Rough process planning for a set based concurrent engineering design

This dissertation examines the integration of Set-based concurrent engineering new product design approach and its requirements for rough production planning. By delaying decisions, is achieved, and rework is eliminated. However there is no existing literature on a methodology for integrating design with manufacturing. According to many researches, the involvement of production or manufacturing function in early design process is of great importance. In fact, errors made during the early stages of design tend to contribute as high as 70% to the cost of production (Boothroyd, Bewhurst, & Knight, 1992) (Phal & Beitz, 1997). When Sobek et.al. 1999 devised the principle of set based concurrent engineering (SBCE), the interface between manufacturing planning and design process was highlighted (Sobek, Ward, & Liker, Toyota's Principles of Set-Based Concurrent Engineering, 1999). SBCE methodology is proven to achieve lower time to markets, elimination of rework and development of successful products by considering sets of designs and converged gradually into one best design delaying decision making until more information is available. In particular, Principle 2 “integration by intersection” and principle 3 “Establish feasibility before commitment” address the communication and integration of design and manufacturing function to facilitate narrowing sets of design alternatives. However, the details and the levels of integration are not systematically investigated in their research. Indeed, it cannot give a concrete guideline and method to execute the principles. Such methods or guidelines will have dual purposes; designers able to narrow to optimal design alternatives taking manufacturing constraints and opportunities, and manufacturing will early be informed about the possible design alternatives so that manufacturing planning and execution follow smoothly. Starting production planning after detail design will bring immense constraints and infeasibility from manufacturability perspective. That ultimately results in design rework and iteration which negatively affects time to market, cost and quality of the product given a certain process. In order to know and control the process cost from the beginning of the design, the manufacturing requirements of SBCE should be considered. This thesis is an assessments of how companies with a Set-based concurrent engineering strategy for design prepare their production plan, paying much attention to the rough production plan, which is done during the early phases of design by analyzing a survey specially design for this purpose.