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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

A petri net based system analysis and design approach for computer integrated manufacturing

Huang, Nan January 1994 (has links)
No description available.
212

An integrated approach to process planning and scheduling

Carvalho, Jose Dinis de Araujo January 1996 (has links)
No description available.
213

Functional tolerancing in CAD/CAM

Cheikh, Abdelmadjid January 1990 (has links)
No description available.
214

A time-of-flight optical range sensor for mobile robot navigation

Brownlow, Michael James January 1993 (has links)
No description available.
215

An application of an ethernet based protocol for communication and control in automated manufacturing

Bertolissi, Edy January 1997 (has links)
The exchange of information in the industrial environment is essential in order to achieve complete integration and control of manufacturing processes. At present the majority of devices present in the shop floor environment are still used as stand alone machines. They do not take advantage of the possibilities offered by a communication link to improve the manufacturing process. The subject of this research has been centered on the development of a simple, flexible and inexpensive support system for communication and control of manufacturing processes. As a result, a system with these features has been proposed and implemented on a simulated workcell. The area footwear manufacturing was chosen for modelling the workcell. The components of the manufacturing support system were developed using an object oriented approach which allowed modularity and software reuse. In order to achieve communication between the components, a communication protocol was developed following the process defined in the rapid protocol implementation framework. Ethernet was selected for implementing the lower levels of the protocol. Java, a new object oriented programming language used for the implementation of the system, showed that it could became a promising language for the implementation of manufacturing applications. In particular the platform independence feature of the language allows the immediate porting of applications to systems with different features. The manufacturing cell simulation had shown that the times associated with the manufacturing support system operations are compatible for its use in applications where the response times are in the order of one second.
216

MODELING THE INFLUENCE OF DESIGN GEOMETRY ON THE COINING PROCESS

Koivisto, Tristan 04 March 2013 (has links)
A number of aspects of the coining process are investigated, both through experimentation using several types of tooling using blanks made of copper 110 or brass 260, and by developing and using a FEA model. Several relationships have been found which describe the effects of changing the type of coin blank or the geometry of the coining tooling on how much volume of the coin is formed at different forces. The open-die bulk upsetting test was used to find the true stress and strain curves of both materials, and the ring test was used to determine the coefficient of friction. Coins were made over a large range of forces in order to test the general nature of how the diameter and design of a coin are formed. While the diameter begins to increase, the thickness of the coin reduces and material is pushed into the punch cavity, filling the design’s volume up rather linearly. Tests on the effects of changes in the wall angle were inconclusive. As the punch design depth increased the force requirement went down in a manner roughly inverse to the ratio of the increase in depth. Effects of coining with a punch on one side versus two sides were tested. Effects of the perimeter of the punch design showed that a longer perimeter actually reduced the forces required for thinner coins, a difference that got smaller as the coin blanks got thicker. Blanks required 1.4 times the force to form than a coin half its thickness. A direct correlation of forming force to the yield stress of the material was expected but rather appeared to be related to the full nature of the true stress-strain curves. The FEA model was able to match experimental results relatively closely, but only up to about 333.3 kN, the lowest force used for the bulk of the experimental samples. The FEA model provided a good look into what happens to the coin while it is under load and the mysteries of ghost coining were unveiled. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2013-03-01 06:28:50.729
217

A development and extension of the engineering solutions for the Miles and Snow's adaptive cycle

Dai, Yang January 2007 (has links)
Miles and Snow proposed their theory about organisation strategy, structure and process in 1978. The key point of their theory is the adaptation cycle of an enterprise among entrepreneurship domain, engineering domain and administration domain. They propose three successful strategy types: Defender, Prospector and Analyser, which can successfully adapt to changes in the environment in their own way. Since the theory first appeared in the 1970s, it has been applied and examined in strategy, organisational theory, human resource management, operations management, marketing and accounting, but has not been rigorously applied to nmodern manufacturing. This research aims to test and develop Miles and snow's engineering solutions of Defender, Prospector and Analyser in the adaptive cycle model. A series of propositions and hypotheses have been generated based on the EE (Entreneurship - Engineering) and the EA (Engineering - Administration) models that created in this research, which are based on the literature review of manufacturing technologies, strategic theories and Miles and Snow typology. AMTs (Advanced Manufacturing Technologies) are chosen to test the EE and EA models, as well as original Miles and Snow's engineering solution. Both quantitative and qualitative methods have been applied in this research in order to validate these propositions and hypotheses. The research has generated a number of successful outcomes relating to its aim and objectives: Firstly, the Miles and Snow model is extended into an area that was not only under represented in the original exposition, but also has changed dramatically since their framework was derived. Secondly, the research places manufacturing strategy issues into a well-validated organisational model, thereby reducing the implicit passivity of many manufacturing strategy prescriptions. These two contributions will enable further contributions of value to both theorists and practicioners. Implementation difficulties associated with organisational obstacles can be assessed in terms of organisational solutions and these might be contrasted with technical solutions prevalent in the literature. Further research can be explored in the following areas based on the validation of the EE and the EA models: in other technologies, other industries, and other countries.
218

