AN OBJECT-ORIENTED KNOWLEDGE-BASED SYSTEM FOR MANUFACTURABILITY OF PRINTED WIRING BOARDS

Design for manufacturability has been proved to be a solution that avoids the problems created by design not amenable to manufacturing. The designer should be aware of the manufacturing constraints to achieve the design for manufacturability. The rapid change in printed circuit board manufacturing with the induction of surface mounted components and robotic assembly has changed the scenario of the design. The high-density packaging capability of surface mounted technology has contributed enormously to the development of new trends in printed wiring board manufacturing. PWBMA, Printer Wiring Board Manufacturability Advisor (printed wiring board is another name for printed circuit board), a knowledge-based system, is developed to capture this new technology and its interaction with the existing through-hole mounting technology. Rules and guidelines pertaining to manufacturability of the board are formulated and incorporated into the knowledge base in building the system, which is built on an object-oriented paradigm. The importance of the object-oriented approach, the implementation of the object-oriented paradigm, object-oriented programming using Smalltalk-80, and the hierarchical rule structure paradigm are discussed. The implementation of meta-level to increase the efficiency of the system is also presented. Furthermore a rating system is introduced to rank various designs. PWBMA is capable of suggesting design modifications at the early stage of design to eliminate the manufacturing problems in the later phase of board production. The system is very easy to use with a broad user interface.