Surendra M. Gupta
Sagar V. Kamarthi, Seamus M. McGovern
Date of Award
Doctor of Philosophy
Department or Academic Unit
College of Engineering. Department of Mechanical and Industrial Engineering.
Disassembly, Inventory Control, Reverse Logistics
Recent years have witnessed Reverse Supply Chain (RSC) become the center of attention for researchers and Original Equipment Manufacturers (OEMs). The fast depletion of virgin resources and the rapid increase of product returns from customers to original manufacturers for maintenance, repair or to be disposed of can be said to be one of the main reasons behind this interest. Electronics manufacturers have introduced state-of-the-art technologies in quick succession. As a result of this, the end-of-life (EOL) products returned by customers have grown significantly in volume. But often these EOL products are found to be in excellent working conditions (functional). Customers return them because of the various marketing programs or favorable incentives offered by service providers or manufacturers that create a "must have" sense in the minds of customers to acquire upgraded products. In the past two decades environmental concerns have influenced production processes, as environmental regulations have targeted pollution from industry. However, there is growing awareness that this may not be sufficient and it is increasingly recognized that the use and disposal phases, as well as the production phase of the product life cycle, are important. Environmentalists have always demanded that the manufacturing companies should take these products back and manage them in an environmentally conscious manner. End-of-Life (EOL) products can be remanufactured, reused, recycled, or disposed of. However, manufacturers have not invested or engaged themselves in such initiatives because of the uncertainty associated with the process.
Many corporations have understood the economic and environmental benefits of minimizing the use of virgin resources. Also, due to evolving environmental legislation, they have started to comprehend the importance of the recovery process and are taking serious steps in restructuring their supply chain processes to meet the new regulations. The idea behind the change is to use materials and parts more than once before they are finally discarded. Thus, effective supply chain management is vital in gaining a competitive edge over other corporations. The take-back process is clearly more environment friendly than the traditional forward supply chain process as it "closes the loop" of the supply chain process and transforms the EOL products into new serviceable products. This new portion of the supply chain is known as Reverse Supply Chain. It has been found that the original supplier is in the best position to control the return process. The reverse supply chain logistics model operates independently of the forward supply chain that delivered the original product.
In comparison to regular supply chain management, the management of reverse supply chain is more challenging because it is much more reactive and less visible. A major challenge is inventory control and value management of EOL products. Due to the disparity between demand for parts and materials and their line yields, the decision maker faces economical as well as physical constraints when trying to take a decision on how many products to take back and when to take them back, and when to keep them and for how long before they are finally disposed of.
The objective of this research is to develop inventory control policies of on hand inventory (OHI) of returned products and disassembled parts in such a way that total variable costs of the system is minimized and the profit is maximized, and also to provide management tools that can help improve the overall performance of the disassembly line. These inventory management and planning questions have not been fully addressed in the literature.
In this research, two types of approaches have been presented and tested to model the inventory control problem in context of disassembly. The first type of approaches is deterministic, while the second type of approaches is stochastic. The performances of the two approaches have been tested given the uncertainty of demand, return and product on the total solution cost. The results show that stochastic models outperform the deterministic model when uncertainty levels are high, and provide a better solution.
The various techniques presented in this dissertation provides knowledge that helps in understanding the challenges and opportunities associated with inventory control in a disassembly line context and form a body of knowledge that helps in addressing the inventory problems associated with a disassembly line.
Badr O. Johar
Johar, Badr O., "Inventory control issues in a disassembly line" (2010). Industrial Engineering Dissertations. Paper 9. http://hdl.handle.net/2047/d20002809
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