An Economic Assessment of Alternative Manufacturing Processes for the Camshaft 901741
As material, labor, and energy costs have increased, there has been a growing need to look for more cost effective processing methods to manufacture engineering components. A study was undertaken to assess the competitive position of alternative processing routes for high volume production of the automotive camshaft.
The techniques employed in the course of the study were Technical Cost Modeling and Multi-At-tribute Utility Analysis (MAUA). The use of cost modeling and attribute analysis offers a novel system-based approach to treating the problem of materials substitution. A computerized spreadsheet is used for writing the model, which simulates the cost of the manufacturing process. MAUA, a decision analysis technique that has been successfully applied to materials selection problems, helps clarify the importance of critical performance attributes to the materials selection problem for a given application, and then helps rank the materials based on their acceptability.
The automotive camshaft was chosen as a case study to demonstrate the use of these techniques. Five different production scenarios were evaluated: nodular casting, steel forging, microalloy forging, a hybrid process (segmented camshaft) using a hollow steel tube with forged lobes held in place by hydraulic expansion of the tube, and the fully machined camshaft. The study showed a close dependence of material/processing route choice with production volume. The results indicate that changes in engine design and movement toward faster and higher performance engines holds promise for steel forgings as the material of choice for this application.