Research Of Process Planning Based On Genetic Algorithm

Optimization of process planning is the important method to ensure product quality, to improve efficiency and to reduce cost. Optimization algorithm for process planning is related with many elements such as machining method, operation sequencing, cutting parameters, machining tool and cutting tool etc, which are affected one another. A uniform optimization model of process planning is brought forward to gain the global optimum in entire solution space for process planning using genetic algorithm. Operation sequencing, jigging toolselecting, and cutting toolselecting in each operation are optimized as the whole. The optimal process planning is educed by genetic computation.The basic processes of the generation of AP-238 document is introduced, including geometry information extraction of parts from the AP-203 document, feature identification, technical planning. After these preparations completed, AP-238 documents can be generanted. This paper mainly focuses on the importance of processing path planning in the generation of AP-238 document. First of all the description of parts and restriction relations among the features are analysed, and restriction relations among the shape features is introduced, and using the AOS tree structure to describe the restriction relations among the shape features. Then resources required for the processing of the parts is analysed, and modeling for processing resources. Finally, the basic path planning process is given.Firstly, the scheme graphs are created by analyzing machining methods of typical machining surfaces. The graphs which are transformed to adjacency-list representations are searched and traversed using graph algorithm. We can get the best machining method or the approximate best from all the machining methods of any machining surface knowing the machining start and end.Secondly, according to the step, the constraint relation of machining operation sequence is analyzed, the model is built and the mathematics model for machining operation is formulated for it. The evaluating system for process planning, considering such criterion as time, precision and cost, is created, which is based to compute the fitness of process planning chromosome.Lastly, the prototype system that realizes the research contents of the dissertation are given, and the prototype system is applied to a practical process planning case. Therefore, the feasibility and the effectiveness of research results are validated.