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    An investigation of the dispatching and expediting rules in buffer management : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Production Technology at Massey University
    (Massey University, 1997) Simatupang, Togar Mangihut
    Buffer Management is a proactive way of controlling the flow of materials on a shop floor. For shops using the Drum-Buffer-Rope (DBR) scheduling system, information on the effectiveness of non-constraint resources can be captured by monitoring the buffer status. Practitioners use this information to initiate improvement efforts and to decide to expedite when some of the inevitable disruptions are likely to undermine shop performance. This study attempts to investigate three areas in Buffer Management: dispatching rules, expediting rules, and variance reduction. The selected dispatching rules are First-Come-First-Served (FCFS), Shortest Processing Time (SPT) and Minimum Slack Time (MINSLK). Both static and dynamic expediting rules are compared. Reduction in the coefficient of variance for processing times from 100% to 50% corresponds to the process of quality improvement. Mean protective capacity of non-constraint resources is varied to represent different levels of loading on the shop. Inventory and due date measures are used to appraise shop performance. Simulation results indicate that the FCFS dispatching rule is the method of choice if due date performance is important. The shop using the SPT dispatching rule produces lower cycle times. The dynamic expediting rule is only preferred in the shop using FCFS and when mean protective capacity is low. The reduction in processing time variability renders a dramatically improved shop performance.
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    Global manufacturing : study of company integration within a country : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Production Technology at Massey University
    (Massey University, 2004) Yusmira, Herwan
    A number of studies on Global Manufacturing Practices and the establishment of global company integration based on the similarity of practices among countries or regions have been conducted in the past. However, very few studies have been conducted on the integration of companies within a country. This study, using a survey approach, investigates an integration method based on Global Manufacturing Practices data collected from small and medium manufacturing companies in Indonesia. The development of successful joint ventures, integration, and other forms of collaboration depend on the ability to successfully integrate the production activities (Gyula Vastag, 1993). Global Manufacturing Practices developed by D). Clay Whybark, describe methods to examine the aspect of manufacturing activities based on the compatibility index (i.e. manufacturing practices) among participating companies around the world. The measurement of compatibility developed in his study is based on the data compiled by the Global Manufacturing Research Group (GMRG). Several comparisons, primarily based on statistical analysis, are helpful in understanding differences in manufacturing practices. Using the Global Manufacturing Practices survey, the study examines the participant perceptions of the manufacturing practices within their companies. The survey subjects are small and medium manufacturing firms (SMEs) from different regions of Indonesia. In addition to making general conclusion about manufacturing practices, the research proposes suggestions for development of integration based on measurements of the compatibility index of manufacturing practices relative to the Polman1 Politeknik Manufactur Bandung (Bandung Polytechnic for Manufacture), an Educational institution (see chapter 4). base region. The study evidence indicates the following major finding: • Hie participating companies indicated that a manufacturing activities database of Global Manufacturing Practices is an important knowledge resource and should be established on the basis of being clearly defined and accessible to all, including people outside the contributing companies. • To gain the most potential benefit, this data should be used for strategic planning prior to collaboration. The findings of the study suggest that a successful production activities integration process is dependent, to some degree, on the compatibility of manufacturing practices between collaborative parties. Further work, to confirm the suitability of the Compatibility Index for predicting actual compatibility, will be needed, but was judged to be beyond the scope of this thesis.
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    Design and development of a hybrid flexible manufacturing system : a thesis presented in fulfilment of the requirements for the degree of Master of Technology at Massey University
    (Massey University, 1999) Jolly, Matthew J
    The ability of a manufacturing environment to be able to modify itself and to incorporate a wide variety of heterogeneous multi-vendor devices is becoming a matter of increasing importance in the modern manufacturing enterprise. Many companies in the past have been forced to procure devices which are compatible with existing systems but are not as suitable as other less compatible devices. The inability to be able to integrate new devices into an existing company has made such enterprises dependent on one vendor and has decreased their ability to be able to respond to changes in the market. It is said that typically 60% of orders received in a company are new orders. Therefore the ability of a company to be able to reconfigure itself and respond to such demands and reintegrate itself with new equipment requirements is of paramount importance. In the past much effort has been made towards the integration of shop floor devices in industry whereby such devices can communicate with each other so that certain tasks are able to be achieved in a single environment. Up until recently however much of this was carried out in a very much improvised fashion with no real structure existing within the factory. This meant that once the factory was set up it became a hard-wired entity and extensibility and modiflability were difficult indeed. When formalised Computer Integrated Manufacturing (CIM) system architectures were developed it was found that although they solved many existing shortcomings there were inherent problems associated with these as well. What became apparent was that a fresh approach was required that took the advantages of existing architectures and combined them into an new architecture that not only capitalised on these advantages but also nullified the weaknesses of the existing systems. This thesis outlines the design of a new FMS architecture and its implementation in a factory environment on a PC based system.
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    A computer integrated manufacturing system for small scale production of electronic units : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Production Technology at Massey University
    (Massey University, 1995) Biersteker, Ronald John
    This research project concerns the design of a rapid response, computer integrated Printed Circuit Board (PCB) Component Assembly System (CAS). The CAS system forms an integral part of a commercially viable Manufacturing Pilot Plant (MPP) for the design, production, and assembly of high quality special purpose PCBs in low volumes. The design of the CAS system begins with the identification of the characteristics and deficiencies of conventional low volume, high variety PCB manufacturing systems. Next, a vision for the MPP as a whole is presented, with particular emphasis on the CAS system. A Generic Manufacturing System Design Methodology (GDM) is then derived, and is applied to the design of the CAS system. Through the GDM a working CAS system is constructed, based around a central CAS Master and 3 assembly workstations. The working CAS system is then analysed through a comparison with a typical conventional low volume manual assembly system. The results support the expectation of superior performance from the envisioned system. Finally, areas requiring further work are identified.
