MBD-based three-dimensional process designing method and platform for typical automobile machined part

An MBD-based three-dimensional process designing method for a typical automobile machined part, characterized in that, the MBD-based three-dimensional process designing method for the typical automobile machined part comprises the following steps of:

• by taking three-dimensional CAD software as a carrier, an MBD design model as an unique data input, and a three-dimensional process MBD model as a data output, sequentially carrying out establishment of MBD-related standards, creation of an MBD design model, feature classification and creation of a feature information library, feature recognition and information extraction, generation of manufacturing elements, clustering of the manufacturing elements and generation of procedures, sequencing of the procedures, and creation of manufacturing feature bodies and procedure models;
• and generating a process MBD model integrating the procedure models and the manufacturing feature bodies to realize visualization of a process design flow:
• comprising the following steps of:
• Step 1, establishing MBD-related standards according to requirements for the creation of an MBD design model;
• Step 2, according to a set of the established MBD standards, determining all process information of part process design, including sizes and dimensional tolerances, geometric tolerances and references, face roughness degrees, technical requirements, process information and attribute annotations, and defining and labelling, in a three-dimensional labeling module of the CAD software, all the information of the process design to complete the creation of the MBD design model;
• Step 3:
• according to a design model of a typical part, carrying out attribute customization and feature classification on features of the model, wherein the customized features are classified according to a manufacturing face adjacency graph (MFAG) of the feature, and the classified features include individually manufactured faces, steps, holes, grooves and bosses;
• and then completing creation of a manufacturing feature information library in an XML file format, wherein the feature information library includes attributes of the customized feature faces and edges in various types, wherein attributes of a face mainly include a type of the face, a normal vector, and inner and outer loop information of the face;
• and attributes of an edge include a type of the edge, a normal vector, and concavity and convexity of the edge;
• Step 4:
• according to a STEP-format file of the part design model, acquiring an attribute adjacency graph (AAG) of a part, deleting all transitional features, blank faces and edges adjacent to the blank faces, and simplifying the attribute adjacency graph of the part to a manufacturing face adjacency graph (MFAG) of a feature;
• carrying out feature matching on the MFAG and the manufacturing feature information library, and if the matching is successful, recognizing corresponding features;
• if the matching is not successful, carrying out attribute decomposition on the MFAG, and integrating or dividing corresponding faces to obtain a plurality of feature sub-graphs, then carrying out feature matching on the feature sub-graphs and the manufacturing feature information library, and if the matching is successful, recognizing corresponding features;
• and for the recognized features, extracting product manufacturing information of each feature manufacturing face, including basic process design information and process auxiliary information, and outputting and storing the product manufacturing information in the XML file format to a background;
• Step 5:
• according to content of a process decision rule, extracting feature information from the manufacturing feature information library, and carrying out information mapping on the feature information and a feature manufacturing rule library to complete the creation of a manufacturing element, wherein the manufacturing element comprises all manufacturing information of a feature or a feature face, including a manufacturing element name, a manufacturing feature type, a manufactured portion, a manufacturing method, a manufacturing precision, a manufacturing tool, a manufacturing machine tool, a manufacturing time, a work fixture, a cutting amount, a manufacturing allowance, a main shaft rotation speed and a cutting speed;
• Step 6, for the manufacturing element created in Step 5, by means of a manufacturing element clustering algorithm based on a weighted attribute fuzzy c-means (WAFCM), according to the influences of different manufacturing attributes on a clustering result, assigning different weights to attributes such as the manufacturing method, the manufacturing precision, the manufacturing tool, the manufacturing machine tool and the work fixture, determining a number of clusters c, an iteration ending threshold s and a number of iterations T, and clustering manufacturing elements with similar manufacturing attributes to generate manufacturing procedures by integration;
• Step 7, by means of a genetic algorithm, carrying out optimized sequencing on the procedures generated in Step 6 to obtain an optimal procedure sequencing list for the part;
• and
• Step 8:
• with regard to the feature to be manufactured by each procedure, according to a reverse generation thought, using a half-space intersection or parametric modeling method to create, from the MBD design model, a manufacturing feature body of an Nth procedure, wherein a procedure MBD model of the Nth procedure is a collection of the MBD design model and process information of the procedure, and therefore, a procedure model of an (N−1)th procedure is generated by means of carrying out a Boolean addition calculation on the manufacturing feature body and the design model, and on this basis, creating manufacturing feature bodies and procedure models of the remaining procedures, until a final blank model is created, and then completing the creation of the procedure model.