| Tolerance synthesis attempts to minimize the manufacturing cost of a product by specifying an optimal set of tolerances without compromising product performance. Concurrent engineering is a new approach in product design. Tolerancing is a bridge among design, manufacturing and quality engineers and plays a key role in concurrent engineering. Since cost and quality are fundamental product issues, simultaneous tolerance synthesis for manufacturing and quality is an excellent way to implement concurrent engineering.;In this thesis, a new tolerance synthesis method, Simultaneous Tolerance Synthesis for Manufacturing and Quality (STSMQ), is presented. A nonlinear optimization model is constructed to implement this method. In this model, the manufacturing cost and quality loss are combined together into a single objective function. Both process tolerance and design tolerance are chosen as decision variables. The manufacturing cost decreases as tolerance is loosened while the quality loss increases as tolerance is loosened. The purpose of this model is to balance both manufacturing cost and quality loss to achieve optimum design tolerances and process tolerances under the minimum total cost of manufacturing and quality loss. A procedure of implementation of this model is also included.;The proposed method is tested by some examples. The results show that a significant reduction in total cost in manufacturing and quality loss is obtained compared to other techniques. |
