| Undoubtedly, the estimated manufacturing cost is the best indicator to check the profitability of manufacturing a product. This research proposes a framework to estimate the lowest product manufacturing cost from geometric design data at the design stage. Although, the manufacturing costs considered include the machining cost, the fixture cost, the setup cost, and the material handling cost, the fixture and setup costs were treated in an aggregate form. Unlike some earlier research which analyzed a single arbitrary process sequence, the cost evaluation system developed in this research is based on the choice of one best process sequence with the objective of minimizing total manufacturing cost from among all the feasible process sequences. It considers a much broader domain of factors than previous research have and therefore provides a more meaningful cost estimate. Several features which improve the means for cost estimation at the design stage have been considered and included in the research. These are (1) generation of process alternatives, (2) manufacturability verification, (3) estimation of the manufacturing cost for each process alternative, and (4) selection of the process sequence with the lowest cost. Because the manufacturing cost is sequence dependent, a mathematical model is developed to present the problem. A heuristic algorithm is also provided to find the process sequence with the lowest cost. A performance analysis of the heuristic algorithm is carried out to assess the quality of solution it provides. The algorithm performs well according to the analysis. Three example problems are used to verify the functionality of the framework. In the research, the practice of exploring multiple alternatives for processing a part enhances manufacturing flexibility and reduces manufacturing cost. Furthermore, the developed mathematical model is capable of representing the general cost evaluation problem because the model considers various manufacturing cost sources. Finally, the framework makes the development of a complete manufacturing cost estimation system in the future more transparent, tractable, and with a clearer definition of direction. |
