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No description available.

It is now a common sense that manufactures including machine suppliers and system integrators of the 21 st century will need to compete on global marketplaces, which are frequently shifting and fragmenting, with new technologies continuously emerging. Future production machines and manufacturing systems need to offer the "agility" required in providing responsiveness to product changes and the ability to reconfigure. The primary aim for this research is to advance studies in machine control system design, in the context of the European project VIR-ENG - "Integrated Design, Simulation and Distributed Control of Agile Modular Machinery".

Wire+arc additive manufacturing is a technique suitable for the deposition of large components; a variety of materials can be processed, including titanium. For the alloy Ti{6Al{4V, an experimental model based on design of experiment and linear regression was developed to control layer geometry during deposition. The modelled variables were wall width and layer height; the former was dependent on the heat input, and the latter on the heat input as well as on the wire feed speed to travel speed ratio. Equations enabled the automatic selection of process parameters based on geometric requirements speci c to the part being built. This could ensure minimisation of production time and material waste. Additively manufactured parts are a ected by distortion and residual stress; the e ect of high pressure rolling on these two, as well as on geometry, microstructure and mechanical properties was studied. Due to plastic deformation, rolled linear deposits were characterised by a larger width and smaller height. The variability of the layer height was reduced, a bene cial e ect from a production implementation viewpoint. Distortion was less than half in rolled components, a change associated with the reduction in residual stress which were still tensile in the bottom of the parts and compressive in their top; however their overall magnitude was smaller than in the unrolled samples. The contour method showed relatively good agreement with the neutron di raction measurements, and although destructive it proved to be a fast way to characterise residual stress in additively manufactured components. Microstructurally, the columnar prior grains con guration observed in all unrolled deposits, also a ected by a strong texture developed in the building direction, was changed to equiaxed grains due to the recrystallisation triggered by both the strain introduced by rolling and the repeated thermal cycles induced by each layer deposition. The microstructure was overall considerably ner and the texture randomised. A fundamental study was performed to discern the extent of the deformed zone from the one a ected thermally. While the deformed zone could not be identi ed precisely, the thermally in uenced zone showed a relationship between rolling load and depth of the recrystallised volume. Finally, testing of hardness and tensile strength showed superior properties of rolled specimens than in the unrolled specimens. The mechanical performance of rolled samples was fully isotropic too. This project was entirely sponsored by Airbus Group Innovations (formerly EADS Innovation Works).

It became evident that Preshearing had simplified the layup process to such an extent that automation had become a more feasible option. Subsequently, a two stage automated process was developed. The preshearing was applied using a custom built press with blank holders around the perimeter to control shearing and prevent wrinkling by applying in-plane tension. A short study on the deformation of prepreg material showed that by heating the prepreg, the deformation could be held in the ply for over an hour after preshearing. Once the plies had been presheared they were passed on to a robotic layup cell based around an industrial six axis robot. Inspired by the way the human laminators used their hands alongside additional hard tools to adapt to different mould features, three bespoke end effectors were developed to tackle different geometric features. A large cylindrical roller was used to consolidate flat and convex regions, while a second ' discus ' shaped roller with a 60° angle at its outer edge was used to tackle tight concave corners. A third end effector was required to tackle tight doubly curved convex corners. A number of hard plastic based tools were trialled, but a hybrid of a silicone wedged tip with an aluminium core provided the right balance of high pressure and conformity. In combination, these three end effectors successfully completed a series of increasingly complex layup tasks. The robotic system was then combined with plies which had been presheared in the press, and an entire sample panel ply was laid-up without any human interaction other than transferring the ply from the press to the mould. Two complete three ply panels were laid-up with the automated system and cured into finished parts. The quality of these layups compared favourably to an additional example made by hand.

