• Journal of the Korean Society for Precision Engineering
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• v.5 no.3
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• pp.31-42
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• 1988

This paper describes a computer aided process planning system called "Deep-Drawing", "Deep-Drawing" is designed for the drawing sequence of cylindrical and rectangular cups with or without taper and flange. The computer program has written in BASIC language with personal computer. Design Rules for process planning are formulated from process limitation, plasticity theory and experimental results including the know-how of many manufacturing factories. "Deep-Drawing" Capabilities include the analysis of drawing sequence by the determination of optimal drawing ratio, the determination of intermediate shape, dimensions, punch and die radius etc., the calculation of drawing loads and blank holder force to perform each drawing step, and the graphic outputs for the operation sheet.tputs for the operation sheet.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.1
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• pp.26-32
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• 2001

An ecpert system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has not been reported yet. This study construsctus and expert system for non-axisymmetric motor frame which shape is classified into ellipse in deep draqing process and investigates process sequence design with elliptical shape. The developed system consists of four modules. The first is recognition of calculate surface area for non-axisymmetric products. The third is blank design module the creates an oval-shaped blank with the same surface area. The fourth is a processplanning module based on production rules that play the best important roles in an expert system for manufacturing .The production rules are generated and upgraded by interviewing field engineers. Especially, drawing coefficient, punch and die radii for elliptical shape products are considered as main design parameters. The constructed system for elliptical deep drawing product would be very useful to reduce lead time and improve accuracy for products.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.236-239
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• 2009

Cowl cross bar, a component of automotive cockpit module, has been manufactured by using welding processes of several tube parts with different diameters. However, in order to reduce costs and increase the quality, it is required to develop a new production method to manufacture the cowl cross bar as one-piece In this study, therefore, eliminating the welding process, tube drawing process which is one of metal forming processes was designed by using combined drawing technique. In addition, the selectable range of area reduction ratio was defined as a design guideline and the designed process sequence was verified by finite element analysis.

• Transactions of Materials Processing
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• v.7 no.6
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• pp.562-569
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• 1998

The limit drawing ratio (LDR) is a major process parameter in the process design of deep drawing. If the actual drawing ratio is greater than the LDR for a particular stage then an intermediate stage has to b added the process sequence to avoid failure during the drawing operation and the optimal process design considering for the first-drawing and redrawing by using finite element method combined with ductile fracture criterion. From the results of finrte element analysis the optimal value of drawing ratio is obtained which contributes to the more uniform distribution of thickess and the smaller values of the ductile fracture infinal cup.

• Transactions of Materials Processing
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• v.4 no.1
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• pp.28-38
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• 1995

An integrated process planning system can determine desirable operation sequences even if they have little experience in the design of multistage cold forging process. This system is composed of seven major modules such as input module, pre-design module, formability check module, forming sequence design module, forming analysis module, FEM verification module, and output module which are used independently or in all. The forming sequence for the part can be determined by means of primitive geometries such as cylinder, cone, convex, and concave. By utilizing this geometrical characteristics(diameter, height, and radius), the part geometry is expressed by a list of the primitive geometries. Accordingly, the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the dimensional tolerances and the proper sequence of operations for parts, is generated under the environment of AutoCAD. Several forming sequences generated by the planning system can be checked by the forming analysis module. The acceptable forming sequences can be verified further, using FE simulation.

• Transactions of Materials Processing
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• v.18 no.7
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• pp.538-543
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• 2009

The cowl cross bar of an automobile is a frame component that is installed inside the cockpit module to provide a guide surface, to which functional components for electricity and air condition are attached. In the recent years, the geometries of cowl cross bars are getting more complex in order to meet the demands of a wide variety of embedded functional components and the reduced weight of frame parts with enhanced mechanical and noise/vibration characteristics. There for, welding processes between tubes with different diameters are widely conducted while the welded parts are experiencing various problems such as undermined appearance, low production efficiency and poor mechanical characteristics. Therefore, this paper seeks to develop an one-piece forming process which eliminate welding process for the cowl cross bar by applying the tube drawing process. However, it was predicted that a conventional tube drawing can not be applied directly to the current part since the area reduction ratio of the drawing process reaches 51.7% which exceeds the general limiting value. Therefore, in this study, a combined drawing process which adds a compressive force to a tensile force of the conventional drawing process was proposed and 2-stage drawing process was designed by using CAE analyses. In addition, drawing tryouts were carried out by using the manufactured combined drawing machine in order to verify the designed process.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.145-150
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• 1997

A computer-aided process design system for axisymmetric deep drawing products has been developed. An approach to the system is based on the knowledge based system. The hypothesized process outline of the deep drawing operations is generated in the geometrical design module of the system. In this paper, the module has been expanded. The rules of process design sechems for complex cup drawings are formulated from handbooks, experimental results and empirical knowhow of the field experts. The input to the system is final sheet-metal objects geometry and the output from the system is process sequence with intermediate objects geometries and process parameters, such as drawing load, blank holding force, clearance and cup-drawing coefficient.

• Transactions of Materials Processing
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• v.5 no.1
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• pp.61-71
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• 1996

A computer-aided process design system for axisymmetric deep drawing products has been developed. An approach to the system is based on the knowledge based system. Knowledges for the system are formulated from the plasticity theory handbooks experimental results and empirical knowhow of the field experts. the system is composed of four main modules such as geometrical design test & rectification and user modification. The input to the system is final sheet-metal object geometry and the output from the system is process sequence with intermedi-ate objects geometries and process parameters, such as drawing load blank holding force clearance cup-drawing coefficient.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.74-82
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• 1998

The limit drawing ratio (LDR) is a major process parameter in the process design of deep drawing. If the actual drawing ratio is greater than the LDR for a particular stage, then an intermediate stage has to be added to the process sequence to avoid failure during the ratio. In this study, the optimal process design considering forming limit is performed for the first-drawing and redrawing by using finite element method combined with ductile fracture criterion. The LDR and the site of fracture initiation are predicted by means of the fracture criterion. From the results of finite element analysis, the optimal value of drawing ratio is obtained, which contributes to the more uniform distribution of thickness and the smaller values of the ductile fracture in final cup.

• Korean Journal of Computational Design and Engineering
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• v.7 no.1
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• pp.9-17
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• 2002

The study is insufficient on process planning of the elliptical deep drawing product. Thus, in this present study, the expert system for elliptical deep drawing products was constructed by using process sequence design. The expert system was developed to be based on the general concept of each entity. The system was developed in this work consists of sixth modules. The first one is a shape recognition module to recognize non-axisymmetric products and to generate Entity_list. The second one is three dimensional (3-D) modeling module to calculate the surface area for non-axisymmetric products. The third one is a blank design module to create suggested blanks of three shapes with the identical surface area. The fourth one is shape design module based on the production rules that play the most important role in an expert system for manufacturing. The production rules are generated and upgraded by inter- viewing field engineers, plastic theory and experiments. The fifth and sixth ones are a graphic module to visualize results of the expert system and a post module to rise user's convenience, respectively. According to constructed the expert system for process sequence design, it was possible to reduce the lead time.