This research is concerned with certain production planning problems associated with flexible manufacturing systems (FMS) with high tool variety. In this environment of FMS, the tool requirements at workstations exceed the respective tool magazine capacities. During an extensive survey of related literature, it appeared that the problems associated with this type of FMS have been overlooked by the FMS research community. The operational problems of FMS are discussed with special reference to the constraints imposed by tooling. The characteristics of the selected FMS type are clearly defined. This discussion is supplemented with a detailed description of a real FMS which resembles the operations of the selected type of FMS. Having identified certain drawbacks of some existing simulation software, the development of a comprehensive FMS simulator which uses a novel hybrid modelling technique is discussed. The use of a graphical post-processor which can be used to enhance the system logic of the FMS is also described number of parameters associated with the tool management system are identified and the methods are described to evaluate these parameters. The importance of evaluating these parameters in design and operation of an FMS is stressed. The development of a tool post-processor which can assist in identifying the scale of the tooling problem and in evaluating tool management parameters is presented. A variety of tool availability strategies which reduce the tool exchange rates are suggested and evaluated. Finally, the part selection (for immediate processing) problem is solved using a novel technique which takes the advantage of the availability of real time data in FMS.

No description available.

No description available.

It is well understood that optical fibre quality can be affected by the conditions present during fibre drawing. fibre tension , drawing speed, furnace temperature, the atmosphere within the ddrawing zone, viscosity of the glass, pre-form neck down shape and vibration in the drawn fibre are all factors which may affect the drawing process, and consequently the properties of the optical fibre. Most of these factors can be affected by the behaviour of the drawing furnace. Therefor monitoring furnace condition and predicting furnace decay are very important to the optical fibre manufacturing process. However, furnace conditions are very complicated and cannot be described by traditional mathematical models. In order to implement condition monitoring more effectively, the effects of process parameters and vibrations on the porperties and geometry of germanium-doped silica-core single-mode fibre, the subject of the current study were investigated by experiments and literature survey. These results can be used to determine the optimum processing conditions and select feature parameters for a condition monitoring system. Sources of vibration were analysed in order to provide information on which subsequent work to minimise vibrations on the drawn fibre could be based. The feature parameters which relate to furnace decay were extracted from the selected drawing parameters and are presented in this thesis. A new non-contact tension measurement system was devised. Different kinds of neural networks and their application in the furnace condition monitoring systems were investigated and the results are reported. A neural network software with fast training speed and a data exchange interface was developed to meet the needs of this furnace monitoring system. This thesis oresents a novel on-line condition monitoring system for drawing furnaces in the optical fibre drawing process. This system utilises the feature parameters extracted from drawing parameters and a neural network as the learning and decision making component. It can monitor the performance of the drawing process and give a pre-warning when furnace decay occurs or drawing parameters exceed the allowed working range. Hence, fibre properties can be enhanced, the production yield can be improved and machine utilities can be increased. This system has been used on a production optical fibre drawing tower at Pirelli Cables Limited and a high success rate for recognising furnace condition was achieved.

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In the increasingly competitive business environment reduced project cost, improved time-to-market, better quality products, and customer involvement are becoming the key success factors for any product development process. Many organisations within different industries are now focusing on Concurrent Engineering (CE) to bring improvements to their product development process in order to keep pace with the competitive environment. The adoption of CE has shown positive effects on project quality, cost, lead time, schedule, and customer satisfaction. For a targeted and effective implementation, it is recommended to carry out a readiness assessment of an organisation prior to the adoption of CE. This thesis discusses the adoption of CE within the construction industry, reviews existing CE readinessa ssessmentto ols used in other industry sectors,a nd assessesth eir applicability to construction. It then presentsa new developedC E readinessa ssessmentto ol for construction called the 'BEACON Model', its associated questionnaire, and an associated software. Description and results of CE readiness assessment case studies, which were conducted within five sectors of the construction industry, are then presented. At the end of the thesis, CE implementation strategiesa nd considerationsa re presentedb asedo n the assessmenrte sults, followed by conclusions, recommendations and future work. The most important conclusion, which could be drawn from the research, is that the construction industry as a whole still needs improvements in most of the critical areas identified by the BEACON Model in order to adopt CE effectively.

The aim of the study described in this thesis is to investigate the application of expert system technology to acrylic fibre production, with a particular emphasis on knowledge acquisition requirements. In doing so, it is intended to provide an understanding of the requirements and appropriate techniques for the effective application of expert systems in the process industries; The scope of the study is limited to process fault administration which involves detecting, diagnosing arid correcting abnormalities in process operation. A methodology is provided for the systematic development of expert systems within the defined area of application. An important phase in the development methodology is that of expert system specification. This involves an analysis of expert behaviour and the specification of expert system functionality: In order to assist system specification, generic knowledge types and human expert activities have been identified within the context of process fault administration. Knowledge acquisition is discussed in terms of the requirements during each phase of the proposed development methodology. A detailed review is given of the available techniques for knowledge acquisition and an assessment is presented of the most appropriate techniques to apply during each phase of the methodology. A new knowledge acquisition technique is described. The technique is designed to record knowledge of process operation and process fault diagnosis. It is based on a hierarchical decomposition of the process in terms of process objectives. Two complementary forms of knowledge representation are produced: a hierarchy diagram which shows the dependency relationships between individual process objectives and a task statement table which provides a more. detailed explanation of the objectives. Finally, three. case studies are described in which the techniques described in the thesis were applied and developed.