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More than ever, efficiency and quality are key words in modern industry. This situation enhances the importance of quality control and creates a great demand for cheap and reliable automatic inspection systems. Taking into account these facts and the demand for systems able to inspect the final shape of machined parts, we decided to investigate the viability of automatic model-based inspection of mechanical parts using the dense range data produced by laser stripers. Given a part to be inspected and a corresponding model of the part stored in the model data base, the first step of inspecting the part is the acquisition of data corresponding to the part, in our case this means the acquisition of a range image of it. In order to be able to compare the part image and its stored model, it is necessary to align the model with the range image of the part. This process, called registration, corresponds to finding the rigid transformation that superposes model and image. After the image and model are registered, the actual inspection uses the range image to verify if all the features predicted in the model are present and have the right pose and dimensions. Therefore, besides the acquisition of range images, the inspection of machined parts involves three main issues: modelling, registration and inspection diagnosis. The application, for inspection purposes, of the main representational schemes for modelling solid objects is discussed and it is suggested the use of EDT models (see [Zeid 91]). A particular implementation of EDT models is presented. A novel approach for the verification of tolerances during the inspection is proposed. The approach allows not only the inspection of the most common tolerances described in the tolerancing standards, but also the inspection of tolerances defined according to Requicha's theory of tolerancing (see [Requicha 83]). A model of the sensitivity and reliability of the inspection process based on the modelling of the errors during the inspection process is also proposed. The importance of the accuracy of the registration in different inspections tasks is discussed. A modified version of the ICP algorithm (see [Besl &; McKay 92]) for the registration of sculptured surfaces is proposed. The maximum accuracy of the ICP algorithm, as a function of the sensor errors and the number of matched points, is determined. A novel method for the measurement and reconstruction of waviness errors on sculp¬ tured surfaces is proposed. The method makes use of the 2D Discrete Fourier Transform for the detection and reconstruction of the waviness error. A model of the sensitivity and reliability of the method is proposed. The application of the methods proposed is illustrated using synthetic and real range images.

In the modern commercial environment, companies are continuously trying to reduce costs by improving manufacturing efficiency. As equipment reliability directly affects manufacturing efficiency an investigation of equipment would be the first step to reducing equipment downtime. The most common method of identifying the contributors to poor performance is Reliability Centred Maintenance (RCM). This technique however, has had relatively few applications, as it has been perceived as too rigorous and requiring excessive financial and manpower investment. The sponsoring company, Wolfson Maintenance (WM), identified a market opportunity in that a simple cost effective method of analysing maintenance performance did not exist. They developed a process called Review of Equipment Maintenance (REM), which utilises Failure Mode & Effects Criticality Analysis (FMECA) techniques to gather together the knowledge gained through the application of an existing maintenance plan. This process has had notable success in a number of applications but WM feel that because of its lack of structure it has not reached its full potential consequently, this project was proposed to research and formalise the REM process.

Intensified competition in a number of global manufacturing industries has triggered renewed interest in the manufacturing function and the contribution it can make to a company's overall competitive success. There has been a growing recognition that manufacturing can be a formidable competitive weapon if equipped and managed properly, and that a key to doing that is the development of a coherent manufacturing strategy which is in line with the business strategy of the company. 600 Lathes is a medium sized batch manufacturer of products, for the machine tool market, who has adopted a market led business strategy. However, in order to improve its competitive position within a highly volatile market, the company has recognised the need to align its manufacturing capabilities with this business strategy. This thesis investigates the cross-functional integration of business, marketing and manufacturing strategies at 600 Lathes. Its underlying hypothesis is that the alignment of functional strategies at 600 Lathes requires the adoption of a formal planning process, which ensures a multi-disciplinary approach. Using multiple cycle action research, a framework is developed which outlines a process for creating an integrated strategy. The development of this framework is built upon the findings from the empirical research on the process of strategy development at 600 Lathes, and a study of the level of strategic integration in a sample of UK manufacturing companies. The research demonstrates that a formal planning process can be used to aid the sequential development of business and functional strategies, and that by doing so, strategic integration can be achieved. The key elements of this process are the use of cross-functional teams, aligned goals, objectives and performance measures and the use of a comprehensive SWOT analysis. The formal process has been applied to the revision and development of business strategies at both 600 Lathes and a sister company, Electrox.