摘要:

The Adaptive Resonance Theory (ART) neural network is a novel method for the cell formation problem in group technology (GT). The advantages of using an ART network over other conventional methods are its fast computation and the outstanding ability to handle large scale industrial problems. One weakness of this approach is that the quality of a grouping solution is highly dependent on the initial disposition of the machine-part incidence matrix especially in the presence of bottleneck machines and/or bottleneck parts. The effort of this paper has been aimed at alleviating the above mentioned problem by the introduction of a set of supplementary procedures. The advantages of the supplementary procedures are demonstrated by 40 examples from the literature. The results clearly demonstrate that our algorithm is more reliable and efficient in cases of ill-structured data.

ISSN:0020-7543    

DOI:10.1080/00207549508930150

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In foundries with automatic moulding plants a complex system of different kinds of material flow exists. The multitude of technological constraints results in a dynamic and unstable production process. Therefore, small variances in process parameters may entail interruptions of a material flow and consequently cause downtime. Automatic moulding plants consist of rigidly chained units, so that to secure a high reliability corresponding expenditure is required. We present the results of an investigation of 21 automatic moulding plants in 15 German foundries. The analysis of the structure of downtime shows that the low efficiencies result not only from technical reasons, but also from missing materials and personnel, and technological disturbances due to planning and scheduling.

ISSN:0020-7543    

DOI:10.1080/00207549508930151

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The design and balancing of a line which assembles car heaters is examined. To accomplish a balance, the general assembly line balancing model is extended to cope with some restrictions due to the physical structure of the production line: namely, incompatibilities among operations and operations that must be necessarily performed by certain work stations. A polynomial time dynamic programming algorithm is provided to balance the workloads among the work stations taking into account these additional constraints, exploiting the special structure of the operation graph. The algorithm was applied to two designs: a single line on which all the heater components are assembled, and also to several segmented lines, which collectively assemble heaters. Demand volume variations are also addressed.

ISSN:0020-7543    

DOI:10.1080/00207549508930152

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We present an algorithm for tool placement in an automatic tool change (ATC) magazine, such as used in CNC machining centres. Given the sequence of tools used to execute the manufacturing processes in the machining centre, the objective of the algorithm is to allocate the tools to positions in a tool magazine, in such a way that the tool change time is minimized. The problem has been reduced to being described as a travelling salesmen problem (TSP). The suggested algorithm solves this problem using a modified 'nearest neighbour' procedure, with a series of different weight parameters. Extensive testing of the procedure on a large set of randomly generated problems with various characteristics, leads to recommendation of the best set of parameters to be used with the nearest neighbour procedure. The algorithm, when implemented with the best set of parameters, is especially effective for complex problems with large number of tools and low frequency of tool use (up to 15% improvement in comparison with existing methods). The algorithm is very fast and can be executed in real time. As such, it may become part of the controller software of SSMS and FMS, and be used for real-time optimal tool placement in a computer-integrated manufacturing environment.

ISSN:0020-7543    

DOI:10.1080/00207549508930153

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The first step towards implementing Group Technology in manufacturing is the decomposition of the manufacturing system into manufacturing cells consisting of various machines and part-families assigned to it. We formulate the problem as a Quadratic Integer Program. This formulation offers considerable flexibility to the system designer in deciding the number and size of cells. The formulation can also handle situations where there are multiple machines of the same type. A simple heuristic is developed to solve the problem. Computational tests reveal that the heuristic algorithm obtains solutions that are as good or better than other methods for simultaneous formation of machine cells and part-families.

ISSN:0020-7543    

DOI:10.1080/00207549508930154

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

When implementing the kanban method in non-serial production lines, an interesting prioritization problem arises. Often a single server station will be linked withMdifferent downstream stations viaMseparate kanban loops. Then the K-priority problem may be described as determining which kanban card should be processed next, given that empty cards are waiting in more than one loop. The objective in prioritizing the kanbans is to reduce back order or shortage costs and inventory costs at the downstream stations. Utilizing the theory of Markovian decision process and dynamic programming concepts, a solution to the K-priority problem is developed. This solution is labelled the K-rule, and was found to outperform the first-come-first-served and longest queue rules, plus a cost inclusive heuristic rule, in experimental tests,

ISSN:0020-7543    

DOI:10.1080/00207549508930155

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In order to estimate the amount of tool flank wear in real time during stable turning operations, tool wear in the machining of stainless steel was studied in terms of an experimental index related to cutting damping in the cutting zone, as measured directly with a developed device. The correlation between tool wear and the experimental index was analysed. Results show that the experimental index can be used as a reliable indicator to identify tool flank wear in real time during machining operations.

ISSN:0020-7543    

DOI:10.1080/00207549508930156

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We describe a hybrid intelligent design retrieval and packaging system by utilizing techniques such as fuzzy associative memory, backpropagation neural networks, and adaptive resonance theory. As an illustrative example, a prototype of the proposed system has been developed to intelligently retrieve a design from a standard set of chair designs that can satisfy the required needs. The system then automatically passes the design to an intelligent packaging system which locates the parts needed from a designated area and packages the parts in the packaging area. This novel application of neural networks could establish the basic foundation of a true intelligent manufacturing system.

ISSN:0020-7543    

DOI:10.1080/00207549508930157

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The aim was to develop an effective inspection planning strategy for sculptured surfaces by using a Coordinate Measuring Machine (CMM). The optimum measuring point locations are first determined to obtain more effective inspection results for the given sampling numbers. The suitable measuring point locations are determined based on the mean curvature analysis and a constant called theRegion Selection Ratiowhich is suggested to optimise distribution of the measuring points. As a next step, various methods are tested to determine the optimum probe path to minimize the inspection time and the measuring errors. The experimental results show the sculptured surfaces can be inspected more effectively by choosing a suitable Region Selection Ratio. Also, the inspection time can be reduced significantly by using the proposed probe path generation methods.

ISSN:0020-7543    

DOI:10.1080/00207549508930158

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Performance monitoring is crucial in maintaining normal machine operating conditions for the continued production of high quality parts. The objective of the following research is to develop an effective performance monitoring technique to assess the condition of rotating machinery through vibration signature analysis. An autoregressive (AR) model is utilized to characterize normal vibration signals, the modified covariance method calculates the deviation of the current condition from a normal condition, and an exponentially weighted moving average (EWMA) statistic measures the current machine condition by signalling either a normal or an out-of-control condition, The following paper discusses the statistical techniques employed in performance monitoring. Preliminary studies show that these techniques provide accurate performance monitoring of the operating condition of rotating machinery using vibration signals.

ISSN:0020-7543    

DOI:10.1080/00207549508930159

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor