摘要:

This paper describes the progress to date in the development of a software package for the machining of free-form surfaces by the real-time generation of NC control blocks at the machine tool. The salient features of the system are the complete elimination of paper-tape from the machining process and increased flexibility at the machine tool, particularly allowing production-orientated decisions to be made on the shop-floor rather than on the CAD system.

ISSN:0020-7543    

DOI:10.1080/00207548608919706

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The material handling system of a flexible manufacturing system (FMS)consists of load and unload mechanisms, transfer mechanisms, and internal storage facilities, each of which may be configured in many different ways. In addition, many options are available for dispatching work-parts between work-stations. The inherent flexibility of an FMS affords the opportunity for enhanced system efficiency, yet it also makes the analysis and design of the system extraordinarily complex and difficult. This paper develops a combined process interaction-discrete event simulation model to analyse the material handling and dispatching system of an FMS. The model is implemented in SLAM (Simulation Language for Alternative Modeling)The SLAM model is applied to an example FMS and is shown to be an effective tool for designing the material handling system and for selecting the appropriate work-part dispatching option. It provides greater flexibility in both modelling and output analysis than conventional process interaction simulation based on Q-GERT or GPSS and in consequence it may be used to enhance.significantly the efficiency of flexible manufacturing systems.

ISSN:0020-7543    

DOI:10.1080/00207548608919707

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The optimal reorder point and reorder quantity are calculated to minimize the sum of holding, set-up, and stockout costs, where the stockout cost is simply the expense of expediting the manufacturing lead time. It is argued that this cost model is applicable in many real-world manufacturing situations, and it has the great advantage of using cost coefficients which can be roughly estimated. In addition, formulas are given for the 'implied' and 'critical' charge for expediting, the latter being defined as the point below which it doesn't pay to carry safety (buffer) stock.

ISSN:0020-7543    

DOI:10.1080/00207548608919708

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Transient performance of the flowshop is approximated using a model which is based on the assumption that operation start and finish times are related by the multivariate normal distribution. Start times are defined by evaluating the maximum of the finishing times which determine the epoch at which an operation can begin. Fundamental relationships among the correlations of start and finishing times are derived and used in several computational procedures to estimate start times. Examples which demonstrate application of the approach to flowshops with finite and infinite buffer capacities are given. Applications of the approach to more complex queueing networks and assembly systems are described.

ISSN:0020-7543    

DOI:10.1080/00207548608919709

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Standard lot-sizing models are often not directly applicable in practice. Different assumptions in lot-sizing models and the extent to which these assumptions are valid in various practical situations are discussed. Practitioners also tend to prefer simple standard methods even for complex problems, which means that adjustment of the lot sizes may be desirable. The ways in which such adjustments can be carried out are analysed.

ISSN:0020-7543    

DOI:10.1080/00207548608919710

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This paper demonstrates that integer programming can be used as a formulation and solution technique for designing efficient production lines by allocating tasks to multiple manned work stations. The paper considers a formulation of the problem by Shtub and reformulates it in a more straightforward way.

ISSN:0020-7543    

DOI:10.1080/00207548608919711

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Sampling optimality can arise only in connection with prior distributions of defectives in submitted lots. The basic concept underlaying the problem of selecting acceptance sampling plans based on economic considerations is discussed. Also presented is a simple heuristic procedure for deriving sampling plans by using the break-even fraction defectives, given a prior distribution of the lot fraction defectives. The effectiveness of the procedure is evaluated by comparing its results with those obtained from optimal acceptance bayesian plans.

ISSN:0020-7543    

DOI:10.1080/00207548608919712

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A decision model is presented for optimally timing the disposal of perishable inventories under conditions of fixed lifetime perishability and stochastic demand. The method has the important feature of keying on expected remaining time until item demand occurs, instead of on inventory levels. In addition, the decision process is independent of the stock replenishment policy and of profit contribution, salvage value, and inventory holding cost estimates. Disposal probabilities for fresh items subject to Poisson demand are derived.

ISSN:0020-7543    

DOI:10.1080/00207548608919713

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Cermets are a fairly recent entry in the growing list of commercial cutting tool materials and their behaviour and wear characteristics are being extensively studied and tested. This project was aimed at understanding the failure mechanisms of three brands of commercially available Cermet cutting tool inserts. Scanning electron microscopy assisted by chemical analysis was used to study the inserts as received and after being used to machine two different kinds of steel bars in turning operations. The turning operations for every workpiece material were conducted at both high and low rates of metal removal (4-86 and l-50m.s/mjn respectively). The metallurgical diagnosis showed different dominating characteristics for each of the inserts while the analysis of the failure mechanisms exhibited varied wear resistance patterns for each Cermet/work material combination. This variability is believed to be due not only to the different properties of the tools but also to the unique interaction of each tool material/work material combination.

ISSN:0020-7543    

DOI:10.1080/00207548608919714

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

When demand temporarily decreases, traditional aggregate-scheduling techniques call for either lay-offs, inventory build-ups, or increased worker idle time. For products made in batches or lots, an alternate method is to reduce the lot size, which in turn increases the number of set-ups and decreases the total production without affecting the work-force level. The latter effect is of particular significance in businesses that desire to maintain a constant workforce.

ISSN:0020-7543    

DOI:10.1080/00207548608919715

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor