Abstract
Development of an invaluable CAD/CAM system, from a pragmatic perspective, depends on the careful design of its data representation scheme to cover the specific domain and ultimately increase productivity with good information support. Designers and manufacturers in the sheetmetal industry have a particularly strong need for finding data representation schemes that can increase the efficiency and effectiveness of sheetmetal production. Previous research in the area can hardly be applied because shapes and processes of sheetmetal parts are quite different from the most-studied metalcutting parts. In this paper, a unique process-driven, feature-hierarchical data representation scheme is proposed. We develop a scheme for sheetmetal parts so that a designer can use the process-related feature hierarchy to describe them and at the same time express design intention and tolerances. Features can be classified into two types. One is called the master feature, which is used to represent the primary profiles of sheetmetal parts. The other type is called the manufacturing feature, which represents a single sheetmetal manufacturing process. Primitive features are defined to represent the manufacturing features. Compound features can be defined by combining primitive features to fulfill a specific design intention. To present a sheetmetal part design that is ready for processing, assembly, and inspection, the geometric and dimensional tolerance information is added to the feature definition. The data structure for the scheme is developed considering the topology, geometry, and tolerance data. Finally, a prototype system called SMCAD is implemented using the solid modeler ACIS to demonstrate the proposed sheetmetal design scheme. © 1995.