A multi-objective methodology for evaluating product end-of-life options and disassembly

In recent years, sustainable manufacturing has become important all over the world. Manufacturers have begun to realise the need for the responsible use and management of resources in the life cycle of a manufactured product, especially the planning for product retirement. The common end-of-life options are reuse, remanufacture, recycle, landfill, and incineration. This paper discusses a multi-objective methodology for determining appropriate end-of-life options for manufactured products, set against the often conflicting objectives of minimising environmental impact and minimising deficit (or sometimes maximising surplus). Guidelines for determining feasible end-of-life options (including the economic value of products and their components) are discussed. A numerical index of the environmental impact of a material or process - the eco-indicator - is adopted. Except for landfill and incineration, components of economic value destined for reuse, remanufacture, or recycling have first to be extracted from the product. It is therefore necessary to determine the optimal stage of disassembly, when all economically valuable components are retrieved. In order to determine the extent to which a product should be disassembled during its retirement, one may consider minimising environmental impact or associated costs or maximising the rate of return. Two end-of-life disassembly charts are introduced showing the impact on the environment and cumulative costs incurred as a product is disassembled. One of the charts can be used to assist in product design or redesign, whereas the other can be used to determine the optimal stage of end-of-life disassembly of the product. An end-of-life disassembly chart for a telecommunication pager revealed that if the pager is disassembled and its components reused, remanufactured, or recycled, the costs incurred will be very high. The pager is not designed for end-of-life retirement. It is best landfilled. The end-of-life options of a coffee maker were investigated using the methodology. It is concluded that the coffee maker is designed for end-of-life retirement. Complete product disassembly is always mandatory. If the coffee maker were completely disassembled and all components processed, the total disassembly time is 97 s, and a surplus of US$0.1918 is even realisable. The coffee maker was found to be designed for end-of-life retirement.