The aim of this research was to understand and solve problems associated with the integration of a Machine Planner within a product model environment. This work was carried out in conjunction with other researchers, pursuing parallel integration issues related to pre-production proving and product data representation. Product data representations of component level planned, processes and feature level process data have been explored as sub-sets of -a product data model to aid integration. Geometric queries on a cell decomposition solid, model. have been explored as a means of providing feature geometric interaction data, while the dimensional interactions between features have also been addressed. Product data representations have been modelled using a prototype software tool, providing an environment for the exploration of the integration of a Machine Planner using a feature based design approach. Necessary Machine Planning functions have been implemented, using the ADA programming language, to explore the integrating capability of the product model environment, concentrating on the use of a prismatic benchmark component. Using the experimental implementation, setup and operation plans have been produced and machining part programs generated from product model representations of variants on the benchmark component. These have been successfully machined using a3 axis vertical machining centre. Such experiments, as well as others in conjunction with co-researchers, have shown that a product data model can provide a common base of data for the integration of a range of design and manufacturing activities.

An important element for the integration of CAD/CAM is the representation and handling of data used during the design and manufacturing activities. The use of features and product modelling techniques bring a better handling of this data and provide CAD/CAM with an excellent platform for integration. The thesis explores the use of a predefined set of features in a product modelling environment for the design and machining of rotational components. Theword features in this research implies a set of functional, geometrical and technological information with a unique form. Those features are pre-defined and comprise of a limited number of elements which carry the information related to design and manufacturing activities. The thesis is divided into three main parts. The first part contains a review of topics related to the research e. g. group technology, component features, CAD/CAM and also contains a literature survey of related research works. In the second part the "features" are defined and presented. Also the product modelling environment is explained and the basic rule based procedures which are used to automatize the operation planning activities are presented. In the last part a description of the case-studies used for automatic NC code generation is presented followed by a discussion of the results. Lastly, the conclusions are drawn and ideas for further work presented.

Building contractors are unhappy about the existing post-tender use of the bills of quantities, particularly the way in which data produced by the estimator may be independently produced again or amended to a suitable format by other management functions. This research aimed at proposing better formats and presentations for the estimating data in order to reduce the repetition and re-work involved in the post-tender use of estimating data, hence to reduce the complexities in data flow in building contractor organizations. The work was primarily carried out for the Sri Lankan industry. To establish the scale and nature of the problem, past work on the format and presentation of estimating data and its current management was studied through literature, interviews and discussions with professionals in ten case studies. Proposals were formulated defining; an efficient classification and coding system, a well defined library structure, a new format to the contractor's copy of the estimate, and effective uses of the computer. The main proposal was to split the unit rate into its components and to provide a breakdown of resource requirements for each bill item. The documents prepared in two test projects were used to demonstrate the feasibility of the proposals in the earlier case studies, and feedback was obtained on the use and extent of use of the improved estimate in post-tender works. A live project was undertaken to investigate the practicability of implementing of the proposals. Finally, an independent survey, without disclosing the results derived from test projects, case studies and the live project was carried out to assess the acceptability of the proposals in the whole industry. All practical work was undertaken in Sri Lanka. The main conclusions derived from these works are; Any research that would investigate the contractor's efficient post-tender use of estimates hould be addressed to contractor organisations; and any proposal that would improve the contractor's data management should be based on contractor's presentation of the estimate. Although the contractors widely use the estimate in their management functions, the full potential is not obtained throughout the contract. Substantial re-work exists in the use of estimate in contractor's post-tender works. The average extent of use of the estimating data was measured at 50% the other 50% of data required re-work. Proposals presented in this research would increase the extent of use of the estimate, hence improve the contractor's data management. The new average extent of use of estimating data (after the introduction of proposals) derived from case studies was 75%. This new average, when compared with the earlier average (50%) showed a 50% possible improvement in the extent of use of estimate in the industry. Test projects, the live project and the independent survey, all showed that the proposals are not only feasible and practicable to implement in contractor organizations, but also acceptable in the whole industry as solutions which would improve the extent of use of the estimate and reduce the complexity of data flow in contractor organizations. The significance of these conclusions is that any contractor organization can adopt the proposals to improve their management because not only has their practicability been investigated but also their acceptability in the whole industry in Sri Lanka as a solution to data complexities is established. The conclusionsa re also of value to other countries.