A STRUCTURED APPROACH TO DESIGN FOR REMANUFACTURE

Product design for ease of remanufacture could be a means for realizing resource conservation and waste disposal minimization. Unfortunately, few design for remanufacture guidelines are available. To gain insight into how to design for the overall remanufacturing operation, the design structure matrix, applied to a sequence of remanufacturing processes, is used to identify the information flow patterns between processes at different stages of the remanufacturing operation. It is concluded that iteration loops between processes as applied to a single product unit should be eliminated and that other interprocess dependencies should be minimized. Next, axiomatic design is applied to specific remanufacturing processes to gain insight into how products should be designed to facilitate each process. Finally, use of axiomatic design to perform remanufacturing process planning for an existing product is discussed. A simple case study involving the design of a panel for an appliance, or other apparatus, to facilitate refurbishment is presented. These methodical techniques seem well suited to support a computer-based design for remanufacture advisor. MOTIVATION Design of durable products for ease of remanufacture is often a sensible approach to environmentally responsible product design. Remanufacturing transforms durable products that are worn, defective, or obsolete to a “likenew or better” condition through a production-batch process of disassembly, cleaning, refurbishment and replacement of parts, reassembly, and testing. Value is added during the original manufacturing process in the form of energy and labor required to shape the raw material into a usable component. By recycling at the higher level of components rather than the raw material level, remanufacturing preserves this value-added as well as the material content of the product [Lund 83]. Not only is resource consumption for unnecessary reprocessing of material avoided, but the eventual degradation of the raw material through contamination and molecular breakdown, frequently characteristic of scrap material recycling, is postponed. Also, the production-batch nature of the remanufacturing industry enables it to salvage functionally failed, but repairable products that are discarded due to high labor costs associated with individual repair [Warnecke & Steinhilper 85]. One limiting factor in remanufacturing has been the availability of cores in good condition at a sufficiently low price. Another obstacle develops when original equipment manufacturers (OEMs) view independent remanufacturers as competitors. Consequently, OEMs may act to discourage remanufacture of their products by not sharing product specifications and manufacturing processes, or more aggressively, by incorporating subtle design changes that specifically hinder remanufacturing [Lund 83]. Product takeback laws such as those proposed in Germany [Ziwica 93] that require manufacturers to take back their durable products at the end of life would help to remove these hindrances. If Germany’s proposed takeback law is a harbinger of future practices globally, it may behoove the OEM to design products that are easy to remanufacture. Unfortunately, there is a paucity of available knowledge on how to design for ease of remanufacture. The few rules found in literature that are generated from experience tend to be product specific. The basis and application range of these rules are not always available, resulting in a set of seemingly conflictive guidelines. The apparent arbitrary nature of these rules induces low confidence that the sets of rules are complete. A structured, systematic approach to viewing the remanufacturing process is needed to generate a sense of how to best design for it.