Abstract: Based on the research of some recent algorithms of the initial solution guess work of one step forming, an improvecd algorithm based on the geometry expanding, section curve expanding method was presented. This algorithm has the merits of geometry expanding method and overcomes the difficulty for searching symmetry curve confronted by the "Geometric Mapping" method. So it enabled the one step forming method more practical. The computer program was also developed. The comparison of the simulation results of flower-shaped cup with experimental data shows that the initial blank shape obtained by one step method quite agres with those obtained by the experiment and verifies the effectiveness of the present method.

Key words: stamping forming process, one step forming, initial solution, section curve