摘要:

The problem of tool and fixture resources dimensioning is considered and examined for a productive environment with flexible features. With reference to previous studies, different tool management strategies are pointed out and commented upon; a further control policy based on workpiece batching is suggested and tested. In the second section of the paper, an analytical interpretation of the question in hand is presented and discussed; the effectiveness of the procedure itself is tested by comparing analytical data with results derived from the detailed simulation of a real tool management area. Results are shown in the last section

ISSN:0020-7543    

DOI:10.1080/00207549208942963

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The development of strategies for sequencing slabs through the reheat furnace and rolling mill of a modern steel production facility is complicated by multiple, and often conflicting production objectives. Optimal energy efficiency through the reheat furnace may lead to inefficient rolling sequences or less than desirable product delivery schedules. Not only is model formulation complicated, but the combinatorial nature of the problem precludes optimal solution. A heuristic procedure for solving this multi-objective product sequencing problem has been developed and tested under production conditions in a Danish steel mill. The methodology, which is based on a modified ‘greedy’ algorithm is presented and results using actual production data are discussed

ISSN:0020-7543    

DOI:10.1080/00207549208942964

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Tool management issues are gaining importance as they represent complex obstacles to the implementation of flexible manufacturing systems (FMSs). Both researchers and FMS users are interested in tool management; the most dynamic facility involving large numbers and varieties. To comprehend many complex asynchronous concurrent transactions in its management systems, the need for rigid mathematical algorithms is often stressed. In this paper, Petri nets (PTNs) are applied to analyse the issues at machine group level to get a better insight into tool management. Importance and relevance of PTNs for investigating tasks involved in the functioning and designing of tool management systems is made clear at various hierarchical levels (tool, machine, group and system levels). To establish the potential use of PTNs they are applied to the modelling of tasks involved in a centralized tool management system. Quantitative analysis is carried out by associating times with some or all transitions in the Petri net model. The system considered for analysis comprises a tool crib, three AGVs, two robots, one presetting station and two machining centres. Performance criteria used are (i) the production rate and (ii) the dynamic behaviour of the FMS. Analysis considers one of the possible product varieties for two different production volumes at two different machining centres, but it can be extended to different products. Performance of the system with tool sharing among the machining centres is found to have advantages over that where tool sharing is absent

ISSN:0020-7543    

DOI:10.1080/00207549208942965

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Sculptured surfaces often appear in mechanical parts of various industrial products as external form or the functional surface and are commonly found in moulds and dies. In this study a sculptured surface is denned by a non-uniform rational B-spline surface that provides the flexibility and freedom for surface description. Work proposed here includes the evaluation of machining information, decision for machining process sequence selection, and automatic cutter selection and path generation. Machining information is first evaluated by using series of hunt planes and calculating geometric shape, and constraints of the machining cavity. A decision on the process sequence in made based on the evaluated machining information. Cutter size is automatically determined by considering geometric constraints, maximum material removal rate in the roughing process, and minimum cutter movement with the required accuracy in the finishing process. Roughing is done by pocketing procedures that consider arbitrary shaped pockets with islands on the cutting planes. Cutter movement and selection are optimized by considering machining conditions on adjacent cutting planes

ISSN:0020-7543    

DOI:10.1080/00207549208942966

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Since initial work done by Goldratt in the mid-1980s and as the concepts related to the theory of constraints (TOC) have become more developed, many have concluded that the TOC approach offers nothing in addition to what can be accomplished through linear programming (LP). Through the use of an example, this paper compares TOC to LP and clarifies the differences surrounding the TOC philosophy and the LP technique

ISSN:0020-7543    

DOI:10.1080/00207549208942967

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0020-7543    

DOI:10.1080/00207549208945376

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0020-7543    

DOI:10.1080/00207549208945378

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor