摘要:

The design of material flow systems is a multifaceted problem. The designer is required to process large amounts of information and make complex decisions concerning the design objectives. A design framework for building material flow system models has been developed by the authors to take key steps towards the management of design complexity. This paper addresses the issue of selecting and sequencing software tools for building material flow system models within a design environment that contains a variable set of design tools. Strategies for performing these tasks as well as their implementation are discussed.

ISSN:0020-7543    

DOI:10.1080/00207549408956931

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The underlying assumptions of the Taguchi method for on-line quality control are developed. The method is applied to the simple random-walk case in a numerical simulation and in a gedanken experiment. Results are compared with conclusions in the literature. The occasional catastrophes are explained in a different way. Limits to consider when using the Taguchi method for the random-walk case are given.

ISSN:0020-7543    

DOI:10.1080/00207549408956932

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

When alternative process plans are considered in cellular manufacturing systems, there is potential for performing an operation required of a part on alternative machines. Under these circumstances, the cell formation problem of determining the assignment of parts and machines to each manufacturing cell can be viewed as being divided into two phases. The first phase deals with the problem of determining the number of machines of each type and a unique process plan for each part. In the second phase, the assignment of parts and machines to each manufacturing cell should be determined. This research examines the first-phase problem. A realistic formulation of the model is presented when the product-part mixes are stable over the planning horizon. As the problem is proven NP-hard in the strong sense, two different higher-level heuristics, based upon a concept known as tabu search, are presented. Each heuristic is further extended into two methods: 1 and 2. An extensive statistical analysis, based upon randomized block design, has been conducted to compare the performances of the heuristics. In three different problem structures attempted with a block size of 10, the results obtained show the superior performance of heuristic 2 over 1 with both methods. This further substantiates the fact that there is clearly a need for efficient heuristics to solve problems in manufacturing cell design that have any practical significance and one cannot rely on an exhaustive search algorithm such as the branch-and-bound technique incorporated in packaged software (LINDO and MPSX/M1P 370) as indicated in some of the published literature.

ISSN:0020-7543    

DOI:10.1080/00207549408956933

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The theory of constraints (TOC) is a production planning and control system reported to improve manufacturing performance surpassing both materials-requirement planning and just-in-time systems. One requirement of TOC is the assumption of a cost-accounting system that is very different from traditional cost accounting. This study examines the conflict between traditional cost accounting and TOC accounting, presents a description of how the TOC method operates at The Trane Company (Macon, GA) and how the cost accounting aspect of TOC was used to evaluate the addition of a new product line proposed by marketing.

ISSN:0020-7543    

DOI:10.1080/00207549408956934

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This paper formulates Shewhart mean (X-bar) and range (R) control charts for diagnosis and interpretation by artificial neural networks. Neural networks are trained to discriminate between samples Prom probability distributions considered within control limits and those which have shifted in both location and variance. Neural networks are also trained to recognize samples and to predict future points from processes which exhibit long-term or cyclical drift. The advantages and disadvantages of neural control charts compared with traditional statistical process control are discussed.

ISSN:0020-7543    

DOI:10.1080/00207549408956935

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A flexible flowline is a generalized production model employed in a wide variety of manufacturing assembly applications to produce a range of products in small batch quanitites. The MRP systems, which are commonly used in such environments, lack the detail to carry out daily scheduling. Recently, finite capacity planning tools have been suggested as a means of generating short-term production schedules. These tools employ techniques that take a global view of the problem and are based on static ‘snapshots’ of the manufacturing system. However, they ignore any inherent dynamics and therefore are inadequate in managing disruptions that can be very costly in terms of the inability to meet throughput requirements and prior delivery commitments. A simulation-based scheduler, on the contrary, is effective in accommodating the dynamic and/or stochastic nature of the system in arriving at a sheduling solution. In this paper, we introduce a simulation-based scheduler which is used to study a general class of parametric dispatching rules for flexible flowlines, under a variety of shop loading conditions. A scaled model of an actual manufacturing system is used to study the apparent tardiness cost based scheduling rule. The simulation-based scheduler has the facility to model a variety of manufacturing scenarios ranging from PCB lines to complex flexible flowlines. The scheduler is designed on pragmatic considerations and provides a test platform for studying static as well as dynamic scheduling rules for real manufacturing environments. It serves as an expedient to evaluating the practical effectiveness of scheduling rules. Additionally, it can also be used to develop detailed short-term capacity plans that form the basis for finite capacity scheduling.

