next up previous
Next: Other Miscellaneous Efforts Up: Representative Systems Previous: Machining

Electro-Mechanical

  In the realm of the electro-mechanical components, the role of the designer is broader. Usually the designer selects different components from commercially available ones. The selection of the components and their interrelation in turn dictates the production method. In a way it can be said that the product and the process plan is developed together in this case. Hence, the systems for manufacturability analysis are ideally plan based. However, for smaller sub-class of problems within this domain, rules are also used very often.

Similar to design for assembly, many major electronic manufacturers have taken the lead in developing metrics for evaluation of printed circuit board (PCB) designs. NEC corporation [77], General Electric [78] and Xerox [79] has reported in house systems for evaluating PCB designs and assembly.

O'Grady et al. [8] developed a constraint-based system (LARRY) that addresses various life-cycle considerations during the design of printed wiring boards. They treat the design process as constraint satisfaction problem where the various manufacturability considerations are represented as a constraint network. As designer adds features to the design, the constraint network is evaluated for possible violations. If violations are found, the designer can either select different manufacturing resources or modify the feature that caused the violation. Their approach is computationally intensive: as more features are added to the design, the constraint network grows in size. Their system considers only drilling of holes on printed wiring boards and it is not clear how their approach will handle the computational problems posed by consideration of additional manufacturing operations.

Harhalakis et al. [80] developed a system for manufacturability evaluation of microwave modules. Their system works with a STEP form feature based representation of the design, and uses rough-cut process plans to assign a manufacturability rating on a scale from 1 to 10. Their rating system was developed by interviewing the machinists on the shop floor. Though these ratings reflect difficulty associated with manufacturing, there is no direct correspondence between these ratings and manufacturing cost or time. Their system has a limited capability to perform geometric reasoning to identify interacting features and the effects of precedence constraints, tool changes, setup costs, etc., are not considered in their evaluation criteria.

Other works in manufacturability analysis of PCBs include [81,82,83,84]. These works are mostly for a very specific sub-domain of PCBs. Most of these systems are rule based and because of the very fast pace of technological changes, these rule bases need to be updated regularly. Most of the state-of-the-art research in this area is happening in the manufacturing industry.



next up previous
Next: Other Miscellaneous Efforts Up: Representative Systems Previous: Machining



Generated by latex2html-95.1
Fri Apr 14 13:59:16 EDT 1995