ECONOMICS OF NEAR NET SHAPE FORMING

摘要

Recent decades have seen growing interest in fabrication processes that cut losses in materials, labor, and energy while delivering the same high quality of performance. While new processing routes offer enhanced performance attributes to varying degrees, the main motivation in using them stems from the promise of reduced costs. Consequently net shape and near net shape forming technologies are gaining in importance. A study was undertaken to assess the economics of alternate net shape forming routes, within the scope of engine components. A technique called Technical Cost Modeling was employed for cost estimation, and a decision analysis technique called Multi-Attribute Utility Analysis was used for performance evaluation. The synthesis of the results of the two techniques helped determine the optimal choice of material/processing route for each application. Further, the sensitivity of the results to changes in specific processing parameters was evaluated. The methodology was applied to the automotive camshaft. A wide range of processing scenarios were treated, including sand casting of camshaft, conventional forgings of camshaft, and a hybrid assembled camshaft consisting of a hollow shaft with forged lobes. The results for the camshaft indicate the growing importance of near net shape routes such as forging and the hybrid assembled system. Overall, near net shape technologies have a promising future for these applications.