摘要:

The flexible manufacturing system (FMS) represents an important new development in computerized manufacturing systems. Since its inception, researchers and practitioners alike have found managing FMSs more complex than managing hardwired automation or stand-alone machines. Complexity arises from the perceived need to exploit theproduction-scope flexibilityof the FMS to its fullest potential. This paper presents some analytical insights on the benefits of restricting this flexibility, and offers a methodology for streamlining the material flow. Curtailing the production-scope flexibility shifts the emphasis in material handling, buffer storage, and distributed-computer control to process planning and simplifying and automating the system changeover. From the system operation standpoint, streamlining the material flow simplifies production planning and control. Instead of having to deal with the complexities associated with jobshop scheduling, the problem reduces to that of balancing the programmable flow shop, and the sequencing of the batches to minimize changeover time or cost.

ISSN:0020-7543    

DOI:10.1080/00207549208948103

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Optimal selection of process parameters is an important problem faced by most process planners and NC programmers. Computerized systems and mathematical models are available in literature for machining parameter selection. These systems are usually constructed with compiled handbook data. The machining process is non-linear and exhibits piecewise behaviour within different cutting ranges. If this piecewise behaviour can adequately be represented in machinability parameter selection systems, more insightful selection of cutting conditions can be achieved.

ISSN:0020-7543    

DOI:10.1080/00207549208948104

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In this paper, knowledge of relevance to dimensional inspection and three progressive levels of automation technology, ranging from the facility automation to information and decision automation, are examined. The objective is to create and advance the related knowledge and automation technologies in dimensional inspection. These knowledge and automation technologies are then integrated with traditional engineering methods for the implementation of a highly automated dimensional inspection environment. CATIA of the IBM CAD/CAM system and CORDAX RS-30 Coordinate Measuring Machine (CMM) are used as the primary tools for system implementation. The developed inspection environment consists of five key elements: (1) specification module; (2) planning module; (3) verification module; (4) execution module; and (5) comparative analysis module. These modules are being developed to bridge the missing links between inspection and design as well as manufacturing, and to become an important component of a computer-integrated manufacturing environment.

ISSN:0020-7543    

DOI:10.1080/00207549208948105

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A methodology to predict the occurrence of out-of-control process conditions in a composite board manufacturing facility was developed using neural network theory. Multi-variable regression and time series analysis techniques were applied to analyse the data set for comparison and informational purposes. Regression models were developed to mode] specific process parameters and could account for only 25% of the variation in those parameters. When analysed as a time series, the data stream was non-stationary in the variance and transformations failed to achieve stationarity. Back-propagation neural networks were successfully trained to represent the process parameters. Inputs to the network consisted of data representing the current process condition along with historical data on relevant parameters, including temperature, moisture content, and bulk density. The training data set was graphically analysed to demonstrate the type of response surface successfully modelled. The trained neural networks were able to successfully predict the state of control of the specific manufacturing process parameters with 70% accuracy, thus, demonstrating the potential of neural networks in manufacturing process analysis.

ISSN:0020-7543    

DOI:10.1080/00207549208948106

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Transfer batches permit the processing of part of a job-lot on downstream machines before completion of the lot on the current machine. This paper studies the effects of transfer batches in two- and three-machine flow shops. It establishes conditions under which each unit of a job can optimally be viewed as a separate transfer batch. Issues of interrupted versus continuous production on downstream machines, and job-splitting (lot-sizing) are discussed. Examples are provided which show that even with a regular measure of performance and no setup times, job-splitting can yield a better solution than is possible without splitting jobs. A modification of Johnson's Algorithm for makespan minimization is derived under suitable conditions in two-machine flow shops and in special three-machine flow shops. An empirical study of transfer batch effects in two-machine flow shops is undertaken for both the makespan and the total flow time criteria under the assumption that jobs are not split. The no-split jobs restriction allows a meaningful comparison to be made between schedules with and without transfer batches.

ISSN:0020-7543    

DOI:10.1080/00207549208948107

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A framework for evaluating acquisition of new manufacturing technology is presented based on extensive reviews of various approaches available in the literature. The suggested evaluation procedure involves three hierarchical levels, namely, strategic evaluation, operational evaluation and financial evaluation. The need for quantifying intangible and complex strategic benefits, and comparing them with tangible financial benefits at the same level is eliminated. The paper describes a methodology for strategic evaluation, and suggests techniques that can be used for operational and financial evaluation. The framework identifies important research areas and provides guidelines to develop a better procedure for evaluating acquisition of new manufacturing technology.

ISSN:0020-7543    

DOI:10.1080/00207549208948108

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In this paper we consider the problem of assigning operations of part types to one or more machines in a cellular manufacturing system. We develop a mixed integer linear model considering trade-off between refixturing and material handling movement. Examples are included to illustrate the applications of the models developed.

ISSN:0020-7543    

DOI:10.1080/00207549208948109

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Although a significant amount of research has been carried out in the scheduling of flexible manufacturing systems (FMSs), it has generally been focused on developing intelligent scheduling systems. Most of these systems use simple scheduling rules as a part of their decision process. While these scheduling rules have been investigated extensively for a job shop environment, there is little guidance in the literature as to their performance in an FMS environment. This paper attempts to investigate the performances of machine and AGV scheduling rules against the mean flow-time criterion. The scheduling rules are tested under a variety of experimental conditions by using an FMS simulation model.

ISSN:0020-7543    

DOI:10.1080/00207549208948110

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We consider a multi-stage production system with finite buffers under the so-called repetitive-service blocking mechanism, modelled by a tandem queueing system with blocking. The objective is to find to which stage each server should be assigned in order to maximize the throughput. For this server assignment problem we first derive a throughput upper bound which is found to be very close to the exact one to be used as a substitute measure. Based on this measure we show that the rules of placing the worst servers from the outermost stages by Yamazaki et al. ( 1989) for the case of no buffers, are effective for the case with buffers of equal size. For the general case with buffers of different sizes, we propose an algorithm based on the observation that our throughput upper bound can be increased fastest by placing the fastest servers around the smallest buffered stage. Effectiveness of this algorithm as well as the proposed rules are well demonstrated by the extensive computational experiments conducted with a number of test examples ranging up to five stages.

ISSN:0020-7543    

DOI:10.1080/00207549208948111

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In order to diagnose properly quality problems that occur in manufacturing the diagnostician, be it human or computer, must be privy to various sources of information about the process and its behaviour. This paper describes how neural networks and Bayesian discriminant function techniques can be used to provide knowledge of how a product characteristic changed, i.e. shift in mean or variability, when so noted by the control chart application. Such information is useful because there usually exists some underyling knowledge about the physical phenomena in question that relates the behaviour of the observed characteristic to its processing variables. When a change in the process is detected by the appropriate statistical method, a feature vector of process-related statistics is used to identify the change structure as a shift in mean or variance. This paper addresses various issues concerned with this problem, namely: process change detection, feature vector selection, training patterns, and error rates. Simulation experiments are used to test various hypotheses and also compare the effectiveness of the two proposed approaches against two simpler heuristics. Results show the neural network and quadratic discriminant function approaches to be fairly similar, with a success rate of 94% and both to be superior to the simpler heuristic approaches.

ISSN:0020-7543    

DOI:10.1080/00207549208948112

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor