| This thesis develops a system to facilitate the integration of computer-aided design and computer-aided manufacturing using three axis milling. Specifically, algorithms are presented for feature recognition from boundary representations of solid models and for high-level process planning or macroplanning.;A feature-based approach is taken to define the context within which the integration can take place. Components of the system are described and their interfaces are specified. The conventional classification of features into specific types is seen to be an encumbrance and are abandoned in favor of a definition of features as machining volumes with attributes and a hierarchical structure that captures information about feature interactions. The process planning system described accepts features that are specified directly in a specialized design interface or are obtained from a feature recognition system. Algorithms for feature recognition that adopt a volume decomposition approach are presented for 2.5D as well as for a limited class of 3D components. The feature recognition module accepts a boundary representation of the component and is thus general enough to interface with most currently available CAD systems. The features found are then used by a high-level process planner, the macroplanner, in conjunction with a low-level planner, the microplanner, to determine fixturing locations, setup, and operation sequences, so as to minimize costs and time. The result is an integrated system that provides a bridge between design and manufacturing and allows the designer to check the manufacturability of the part periodically. |
