Reggie J. Caudill

Disassembly modeling, planning, and application

Abstract The practice of industrial recycling and remanufacturing is growing in importance due to increasing environmental and economic pressures. Industrial recycling and remanufacturing involves product disassembly to retrieve the desired parts and/or subassemblies by separating a product into its constituents. Disassembly modeling and planning is more challenging than assembly because its terminal goal is not necessarily fixed, but may depend on product usage and market demands for used parts and recycled materials. Moreover, disassembly is accompanied by more uncertainty in system structures and component conditions than is assembly. This paper presents recent methods for modeling and process planning in disassembly and the applications to industrial products. The main purpose of this paper is to survey the state of the art of this emerging area to supply important information for future study.

An integrated e-supply chain model for agile and environmentally conscious manufacturing

This paper presents a mathematically sound model for the design and optimization of supply chains in terms of such important performance indexes as product cost, cycle time, quality, energy and environmental impact in the context of global and Internet-based manufacturing. The two layer model is a hyper-network of material flows overlaid with an e-business information network. It extends from a traditional supply chain having suppliers, distributors, and users to include end-of-life product collectors and de-manufacturers. Furthermore, it extends the performance considerations from cost and productivity to include environmental performance. Such extensions allow one to develop Internet-based manufacturing systems that are agile and can produce desired products with the minimum environmental impact over their life cycles. Fuzzy logic-based optimization goals are used in the proposed multiobjective optimization model. A personal computer containing such mechatronic components as hard disk driver, keyboard, and mouse is used as an example to illustrate the application of the proposed integrated e-supply chain model.

Methods toward supply chain risk analysis

Events like the 9/11 terrorist attack on the World Trade Center and the 11-day work stoppage at 29 West Coast ports have exposed the vulnerabilities of a key element of Americas economic infrastructure-business supply chains. To sustain business in todays new risk environment, it is necessary to assess the vulnerability of business chains and develop continuity and operational plans to mitigate consequences and assure continuation of critical processes. This paper reviews existing techniques used in decision making for risk analysis and presents a modeling and analysis framework for assessing business risk and evaluating safeguards to secure the supply chain.

Design of artificial neural networks for tool wear monitoring

An on-line scheme for tool wear monitoring using artificial neural networks (ANNs) has been proposed. Cutting velocity, feed, cutting force and machining time are given as inputs to the ANN, and the flank wear is estimated using the ANN. Different ANN structures are designed and investigated to estimate the tool wear accurately. An existing analytical model is used to obtain the data for various cutting conditions in order to eliminate the huge cost and time associated with generation of training and evaluation data. Motivated by the fact that the tool wear at a given instance of time depends on the tool wear value at a previous instance of time, memory is included in the ANN. ANNs without memory, with one-phase memory, and with two-phase memory are investigated in this study. The effect of various training parameters, such as learning coefficient, momentum, temperature, and number of hidden neurons, on these architectures is studied. The findings and experience obtained should facilitate the design and implementation of reliable and economical real-time systems for tool wear monitoring and identification in intelligent manufacturing.

Disassembly modeling, planning and application: a review

Industrial recycling and remanufacturing is practice of growing importance due to the increasing environmental and economic pressures. It involves product disassembly to retrieve the desired parts and/or subassemblies by separating a product into its constituencies. The disassembly process modeling and planning is more challenging than assembly since its termination goal is not necessarily fixed depending on the system status. Moreover, it is uncontested that disassembly is charged with more uncertainty in system structures and component conditions than assembly. The paper reviews methods for modeling and process planning in disassembly. Its purpose is to survey the state-of-the-art of this emerging area to supply important information for future study.

Disassembly Petri net approach to modeling and planning disassembly processes of electronic products

A principal process during the remanufacturing of worn-out or malfunctioning products is disassembly that enables the dumping, cleaning, repair or replacement of components as desired. Products subjected to disassembly exhibit uncertainty in the product structure and component conditions. Hence the termination goal (the level of disassembly) is subject to change, and the disassembly plan must be adapted. This paper proposes a disassembly Petri net (DPN) for the modeling and adaptive planning of disassembly processes. The proposed methodology and algorithms are demonstrated in the paper through the sample disassembly of a telephone.

MULTI-LIFECYCLE PRODUCT RECOVERY FOR ELECTRONIC PRODUCTS

Sustainable industrial development seeks to meet current needs of society without compromising the ability of future generations to satisfy their own needs. In order to be able to sustain further the growth and development, we have to become more environmentally conscious in the development, manufacturing, use, and post-life treatment of products. Based on the concept of design for environment and multi-lifecycle engineering, this paper introduces a multi-lifecycle product recovery model, optimal retirement planning, and design selection methods. Two electronic products are used to illustrate the proposed concepts and methods. The results are useful in helping designers take into account the environmental impact into their product and process design activities.

A hybrid heuristic search algorithm for scheduling flexible manufacturing systems

This paper presents a hybrid search algorithm for scheduling flexible manufacturing systems (FMS). The algorithm combines heuristic best-first strategy with controlled backtracking strategy. Timed (place) Petri nets are used for problem representation. Their use allows to explicitly formulate concurrent activities, multiple resources sharing, precedence constraints and dynamic routing in FMS operation. The hybrid heuristic search algorithm is combined with the execution of the timed Petri nets to search for an optimal or near-optimal and deadlock-free schedule. The backtracking strategy is controllable. One can only employ the pure best-first search to obtain an optimal schedule thanks to a proposed admissible heuristic function. The presented method is illustrated through an FMS scheduling problem.

Vibration control of linear robots using a piezoelectric actuator

This paper presents the results of vibration control strategy for high-speed linear robots using an auxiliary piezoelectric actuator. With acceleration reaching 3 g, rapid horizontal slewing motion inevitably excites the structural resonances of the robot and generates vertical vibration forces exceeding the tolerance of the end-effector. Instead of controlling the robot vibration from the main actuators (ac servomotors with limited bandwidth), a piezoelectric actuator is deployed to provide vibration suppression at the load in the z direction. This way the robot is treated as a disturbance generator while the piezoactuator is considered as the plant. A digital servocompensator is then designed and implemented to suppress these vibration modes. Typically, attenuation is achieved for the dominant mode with 30 dB and other modes with 15 dB. Suppression of vibration up to seven modes has been implemented satisfactorily.

Integration of disassembly leveling and bin assignment for demanufacturing automation

As an integral part of a product life cycle, demanufacturing is a process of disassembling a product and assigning collection bins for the resultant subassemblies and parts, which are then reused, remanufactured, reengineered, or disposed of. This paper proposes an algorithm to determine disassembly levels and bins in an integrated way to maximize the profit from a used product through balancing the resource invested in disassembly processes, the return, and the environmental impact caused by them. The algorithm utilizes the information from a computer-aided design system and requires minimal user input with the computational complexity of O(n/sup 2/+mn), where n is the number of parts and final subassemblies in a product, and m is the number of collection bins. It has been successfully used in the development of a demanufacturing stage of a multi-life cycle assessment and analysis tool. The benefit of the proposed algorithm is illustrated through a laptop computer example.