摘要:

In this paper a framework for the equipment requirements problem is presented, It allows one to specify requirements for machine tools and materials handling components. The framework is based on two integer programming models. The models require a set of data which are easily available. A numerical example and some computational results are presented. Alternative solution approaches and directions for future research are suggested.

ISSN:0020-7543    

DOI:10.1080/00207548708919843

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper presents a model for calculating optimal cutting speeds and tool replacement policies for both operations of a two-stage machining problem when the unit cost is minimized or the profit rate is maximized. The tool life is assumed to be a stochastic variable and penalty costs are imposed for tool failures during production. The optimal size of buffer space between the two machines is also calculated analytically. It is shown that the unit cost increases as the tool variability and/or the penalty cost increase. The cutting speeds and tool replacement policies on both operations depend strongly on the tool variability and the penalty cost. The cutting speeds differ from those determined independently for each operation. Finally, the optimal buffer space size is the one necessary to keep the critical machine running when there is a tool change on the non-critical machine, and its optimal size can be calculated analytically.

ISSN:0020-7543    

DOI:10.1080/00207548708919844

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Successively more complex Markov models are used to describe an easily understood production process. As the models become more complex, they become more useful, in particular including more cost categories and more types of data. Rework and work-in-process inventories are modelled, together with inspections and scrap rates, and a method is shown for taking tool wear into account. The scheduling impacts of rate-dependent tool wear are also analysed using the Markov models developed.

ISSN:0020-7543    

DOI:10.1080/00207548708919845

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In an attempt to simplify the application of work measurement data, the technique known as ‘time-slotting’, is used. Time-slotting consists of collecting data in a specified work area, dividing the whole time range into segments, or slots, and letting a single time, in each slot, represent the time standard of all of the jobs whose true standard times fall into the slot. This technique has been widely used in developing time standards for low repetitive tasks, such as in the area of maintenance, where research has been carried out on the behaviour of different methods of designing slotting scales. Nevertheless, there does not appear to be one generally accepted method of designing these time-slotting scales. In this paper the theory of time-slotting is considered in general terms. First the principal errors which may occur in time-slotting are delineated and then the ways in which two of these errors can be determined,a priori, are demonstrated. The effect of variables of the time-slotting scale upon each type of error is then discussed. The principles and equations evoked in the paper will provide the basis for the evaluation of time-slotting scales under many varying conditions. Furthermore, a means of separating component errors in computer simulation of time-slotting scales has been established.

ISSN:0020-7543    

DOI:10.1080/00207548708919846

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper develops a heuristic procedure for generating feasible solutions for the single-machine, multi-product, infinite-horizon, lot scheduling problem. This problem occurs in several practical situations, for example, in metal stamping factories, on appliance assembly lines, in the beverage blending and bottling industries, in paint production and on motor car assembly lines. The proposed heuristic divides theNproducts intoGgroups and the products belonging to the same group are produced in the same cyclical pattern. Thus the problem of schedulingNindependent products is reduced to that of schedulingGgroups of products. SinceGis much less thanN, the problem is made simpler. The proposed heuristics has two main advantages: implementation facility and effectiveness. Computer codes are available for several mini and micro computers. The effectiveness is demonstrated by two tests. First, we solved the six problems originally solved by Elmaghraby (1978 a). Obviously, the results based on only six problems, cannot be generalized. Second, theG-group heuristic, as well as five other heuristics, was applied to 270 random computer-generated problems. The results show that it performed better.

ISSN:0020-7543    

DOI:10.1080/00207548708919847

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper introduces an automatic algorithm for nesting of irregularly shaped parts whose geometries were approximated by composites of non-overlapping rectangles. A performance test using randomly generated bills-of-materials (BOM) shows that the algorithm is efficient in terms of speed and material usage. This algorithm is then used to study the relationship between BOM characteristics and material trim loss. An experiment using a 25factorial design is used to estimate the impact that the total number of parts, the number of unique part types, the part sizes (in relation to material sheet size) and the percentage of irregular parts in the BOM all will have on the material trim loss in the nesting process.

ISSN:0020-7543    

DOI:10.1080/00207548708919848

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Learning curves and progress functions are well established management tools used to predict productivity in the start-up of new product lines, and to describe the performance of individual employees. As the authors, amongst others, have shown, these tools have been successfully applied to a wide range of tasks in highly varied industries. It is particularly useful, especially for inter-firm comparisons to compress the learning curves and progress functions into simple mathematical models in which the parameters may be determined by least squares error curve fitting or other convenient techniques. When on-line prediction is required, a digital computer algorithm is used to estimate the model parameters. It is essential that the parameter estimation technique used is robust in the presence of large amounts of scatter in the raw data. Particular problems arises in task in which the human operator is subject to job rotation, job re-design, or has to perform a variety of similar, but not identical tasks during batch production. Previous experience can therefore be regarded as prior practice in skill acquisition and it is important for management to determine the appropriate starting point on the new learning curve. Little has so far been published on this important topic. This paper will review the present state-of-the-art and show that in certain circumstances prior practice may he accounted for by relatively simple modification to learning curve. The results obtained are of particular relevance to production management in setting performance standards, production scheduling, labour cost evaluation and delivery date forecasting.

ISSN:0020-7543    

DOI:10.1080/00207548708919849

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Both industry and academia are currently devoting considerable interest to cellular manufacturing systems. Despite this growing attention, the existing literature does not adequately address a number of issues related to the successful adoption of these systems. This paper identifies a large number of research topics related to cellular manufacturing, discusses the need for their investigation, and suggests appropriate methodologies for their study. This research agenda is presented in the context of four important decision areas for new technology adoption—applicability, justification, system design, and implementation. The volume and variety of topics identified allow us to conclude that cellular manufacturing is an area with many researchable issues, spanning several academic disciplines, and requiring a multitude of research methodologies.

ISSN:0020-7543    

DOI:10.1080/00207548708919850

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Electro-chemical Machining (ECM) has found wide applications in aerospace, automobile, nuclear and similar other industries. However, tool design in ECM is still a problem which delays the use of this process. This paper has focused attention on some of the problems that should be studied before it would be possible to obtain an analytical design of toolings for ECM. Non-uniform electrolyte distribution, different electrolyte flow path lengths and variations in current density have been found to be the main features that characterize the nature of the elliptical hole shape by ECM. The resistance model technique has been applied for the analysis of the elliptical hole shape. A parametric study of the process which highlights certain guidelines for ECM tooling designer is also presented. Experimental results have revealed significant variations in the resultant side gap length at major and minor diameters of the tool. The experimental tests have been in agreement with the present analysis. Further, resistance model technique has proved its validity for use in evaluating the power consumption in ECM.

ISSN:0020-7543    

DOI:10.1080/00207548708919851

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The purpose of this paper is to integrate a quality control (inspection) procedure into a job shop manufacturing process described by anM/M/1queue. Given a joint inspection and queueing system, an optimization problem for minimizing inspection and queueing related costs is formulated and resolved.

ISSN:0020-7543    

DOI:10.1080/00207548708919852

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor