Automatic Programming Of Integral Compartment Parts Based On Feature Recognition

Due to the large number of machining features on the parts of the aerospace,the machining parameters,process and tool path data of the parts are determined according to the requirements of the part processing drawings.Then CAD/CAM software is used.The machining program is programmed and finally imported into the CNC system.For the processing of large-volume parts,the programming of the processing program is cumbersome and time-consuming,relying on manual operation and low efficiency.In this paper,this paper studies the automatic programming method of integral compartment parts based on feature recognition to realize the automation of NC programming of such parts.The feature type and shape are analyzed.The specific implementation methods based on boundary matching and decomposition-based feature recognition are studied.The rule-based feature recognition method,graph-based feature recognition method and feature decomposition method based on volume decomposition are compared.In the whole cabin part,the graph-based feature recognition algorithm is selected;the automatic programming flow based on feature recognition and the system construction scheme of automatic programming are established.Aiming at the graph-based feature recognition method,the B-Rep expression of the 3D solid model is studied.The algorithm is designed to transform its B-Rep structure into attribute adjacency graph,and the matrix is used to store the graph structure.The problem of sex defines the extended attribute adjacency matrix,and realizes the matrix storage entity model with extended definition.The feature library is built for storage.According to the characteristics of the whole compartment part,the algorithm is designed to extract the sub-adjacency matrix from the part matrix.The graph isomorphic solving strategy is used for feature matching,which realizes automatic recognition of processing features.According to the processing quality requirements of the whole compartment parts,after analyzing the process of the parts,the machining process route is determined;the workpiece coordinate system is set based on the process,the common processing methods and process parameters are selected;the process knowledge base is established and constructed.The mapping method from processing features to processing technology knowledge uses MySQL for storage;template technology is used for automatic programming;and process-based automatic programming template is implemented in UG CAM environment.An automatic programming software for aerospace integrated cabin parts was developed.The physical model was tested to verify the effectiveness of the method and the availability of the tool path template.The actual machining simulation was carried out with Vericut,and the test was carried out with the Jinan two-machine CA double-pendulum five-axis machining center,which proved the effectiveness of the tool path.