Abstract。 This paper presents the development of a design supporting system for press die of automobile panels。 The proposed system supports the design process of press die efficiently and systematically by utilizing  standard  data, and reflecting knowledge of press die design collected and accumulated through the interviews with design specialists working in a Korean motor company。 This paper illustrates a methodology for systematic press die design, automatic checking of dimensions and implementation。In addition the rule-based design system is developed based on the product data。 All components of the press die are regarded as product data and the components are regarded as the unit of press die。 Parametric design using knowledge base and standard database is in- troduced to make it easier to deal with the complicated design knowledge eas- ily。 For implementation, the rule-based design system is programmed with C++ and Motif and the system can be linked with CATIA。74972

1 Introduction

Reducing manufacturing cycle time is an important issue in the recent automobile industry with changing customer needs。 Although the industry has adopted various new technologies such as CAD/CAM and factory automation, the results do not meet the expected level。 The main reason is that the new technologies must be adapted to the industry’s own know-how and knowledge workflow, as well as administrative traits of a particular company。 [1]

In designing and manufacturing of trim die and draw die, the variety of car panel shapes and the complexity of the structures complicate the problem even more。 A lack of consistency in the design may cause weak relationship between the design and manufacturing, and presents difficulties in finding out the errors of designer。 Due to these problems, a lot of time and resources are wasted。 [1]

In spite of the variety and the complexity of the car panel structure, some consis- tencies can be found in the rules, knowledge and the methods of design, although they are redundant sometimes。 [2-3]

W。 Shen et al。 (Eds。): CSCWD 2006, LNCS 4402, pp。 207–216, 2007。

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Hence, it is helpful to develop a design supporting system for trim die and draw die。 The design supporting system can be developed by systematically converting the regulation of the design characteristics and the know-how’s of design specialists into the decision rules and knowledge bases。 [4]

2 The Current Design Process

Since the dies are essential tools in manufacturing the body panel of an automobile, the design processes and the process plans of the dies determine the cost, quality, processing time and even the safety factors。 [5]

In the stamping process many kinds of dies such as draw dies, trim dies, flange dies, cam dies, flanking and piercing dies and progressive dies are used。 Among them the trim dies are used in the shear forming pressing process which cuts and removes the panel material by the force of fracture made with cast iron or steel die。 [1] The main functions of the trim die are as follows: 1) trimming to cut the bound- ary of a body panel, 2) removing the scraps, 3) piercing to make holes on a body panel。

Until now, these three processes were performed manually due to the  complexity of rules to determine various design variables even if the designers are experts of commercial CAD system。 They use approximate work-piece sizes and tentative methods, and relied on past experience to layout the die sets。 Also the resulting designs are prone to errors since it is difficult to figure out 3D free surface from the 2D draft and it is very complicated task to calculate the angles of normal and tan- gent vectors of the trim line and the heights of the inner shapes。 To facilitate the die design process and perform the above three processes in a single step a design sup- porting system is proposed。