The Research On Automatic CNC Programming System Of Cavity Parts Based On Feature Recognition

In the CNC machining process, CNC programming is an important part of theprocess, which can directly affecting the quality of the parts. While using of CAD/CAMsoftware for programming, it needs experienced staff to complete by a large number ofhuman-computer interaction. As a result, it is not only poor programming efficiency, butalso needs more experienced staff of numerical control processing. More importantly, theoperation is error-prone in the graphics options and parameter settings, because of itsrepeated tedious. At the same time, the structure of the cavity parts itself is complex, evenfor the same cavity part, different programmers can give various process plans, whichcauses process plans random. So the paper proposes the CNC automatic programmingsystem of cavity parts based on feature recognition of the UG platform, by researching lotsof cavity parts and their process plans.The system is divided into two modules: automatic feature recognition module andCNC automatic programming module. The automatic feature recognition moduleidentifies manufacturing features by figure decomposition ofAAG. TheAAG is got byanalyzing the geometric process characteristics of parts. It is changed into differentsubgraphs by deleting rough surfaces, disconnecting the inner loop of decomposition basesurfaces, combining the merger surfaces, segmenting the special surface and so on. Thesesubgraphs match the graphs of manufacturing features in predefined feature library toidentify the features of parts.The CNC automatic programming module is used after the automatic featurerecognition module. The appropriate templates are selected depending on the types ofcomponent surfaces of features. Then these templates build up a reasonable order ofoperations in accordance with roughing, semi-finishing, finishing. Each operation selectsright tool according to geometric data of the machined surface and other manufacturingfeatures around, and the appropriate processing parameters based on the tool. The processplan is finished. At last, it checks whether the tool path is right after generating the toolpath automatically. It also can generate NC code if the type of machine and the clamping way are selected. After the actual verification, for medium complexity cavity parts, theprocess plan is reasonable which is generated automatically by the system and theprogramming efficiency is also improved obviously.