A Nongraphical Method to Determine the Optimum Disassembly Plan in Remanufacturing

Optimizing a disassembly process involves maximizing the number of disassembled valuable parts (cores) and minimizing the number of disassembly operations. Usually, some disassembly operations are in common among two or more cores, or sometimes removing a core requires prior removal of other cores (known as precedence relations); these correlations complicate the allocation of the disassembly cost to the cores. To overcome this complexity, the current optimization methods (decision trees) determine the optimum sequence of disassembly operations rather than the optimum set of cores to be disassembled. These methods become difficult to implement when the number of cores increases. In this paper, we developed a mechanized nongraphical approach to determine the optimum set of cores to be disassembled and their required disassembly operations based on the functionality statuses of the cores. This approach introduces a new characterization of the disassembly process and its precedence relations, and can be implemented conveniently using computer codes even when the product consists of many cores. The application of the method is explained with an example. Using this example, it was shown that the optimum disassembly can increase the net profit significantly compared with the complete disassembly.

Disassembly Sequence Planning for Product Maintenance

Environmental and sustainable issues have brought more and more attention to industries in product design and manufacturing. It is important for a product to meet its lifecycle requirements in repairing, replacing and recycling. Disassembly is required in product maintenance and recycling. An efficient disassembly plan can reduce the cost of product maintenance and minimize the product repair time. This paper introduces an efficient method for selective disassembly planning for the need of product maintenance and recycling to reduce the product operation time and cost. The method is based on an efficient product representation and effective sequence searching. It considers the product structure, removing direction of components, operation constraints and complex in the product representation and sequencing planning. An example is used to verify the proposed method. Challenges and further work are also discussed.

A Label Correcting Algorithm for Partial Disassembly Sequences in the Production Planning for End-of-Life Products

Remanufacturing of used products has become a strategic issue for cost-sensitive businesses. Due to the nature of uncertain supply of end-of-life (EoL) products, the reverse logistic can only be sustainable with a dynamic production planning for disassembly process. This research investigates the sequencing of disassembly operations as a single-period partial disassembly optimization (SPPDO) problem to minimize total disassembly cost. AND/OR graph representation is used to include all disassembly sequences of a returned product. A label correcting algorithm is proposed to find an optimal partial disassembly plan if a specific reusable subpart is retrieved from the original return. Then, a heuristic procedure that utilizes this polynomial-time algorithm is presented to solve the SPPDO problem. Numerical examples are used to demonstrate the effectiveness of this solution procedure.

Dynamic Disassembly Planning for Remanufacturing of Multiple Types of Products

With the increased need for remanufacturing of end-of-life products, achieving economic efficiency in remanufacturing is urgently needed. The purpose of this study was to devise a cost-minimization plan for disassembly and remanufacturing of end-of-life products returned by consumers. A returned end-of-life product is disassembled into remanufacturable parts, which are supposed to be used for new products after being remanufactured. Each end-of-life product is disassembled into parts at variable levels as needed, taking into account not only disassembly but also manufacturing, remanufacturing, and holding inventory of remanufacturable parts. This study proposes a linear programming model for derivation of the optimal disassembly plan for each returned product, under deterministically known demand and return flows. For the purposes of an illustrative example, the proposed model was applied to the formulation of an optimal disassembly and remanufacturing plan of ‘Fuser Assembly’ of laser printers. The solution reveals that variable-level disassembly of products saves a significant remanufacturing cost compared with full disassembly.

Disassembly Planning and Timing Through a Petri Net Approach

Disassembly planning and costing is a major task in the achievement of sustainable manufacturing. This paper presents a systematic approach to identify the feasible ways to disassemble a product then to select the most economical one using reliable time data gathered from experimental and practice-oriented sources. The disassembly process is modeled after the Petri Net approach, a technique that has proven to be fairly popular with the research community in the last few decades. The result of our systematic approach is a reliable derivation for a time-effective disassembly plan.