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No description available.

No description available.

No description available.

No description available.

No description available.

Selecting the best set of tools to produce certain geometrical shapes/features in sheet metal punching is one of the problems that has a great effect on product development time, cost and achieved quality. The trend nowadays is, where at all possible, to limit design to the use of standard tools. Such an option makes the problem of selecting the appropriate set of tools even more complex, especially when considering that sheet metal features can have a wide range of complex shapes. Another dimension of complexity is limited tool rack capacity. Thus, an inappropriate tool selection strategy will lead to punching inefficiency and may require frequent stopping of the machine and replacing the required tools, which is a rather expensive and time consuming exercise. This work demonstrates that the problem of selecting the best set of tools is actually a process of searching an explosive decision tree. The difficulty in searching such types of decision trees is that intermediate decisions do not necessarily reflect the total cost implication of carrying out such a decision. A new approach to solve such a complex optimisation problem using the Monte Carlo Simulation Methods has been introduced in this thesis. The aim of the present work was to establish the use of Monte Carlo methods as an "assumptions or rule free" baseline or benchmark for the assessment of search strategies. A number of case studies are given, where the feasibility of Monte Carlo Simulation Methods as an efficient and viable method to optimise such a complex optimisation problem is demonstrated. The use of a Monte Carlo approach for selecting the best set of punching tools, showed an interesting point, that is, the effect of dominant "one-to-one" feature/tool matches on the efficiency of the search. This naturally led on to the need of a search methodology that will be more efficient than the application of the Monte Carlo method alone. This thesis presents some interesting speculations for a hybrid approach to tool selection to achieve a better solution than the use of the Monte Carlo method alone to achieve the optimum solution in a shorter time.

There is growing interest in the development of fabrication techniques to cost effectively mass-produce high-resolution (micro/nano) 3D structures in a range of materials. Biomedical applications are particularly significant. This work demonstrates a novel technique to simultaneously fabricate a sacrificial mould having the inverse shape of the desired device structure and also create the desired device structure using electroplating deposition techniques. The mould is constructed of many thin layers using a photoresist material that is dissolvable and sensitive to UV light. At the same time the device is created in the emerging mould layers using Gold electroplating deposition technique. Choosing to fabricate the mould and the 3D structures in multiple thin layers allows the use of UV light and permits the potential cost-effective realization of 3D curved surfaces, the accuracy and geometric details of which are related to the number of layers used. In this work I present a novel idea to improve the LIGA process when using many masks to deposit multi thin layer over each other. Moreover, this technique can be utilized to produce a curved surface in the vertical direction with any diameter. Practically, a 2 µm thickness of layer is applied in the proposed technique. However, a layer of 0.5 µm or less can be deposited. An example is provided to explain the novel fabrication process and to outline the resulting design and fabrication constraints. With this technique, any structure could be made and any material used. The work employs conventional techniques to produce a 3D complex shape. By using conventional techniques with multi layers to produce a 3D structure, many problems are expected to occur during the process. Those problems were mentioned by many researchers in general but have not been addressed correctly. Most researchers have covered those problems by leaving the conventional and using a new technique they invented to produce the required product. However, in my work I have addressed those problems for the first time and I offered a new and effective technique to improve the MEMS technology and make this technology cheaper. This was achieved by using a research methodology requiring a rigorous review of existing processes, as outlined above, then by proposing a concept design for an improved process. This novel proposed process was then tested and validated by a series of experiments involving the manufacture of demo-devices. The conclusion is that this new process has the potential to be developed into a commercially implementable process.

There is an ongoing trend towards advanced fixturing systems that can be automatically reconfigured for different workpieces and dynamically adapt the clamping forces during the manufacturing process. However, the increased utilisation of computer technology and sensor feedback currently requires a significant amount of programming effort during the development phase and deployment of such fixtures which impairs their successful industrial realisation. This research addresses the issue by developing the core concepts of a novel software framework that facilitates the deployment and operation of reconfigurable and adaptive fixturing systems. This includes a new data model for the representation of the fixturing system, using object-oriented modelling techniques. Secondly, a generic methodology for the automatic reconfiguration of fixturing systems has been developed that can be applied to a plethora of different fixture layouts. Thirdly, a flexible communication infrastructure is proposed which supports the platform-independent communication between the various parts of the fixturing system through the adoption of a publish/subscribe approach. The integration of these core knowledge contributions into a software framework significantly reduces the programming effort by providing a ready-to-use infrastructure that can be configured according a given fixture layout. In order to manage the complexity of the research, a structured research methodology has been followed. Based on an extensive literature review, a number of knowledge gaps have been identified which were the basis for the definition of clear research objectives. A use case analysis has been conducted to identify the requirements of the software framework and several potential middleware technologies have been assessed for the communication infrastructure. This was followed by the development of the three core knowledge contributions. Finally, the research results have been demonstrated and initially verified with a prototype of a reconfigurable fixturing system, indicating that the utilisation of the software framework can eliminate the need for programming, thereby drastically reducing deployment effort and lead time.