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The automotive crankshaft, one of the more metal intensive components in the engine, provides an attractive opportunity for the use of alternate materials and processing routes. Although performance requirements are important in the choice of a particular material or fabrication route, the final decision is usually dictated by cost. This study evaluated the cost effectiveness of various material alternatives for the crankshaft. The technique of “Technical Cost Modeling” was utilized to estimate the manufacturing costs of the various material alternatives. Four processing routes for the manufacture of the automotive crankshaft were evaluated: steel forging, nodular casting, microalloy forging and austempered ductile iron casting. The results indicate that although nodular cast iron is the most widely used material today, it appears that, with changing engine design, microalloyed steel can effectively compete in this application.

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.

Low volume manufacturing has become increasingly important for the automotive industry. Globalization trends have led automakers and their suppliers to operate in developing regions where minimum efficient scales can not always be achieved. With proper maintenance, standard cast iron stamping tools can be used to produce millions of parts, but require large investments. Thus at high production volumes, the impact of the tooling investment on individual piece costs is minimized. However, at low volumes there is a substantial cost penalty. In light of the trends towards localized manufacturing and relatively low demands in some developing markets, low cost stamping tools are needed. Several alternate tooling technologies exist, each of which require significantly lower initial investments, but suffer from greatly reduced tool lives. However, the use of these technologies at intermediate to high volumes requires multiple tool sets thus eliminating their cost advantage.