| DFA (Design for Assembly) is an important factor in manufacturing since it can substantially reduce the estimated 15-70% of manufacturing cost that is attributable to assembly. Besides the reduction in cost, DFA promises additional benefits in increased quality, increased reliability, and shorter manufacturing time. The present approaches to DFA are limited in scope in that they operate as essentially post-design evaluators, that is they require the detailed design to be completed. A designer can then be faced with a major redesign to rectify problems that are brought to light during the DFA process. Furthermore, most DFA approaches are limited to the domain covered: most are oriented towards mechanical assemblies and cannot be used effectively in other domains. A feature-based design approach is proposed for the development of an Integrated DFA system that can be used during the design process to reduce wasted design efforts in current DFA systems.;This dissertation presents a new approach to DFA. This new approach is based on four key new developments: A design process model for DFA. This design process model extends prior approaches by allowing for a wide variety of design and DFA activities to be carried out in a flexible sequence.;A feature-based representation of both part and assemblies. This new feature-based representation allows for the representation of assemblability factors.;A set of feature-based design operations. This provides the means to make necessary design changes in the feature-based representation of parts and assemblies.;A methodology for evaluating the design at different stages. This methodology goes beyond the present approaches to DFA to allow for the design to be evaluated at any stage from the onset of design to the final stage of design.;There are three advantages to the proposed approach. First, it lays a firm foundation for an Integrated DFA system, that is domain independent. Second, it provides a means of applying DFA at different points in the design process, including the earlier, more conceptual, phases of design. Third, the approach provides a natural link to more advanced CAD systems and constraint processing systems. |
