AISI304 austenitic stainless steel were investigated to evaluate press formability. Local and uniform deformation capacity of AISI304 steel were compared to those of ferritic AISI430 steel and Al killed low carbon steel. Nine kinds of austenitic stainless steels having different austenite stabilities were made in laboratory scale to examine the transformation behavior in various deformation mode and variation of mechanical properties. Deformation path and strain distributions along edge corner of commercial sink die were illustrated and effect of austenite stability on press forming of sink die was clarified with experiments using square cup drawing tools.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1992.03a
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• pp.27-46
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• 1992

In this study a new simplified three-dimensional numerical method and the associated computer program have been developed to simulate the non-axisymmetric extrusion processes. The two-dimensional rigid-plastic finite element method under the generalized plane-strain condition, is combined with the slab method. To define the die geometry for non-axisymmetric extrusion, area mapping technique was used. Streamlined die surface was used to miniminze the total extrusion pressure. Extrusion of square, hexagonal and "T" section from round billet have been simulated and experimented with a model material. The computed results were in good agreement with the experiments in cross-sectional grid distortion. Computational results will be valuable for designing tool geometries and corresponding processes.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.05a
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• pp.56-59
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• 1999

In the present study, in order to investigate the effect of the corner filling in the drawing of the rectangular rod from a round bar, the drawing of the square rod from a round bar has been simulated by using rigid-plastic finite element method and artificial neural network has been introduced to reduce the number of simulation. The experimental investigation has been also implemented to verify the efficiency of the application of results of present and previous study. According to the results of present and pervious study, the combination of semi-die angle gives a great effect on the corner filling in case of the irregular shaped drawing process, but, in case of the regular shaped drawing process, the main process variable on the corner filling is reduction in area.

• Design & Manufacturing
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• v.9 no.3
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• pp.1-8
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• 2015

This study presents the preform injection molding and the blow molding of the injection stretch-blow molding process for PET bottles. The numerical analysis of the injection molding and the blow molding of a preform is considered in this paper using CAE with a view to minimize the warpage and the thickness. In order to determine the design parameters and processing conditions in injection/blow molding, it is very important to establish the numerical model with physical phenomenon. In this study, we appropriately predicted the warpage, deformation and thickness distribution along the product walls.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.277-280
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• 2005

A shape optimization is applied to achieve a design objective in three-dimensional forging processes. In multi-stage forging processes, among the important design aspects, the die shape fur preforming is regarded as the design variable since it influences the forged part relatively higher than the others. The rigid-plastic finite element method and the sensitivity method are employed and formulated to solve a formulated optimization problem. An approximation scheme is also used for the direction search during the optimization. The upset forging of a square box is selected as a test example in order to demonstrate and verify the optimization process of this study. After the optimization, the optimized shape of the die yields a finial product of desire shape.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.2
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• pp.27-39
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• 1992

3 Dimensional measurement system using camera and laser slit-ray is studied. Precise calibration technique in this system is suggested. Calibration is accomplished with calibration die, calibration block and robot. For obtaining calibration parameters, the equations are solved using least square error method from a great many calibration points to reduce measuring error. Continuous measurement is possible for the object which is larger than one frame of camera. The efficiency and usability are proved by applying to the tire profile measuring system which measures tire profile using robot and this system.

• Transactions of Materials Processing
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• v.12 no.3
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• pp.236-243
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• 2003

Maintaining the required dimensional accuracy after springback becomes the main concern of sheet-forming die designers when formability is secured through beforehand tryouts. As a part to build guidelines for springback control in automobile frame forming, experiments are carried out to show the effects of process parameters, such as holding force, blank size, and lubrication, on corner angles of channels formed by U-bending or by square-cup drawing and trimming. The results predicted by a commercial FE package were compared with the experiment and the current limitations on springback evaluation were closely discussed.

• Transactions of Materials Processing
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• v.9 no.5
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• pp.526-532
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• 2000

Springback simulation is receiving increasing attention throughout the automotive industry and the academic world. The knowledge of the real springback of stamped parts can help the stamping technicians to modify the process parameters or die geometry in order to reduce the shape defect. This paper presents the results of springback simulation after aluminium square cup deep drawing and trimming simulation, and results of springback optimization using response surface method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.90-93
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• 2002

Assuring required dimensional tolerance after spingback becomes the main concern of sheet-forming die designers when formability is secured through previous tryout. As a part to build a guideline to control springback in automobile frame forming, experiments are carried out to show the effects of process parameters, such as holding force, blank size, and lubrication, on corner angles of channels formed by U-bending or by square-cup drawing and trimming. The results are resented in the viewpoint of evaluating parameters.