ISSN:0020-7543    

DOI:10.1080/00207549408956936

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The objective of this research is to develop a geometric error model for multi-axis machine tools based on a closed-loop configuration. In this study, the geometric error model of each axis is derived by using 4×4 homogeneous transformation matrix. The ideal cutter location of the sculptured workpiece surface is calculated using the Bezier bicubic parametric surface representation method and machine geometric errors. The actual cutter locations is calculated by considering runout error of the cutting tool and machine geometric errors. Then, the step-by-step volumetric error analysis method is suggested on the basis of the closed-loop configuration of the multi-axis machine tools. The simulation study shows the simplicity and effectiveness of the proposed strategy.

ISSN:0020-7543    

DOI:10.1080/00207549408956937

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We have studied here the real-time production scheduling problem for multiple-part-type flow shops. The system under consideration consists of many machines and produces many product types. Each part goes through the system following a pre-defined routeing and may visit each machine at most once. We consider three classes of activities: operations, failures or repairs and starvation or blockage. The scheduling objectives are to keep the actual production close to the demand and to reduce the work-in-process inventory and cycle time. A three-level hierarchical production control model is developed to regulate production for the manufacturing systems. The control policy specifies how to react to machine failures. It also tells how to allocate limited system capacity among all the part types. It utilizes the material and the space in the storage buffers to alleviate the propagation of a failure to other machines in the system.

ISSN:0020-7543    

DOI:10.1080/00207549408956938

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This study presents a three-stage procedure for designing a line-type cellular manufacturing system with the objective of minimizing operating and material-handling costs. At the first stage, alternate part routeings are considered to determine the best part routeing that minimizes the operating cost. The results from the first stage form a 0-1 part-machine matrix. This binary matrix is used as the input to an ART1-neural-network-based cell formation module to group machines into a specified number of cells at the second stage. The facility layout module of a STORM software is finally used at the third stage to determine the layout and material-handling cost for the cell design. An example is used to demonstrate that the procedure could be used to resolve a load imbalance problem for a focus-factory-based system.

ISSN:0020-7543    

DOI:10.1080/00207549408956939

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This paper discusses an audit plan, based on a continuous sampling technique, queuing theory and sequential analysis. For a given test operation, if all tested products can successfully pass the operation, only a portion of the arrivals will be tested, that is the process is in an audit mode. However, once a failure occurs, all subsequent products must be tested (i.e. in a screen mode) until K consecutive good products are observed. In this case, the operation will return back to the audit mode. The portion of the products to be tested is determined by the arrival process and the capacity of the test operation. If the test capacity is below the arrival rate, line congestion may occur owing to line screening triggered by a product failure. The degree of congestion is measured by the level of work in process and the actual throughput. Furthermore, products may bypass the test operation under the audit plan. One must carefully estimate the escape rate. Finally, it is always desirable to detect process problems before a large number of faulty products are built. The sequential analysis may be used to establish a real-time problem detection scheme. The same approach can also help to identify test equipment problems. This work was developed for a test operation in an assembly line. It can be implemented either in a computer-controlled environment or in a manual operation mode. Performance of an audit plan is a function of line throughput, escape rate, test capacity and work in process. Numerical examples are presented for tradeoff analysis.

ISSN:0020-7543    

DOI:10.1080/00207549408956940

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor