Surendra M. Gupta

Environmentally conscious manufacturing and product recovery (ECMPRO): A review of the state of the art.

Gungor and Gupta [1999, Issues in environmentally conscious manufacturing and product recovery: a survey. Computers and Industrial Engineering, 36(4), 811-853] presented an important review of the development of research in Environmentally Conscious Manufacturing and Product Recovery (ECMPRO) and provided a state of the art survey of published work. However, that survey covered most papers published through 1998. Since then, a lot of activity has taken place in EMCPRO and several areas have become richer. Many new areas also have emerged. In this paper we primarily discuss the evolution of ECMPRO that has taken place in the last decade and discuss the new areas that have come into focus during this time. After presenting some background information, the paper systematically investigates the literature by classifying over 540 published references into four major categories, viz., environmentally conscious product design, reverse and closed-loop supply chains, remanufacturing, and disassembly. Finally, we conclude by summarizing the evolution of ECMPRO over the past decade together with the avenues for future research.

Disassembly modeling for assembly, maintenance, reuse, and recycling

DISASSEMBLY PRACTICE Introduction Assembly and Disassembly History Levels of Aggregation Disassembly Optimization Basic Terminology Product Modeling Summary of the Chapters References Context of the End-Of-Life Disassembly Introduction Industrial Ecology Complex Products Complex Products Waste Breakdown Analyses of Some Prominent Complex Products Conclusion References The Disassembly Process Introduction The Product The Process Cost Metrics Revenue Metrics Economic Optimization Economic-Ecological (Eco-Eco) Models Example: Disassembly of Discarded Cars Conclusion References DISASSEMBLY SEQUENCING Disassembly Network Features Introduction Disassembly Process Representation Unconstrained Products Topologically Constrained Products Weakly Connected Products Geometrically Constrained Products Conclusion Appendices References Geometrical Constraints and Precedence Relationships Introduction Earlier Research on Precedence Relationships Bourjaults Method The Cut-Set Method A Moderately Complex Example m-Disassemblable Products Complex AND/OR Relationships Three-Dimensional Applications Disassembly Precedence Graphs Constrained Connection Diagrams Conclusion References Surface- and Direction-Oriented Analysis, and Modularity Introduction Product Representation and Classes Surface-Oriented Analysis Direction-Oriented Approach Interference Graphs Modularity Analysis Stability Analysis Force-Flow Analysis Conclusion References Selecting the Optimum Disassembly Sequence Introduction Sequence Independent Costs Sequence Dependent Costs, Heuristics, and Restricted Exact Methods Rigorous Exact Methods Demand-Dependent Problems Conclusion References DISASSEMBLY PLANNING Disassembly to Order Problems: Multi-Criteria Methods Introduction Multi-Criteria Methodologies Goal Programming Linear Physical Programming Conclusion References Disassembly Line Balancing Problems Introduction An Assembly Line Versus a Disassembly Line Balancing a Disassembly Line Description of the Disassembly Line Balancing Problem Heuristic and Metaheuristic Methods For Solving the DLBP Conclusion References

Operations Planning Issues in an Assembly/Disassembly Environment

The establishment of disassembly plants and the creation of product designs which specifically facilitate disassembly are enabling manufacturers to carry out item segregation. Item segregation is defined as the separation from an assembly of a part or a group of parts by following a reverse assembly process. Once segregated, the items can be reused, recycled or discarded. However, there are operational problems associated with item segregation. Foremost among these are the lack of planning and scheduling mechanisms, difficulty in coping with reverse flow of materials and item explosion. Despite the economic and environmental benefits of disassembly, researchers and practitioners are lagging behind in developing methodologies to address the operations and production planning and control issues associated with item segregation. These issues are addressed.

Disassembly line in product recovery

There are several situations in a product recovery environment where products may be disassembled for economical and regulatory reasons. The disassembly line is perhaps the most suitable setting for disassembly of large products (consisting of numerous components) as well as small products received in large quantities. This paper discusses the importance of a disassembly line in product recovery. The objective of the disassembly line is to utilize the available resources as efficiently as possible while meeting the demand for recovered parts. However, there are many complicating matters that need to be considered to create an efficient disassembly line. Our primary goal is to discuss these issues and provide a better understanding of the complications and their effects on the disassembly line. We also demonstrate how some important factors in disassembly can be accommodated to balance a paced disassembly line by modifying the existing concept of assembly line balancing. An example is presented to illustrate the approach.

