ENVIRONMENTAL-FACTORS IN PARAMETRIC DESIGN OF COMPUTER CHASSIS

Environmental issues in industry have transformed from those of compliance to those of competitive advantage through increasingly stringent environmental regulations, the emergence of product take-back and recycling initiatives, and growing consumer preference for ''green'' products. While there has been much research devoted to systems-level disassembly and recycling of computer products, a significant life-cycle component of the wastes associated with the product occurs at the primary manufacturing stages. This paper examines the linkages between manufacturing process waste generation and decisions made at the component design stage. An application of this linkage is in the area of sheet metal components for computer chassis. Critical processes include blanking, punch, metal deformation, finishing and welding. The availability of data at several levels of aggregation is supplemented by the development of analytical models of process physics to derive a process-level inventory of energy utilization, primary scrap and secondary catalysts (tool, fluid and vapor waste streams). The mass flows of waste streams can be weighted by the impact on factors such as toxicity, carcinogenesis, reactivity, flammability and irritation using material safety data and survey of site-specific factors. The trade-offs between environmental, manufacturing and product performance factors are discussed, as well as the environmental impact of material selection and definition of geometric features. The methodology for estimating energy utilization and process wastes is demonstrated through calculations for the manufacture of a workstation chassis. Several case studies of chassis components are also presented to illustrate the influence of incremental component design decisions on environmental impact. The role of product specifications such as aesthetics, thermal requirements, shielding and structural requirements are examined.