Intelligent design of manufacturing systems

Quinn, Liam January 1996 (has links)
The design of a manufacturing system is normally performed in two distinct stages, i.e. steady state design and dynamic state design. Within each system design stage a variety of decisions need to be made of which essential ones are the determination of the product range to be manufactured, the layout of equipment on the shopfloor, allocation of work tasks to workstations, planning of aggregate capacity requirements and determining the lot sizes to be processed. This research work has examined the individual problem areas listed above in order to identify the efficiency of current solution techniques and to determine the problems experienced with their use. It has been identified that for each design problem. although there are an assortment of solution techniques available, the majority of these techniques are unable to generate optimal or near optimal solutions to problems of a practical size. In addition, a variety of limitations have been identified that restrict the use of existing techniques. For example, existing methods are limited with respect to the external conditions over which they are applicable and/or cannot enable qualitative or subjective judgements of experienced personnel to influence solution outcomes. An investigation of optimization techniques has been carried out which indicated that genetic algorithms offer great potential in solving the variety of problem areas involved in manufacturing systems design. This research has, therefore, concentrated on testing the use of genetic algorithms to make individual manufacturing design decisions. In particular, the ability of genetic algorithms to generate better solutions than existing techniques has been examined and their ability to overcome the range of limitations that exist with current solution techniques. IIFor each problem area, a typical solution has been coded in terms of a genetic algorithm structure, a suitable objective function constructed and experiments performed to identify the most suitable operators and operator parameter values to use. The best solution generated using these parameters has then been compared with the solution derived using a traditional solution technique. In addition, from the range of experiments undertaken the underlying relationships have been identified between problem characteristics and optimality of operator types and parameter values. The results of the research have identified that genetic algorithms could provide an improved solution technique for all manufacturing design decision areas investigated. In most areas genetic algorithms identified lower cost solutions and overcame many of the limitations of existing techniques.
219

3D numerical modelling and manipulation of a shoe last

Gordeyeva, Olga V. January 1998 (has links)
As global competition continues to increase causing market windows to shrink and product life cycles shorten, manufacturers today can no longer function without advanced design tools. These market pressures dictate that designers must embrace new, faster and better design technologies than ever before if they are to remain competitive. This is especially true in the shoe industry with the employment of up-to-date methods of design and manufacture. The development of modem CAD/CAM systems, the availability of powerful hardware at reasonable cost and vast improvements in colour graphics capabilities have made the automation of the footwear design process feasible at low cost. All of this economically justifies the creation of a system for direct shoe last design without a prototype model last. A specific onscreen methodology of a shoe last design directly from individual anthropometric data has been proposed and evaluated. A numerical methodology for onscreen visualisation with application of a new scheme of segmentation of the last surface and further manipulation of the last elements in order to create new last styles have been developed. In order to achieve this, the principles of shaping the last, the laws governing its deformation when changing the heel height and the list of possible modifications to its shape have been defined. Five global manipulation procedures have been implemented, in particular those that relate to changing the heel height. Special software has been written to visualise the results. Experimentation has proved the validity of the approach. Lasts of similar style but with different heel heights were measured and numerically modelled to compare with computer generated and modified last models. The accuracy proved to be within the limits of practical and traditional constraints.
220

A reference architecture for flexibly integrating machine vision within manufacturing

Edwards, John M. January 1993 (has links)
A reference architecture provides an overall framework that may embrace models, methodologies and mechanisms which can support the lifecycle of their target domain. The work described in this thesis makes a contribution to establishing such a generally applicable reference architecture for supporting the lifecycIe of a new generation of integrated machine vision systems. Contemporary machine vision systems consist of a complex combination of mechanical engineering, the hardware and software of an electronic processor, plus optical, sensory and lighting components. "This thesis is concerned with the structure of the software which characterises the system application. The machine vision systems which are currently used within manufacturing industry are difficult to integrate within the information systems required within modem manufacturing enterprises. They are inflexible in all but the execution of a range of similar operations, and their design and implementation is often such that they are difficult to update in the face of the required change inherent within modem manufacturing. The proposed reference architecture provides an overall framework within which a number of supporting models, design methodologies, and implementation mechanisms can combine to provide support for the rapid creation and maintenance of highly structured machine vision applications. These applications comprise modules which can be considered as building blocks of CIM systems. Their integrated interoperation can be enabled by the emerging infrastructural tools which will be required to underpin the next generation of flexibly integrated manufacturing systems. The work described in this thesis concludes that the issues of machine vision applications and the issues of integration of these applications within manufacturing systems are entirely separate. This separation is reflected in the structure of the thesis. PART B details vision application issues while PAIIT C deals with integration. The criteria for next generation integrated machine vision systems, derived in PART A of the thesis, are extensive. In order to address these criteria and propose a complete architecture, a "thin slice" is taken through the areas of vision application, and integration at the lifecycle stages of design, implementation, runtime and maintenance. The thesis describes the reference architecture, demonstrates its use though a proof of concept implementation and evaluates the support offered by the architecture for easing the problems of software change.

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