Showing papers on "Remanufacturing published in 1997"

Simple optimal replenishment and disposal policies for a product recovery system with leadtimes

Abstract: The paper addresses a problem of product recovery management where a single product is stocked in order to fulfill a stochastic demand of customers who may return products after usage, thus generating also stochastic product returns. The material flow can be controlled by procuring new products on the one hand, and by remanufacturing or disposal of returned items on the other. A situation is considered where all costs are proportional and where remanufacturing as well as procurement needs a fixed deterministic leadtime which can be different for both activities. For periodic review control it is shown how the optimal decision rules for procurement, remanufacturing and disposal can be evaluated by exploiting the functional equations of a dynamic programming formulation. The serious impact of leadtimes on the complexity of the control rule is elaborated, and it is demonstrated for which leadtime situations simple optimal policies can be derived.

The economics of tire remanufacturing

Abstract: The world market for tires is described to identify the current material flow from raw materials to tires and the used tire disposal problem. Then, I describe the value-adding operations in the tire production process and in the tire retreading process. Once retreading is identified as the only recovery alternative that maximizes tire utilization, I explain why heat generation is the only recovery alternative, when retreading is not technically feasible. The economic values of heat generation in electric plants and in cement kilns are discussed. The paper culminates with the case of retreading, the tire remanufacturing process and the recommendation of a simple decision rule for selecting the number of times a tire should be retreaded to maximize its utilization.

An evaluation of capacity planning techniques in a remanufacturing environment

Abstract: Remanufacturing is a growing segment of the manufacturing industry, aided by environmental greening initiatives. There is scant literature on how to manage operations in this emerging industry segment. In this study, an important component of the manufacturing planning and control function, capacity planning is analysed. It is shown that the remanufacturing environments characteristics are sufficiently different from the traditional new product manufacturing environments that production planning and control techniques need to be different. New capacity planning techniques are developed and implemented along with some standard capacity planning techniques in a remanufacturing environment. The results show that the new techniques, developed for the remanufacturing environment are significantly better than the standard techniques, which had been developed for the traditional new product manufacturing environment.

Product structure complexity and scheduling of operations in recoverable manufacturing

Abstract: Recoverable manufacturing is becoming an increasingly important alternative to firms as they develop environmentally sound strategies aimed at minimizing waste and resources. Remanufacturing helps minimize costs and conserve resources through methods such as extending product life cycles via refurbishments and technical upgrades which require the use of only a fraction of the resources and energy associated with a new product. In this study the impact of product structure complexity on other managerial operating decisions is examined in a remanufacturing environment. It is shown that in the remanufacturing environment, with its greater inherent uncertainty, product structure complexity significantly affects the choice of scheduling policies used. Recommendations as to the scheduling policy to use for a dominant product structure in a given environment are made.

The economics of personal computer remanufacturing

Abstract: Personal computers (PCs) are among the durable goods of shortest life cycle Given the increased population of PCs, and their quick turnover, their disposal represents a considerable environmental concern However, many users do not require the latest technology for running their applications This opens an opportunity for renovated or remanufactured machines This paper addresses the complexity of PC manufacturing and the difficulties in developing adequate recovery processes A recovery process is proposed and evaluated It allows the coexistence of two markets: one for remanufactured PCs and another for all-new PCs

Buffering from material recovery uncertainty in a recoverable manufacturing environment

Abstract: Remanufacturing is becoming an increasingly important alternative to firms as they develop environmentally sound strategies aimed at minimizing waste and resources. Remanufacturing helps minimize costs through such methods as extending product life cycles via refurbishments and technical upgrades which require only a fraction of the resources and energy associated with a new product. The remanufacturing environment is characterized by a far greater degree of uncertainty than new manufacturing, due to such factors as material recovery uncertainty and probabilistic routings. In this study the use of safety stocks, with a material requirement planning system, to deal with the high inherent uncertainty in the system is examined. It is shown that some safety stocks must be kept in the system but have limited applicability. Additional safety stocks do not provide the manager in this environment with any added benefit beyond that obtained by keeping a minimum recommended level. The results obtained are somewhat counter-intuitive, since adding additional levels of safety stock does not add additional coverage when lead times are greater than one planning period. This lead time effect is explained fully and recommendations as to safety stock level to invest in are made.

Rough-cut capacity planning for remanufacturing firms

Abstract: Capacity planning is a critical element of any successful production planning and control system. A method of rough-cut capacity planning is developed, based on the bill-of-resources approach, that can be used to plan for capacity required for firms in a remanufacturing including overhaul repair operations environment. The modified bill-of-resources approach developed takes into account two major stochastic elements inherent in this environment; probabilistic material replacement factors and probabilistic routing files. A detailed example from an actual repair overhaul operation is presented to illustrate the technique.

Production planning for companies with product recovery and remanufacturing capability

Abstract: We present an integrated set of models addressing issues of production planning in supply chains involving product recovery and disassembly. The supply chain models can be used to develop production plans in the short term, or examine the effects of different strategies in the long term. Uncertainty is addressed by using deterministic models to solve a range of different scenarios. We also develop models to determine profitable disassembly configurations for single and multiple products. Results to date are reported and future directions discussed.

Opening the books.

