Fixtures are devices designed to repeatedly and accurately locate the processed workpiece in a desired position and orientation, and securely hold it in the location throughout the manufacturing process. Fixtures are also charged with the task of supporting the workpiece to minimise deflection under the loads arising from the manufacturing process. As a result, fixtures have a large impact on the outcome of a manufacturing process, especially when the workpiece presents low rigidity. Traditionally, in manufacturing environments, where thin-walled components are produced, the utilised fixtures are dedicated solutions, designed for a specific workpiece geometry. However, in the recent decades, when the manufacturing philosophy has shifted towards mass customisation, there is a constant technological pull towards manufacturing equipment that exhibits high production rates and increased flexibility/reconfigurability, without any compromise in the quality of the end result. Therefore, fixtures have been the focal point of a plethora of research work, targeting mainly towards either more reconfigurable, or more intelligent/adaptive solutions. However, there have been no attempts so far to merge these two concepts to generate a new fixturing approach. Such an approach, referred to in this work as fully-active fixrturing, would have the added ability to reposition its elements and adapt the forces it exerts on-line, maximising the local support to the workpiece, and thus reducing vibration amplitude and elastic deformation. This results in a tighter adherence to the nominal dimensions of the machined profile and an improved surface-finish quality. This research work sets out to study the impact of such fixturing solutions, through developing suitable models which reflect the fixture-workpiece system behaviour, and a design methodology that can support and plan the operation of fully-active fixtures. The developed model is based on a finite elements representation of the workpiece, capturing the dynamic response of a thin-walled workpiece that is being subjected to distributed moving harmonic loads. At the same time, the workpiece is in contact with an active element that operates in closed-loop control. An electromechanical actuator is charged with the role of the active elements, and it is modelled via first-principle based equations. Two control strategies are examined experimentally to identify the best performing approach. The direct force/torque control strategy with a Proportional-Integral action compensator is found to lead to a system that responds faster. This control architecture is included in the model of the active elements of the fixture. The behaviour of the contact between the fixture and the workpiece is approximated via a combination of a spring and a damper. The overall model is assembled using the impedance coupling technique and has been verified by comparing its response with the time-domain response of an experimental set-up. The developed model serves as the backbone of the fully-active fixture design methodology. The latter is capable of establishing important fixturing parameters, such as the pattern of motion of the movable fixture element, the points on the surface of the workpiece that formulate the motion path of the fixture element, the time instant at which the element needs to change position, and the clamping forces the fixture needs to apply and maintain. The methodology is applied on a thin plate test case. Such a plate has been also used in a series of machining experiments, for which the fixturing parameters used are those that resulted from the test case. A very good quantitative agreement between both experiments and theory was observed, revealing the capabilities of the methodology itself and of the fully-active fixturing approach in general.

Increasingly, services are utilised by manufacturing companies to satisfy demand. This trend is thought by a number of authors to provide opportunities to develop products that satisfy demand at increased resource efficiencies. This thesis considers a special category of services which have been conceptualised by academics and policy makers to realise this - Eco-services Eco-services have been the focus of a number of research projects lead by those practicing and associated with cleaner product design. This work has mainly focused on product policy and whilst a considerable body of knowledge has been accumulated, the array of factors that would lead to the successful transfer (from academia and to UK manufacturing companies) of this exogenous concept were unknown. This thesis sought to identify and understand these. Two inter linked phases of research were initiated and completed. The first was inductive in nature and was comprised of a Pilot Study. In this data was elicited from a variety of sources so as to provide a robust foundation of knowledge upon which subsequent enquiry could be initiated. It concluded with the construction of an initial conceptual framework which described the attributes of receptivity that were found in UK manufacturing firms to be specific to the Eco-service concept. Also, a number of research propositions were generated so as to guide research in phase two. The second deductive phase of research was undertaken so as to test the initial conceptual framework. A Main Study was carried out in order to elicit primary qualitative data from two UK manufacturing companies. This work was guided by the research propositions and a more in-depth understanding of the attributes of receptivity was gained. This body of knowledge was utilised to refine the initial conceptual framework. This research identified and understood the range of factors that give rise to the successful inward transfer of the Eco-service concept in U manufacturing companies. Eight attributes of receptivity were identified and described in the final conceptual framework. The intention of this work was not to refute current trajectories of research within the Eco-service domain, but rather to provide an additional body of knowledge that can be thought to enable those authors in the Eco-service domain to realise the opportunity that the emergent trajectory of services provides to significantly improve resource efficiencies.

