This thesis is concerned with the development and experimental analysis of a resonant gyroscope. Initially, this involved the development of a fabrication process suitable for the construction of metallic microstructures, employing a combination of nickel electroforming and sacrificial layer techniques to realise free-standing and self-supporting mechanical elements. This was undertaken and achieved. Simple beam elements of typically 2.7mm x 1mm x 40µm dimensions have been constructed and subject to analysis using laser doppler interferometry. This analysis tool was used to implement a fill modal analysis in order to experimentally derive dynamic parameters. The characteristic resonance frequencies of these cantilevers have been measured, with 3.14kHz, 23.79kHz, 37.94kHz and 71.22kHz being the typical frequencies of the first four resonant modes. Q-factors of 912, 532, 1490 and 752 have been measured for these modes respectively at 0.01mbar ambient pressure. Additionally the mode shapes of each resonance was derived experimentally and found to be in excellent agreement with finite element predictions. A 4mm nickel ring gyroscope structure has been constructed and analysed using both optical analysis tools and electrical techniques. Using laser doppler interferometry the first four out-of-plane modes of the ring structure were found to be typically 9.893 kHz, 11.349 kHz, 11.418 kHz and 13.904 kHz with respective Q-factors of 1151, 1659, 1573 and 1407 at 0.01 mbar ambient pressure. Although electrical measurements were found to be obscured through cross coupling between drive and detection circuitry, the in-plane operational modes of the gyroscope were sucessfully determined. The Cos2Ө and Sin2Ө operational modes were measured at 36.141 kHz and 36.346 kHz, highlighting a frequency split of 205kHz. Again all experimentally derived modal parameters were in good agreement with finite element predictions. Furthermore, using the analysis model, the angular resolution of the gyroscope has been predicted to be approximately 4.75º/s.

The explosion of SMT and highly-density packages has resulted in more complex and higher density board designs in order to incorporate more features into products while reducing overall package size. This has, in tum, created major challenges for the surface mount manufacturing process, particularly in solder screen printing, component placement, and reflow soldering. Investigation into these areas will contribute to our understanding of the origin of post reflow defects in surface mount assembly and improvement in product quality. The thesis particularly explores empirically the relationship between screen printed paste deposit, the final joint geometry and the fluxing behaviour within the reflowing solder. The thesis also demonstrates the effect of modified screen printing parameters and the lead geometry.

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No description available.

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The future of manufacturing in high-cost economies is to maximise responsiveness to change whilst simultaneously minimising the financial implications. The concept of Reconfigurable Assembly Systems (RAS) has been proposed as a potential route to achieving this ideal. RASs offer the potential to rapidly change the configuration of a system in response to predicted or unforeseen events through standardised mechanical, electrical and software interfaces within a modular environment. This greatly reduces the design and integration effort for a single configuration, which, in combination with the concept of equipment leasing, enables the potential for reduction in system cost, reconfiguration cost, lead time and down time. This work was motivated by the slow implementation of the RAS concept in industry due, in part, to the limited research into the planning of multiple system reconfigurations. The challenge is to enable consideration of, and planning for, the production of numerous different products within a single modular, reconfigurable assembly environment. The developed methodology is to be structured and traceable, but also adaptable to specific and varying circumstances. This thesis presents an approach that aims towards providing a framework for the configuration of modular assembly systems. The approach consists of a capability model, a reconfiguration methodology and auxiliary functions. As a result, the approach facilitates the complete process of requirement elicitation, capability identification, definition and comparison, configuration analysis and optimisation and the generation of a system configuration lifecycle. The developed framework is demonstrated through a number of test case applications, which were used during the research, as well as the development of some specific technological applications needed to support the approach and application.

