Feature-Based Applications in CAD/CAM

With conventional CAD CAM systems, geometric models usually require the elementary part definition data to describe the geometry and topology of the components. For wireframe type of geometric models. the geometric data comprise the vertices and the edges. For surface modellers, the data may include the control points and the corresponding equations for the appropriate surfaces types. For solid modellers, the data include the primitives such as blocks and cylinders which build up a CSG (Constructive Solid Geometry) model, and the hierarchical data structure and the corresponding geometric entities which describe a B-rep (Boundary representation) model. These conventional types of CAD models may be sufficient for the description of the shape and dimensions of a mechanical engineering part, but the geometric model cannot provide any information directly on the method of manufacture. An imporant process in the integration of CAD CAM systems for manufacturing automation is to link up the topological and/or geometrical data and the manufacturing data. To accomplish this task, it is necessary to gcnerate the appropriate machining cr information from a CAD model. In this regard, the use of features have been considered to be the technology which bridges the gap between CAD and CAM in the CIM (Computer Integrated Manufacturing) environment.