As the need for smaller, more compact and integrated products has evolved, it is no surprise that manufacturing technologies have significantly evolved in order to make miniaturisation to smaller scales possible. More specifically non-conventional machining technologies, relative newcomers in the field of machining, have proven well suited to the task at hand. Among those technologies is micro-EDM (short for Electrical Discharge Machining) that has been the subject of numerous developments. A certain number of variants of micro-EDM exists among which are wire micro-EDM, die-sinking micro-EDM, micro-EDM milling and micro-EDM drilling. While die-sinking macro-EDM is quite common, its micro counterpart isn’t due to problematic tool wear. In order to optimise the die-sinking micro-EDM process in terms of time and cost and make its use more interesting and viable, the present work aims at optimizing the initial tool shape so that it compensates for future wear. The first step was to design a simulation tool effectively able to predict the location and magnitude of wear during the simulation process. An iterative geometrical method was developed, first using NURBS as support geometries then voxels embedded in an octree data structure in order to improve speed and accuracy.

The machining characteristics of a glassy thermoplastic (Polyvinyl Chloride) and a semi-crystalline thermoplastic (High Density Polyethylene) have been studied. Chip formation mechanisms, cutting forces and surface integrity were found to be dependent, on the cutting conditions and tool geometry. Results were explained by considering the different nature of the microstructure. Segmented and discontinuous chips were produced with PVC, and continuous and segmented chips were produced with HDPE. It was observed that surface damage was closely related to the nature of chip formation in these plastics. Chip formation, surface damage and tool wear mechanisms when machining Glass-Fibre-Reinforced-Plastic (GFRP) were also studied. Cutting tools used were High-Speed-Steel (HSS), cemented carbide (P type and K type) and coated carbide (titanium carbide - and triple-coated). Discontinuous chips were always produced when machining GFRP. Sliding contact is present at the tool/chip and tool/work interface. The principal aspects of surface damage include fibre breakage, resin cracking, resin decomposition and fibre/resin interface debonding. Cutting temperature is not high, but excessive heat generates when the flank wear land develops. Coated carbide tools showed the best performance and HSS tools the poorest. The main wear mechanisms are abrasive wear with HSS tools, attrition wear with cemented carbides, and discrete plastic deformation followed by attrition wear with coated carbides.

The grinding process must achieve the desired component surface finish without producing detrimental workpiece surface layer alterations. These objectives have traditionally been achieved intuitively by skilled operators. Adaptive control, however, offers an opportunity to monitor and control surface integrity during the grinding process. The cylindrical plunge grinding machine adapted for the purposes of this research monitors normal and tangential grinding forces, wheelpower and the amplitude of chatter vibration. The control system is capable of achieving constant normal force machining by adjusting the plunge infeed rate of the wheel. This research is concerned with the feasibility of controlling surface integrity on this and simi lar grinding machines. The research has been carried out by a combination of long duration tests to examine the behaviour of grinding forces, wheelpower and vibration levels with respect to time and shorter duration tests to examine component surface finishes. The results of the tests have enabled models to be developed which relate component surface finishes to metal removal rates. normal grinding forces and chatter vibration levels. Work piece burn and its prevention have also been studied. A method of eliminating workpiece burn has been proposed which utilises in-process normal and tangential force monitoring.

'Coke' may be described as the cellular residue from the carbonisation of a coking coal in commercial ovens or-retorts at a temperature of about 9000C; and a 'Coking coal' as a coal which will yield a commercial coke when it is carbonised. Some of the questions arising from these descriptions are:- What are the standards required of a commercial coke; what is the cause of coke-formation; what are the characteristics of coking coals and how may they-be judged; and how can the quality of coke be improved? It is not proposed to discuss these questions in detail but it is important to be aware of them in order to understand the way the coking industry has developed. These questions have been asked since coke has been used on a commercial scale and the answers to them have altered with circumstances as science and technology have changed. The qualities which render a coke most useful, or most readily saleable vary according to the use to which it is to be put. For all combustion processes, which account for most of the coke used, it would be expected that the intrinsic 'combustibility' would be important. The manner in which a ooke burns depends-so much however upon such factors asp for example, the size of the pieces and the rate of supply of air to the fuel-bed, that differences in intrinsic combustibility may be masked. From observation of the various factors upon whioh the usefulness of a coke for particular purposes depends, it is possible to indicate those qualities of a coke which render it most valuable, for all, or most, purposes (Continues...).

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