A COMPACT AND PRACTICAL CAD-SYSTEM FOR BLANKING OR PIERCING OF IRREGULAR-SHAPED SHEET-METAL PRODUCTS AND STATOR AND ROTOR PARTS

This paper describes the development of a computer-aided design of bla nking and piercing for irregular-shaped sheet metal products and stato r and rotor parts. An approach to the compact and practical CAD system is based on the knowledge-based rules. Knowledge for the CAD system i s formulated from plasticity theories, experimental results and the em pirical knowledge of field experts, The system has been written in Aut oLISP on the AutoCAD with a personal computer and is composed of six m ain modules, which are input and shape treatment, production feasibili ty check, blank layout, strip layout, die layout, and drawing edit mod ule. Based on knowledge-based rules, the system, STRTDES, is designed by considering several factors, such as complexities of blank geometry and punch profile, availability of press equipment and standard parts , utilization ratio which minimizes the scrap in a single or a pairwis e operation, bridge width, grain orientation and design requirements w hich maximize the strength of the part when subsequent bending is invo lved, Therefore, this system can carry out a die design for each proce ss which is obtained from the results of an automated blank layout dra wing with the best utilization ratio for the irregular shape of the pr oduct, which was successful in the production feasibility check module , and those of an automated strip layout drawing. It can then generate part drawings and the assembly drawing of the die set in graphic form . The developed system provides its efficiency and effectiveness for b lank layout, strip layout, and die layout of irregular-shaped sheet me tal products and stator and rotor parts. (C) 1998 Published by Elsevie r Science Ltd. All rights reserved.