3D Process Model Generation Method And NC Automatic Programming

Process design is a bridge between design and manufacture.At present,most enterprises still use the three-dimensional design model and the two-dimensional drawing process design model to carry on the process design.The information transformation of the three-dimensional model and the two-dimensional drawing leads to the discontinuity of the information transmission,which affects the production efficiency.The 3D CAPP with 3D model as the sole data source can greatly improve the efficiency and quality of manufacture.In order to achieve the 3D CAPP.A three-dimensional process model generation method based on the classification and mapping of machining features andA NC automatic programming method for machining features are realized,and the automatic generation of 3D process model and the NC auto programming system are studied.The main contents are as follows:(1)By analyzing the constraint relationship between design features and machining characteristics,a 3D process model generation method based on machining feature classification and mapping is proposed.The internal relationship between design features and processing features is studied,the design features and processing features are classified and the process information is associated,and the mapping algorithm between the processing features and the design features is constructed based on the method of matching the neighborhood subgraph of attributes,and the transformation between the design features and the processing features is successfully completed.With the guidance of process information,the design model is revert back to the initial blank model,and the three-dimensional process model of each process step is generated.(2)A numerical control programming method for machining features is proposed.The technical knowledge base is constructed,the standard process template is formulated,the surface features of the parts are extracted,the corresponding matching of the processing technology and the processing features is realized,and the processing features related to the NC code are expressed,Based on greedy algorithm,the tool path optimization is realized,and the number of tool paths is reduced to make machining more effective,and the automatic programming of NC is realized.(3)Finally,3D process model automatic generation and NC automatic programming system are developed based on UG.The feasibility of the above method is verified by taking the roof cover of aerospace components as an example.