Development of an automatic part feature extraction and classification system taking CAD data as input

Abstract

Computer-aided process planning (CAPP) is considered to be the bridge that joins computer-aided design (CAD) and computer-aided manufacturing (CAM). One of the most important aspects of CAPP is automatic feature extraction, which is a procedure that aids; in the generation of process plans automatically. In terms of a CAD system, an automatic feature extraction module constitutes a characteristic that facilitates a cooperative design and process planning activity for the overall product realization process. This activity is explicitly defined as concurrent engineering. The purpose of this paper is to present an automatic feature extraction system for prismatic raw materials that would provide a CAD system with the above mentioned module for concurrent engineering. The system takes a file in Initial Graphics Exchange Specification ( iges) format as input and translates the information in the file to classify all the features in the workpiece whose information is in the file. The iges format is used in CAD files to support geometric and topological information about machine parts. Several algorithms are developed to extract and merge features based on geometric and topological information. After each feature is extracted, rough process operations can be determined based on a design classification scheme. The system is written in C on a PC-based system. A sample application description for two workpieces is presented for demonstration purposes.