Reliability engineering techniques have been used in the manufacturing environment for many years. However the reliability analysis of repairable systems is not so widely practised in the steel manufacturing environment. Many different analysis methods have been proposed for the modelling of repairable systems, most of these have had limited application in the manufacturing environment. The current reliability analysis techniques are predominantly used by engineers to construct a “snapshot” in time of a manufacturing system’s reliability status. There are no readily identifiable applications of reliability modelling techniques being applied to repairable systems over a long time period within the manufacturing environment The aim of this work is to construct a method which can analyse and monitor the reliability status of multiple repairable systems within the steel plant over an extended operating period. The developed analysis method is predominantly automated and is facilitated by applying standard reliability analysis techniques to all of the repairable systems failure data sets under review. This Thesis illuminates the methodology used to fulfil the remit of this research by the following sequential steps: Developing a new methodology for the application of reliability analysis techniques to repairable systems within a steel manufacturing facility Utilised an innovative step of combining three reliability analysis methods as complimentary activities Constructed an automated reliability analysis model which fulfils the project remit. In addition the model is capable of the long term monitoring of repairable system reliability The new reliability analysis method has been delivered to Tata Steel and is installed in the Port Talbot Technology Group with a direct link to the Hot Strip Mill (HSM) monitoring database. This reliability analysis method has been tested with four years operational data from the Hot Strip Mill manufacturing area and the analysis has shown that changes and trends in all systems reliability status can be easily identified.

The overall aim of this study is to explore the nature of Industrial Additive Manufacturing Systems as implemented by commercial practitioners, with a specific focus on flexibility within the system and wider supply chain. This study is conducted from an Operations Management perspective to identify management implications arising from the application of contemporary Industrial Additive Manufacturing in the fulfilment of demand. The generation of the theoretical constructs and their evaluation is achieved through an abductive approach. The concept of an Industrial Additive Manufacturing System is developed, through which activities, enabling mechanisms, and control architectures are demonstrated. This is complimented by the proposal of a typology of flexibilities both for the manufacturing system and its supply chain. Twelve case studies are examined through practitioner interviews, observation, and mapping of the production processes at three Industrial Additive Manufacturing companies. These explorations are complimented by interviews with customers downstream of the Additive Manufacturer, and with interviews and a survey of principal upstream machine and material suppliers. This study identifies and classifies types of flexibility relevant to Industrial Additive Manufacturing Systems. It is shown that to achieve requisite flexibilities, it is necessary to manage the whole manufacturing system, not just individual machines. By extension, the internal manufacturing systems’ ability to achieve flexibility is shown to be both facilitated and constrained by the environment in which it operates. In particular, inadequacies in the supply of materials are shown to result in suboptimal practices within the manufacturing system. The principal contribution of this thesis is therefore the development of Industrial Additive Manufacturing from a manufacturing systems perspective, and an evaluation of its implications for flexibility.

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The conventional design of forming rolls depends heavily on the individual skill of roll designers which is based on intuition and knowledge gained from previous work. Roll design is normally a trial an error procedure, however with the progress of computer technology, CAD/CAM systems for the cold roll-forming industry have been developed. Generally, however, these CAD systems can only provide a flower pattern based on the knowledge obtained from previously successful flower patterns. In the production of ERW (Electric Resistance Welded) tube and pipe, the need for a theoretical simulation of the roll-forming process, which can not only predict the occurrence of the edge buckling but also obtain the optimum forming condition, has been recognised. A new simulation system named "CADFORM" has been devised that can carry out the consistent forming simulation for this tube-making process. The CADFORM system applied an elastic-plastic stress-strain analysis and evaluate edge buckling by using a simplified model of the forming process. The results can also be visualised graphically. The calculated longitudinal strain is obtained by considering the deformation of lateral elements and takes into account the reduction in strains due to the fin-pass roll. These calculated strains correspond quite well with the experimental results. Using the calculated strains, the stresses in the strip can be estimated. The addition of the fin-pass roll reduction significantly reduces the longitudinal compressive stress and therefore effectively suppresses edge buckling. If the calculated longitudinal stress is controlled, by altering the forming flower pattern so it does not exceed the buckling stress within the material, then the occurrence of edge buckling can be avoided. CADFORM predicts the occurrence of edge buckling of the strip in tube-making and uses this information to suggest an appropriate flower pattern and forming conditions which will suppress the occurrence of the edge buckling.