Effect of Design for Assembly and Design for Disassembly On Product Recyclability

According to the United States Environmental Protection Agency (EPA), about 11 billion tons of industrial waste (some toxic) is generated annually in the USA.. Europe is already familiar with the problem. According to Hentschel, the volume of electronic waste in Germany exceeded 800000 tons annually in the early 1990s. Designing products for sustainable development has become a pressing concern. One way to achieve this is to undertake a life cycle assessment (LCA) for a product. LCA seeks to minimize the environmental burden arising from the manufacture, use, and eventual disposal of products. Design engineers; in particular, ought to consciously plan for product retirement. For example, should the product be discarded in a landfill, reused, or recycled in whole or in part? Unlike the first environmental revolution in the1970s, which was aimed at cleaning up hazardous waste from contaminated sites and natural resources, the Second revolution is addressing waste reduction at the source. It means bringing the problem into the product design and development process and solving it through product design tools. Between product development process stages, assembly and disassembly play key roles in supporting sustainability. Considering Design issue from manufacturers and recyclers view clarifies an obvious contradiction between their goals. A manufacturer is interested to get higher profit through decreasing the production cost and accelerating the product development process. Obviously, these aims are reachable through considering design for assembly and design for manufacturing. On the contrary a recycler is interested to enlarge the profit by considering End of Life Value and Recycling Cost. These goals are reachable only through Design for Disassembly and Design for Remanufacturing. There are many different Quantitative evaluation procedures to evaluate and improve design for assembly that mostly concentrates on evaluating the design and improving it using quantitative methods. For improving the design, eight guidelines are applied in Boothroyd-Dewhurst quantitative method including reducing part count and part types, striving to eliminate adjustments, Designing parts to be self-aligning and self-locating, Ensuring adequate access and unrestricted vision, Ensuring the ease of handling of parts from bulk, Minimizing the need for reorientations during assembly, Designing parts that cannot be installed incorrectly, Maximizing part symmetry if possible or make parts obviously asymmetrical. In addition, there are some disassembly design guidelines such as combining elements, Limiting material variability, using compatible material, Grouping harmful materials to subassemblies, Providing easy access to harmful, valuable or reusable parts, using Accessible drainage points, Using fasteners easy remove or destroy, Minimizing number of fasteners. All of assembly and disassembly guidelines have prominent effects on design which ends to suitable option for product parts end of life option. This will result on product recyclability in terms of economically justifiable recycling. In this paper based on different case studies including an electric pot, a hair clipper, a speaker and a printer different effects, that applying each guideline from assembly or disassembly view on product parts recyclability may have, are investigated