Research On Process Information Model Based On Manufacturing Feature In 3-D CAPP System

Process planning links product design and manufacture. The efficiency of process planning is considerably improved by CAPP system, which helps companies shorten the product life cycle, upgrade the research ability and enhance the competitiveness of companies in rapid-changing modern manufacturing. This thesis researches on feature-based information models in 3D-CAPP system, mainly on the models in manufacturing feature extraction, process decision based on 3D product models, and process file model.On the basis of analyzing the state of CAPP system and 3D modeling methods, the manufacturing feature modeling methods and various parameter information used in process planning are investigated. The architecture consisting of four layers such as system support layer, data storage layer, function layer and application layer is analyzed of the 3D CAPP system. The key technologies are discussed including part information model extraction, manufacturing feature information extraction, feature level process decision and part level process decision; the mapping relationship is determined from part information model to manufacturing feature model.In this thesis, the process resource models such as cutters and machine tools are analyzed and the logical relations are built internal a certain model and between models. The workflows are planned for the manufacture feature machining methods; the models are modeled of geometric information and attribute information respectively; and the feature classifying and the mapping rules are established; the information and the expression model of the process file are analysed. The feature level process steps are planned via manufacturing feature identification mapping and the part level process procedures are planned via integrating the steps.Based on the above model information and information flow, the sub-systems are developed such as process resource databases and process reasoning; the correlation among the sub-systems is constructed to make the 3D CAPP system function more perfect. At last, in terms of taking a spindle machining process as an example to shows the information processing procedure, the operating mode is demonstrated of process planning by manufacture feature in 3D CAPP system.