Research And Implementation Of Component Region Feature Recognition For 3D Modeling

With the deepening of the fourth industrial revolution,intelligent manufacturing has become a research hotspot in recent years.The most important product in this field is industrial modeling software.In the industrial modeling software,the recognition and application of the regional features of the parts is the key problem to realize the intellectualization of the mold design and manufacturing process.Therefore,this thesis aims to study the three-dimensional shape regional feature recognition technology,design a more complete solution to the above problems,and develop the parts regional feature recognition and application system based on Siemens industrial modeling software NX.Firstly,This thesis analyzes the problems of low intelligent degree of Siemens industrial modeling software NX in the process of mold design and manufacturing,such as the difficulty of batch design,the difficulty of region selection of complex parts,the tedious operation of dimensioning and so on.The root cause of the problem is analyzed: the recognition of regional feature structure in parts is not ideal.In order to solve this kind of problem,this thesis studies the method of feature recognition,and designs four solutions:boundary search,region feature extraction and reconstruction,region similarity matching and knowledge reuse.The details are as follows:(1)based on the feature recognition method of attribute adjacency graph,the sub graph is constructed for the region selected by the user,and boundary conditions such as auxiliary surface are added.The region boundary is searched by depth first traversal.Compared with the whole graph construction method of the original method,the search efficiency is greatly improved.(2)Starting from the point,line,surface and topological relationship in space geometry,the boundary feature information is extracted.From the perspective of three views,the process of human eye restoring the recognition region layer by layer from the top view is simulated.From the two-dimensional region boundary,the original three-dimensional structure is restored according to the topological relationship between surface and edge,and the region model is reconstructed,In addition,parameters such as direction and order are added to represent the relative position of attributes,which lays the foundation for subsequent similarity matching.(3)The similarity matching algorithm of design region divides the similar regions in the parts,and uses the playback method of user design operation in NX automatic test to realize the application of design knowledge.(4)The design knowledge is reused by importing and exporting CSV and XML files.The model knowledge and design knowledge acquired from one component are reused to other components;Finally,in order to combine the above solution with practical application,based on NX secondary development framework,the three-tier architecture design method of presentation layer,business logic layer and data management layer is adopted to develop the regional feature recognition and application system.Taking the typical design of slot,hole and boss as an example,the function test and performance analysis of the system are carried out.The regional feature recognition and application system designed and developed in this thesis has been successfully embedded into the existing NX software,which not only solves the problems of 3D model input,3D structure spatial geometric feature extraction,parts similar region division,design knowledge application and reuse in the process of feature recognition,but also solves the problems of some parts in the field of 3D mold design Batch design is difficult,defect detection accuracy is low,dimensioning process is cumbersome and other engineering problems,which has high application value and practical significance.