A knowledge-based object oriented DFM advisor for surface mount PCB assembly

The volume and complexity of printed circuit boards (PCBs) that use surface mount technology has increased tremendously over the past decade. The intricacy of the design and manufacturing functions associated with this domain is continuously increasing. Several researchers have documented the significance of the design functions on product life cycle costs. In the surface mount PCB assembly area, the integration of the design and manufacturing activity is hampered by the lack of sufficient, in-depth manufacturing knowledge among the PCB designers. Also, the heuristic nature of manufacturing knowledge coupled with the frequent advances in the state-of-the-art has resulted in the lack of widespread in-depth process knowledge. This research focused on the design and development of a knowledge-based methodology which can be used to assist the design engineer in the surface mount PCB assembly domain. The rules relate primarily to the solderability, cleanability and reflow aspects of the design. An object oriented programming (OOP) methodology is used. The OOP framework allows for structured and modular development and implementation of the knowledge-based design advisor. It allows for the easy maintenance and update of the software along with the integration of knowledge bases and databases. The system has been partitioned into three major components - the user interface, the update mechanism along with the inference engine, and the database management utility. An important feature of this research has been the focus on updateability of the design advisor with respect to data and knowledge (rules). The logic or the rules within the system have been developed in an updateable format. The calculations required during the firing of the rules are performed by dynamic linked libraries (dlls). The design advisor has been developed in the Windows operating system using the C++ language. The database manipulation functions are handled by CodeBase 5.0 libraries.