Design function deployment : a concurrent engineering design system
The current state of activities in the design and manufacturing industry is marked by the various CAD/CAM/CAE systems which exist as islands of automation, and are used by engineers and designers in a non-integrated and ill-structured way. Thus the design problem is examined from separate and different perspectives, rather than as a whole. The goal of this research, is to develop a comprehensive, integrated and generic design system, that will ensure the realisation of concurrent engineering in practice. To this end, Design Function Deployment (DFD) has been developed. DFD enables the capture of customers' requirements, the establishment of design specifications and constraints in a solution neutral form, the generation of conceptual designs (architectures), the development of detailed designs layouts), the selection of materials and associated manufacturing processes and the development of suitable production plans. The generated design solutions are optimised against a composite set of multi-criteria (attributes) in a concurrent manner for key factors such as performance, robustness and cost as well as other life cycle issues (manufacture, assembly, serviceability, reliability, environment, etc) in order to choose the most satisfying design. DFD provides a recipe of design methods to support the designer or design team at any stage of the design process. The optimisation process involves the use of these supporting design tools (methods) encapsulated within it. DFD also provides an integrated product modelling environment which integrates both textual and geometric design information, and enables the capture of other design information related to design intent, rationale and history. The research that led to the evolution and development of DFD involved (a) a detailed investigation and research on Quality Function Deployment, QFD, a technique well suited for capturing and translating customer requirements into design specifications, (b) an extensive review of design philosophies, models, methods and systems and (c) an extensive investigation into concurrent engineering. The findings of this research has led to the development of the structure of the DFD system, which incorporates (1) a prescriptive design model, (2) a suite of design methods and (3) supporting knowledge/rulebases and databases, which are used for the generation of the design solution space and the optimal selection of the most satisfying design for subsequent implementation.