Brett A. Peters

Flexible machine layout design for dynamic and uncertain production environments

Flexible manufacturing systems operate in a dynamic environment and face considerable uncertainty in production demands. The development of a flexible machine layout is a critical issue in creating a system that can respond effectively to these requirements. Unlike most existing methods for creating flexible layout designs, the procedure developed in this paper is not restricted to equal size machines. It optimizes the trade-offs between increased material handling costs as requirements change and machine rearrangement costs needed to adapt the layout to these changes. The proposed flexible machine layout design procedure formulates and solves a robust machine layout design problem over a rolling horizon planning time window. The formulation, details of the solution methodology, illustrative examples, and computational results are presented.

Integrated facility layout and material handling system design in semiconductor fabrication facilities

Semiconductor manufacturing is an important component of the U.S. manufacturing industry. Most of todays fabrication facilities and those being designed for the near future use a bay layout configuration and an overhead monorail system for moving material between bays. These material handling systems are usually designed with a spine or perimeter type of configuration. This paper investigates the layout and material handling system design integration problem in semiconductor fabrication facilities and proposes a methodology for solving this integrated design problem. A spacefilling curve approach is used to address the facility layout, while the structure of the spine and perimeter configurations are exploited to create a network flow problem to determine the material handling system design. Computational results are presented and show exceptional promise for this procedure in solving the integrated design problem in a semiconductor manufacturing environment.

A genetic algorithm for facility layout design in flexible manufacturing systems

The flexible manufacturing system (FMS) facility layout problem (FLP) involves the positioning of cells within a given area so as to minimize the material flow costs between cells. The FLP design includes specifying the spatial coordinates of each cell, the orientation of each cell in either a horizontal or vertical position, and the position of each cells pickup and dropoff points. The layout design problem is both tactically and strategically important since the layout plays a large role in determining the efficiency and flexibility of the system. The FMS layout problem differs from traditional layout problems in that there are additional constraints on a cells shape and orientation and the location of the pickup/ dropoff points must be determined. A mixed integer programming formulation for the FLP developed by Das (1993) is adapted and heuristically solved in this paper. Because of the NP-hard nature of the solution space, a genetic algorithm based decomposition strategy is proposed and computationa...

Layout design for flexible manufacturing systems considering single-loop directional flow patterns

To achieve high productivity in a flexible manufacturing system (FMS), an efficient layout arrangement and material flow path design are important due to the large percentage of product cost that is related to material handling. The layout design problem addressed in this paper has departments with fixed shapes and pick-up/drop-off points. It is an open-field type layout with single-loop directed flow path. A two-step heuristic is proposed to solve the problem. It first solves a traditional block layout with directed-loop flow path to minimize material handling costs by using a combined spacefilling curve and simulated annealing algorithm. The second step of the proposed methodology uses the resulting flow sequence and relative positioning information from the first step as input to solve the detailed FMS layout, which includes the spatial coordinates and orientation of each FMS cell. This detailed FMS layout problem is formulated and solved as a mixed integer program. Empirical illustrations show promising results for the proposed methodology in solving real-world type problems.

Simulation metamodel development using uniform design and neural networks for automated material handling systems in semiconductor wafer fabrication

Abstract Simulation is very time consuming, especially for complex and large scale manufacturing systems. The process of collecting adequate sample data places limitations on any analysis. This paper proposes to overcome the problem by developing a neural network simulation metamodel that requires only a comparably small training data set. In the training data set, the configuration of all input data is generated by uniform design and the corresponding output data are the result of simulation runs. A dispatching problem for a complex simulation model of an automated material handling system (AMHS) in semiconductor manufacturing is introduced as an example. In the example, there are 23 4-levels factors, resulting in a total of 423 possible configurations. However, by using the method proposed in this paper, only 28 configurations had to be simulated in order to collect the training data. The results show that the average prediction error was 3.12%. The proposed simulation metamodel is efficient and effective in solving a practical application.

Simulation as a planning and scheduling tool for flexible manufacturing systems

This paper describes a flexible simulation technique which facilitates automated experimentation of different scheduling rules. An enhanced version of Arena/SIMAN is used to develop an extremely high fidelity model of the manufacturing system. The decision making of an FMS is characterized and a framework for simulation-based scheduling and control is also introduced.

A spine layout design method for semiconductor fabrication facilities containing automated material‐handling systems

A bay configuration arranged along a central spine and served by an automated monorail material‐handling system are common designs for the layout and material‐handling system in new semiconductor wafer fabrication facilities. Investigates the facility design problem in semiconductor fabrication facilities and proposes a procedure to determine the optimal spine layout design, given a design of the material‐handling system. Explains and tests the procedure to demonstrate the use of the model for solving semiconductor facility design problems. The procedure is applicable for the important semicondutor industry as well as in other facilities that use a central spine layout configuration.

Closed form models for determining the optimal dwell point location in automated storage and retrieval systems

This paper examines the problem of where a storage/retrieval machine should reside, or dwell, when an automated storage and retrieval system (AS/RS) becomes idle to minimize the expected value of the next transaction time. After a review of the relevant literature on AS/RS dwell point strategies, this paper proposes several analytical models of these expected response times of the AS/RS based on the relative locations of the input and output ports of the AS/RS. It uses a continuous rack approximation to provide analytical models of the dwell point location problem. These models provide closed form solutions for the dwell point location in an AS/RS. Extensions are made to consider AS/RS with a variety of configurations including multiple input and output ports. These models not only provide solutions to the dwell point location problem, but they provide considerable insight into the nature of this problem, which is particularly valuable when the requirements facing the AS/RS are uncertain.

Analysis of dual-shuttle automated storage/retrieval systems

Abstract This paper addresses the throughout improvement possible using a dual-shuttle automated storage/retrieval system. Travel-between time in a dual-command cycle is virtually eliminated, resulting in large throughput improvement. The system is extended to perform an equivalent of two dual commands in one cycle in a quadruple-command mode (QC). A heuristic that sequences retrievals to minimize travel time in the QC mode is developed. Monte Carlo simulation results show that the heuristic performs well, achieving large throughout improvement compared with that of the dual-command cycle operating under the nearest-neighbor retrieval-sequencing heuristic.

Replanning and analysis of partial setup strategies in printed circuit board assembly systems

This paper considers the operation of component placement equipment for the assembly of printed circuit boards (PCBs) in a medium-volume, medium-variety manufacturing environment. It focuses on the setup management and operational planning issues associated with productive use of these expensive resources. The concept of replanning is introduced to adapt to changes in the production environment by explicitly considering the initial state of the system. The partial setup strategy is suggested as a means of efficient adaptation and as a strategy that subsumes other setup strategies encountered in practice and the literature. These concepts are applied to the optimization of a single-placement machine producing multiple products. The results of using partial setups are compared with other commonly used strategies. Experimental results suggest significant gains at the singlemachine level. Future research is being pursued to improve the solution procedures and extend these replanning concepts to the line level.