摘要:

Material requirements planning (MRP) is a way to develop the time phased material and other resource requirements to satisfy the needs of a master production schedule. Hierarchical production planning (HPP) is a framework for analysis and decision making in complex production environments. They are complementary approaches to the decision support system needs of multi-stage production systems. The hierarchical approach provides for efficient management review of proposed plans at corporate, plant, and shop levels while MRP provides a sound and detailed basis for understanding the implications of proposed plans and for executing the selected plan. The relationships between these two approaches are illustrated with an example application.

ISSN:0020-7543    

DOI:10.1080/00207548708919887

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Axiomatic approach to develop an objective theory of flexibility in manufacturing system is presented. On the basis of some plausible axioms for a measure of flexibility, we suggest some information theoretie measures to quantify various types of flexibility. Four entropic measures are identified and the model illustrations for computations are given.

ISSN:0020-7543    

DOI:10.1080/00207548708919888

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In determining inspection plans for quality control, two important variables are the frequency of sampling and the sample size. Typical values are once per hour, with a sample of size 4 or 5. However, this may be far from the most appropriate or efficient scheme in a given setting. Also, the capability index necessary to produce zero defects under the historical maximum and average shift in the process is essential information in providing motivation for process improvement. This paper presents microcomputer-based software using readily available information for determining economically optimal sampling plans and zero-defects capability indices. Great economic benefits can result from more careful attention to sampling plans, and the attainment of zero defect process capability indices.

ISSN:0020-7543    

DOI:10.1080/00207548708919889

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper reports the results of an experimental investigation of scheduling decision rules for a dedicated flexible manufacturing system. A simulation model of an existing flexible manufacturing system (FMS) comprised of 16 computer numerical controlled machines (CNC) was constructed using actual operation routings and machining times to evaluate the performance of various part loading and routing procedures. The results indicate that FMS performance is significantly affected by the choice of heuristic parts scheduling rules.

ISSN:0020-7543    

DOI:10.1080/00207548708919890

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Designers and manufacturers of diaphragm chucks have in the past been limited to the use of empirical data for diaphragm chuck design. This limitation has been due to the complex nature of mathematically analysing the chuck. This work established, by theory and experimental verification, the prediction equation for the gripping force of a diaphragm chuck for any number of jaws. The designer is therefore able to achieve aprioridesign of the diaphragm chuck.

ISSN:0020-7543    

DOI:10.1080/00207548708919891

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

We consider the problem of determining the optimal part delivery dates of a low volume, small lot assembly line which manufactures large and costly products. Parts are assembled at each stage to a subassembly. The arrival time of an assembly part from a vendor is assumed to be a normally distributed random variable. A dynamic programming algorithm is developed to minimize work-in-process inventory of parts and subassemblies. It is implemented on the single job problem. Its further extensions to the multi-job case and to incorporate the cost of setting delivery dates are also discussed.

ISSN:0020-7543    

DOI:10.1080/00207548708919892

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The article describes a fully automatic assembly system for a group of electromechanical timers. The layout of the flexible assembly system corresponds to the structure of the product: the most important components are motor assembly (line 1), drive gear assembly (line 2), bearing plate assembly (line 3), program dial assembly (line 4), final assembly (line 5). Already more than 60 timer variants are produced.

ISSN:0020-7543    

DOI:10.1080/00207548708919893

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Smaller production lots and new products require the application of programmable robots in assembly areas for the production of precision-mechanical and electronic devices. The article provides an overview of the whole subject. The application of robots in timer production for the insertion of components to PC boards and the positioning of special components is explicitly described.

ISSN:0020-7543    

DOI:10.1080/00207548708919894

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper examines the problem of master scheduling for an FMS in Scotland containing six CNC horizontal boring machines. A multiple criteria approach is used to choose the compatible subset of candidate orders for processing by this FMS, subject to resource constraints and potentially conflicting performance objectives. A structured framework for conflict resolution is described and compromise solutions are obtained using standard mathematical programming software.

ISSN:0020-7543    

DOI:10.1080/00207548708919895

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Martempering is well established as a method by which the stresses and strains generated during the quenching of a steel component may be controlled. In this process the component is held at an intermediate temperature in a salt bath subsequent to the initial cooling from the austenitization temperature, but prior to the final quench to ambient. This allows sufficient time for most of the temperature gradient in the component to be eliminated before the transformation of the austenite to martensite in the final stages of the cooling process. It is essential that the intermediate treatment does not cause decomposition of the austenite by diffusional processes, to form soft transformation products. This limits the time available for the intermediate treatment. Doubts have been raised about the fundamental assumptions on which the process is based, since the absence of a vapour blanket stage in the initial cool in the salt bath produces very high surface heat transfer coefficients at the start of the process, when the material is very soft. It has been the purpose of the present investigation to verify these assumptions by the use of a mathematical model of the stress generation process. In the case of 835M30 steel, 87 seconds at 450°C reduced the temperature gradient in a 15 mm thick plate to 5°C, without producing any diffusional decomposition to soft structures. However, the beneficial effect of this small temperature gradient during the later stages of the process, was negated as far as strain was concerned by the increased distortion that occurred in the very early part of the cooling process in the salt bath. This latter effect was due to the very large surface heat transfer coefficient provided by the quenchant at this stage. The martempering operation, however, did successfully remove the thermal stresses by the time the component reached ambient. Modification of the process to include an oil quench from the salt bath was not beneficial, as the stresses and strains produced at the end of the quench were very similar to those produced by a conventional oil quench from the austenitization temperature. The calculated residual stress and strain distributions were checked against the corresponding experimental values. Agreement was reasonably good, except for a small but uniform discrepancy in the case of the strains.

ISSN:0020-7543    

DOI:10.1080/00207548708919896

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor