The Research On Case Based Mold Parts CNC Process Reuse Method

With the continuous popularization of digital manufacturing technology,a large number of CAD/CAM design results have been accumulated in the manufacturing enterprises.Mold enterprises are generally oriented towards a specific industry and their product types are relatively simple.Although their designed mold parts are different in details,they generally have an approximate structure.The effective reuse of the existed mold parts CNC process can quickly complete the compilation of the new parts CNC process and reduce the occurrence of human error.To solve the problem of how to effectively reuse the existed mold parts CNC process,a case based reuse method was proposed.Firstly,the 3D features of the mold parts are described by the improved 3D polar radius surface moments and 3D envelope information,and the case part that is the most similar to the 3D features of the new part is retrieved in the case parts history database.Secondly,using the case part as the CNC process reuse basis,the process information such as processing methods,processing parameters,and processing procedures of the case part are imported into the new part as processing templates to reuse processing scheme.Finally,the improved 3D polar radius surface moments and 3D envelope information are used to extract the 3D features of the machining area of each CNC program of the existed part and each face of the new part,the weighted Euclidean distance is used as a metric to find the most similar matching of each machining area in the new part,and the matching result is optimized by the greedy algorithm based broken surface matching algorithm and the overall optimization algorithm.A prototype system based on this method was developed on the UG NX10.0 platform using NX/Open API.Nearly a hundred new mold parts were verified in the historical database of 31706 injection mold electrode parts that have been programmed with CNC process.The results show that this method can not only flexibly adjust processing procedures,have high versatility,but also can reuse 73% of the parts with more than 80% accuracy,which greatly reduces human-machine interaction and significantly improve the effic iency of CNC programming.