A balancing method and genetic algorithm for disassembly line balancing

Disassembly activities take place in various recovery operations including remanufacturing, recycling and disposal. The disassembly line is the best choice for automated disassembly of returned products. It is therefore important that the disassembly line be designed and balanced so that it works as efficiently as possible. The disassembly line balancing problem seeks a sequence which: is feasible, minimizes workstations, and ensures similar idle times, as well as other end-of-life specific concerns. However finding the optimal balance is computationally intensive with exhaustive search quickly becoming prohibitively large even for relatively small products. In this paper the problem is mathematically defined and proven NP-complete. Additionally, a new formula for quantifying the level of balancing is proposed. A first-ever set of a priori instances to be used in the evaluation of any disassembly line balancing solution technique is then developed. Finally, a genetic algorithm is presented for obtaining optimal or near-optimal solutions for disassembly line balancing problems and examples are presented to illustrate implementation of the methodology.

Disassembly of multiple product structures

In this paper, we address the problem of scheduling the disassembly of discrete parts products characterized by well-defined product structures. We allow for the existence of multiple product structures as well as the existence of common parts and/or materials which make the problem very complex. To this end, we present two companion algorithms which can be applied to obtain a disassembling scheme for such problems. Specifically, the algorithms determine the quantity and operations schedule of disassembly for all product structures (including the ordering of the roots and the disassembly schedule for the roots and the subassemblies) in order to fulfil the demand for the various parts. An example is presented to illustrate the use of the algorithms.

ENVIRONMENTAL CONCERNS AND RECYCLING/DISASSEMBLY EFFORTS IN THE ELECTRONICS INDUSTRY

This paper reviews the problems that many electronics manufacturers are facing in a society of rules and regulations that are becoming increasingly environmentally conscious. The effect of electronics assembly, disassembly, and disposal on the environment is reviewed, and the potential hazards of continuing the present trends in electronics parts disposal is discussed. The paper contains a comprehensive survey of previous works related to environmentally conscious manufacturing practices, recycling, and the complexities of disassembly in the electronics industry. Interest in this area has intensified in recent years due to an increased awareness of the problem in a world of high technology where electronic products dominate. Industrial applications of recycling programs are presented and existing methodologies and evaluation systems are discussed. In order to promote and support this new environmental ethic in electronics assembly and disassembly, the need for improved methods of electronics reuse, minimi...

Petri net approach to disassembly process planning for products with complex AND/OR precedence relationships

Abstract We present a Petri net (PN)-based approach to automatically generate disassembly process plans (DPPs) for product recycling or remanufacturing. We define an algorithm to generate a geometrically-based disassembly precedence matrix (DPM) from a CAD drawing of the product. We then define an algorithm to automatically generate a disassembly Petri net (DPN) from the DPM; the DPN is live, bounded, and reversible. The resulting DPN can be analyzed using the reachability tree method to generate feasible DPPs, and cost functions can be used to determine the optimal DPP. Since reachability tree generation is NP-complete, we develop a heuristic to dynamically explore the v likeliest lowest cost branches of the tree, to identify optimal or near-optimal DPPs. The cost function incorporates tool changes, changes in direction of movement, and individual part characteristics (e.g., hazardous). An example is used to illustrate the procedure. This approach can be used for products containing AND, OR, and complex AND/OR disassembly precedence relationships.

An evaluation methodology for disassembly processes

Disassembly is a systematic process that allows reusable, non-recyclable, and hazardous subassemblies to be selectively separated from recyclable ones. In this paper, we present a methodology to evaluate different disassembly strategies so that the best one could be chosen. Since the identification of all possible disassembly sequences of complex products is not an easy task, we also propose a disassembly sequence generation heuristic which gives a near optimum disassembly sequence for a product. The application of the methodology is illustrated by considering an IBM PS/2 Model 30 computer base.

Disassembly sequence planning for products with defective parts in product recovery

Recycling and remanufacturing are important forms of product/material recovery which involve product disassembly to retrieve the desired parts and/or subassemblies. Disassembly is a systematic method for separating a product into its constituent parts, components or other groupings. Efficient disassembly requires development of disassembly sequence plans (DSPs). Generating DSPs describing the sequence of parts during disassembly is not a trivial problem since DSP generation is described to be NP-complete. Further complicating matters is the presence of a high degree of uncertainty due to upgrading/downgrading of the product during its use by the customers and defects occurring either when in use or during disassembly. In this paper, we address the uncertainty related difficulties in disassembly sequence planning. To this end, we present a methodology to develop a framework for dealing with uncertainty in DSP implementation and demonstrate it using a simple example.