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    Methods of representing the structure of complex industrial products on computer files, to facilitate planning, costing and related management tasks : a thesis presented in fulfilment of the requirements for the degree of Master of Technology in Manufacturing and Industrial Technology at Massey University
    (Massey University, 1992) Burns, Sara
    When the original concepts for the computerisation of product structures were developed in the late 1960's the available computer power was very limited. A modularisation technique was developed to address the situation in which a number of similar products were being manufactured. This technique tried to rationalise these products into family groups. Each member of the family differed from the others due to the possession of different features or options. However there was also a high degree of commonality to give the product membership of the family. Modularisation involved the identification of the options and features providing the variability. Those parts remaining tended to be common to all members of the family and became known as the common parts. Separate Bills of Material (BOMs) were set up for each of the identified options or features. Another BOM was set up for the common parts. The simple combination of the required options and/or features BOMs with the common parts BOM specified a product. Computer storage requirements and redundancy were reduced to a minimum. The Materials Requirements Planning (MRP) system could manipulate these option and feature BOMs to over plan product variability without over planning the parts common to all members. The modularisation philosophy had wide acceptance and is the foundation of MRP training. Modularisation, developed for MRP, is generally parts orientated. An unfortunate side effect tends to be the loss of product structure information. Most commercial software would list 6 resistors, Part No. 123, in the common parts BOM without concern as to where the resistors are fitted. This loss of product structure information can hide the fact that two products using these 6 resistors 'in common' are in fact different as they do not use the resistors in the same 6 places. Additional information must be consulted to enable the correct assembly of the 'common' portion of these products. The electronics industry is especially affected by this situation. This industry has changed considerably since the late 1960's. Product variability can be very high. Changes and enhancements are a constant factor in products having a relatively short life span. The modularisation technique does not have a good mechanism for the situation where an option itself has options or features. This situation can exist down a number of layers of the family tree structure of an electronics product. Maintenance of these BOMs is difficult. Where there are options within options the designers and production staff need to know the inter-relationship of parts between options to ensure accuracy, compatibility and plan assembly functions. The advent of computerised spreadsheets has made the maintenance of this type of product structure information easier. This matrix is another separate document which must be maintained and cross checked. It will inevitably differ from the BOMs periodically. This thesis develops a product structure Relational BOM based on the matrix for the family of products. The processing power of the 1990's computer is fully utilised to derive the common parts for any or all of the selected products of the family. All product structure information is retained and the inter-relationship of parts is highly visible. The physical maintenance of the BOMs is simple. The BOM serves all purposes without the need for supplementary information. It is fully integrated into the Sales Order Entry , MRP, Costing, Engineering Design and Computer Aided Manufacturing (CAM) systems. This technique has been proven by being the only system used in one Electronics Design and Manufacturing organisation for over 1 year without any major problems. As described in Section 1.6 user satisfaction has been high. The response of the users to the suggestion 'lets buy an "off the shelf" package' is very negative, as it would not incorporate this BOM system. Users have expressed the opinion that EXICOM could not continue, with present staffing levels, using the traditional BOM structure.
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    A distributed shop floor control system based on the principles of heterarchical control and multi agent paradigm : a dissertation presented in partial fulfilment of the requirements for a PhD degree in Production Technology - Computer Integrated Manufacturing (CIM) Systems at Massey University
    (Massey University, 2004) Colak, Goran D
    In progressive firms, major efforts are underway to reduce the time to design, manufacture, and deliver products. The programs have a variety of objectives, from reducing lead-time to increasing product quality. The process of improvement starts with customer requirements, which in turn lead to customer-driven manufacturing, incorporating customer requirements more directly into the manufacturing processes. Forecasting customer requirements has not become any easier, in fact, just the contrary. The implication is clear: that if demands cannot be forecast, the manufacturing function must be designed to respond to these demands. To do this rapidly, more and more of the manufacturing decisions are being delegated to the factory floor. To paraphrase; the customer is saying what is to be made, the due date is now, and the work force is figuring out how to do it online. As the manufacturing world moves toward the "zero everything" vision of the future (zero inventory, zero set-up time, zero defects, zero waste), fundamental changes will take place in the factory. These changes will necessitate changes in manufacturing planning and control systems and particularly changes in planning and control on the shop floor level. This dissertation addresses the possible direction that some of these changes might take on the shop floor. The starting preamble of this research is that forecasting in certain type of manufacturing systems is not possible. An example might be systems in which product orders arrive randomly, such as manufacturing facilities involved in production of replacement spare parts). Additionally, in many other manufacturing systems, forecasting generates results that are of a very low level of certainty. In many occasions they are practically useless, since they are applicable only for short time horizons. As an example, small-quantity batch manufacturing systems usually operate under conditions where frequent disturbances make this production unstable at all times. Therefore, addressing these systems, the main idea embodied in this dissertation could be expressed as follows: "Instead of focusing efforts on how to improve the old, or develop new methods for controlling material flows in manufacturing systems, methods that are solely based on the main premise of predicting the future circumstances, this research takes another course. It considers an alternative approach - developing of manufacturing control mechanisms that are "more reactive" to the changes in the systems and "less dependant on prediction" of future events. It is believed that the modern job shop manufacturing facilities, such as mentioned above, can further increase their competitiveness by adopting approaches for shop floor control systems that are discussed in this research study. This is because the proposed system is capable, both dynamically and in real time, of promptly responding to frequent changes in production conditions, always attempting to find the best possible solution for given circumstances.