Abstract: For years, small companies have experimented with forms of open-book management. Open-book systems have smoothed change efforts by giving workers the why instead of just the how of initiatives; they have enabled employees to think like owners. Now divisions of large organizations such as R.R. Donnelley & Sons and Amoco Canada are finding opening the books can work for them, too. It isn't easy, and companies must adapt the principles to their own situations. AES Corporation, for example, found that it had to declare all its employees "insiders" when it went public. One of the reasons for large companies' interest in open-book management is the success of a role-model company, Missouri-based Springfield ReManufacturing. Leaders of divisions of large companies have been able to visit and ask questions. Other early adopters are also showing competitive advantages. Among them are Wabash National, now the nation's leading truck and tractor manufacturer, and Physician Sales & Service, a distributor of supplies to doctors' office. Open-book principles are the same whether a company is large or small: every employee must receive all relevant financial information and be taught to understand it; managers must hold employees accountable for making their unit's goals; and the compensation system must reward everyone for the overall success of the business. Hexacomb Corporation is one large organization that has done well. Workers at the company's seven plants are inspired by a system of splitting profits over budget fifty-fifty: half goes to the company and half to the bonus pool. Such companies are learning the benefits of having everyone work to push the numbers in the right direction.

Recoverable manufacturing systems: a framework for analysis

Abstract: Recoverable product environments are becoming an increasingly attractive way of providing environmentally friendly products. These type of systems avoid the problem of pollution by extending a product's useful life and by recycling materials at the end of a product's life. The management and control of recoverable manufacturing systems are more difficult than in traditional manufacturing systems. Recoverable manufacturing systems include both repair and remanufacturing operations, which differ in key control aspects. In addition, the amount of variability, with respect to materials and scheduling, in both repair and remanufacturing operations is inherently higher than in traditional manufacturing. Here, the authors provide a framework which allows for the analysis of a recoverable manufacturing system and identifies the key areas for research in order to provide effective management and control of such systems.

There shops, three strategies: Using MRP-II, JIT, and TOC in remanufacturing cells

Abstract: Most articles on remanufacturing strategy tend to focus on the overall remanufacturing environment, neglecting the measurement and cost aspects of productivity and quality improvement. Here the author discusses how one organization used a variety of manufacturing strategies in three different remanufacturing shops. He also details how to use simulation models and activity-based costing techniques to ensure that any strategies employed ultimately yield desirable outcomes.

Planning and Re-planning Strategy of Disassembly Processes

Abstract: This paper presents a framework for optimal planning and replanning of disassembly processes. Planning is formulated as a graph search where the graph consists of all the feasible disassembly sequences. The process of re-planning is based on adaptation of the original plan whenever new evidences on the product condition are discovered or new goals are considered. Adaptation scheme uses dependencies among product’s components to propagate uncertainty regarding their condition as sensed during the disassembly process. Using the proposed framework we present a simple algorithm for efficient remanufacturing of product.

Integrating i-deas with remanufacturing and assemblability assessments

Abstract: A growing concern about the environment, and especially about waste and landfill, has motivated research into environmentally conscious design and manufacturing approaches. This has placed new burdens on designers. In order to aid designers in their new tasks, one of our objectives is to minimize the gathering of information and maximize the utility of existing design information. In the research discussed in this paper, the specific objective is to enable the quantification and enhancement of product remanufacturability. Guidelines for integrating some of the commercially available CAD packages (like I-DEAS, Pro/ENGINEER, CATIA) to remanufacturing assessments, and ways to use the input information to these assessments for making other assessments (like assemblability) are developed. A number of case studies are given to illustrate the approach. Our long term goal is to identify the minimum amount of information needed to do effective design for the life-cycle. NOMENCLATURE #Ideal - Total number of ideal parts #Parts - Total number of parts #Ideal Insp - Total number of ideal inspections #Repl - Total number of parts replaced #Tests - Total number of tests conducted before reassembly #Key Parts - Total number of key parts #Key Repl - Total number of key parts replaced #Refurbished - Total number of refurbished parts

A reverse logistics supply chain model within a remanufacturing environment

Abstract: Summary form only given. A recoverable product environment is one in which all, or as much as feasible, of the product is recovered and put back in use after the initial product life is over, rather than discarding the used product. Integral to the recoverable product environment is the recoverable manufacturing system which focuses on recovering the product and extending its life through remanufacture or repair. The flow of materials and products in this environment occurs both from the customer to the remanufacturer, and from the remanufacturer to the customer. Since most of the products and materials are conserved, this essentially forms a closed-loop logistics system. Acquisition of the used product from the consumer base, remanufacturing it at specified locations, and distributing it back to the consumer base are important activities which must be carefully coordinated if a remanufacturing firm is to remain profitable. We provide a mixed integer programming model to accomplish the coordination. The model seeks to minimize the total cost of this process. The model is solved using data generated on the basis of a real remanufacturing facility using the GAMS modeling package. The solution provides the location of the manufacturing/distribution facilities, the product types collected at each facility for remanufacturing from various collection zones, and the distribution of the remanufactured products to the various customer zones, so as to minimize the costs of distribution, inventory and remanufacturing.

The Economics of PC Remanufacturing

Abstract: Personal computers are among the durable goods of shortest life cycle. Given the increased population of PCs, and their quick turnover, their disposal represent a considerable environmental concern. However, many users do not require the latest technology for running their applications. This opens an opportunity for renovated or remanufactured machines. This paper addresses the complexity of PC manufacturing and the difficulties in developing adequate recovery processes. A recovery process is proposed and evaluated. It allows the coexistence of two markets: one for