摘要:

Electron microprobe analysis for the surface deposition and diffusion of tool material was carried out on mild steel (MS), high-carbon steel (HCS) and high-speed steel (HSS) work samples, machined by an electrical discharge process using a relaxation circuit in distilled water and kerosene at 225 and 56·25 mJ pulse energy, with copper and brass as tools. It was observed that high-energy machining results in lower surface deposition but more depth of diffusion. MS-HCS-HSS showed increasing surface deposition but decreasing depth of diffusion in the same order. Machining in distilled water at high-pulse energy resulted in lower surface deposition and depth of diffusion as compared to machining in kerosene. At low-pulse energy kerosene showed similar results.

ISSN:0020-7543    

DOI:10.1080/00207547908919590

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

This paper presents a single machine scheduling problem with sequence dependent changeover times. An optimizing solution procedure and various appropriate heuristics are reviewed. We then go on to consider the performance of these and other heuristics in the dynamic situation, as new jobs arrive to be processed and have to be added into the existing schedule at some time. Clearly an ideal solution would be to reschedule as each new job arrived, but as this is not generally practical from a computational viewpoint, it has to be carried out less frequently. The actual frequency of this rescheduling is clearly of importance, and some of the heuristics are more adaptable to this than others. Some results are presented which attempt to quantify this adaptability for the heuristics in question, and it is demonstrated that the best heuristic for the static problem is not necessarily the best heuristic in the dynamic situation.

ISSN:0020-7543    

DOI:10.1080/00207547908919591

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A statistical approach known as response surface methodology is used to investigate the effect of five independent variables on three responses in a vibratory finishing process. Brinell hardness, projection width, processing time, media size and vibratory frequencies are investigated with respect to workpiece projection height reduction, edge radiusing, and surface finish reduction.

ISSN:0020-7543    

DOI:10.1080/00207547908919592

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The research described in this paper is concerned with machine loading for jobs entering a job shop. The loading method proposed assigns jobs to machines based on the best match of job attributes with machine capability. A piece part coding system similar to the Opitz method is used to define the job characteristics and a machine capability matrix is specified for each processor in the shop. A loading algorithm called the ‘score rule’ assigns jobs to machines. Shop congestion is also considered in the algorithm.

ISSN:0020-7543    

DOI:10.1080/00207547908919593

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Regression analysis applied to the time series productivity data of 114 assembly workers in an electronics firm, covering a period of 152 weeks, suggests that time-dependent individual productivity changes in the post-learning or ‘drift’ phase can be adequately represented with a quadratic time series model. Some 70% of the operators studied are shown to have a maximum shaped curve, so that the long-term drift in production level is downward and thought to be due to a decline in effort. The methodology used suggests that long-term trends of individual operator performance can be readily predicted from work records, thus highlighting the need for job redesign and other motivational aids. The results presented here also provide some support for the hypothesis that the particular form of this model is indicative of the dominant influence of antecedent changes in work attitudes.

ISSN:0020-7543    

DOI:10.1080/00207547908919594

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Three previous authors have presented some evidence in support of the hypothesis that the output rate of perfectly balanced lines with variable station (or operation) times can be improved by deliberately unbalancing the lines in different ways, i.e. through different methods of assigning unequal operation times to the respective stations. This paper reports on the rather extensive computer simulation experimentation undertaken with various configurations of production lines to compare the effectiveness of the three conjectures.

ISSN:0020-7543    

DOI:10.1080/00207547908919595

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

It has now been generally established that the output rate of balanced production lines having variable operation times can be improved by deliberately unbalancing the line through assigning proportionately lower operation times to the middle station(s). Nevertheless, a production line may be balanced in terms of mean operation times at the respective stations yet unbalanced in the sense that the interstage buffer capacity allocation or the operation time variability are not equal for all stations.

ISSN:0020-7543    

DOI:10.1080/00207547908919596

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0020-7543    

DOI:10.1080/00207547908919597

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor