Research On Intelligent Technology Of Process Planning Based On3D Model

The rapid development of modern science and technology provides themotivation for the innovation of technology in manufacturing industry, and makesthe update rate of product faster. It provides higher request for the technologicalcapability of CAPP that enterprises have to improve their market competitivenessby raising the efficiency of the design and manufacture of the product. CAPP is thehinge for the system integration between CAD and CAM, and the bottleneck torestrict the progress of automation, intelligence and informatization. It isincongruent to the actuality that most enterprises adopt the highly-developedtechnology of three-dimensional CAD that the traditional systems of CAPP workbased on2D environment of CAD. Therefore, it is current emphasis and difficultythat the research on intelligent technology of process planning based on3D model.It is different for the representation pattern of model data between CAD, CAPPand CAM. The paper takes STEP which is independent of any system as theexchange file, and analyses the data structure of STEP. It realizes the transmissionof data from CAD to CAPP and designs the algorithm for the data extraction basedon STEP and3D model rebuilding based on OpenGL.Because the information used in the stage of process planning expressed infeature, the paper puts forward a solution for the feature recognition based on theexpanded attribute adjacency matrix. The solution transforms the geometricalinformation described in surface, boundary and point to the attribute informationexpressed in feature. It recognizes the isolated features firstly, and then recognizesthe intersection features based on the information of the isolated features.The paper designs a model for the selection of processing scheme of thefeature on account of rule matching and decomposes the processing scheme intosome machining element. It proposes a method for operations sequenceoptimization based on modified ant colony algorithm synthetically taking intoaccount the constraints of manufacturing resource and precedence relation ofprocess. The method apply a double-deck ant colony algorithm that it takes theweighted hamming distance as the city distance to optimize for the differentmachining elements and treats the distance between the features which the machining elements belong to as the city distance to optimize for the similarmachining elements. In the end, it combines the two optimization results into anintact and optimal process sequence.According to the research on the related technologies of intelligent processplanning, the paper designs a prototype system of CAPP based on the3D modelnamed3D-CAPP. It verifies the validity of the function modules and completes theprocess planning for the moderately complex models.