Abstract: The intelligent process planning is a key technology to realize intelligent manufacturing. For the novel NC data model called STEP-NC, an intelligent macro-process planning method based on an improved BP neural network for STEP-NC 2.5D manufacturing features is proposed. In the method, an integrated BP neural network model used for machining operation decision-making of STEP-NC 2.5D manufacturing features is firstly established. Then, considering the problems of BP neural network such as local optimum and slow convergence speed, an improved BP neural network algorithm for machining operation decision-making of STEP-NC 2.5D manufacturing features is given by combining chaotic algorithm, genetic algorithm with BP neural network. Further, corresponding machining operation methods are intelligently obtained after machining information of a part is normalized and input into the improved neural network. At the end, it has been concluded by a case that the proposed method is effective and feasible.

Key words: STEP-NC, macro-process planning, machining operation method, improved BP neural network