| NC machining technology is the key technology and an important foundation for machine modernization and the development of military industry. And NC Programming is the key to the NC technology. It not only embodies the process planning experience, but also has direct effects on productivity and processing quality. Due to the complexity of NC processes, different engineer may adopt different process, path pattern and processing parameters on the same part, so that leads to disorder and confusion in management. At the same time, because of the limitations of personal experience, the NC process and parameters cannot be optimized according actual factors, so that irrational process is often adopted, and results in a low quality and low processing efficiency.In order to overcome these defects and improve the quality and efficiency of NC machining, the characteristics of NC programming for die and mould were analyzed in this thesis, and a processing template was proposed based on the repetition and diversity of process parameters setting, in which parameterize and standardize NC processing is adopted to improve the productivity of NC programming. First, through rough classification of parts, those parts that have similar process will fall into one category. Then, each type of the processes is optimized to generate the standard NC processing template.A knowledge library of NC processes was established based KBE. It contains template-selection rule base, template instance base, geometry rule base, operation rule base and cutter base. The NC process knowledge and rule were stored in the hierarchical and structural way. Both rule-based reasoning method and case-based reasoning method are used for automatic identification of the geometries to match a new part with the corresponding template, and accomplish NC programming. The validity of the method is verified through application. It can increase NC programming efficiency by more than 60% for electrode and insert especially. |
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