Disassembly Modeling for Assembly, Maintenance, Reuse and Recycling

Citation

McGovern, S.M. (2007), "Disassembly Modeling for Assembly, Maintenance, Reuse and Recycling", Management Research News, Vol. 30 No. 4, pp. 314-316. https://doi.org/10.1108/01409170710722991

Product recovery seeks to obtain materials and parts from old or outdated products through recycling and remanufacturing in order to minimize the amount of waste sent to landfills as well as to allow for the reuse of parts, products, and materials. The first crucial step of product recovery is disassembly. Disassembly is the methodical extraction of valuable parts/subassemblies and materials from discarded products through a series of operations. It is a process that interacts with all phases of product recovery including before life (the period of design and life cycle analysis), the useful period (the time when the product is actually being manufactured or is in‐use), and end‐of‐life (the period in which a product completes its useful life and is ready for further processing, recovery, or disposal). Industry has grown to recognize the value of disassembly processes across a wide range of products. Also, increasing legislation that may soon require mandatory recycling of many post‐consumed goods, along with a desire to develop more environmentally benign end‐of‐life processes has further fueled research into this concept. Traditionally, disassembly has been viewed as the reverse of assembly; however, the recent literature has pointed out the significant (and disassembly's complexity increasing) differences. Disassembly Modeling for Assembly, Maintenance, Reuse and Recycling presents these concepts in the context of the entire product life cycle. In this first text to supply a comprehensive discussion of the theories and methodologies associated with this approach, the authors incorporate real‐world case examples to explore several main areas of theory and application. The text is broken into three parts: Disassembly Practice, Disassembly Sequencing, and Disassembly Planning. From this structure, it then examines the entire product life cycle by combining a scattered body of knowledge into one concise volume, enhancing clarity both by revising the existing theory and through practical examples, making use of 102 figures and 82 tables in the process.

Part I starts with a background on disassembly as well as some interesting historical perspective. In addition, various terms common to disassembly are introduced. The first chapter provides a good deal of well‐researched introductory information on disassembly, giving the novice a sound and appropriately sized collection of relevant introductory information. Chapter 2 provides a more detailed background on recycling, including historical aspects, definitions, and sample data, all of which should be of value to the text's target audience. Different aspects of the product life cycle are treated and the role of waste from complex products is placed within the larger framework of the overall waste issue. Industrial examples are presented and the concept of selective disassembly is discussed. The next chapter focuses on a detailed analysis of complex products as seen from an end of life disassembly perspective, including a cost analysis of disassembly tasks. Part II introduces the theoretical aspects of disassembly sequencing. Mathematically inclined, this section's first chapter reviews general and disassembly or assembly specific aspects of number theory, complexity, set theory, and graph theory. Representations considered include: state diagrams, AND/OR graphs, and disassembly precedence graphs. Physical examples of varying intricacy are presented and are then used effectively throughout the chapter to demonstrate techniques and limitations. The chapter provides a detailed background for any follow‐on study in disassembly planning. Chapter 5 shifts to the level of the product itself. Geometric constraints of products are analyzed and precedence relations are discussed. These are demonstrated with the aid of superset and subset rules, as well as the transformation of precedence relations into selection rules, providing a powerful tool for generating and representing the full set of feasible disassembly sequences. Chapter 6 compiles the theory dealing with the surface and component level, partly based in the literature on assembly. Other real‐world topics reviewed include forces and stability, and directional analysis. A more precise consideration of assembly tasks is visited as well. With this detailed analysis, it is shown how it is often possible to avoid some human intervention in the analysis at the product level, thus offering the opportunity for nearly fully automatic generation of a set of disassembly sequences. The following chapter is devoted to the methods used in finding optimum disassembly sequences. Mathematical programming is used to determine the optimum disassembly sequence, even in the large search space that is usually present. A number of extensions are also discussed. Part III initially deals with products having a hierarchical tree structure with Chapter 8 focusing on disassembly‐to‐order problems as well as multi‐criteria methodologies (including goal programming and linear physical programming). Finally, Chapter 9 introduces the recently defined disassembly line balancing problem, compares it to an assembly line, and solves it with demonstrative heuristic and metaheuristic methods.

Disassembly has gained a great deal of attention in the recent literature due to its role in product recovery, though it has been shown to face many unique challenges. Lambert and Gupta's 2005 text provides a timely introduction to various aspects of disassembly. It describes general and disassembly‐ or assembly‐specific aspects of number theory, complexity, set theory, and graph theory, while product examples of varying complexity are presented and used effectively throughout the text to demonstrate techniques and limitations. The examples chosen are appropriate and should prove helpful to any reader. In general, all terms are well defined and the mathematical notation used is appropriate and consistent throughout. The text provides detailed, valuable background for any quantitative study in disassembly. This is an excellent resource for companies that wish to enact environmentally conscious systems efficiently. With an analysis of associated costs, system design requirements, advantages, and expected results, this is also an indispensable tool for researchers, mechanical and industrial engineers, and professionals including industrial, environmental, management, and manufacturing engineers; engineering and businees school professors; supply chain, operations, and production managers, and European Union Waste Electrical and Electronic Equipment (WEEE) or Restriction of Hazardous Substances Directive (RoHS) directives compliance personnel.