摘要:

A tandem AGV (automated guided vehicle) system is composed of several non-overlapping closed loops. Stations within each loop are served by a single dedicated vehicle. The transit area located between two adjacent loops serves as an interface and allows loads to be transferred from one loop to another. If a load needs to be delivered to a station not located within the same loop, the load needs more than one vehicle to carry it to its destination. We regard this routeing problem as a problem of finding the shortest travel time. After a command to deliver a load is issued, finding a route from the source to the destination as rapidly as possible without disrupting other active travel schedules was the objective of this study. A task-list time-window algorithm to find a shortest travel time based on the current status to route a load from point A to point B is presented. Two idle-vehicle managements are considered: circulating (CIRC) and STAY policies. Experiments showed that the STAY policy is more efficient than the CIRC policy in routeing control.

ISSN:0020-7543    

DOI:10.1080/00207549408957097

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Concern has been expressed that UK organizations are lagging behind their competitors in the adoption of advanced manufacturing technology. It has been suggested that it is not the shortcomings of the technology that is resulting in the rejection of AMT projects but possibly the inappropriateness of the economic evaluation methods used in its appraisal, the difficulties in evaluating the potential benefits and the criteria used to assess management performance. A postal survey, addressed to large UK manufacturing organizations, into the ‘state of the art’ of investment appraisal of AMT projects has identified that there is concern that the traditional financial appraisal techniques may be inappropriate for appraising long-term projects. This research also identified the concern over the difficulties experienced in appraising AMT projects and supports the argument that a short-term business philosophy may exist in some major UK manufacturing companies. Areas for further academic research are highlighted.

ISSN:0020-7543    

DOI:10.1080/00207549408957098

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Past research has shown that the performance of manufacturing cells can be improved if family orientated scheduling heuristics are used, or if jobs are split into smaller transfer batches for processing and material handling purposes. The research has also shown that large amounts of lot splitting results in increased setup frequency due to the reduction in transfer batch size. This can offset any gains in performance. This study examines the combined effect of lot splitting in a manufacturing cell that utilizes family-based scheduling heuristics. The results show that family-based scheduling is an effective means of reducing the negative impact of lot splitting on flow time. Lot splitting, however, has little benefit for due date performance even when scheduling rules that reduce setup frequency are used.

ISSN:0020-7543    

DOI:10.1080/00207549408957099

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

There is a rapidly growing literature on modelling the effects of investment strategies to controlgivenssuch as setup time, setup cost, quality level. Recently, Hwanget al. (1993) studied the multiproduct economic lot size models in which setup reduction and quality improvement can be achieved with one-time initial investment. The aim here is to review and extend their work. First, we point out that their algorithms can produce irrelevant solutions and clarify the cause of the problem. Second, we provide a complete formulation and analyse for the general investment functions using the Lagrangian method. The algorithm to find an optimal solution is provided and an example problem is solved to illustrate the algorithm.

ISSN:0020-7543    

DOI:10.1080/00207549408957100

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Generalized parameter and tolerance design problems have been formulated as nonlinear optimization problems under a broader set of assumptions. A new approach for parameter design and tolerance design problems is outlined. This approach integrates engineering models and numerical optimization methods so it can work in the early stage of design where a good engineering model is available to simulate the real product or process. The new approach is also able to handle multiple quality characteristics and constraints. Several important theoretical results have been derived by the authors for tolerance design problems that could serve as guidelines for optimal tolerance design and tolerance distribution.

ISSN:0020-7543    

DOI:10.1080/00207549408957101

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Here we present the magnetic abrasive process which is used to finish and size those workpieces that have been produced using standard machine tools. The process is proved to be very effective in achieving the desired finish size and roundness of the workpieces. We develop an empirical expression to estimate the machining time to produce a workpiece with specified roundness. The expression has been verified through a series of experiments.

ISSN:0020-7543    

DOI:10.1080/00207549408957102

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Releasing mechanisms are the set of rules which determine when matured orders i.e. those confirmed orders for which materials and tools are available, are dispatched to the shop floor so that processing can commence. This paper presents a simulation in which three such mechanisms are compared with a scenario in which matured orders are automatically released. Two of the mechanisms assume that the set of jobs to be released is given and that capacity cannot be adjusted. In contrast, the third rule allows capacity to be adjusted both as new jobs enter the system and as they are released to the shop floor. The simulation study shows that the latter rule is the best releasing rule under delivery performance and workload measures, but is slightly worse under the workload balance measure. This high performance is achieved at a relatively low cost in terms of increased capacity. In comparison with a scenario in which mature orders are automatically released to the shop, the latter rule performs better under all criteria except the proportion of tardy orders. It is concluded that further research is needed to show whether order release mechanisms can improve all delivery criteria as well as workload criteria.

ISSN:0020-7543    

DOI:10.1080/00207549408957103

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We performed a cost-benefit analysis of the employee cross-training process on a mixed-model assembly line. We first simulated the manufacturing process to demonstrate the savings which result from cross-training. We then presented a linear integer program designed to make cost-effective cross-training assignments for a specified number of assembly jobs and workers. Next, we examined the profitability of these assignments for several work stations over various time horizons. In addition, we derived insights into the cross-training assignment process from these results and we explain how the integer program can be used to improve efficiency in production planning.

ISSN:0020-7543    

DOI:10.1080/00207549408957104

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Cutter path generation is a surprisingly active research and development area. Together with cutter path topology, it is critical to the validity and efficiency of cutter path generation. Here we survey the main generation techniques used and discuss the performance of each method.

ISSN:0020-7543    

DOI:10.1080/00207549408957105

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In many practical situations, coordination of replenishment orders for a family of items can lead to considerable cost savings. A well-known class of strategies for the case where cost savings are due to reduced joint ordering costs is the class of can-order strategies. However, these strategies, which are simple to implement in practice, do not take discount possibilities into account. We propose a method to incorporate discounts in the framework of can-order strategies. A continuous review multi-item inventory system is considered with independent compound Poisson demand processes for each of the individual items. Discounts are offered by the supplier as a percentage of the total dollar value whenever this value exceeds a given threshold. Starting from the can-order strategy as a basic decision rule, we develop a simple heuristic to evaluate these discount opportunities. The performance of the can-order strategy with discount evaluation is compared with that of another class of discount evaluation rules as proposed by Miltenburg and Silver.

ISSN:0020-7543    

DOI:10.1080/00207549408957106

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor