ACIS-Based CAD/CAM System For Sheet Metal Fabrication-The Theory And Its Prototype

Standing on the designing and manufacturing features of sheet metal parts, the author has made an intensive study of the essential theory for developing the sheet metal CAD/CAM system based on the kernel of ACIS and its scheme. A method oriented punch process is presented which blends experimental knowledge and professional skills into the procedure of feature modeling. Based on the research, a solid modeling-based CAD/CAM prototype system for sheet metal (Smart Sheet Metal Prototype System-SSM) is developed during the study.The author designed a novel hybrid solid modeling method called HBCR-Hybrid B-reps/CSG Fabrication Modeling Methodology, which combines "B-reps" and "CSG" modeling methods, to effectively construct the solid model for sheet metal punching parts. In order to effectively utilize the advantages of these two original representations, B-reps definition is adopted to describe the bottom data of a solid model, and CSG modeling method to describe the making-up process. Based on the cross-section feature of sheet metal parts, sweeping modeling method is applied to define dynamically the basic geometric primitives in SSM prototype system.Based on this HBCR, the shape features are extracted from solid model for sheet metal punching part to realize the "feature-based" modeling design. Integrated with necessary process information, the functionally extended shape feature evolves into a total new Processing Geometric Solid Feature PGS. It makes a consistent data flow among the CAD module, Unfolding module and CAM module in SSM, and realizes the concept of DFM. All above establishes theoretical principles for development of the integration for sheet metal CAD/CAM.Research on this topic provides important theoretical principles and practical experiences for the development of sheet metal CAD/CAM system with intellectual property rights.