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Nowadays, progressive dies have a special role in various methods of sheet metal production. The design process, however requires a considerable amount of time and expertise. Strip layout design is a key step in progressive die design, therefore automating strip layout has a vital role in Computer Aided Progressive Die Design (CAPDD). In this paper, a mathematical model, based on set theory, is introduced to analyze the problem of strip layout. The model describes the mathematical nature of the strip layout problem and reveals the reason why researchers have always faced problems in optimizing strip layout automatically. Using the model presented, an algorithm is developed to optimize strip layout using the minimum number of stations and the torque equilibrium criteria. A prototype software is also developed to automate strip layout design based on the presented algorithm. The suitability of the model is then demonstrated through industrial examples.

Nowadays, progressive dies have a special role in various methods of sheet metal production. The design process, however, requires a considerable amount of time and expertise. During the last three decades, different concepts of computer aided progressive die design (CAPDD) have been studied all around the world. CAPDD includes various activities and among them piloting has been paid the least attention by researchers. In this paper, a mathematical model, based on the medial axis transform is introduced. This model analyses the part geometry in order to determine the piloting system. The model optimizes the piloting system using a minimum scrap strategy and other technical considerations. A program is also developed to automatically select the most suitable existing holes or design auxiliary holes on the scrap part of the strip for piloting purposes. The input to the program is the nesting template of the workpiece, which is composed of line and arc segments, and the output is the piloting system. The model is demonstrated through several industrial examples.