The role of complexity in product life-cycle cost
In the past two and half decades, manufacturing researchers have recognized the tremendous gains realizable from designing product that are easily manufactured and assembled. The applications of new design processes such as Design for Assembly (DFA) and Design for Manufacture (DFM) have contributed substantial benefits to the manufacture of discrete electro-mechanical systems in many industries. The gains have been in terms of cost reduction, increased manufacturability, and improved reliability of products. These gains have often been due to reduction in number of parts, replacement of fasteners with plastic snap-on features, and the use of the injection molding process in the manufacture of the complex consolidated components.
However, many companies implement these new product development tools without a-priori consideration of the benefits realizable and the difficulties that may arise in the implementation. Complex consolidated components take longer to develop and could be impossible to manufacture for low capability processes. As product life cycles shrink, the speed to bring products to market fast has intensified. Complex components could delay the timely launching of new products, seriously impairing their profitability.
The impact of component complexity on the profit realizable from a product over its life cycle has been quantified empirically and analytically in this research. The number of dimensions that are used in the design detailing of a component is proposed as a measure of its complexity. This metric was empirically found to have a high correlation with the component's tooling cost and tooling lead-time. Process yield was derived as a function of the “critical-to-function'” dimensions and the specified injection molding tolerances.
Some definitive cost modeling and system consolidation approaches for plastic part design have been developed. New guidelines for component consolidation were proposed, suggesting that components should not be combined if the consolidation will not reduce the number of tools required. Also, if there is uncertainty about the timely realization of the product as well as if there is considerable sales loss sensitivity. The developed algorithms and logic provide powerful new tools for consolidation of multiple parts and functions into fewer, more complex parts.
0548: Mechanical engineering