Current market trends are moving from large quantity production towards small batch production and mass customization. This has led to the high demand for the flexibility and adaptability of manufacturing technology and systems. Several reconfigurable pin type tooling systems have been proposed and developed to satisfy such demands. However, these reconfigurable tooling systems still suffer from several drawbacks, including difficulties associated with positioning and locking the pins and problems of uneven “staircase” surface effects from relying on discrete finite size pins. The main focus of this research is on building a hybrid vacuum-forming machine system (HAVES) based on reconfigurable screw-pin tooling (SPT)as a test bed for understanding the processes involved in developing this technology and to examine the feasibility of implementing such technology in an industrial system. The SPT used is composed of identical screw pins,which are engaged with each other in an array pattern. By adjusting vertical displacement of the screw pins, a wide variety of component geometry can be formed. The adjustment methodology of the SPT is formulated mathematically in order to help construction of the SPT be parametrical thus enabling automatic CNC G-code generation. The HAVES test bed development involves full machine design and hardware and software integration. The hardware integration task included a CNC controller, drive motors, encoders, milling and screw adjustment heads, SPT, vacuum forming system. The software integration task involved the processing of three-dimensional CAD geometry to automatically generate post processed G codes in order to adjust the screw-pin to the required component geometry and subsequent surface machining for driving the final die geometry and minimize operator intervention. The completed HAVES test bed has been tested for accuracy, repeatability and functionalities with quality good results. An economic analysis has been also conducted to verify the economic feasibility of the HAVES test bed by comparing the cost of making vacuum forming components using a dedicated mould versus using the HAVES test bed.

Laser milling is a new application that is challenging for the power contained in the laser light. Due to its small unit of material removal, accuracy and repeatability, laser milling has found an application area in micro manufacturing, especially the manufacturing of microtools. There is a number of micro manufacturing and replication processes on the market at present. Their needs raise the requirements that have to be met by the microtool manufacturing process. Initially, the requirements of micro manufacturing processes, such as micro-injection moulding and hot-embossing, are identified and compared to what the laser milling process can achieve. An investigation is carried out to identify the capabilities of the laser milling process and match them to these requirements. The investigated process characteristics are surface finish, aspect ratio, accuracy and minimum feature size. Furthermore, as surface finish is identified to be a considerable constraint, an investigation is undertaken to improve the resulting surface finish obtained from the laser milling process. A two-dimensional theoretical model is developed to investigate the crater formation on a metal target by a microsecond laser pulse. The model takes into account the absorption of the laser light by the target, and simulates the heating and vaporisation of the material, including an adjustment to compensate for the change of state. A simple numerical technique is employed to describe the major physical processes taking part in the laser milling process. Experimental validation of the proposed model is provided for two common tooling materials. To investigate the formation of the material surface after laser milling, a complex 3D surface model is presented based on the single crater profiles of the 2D theoretical model together with a consideration for the overlapping of the craters. Additional factors, that are influential in the formation of the final material surface, are also considered and their effect on the surface roughness estimated. Finally, a number of techniques for reducing surface roughness are presented. Laser cleaning is a technique that utilises the de-focused laser beam to "smooth out" the material surface irregularities. The other three techniques are applied after laser milling, and are ultrasonic cleaning bath, chemical pickling and electro-chemical polishing.

The principal purpose of the work described in this thesis was to develop an insight into the scuffing performance of steel discs used to simulate gear tooth contacts under severe conditions of load, sliding and high temperature. Different surface conditions of the discs such as ground, superfinished, ground/hard-coated, and superfinished/ hard-coated were investigated in various combinations and at sliding speeds of up to 16 m/s in order to obtain an understanding of the possible beneficial effect of improved surface finish and the application of hard coatings on scuffing performance under the severe conditions experienced in an aerospace transmission such as a helicopter main rotor gearbox. The lubricant used in all tests was an oil commonly used in aerospace transmissions. It was found that the diamond-like coating (DLC) investigated in this work had the effect of markedly improving the scuffing resistance of the hardened steel substrate. In tests using the ground/coated samples, for example, it was not found possible to produce scuffing within the load and temperature limits of the test rig used (2.0 GPa maximum Hertzian contact pressure or 300 C maximum disc bulk temperature) even at the high sliding speed of 16 m/s. In addition to improving scuffing resistance it was found that the effect of the hard coating was to reduce friction and operating temperatures for a given load/speed combination. Superfinishing of the steel discs also led to a reduction in friction, but did not produce a significant improvement in scuffing resistance. It was found that the combination of ground/hard-coated discs running against ground/uncoated discs produced a remarkable behaviour of the discs' bulk temperatures, which suggests that the hard coating acts as a thermal barrier. Micro-elastohydrodynamic lubrication (micro-EHL) analyses were conducted using surface profiles of discs used in the experimental work. These theoretical simulations demonstrated the very severe lubrication conditions which are present in the experiments. Pressure ripples far in excess of the calculated Hertzian pressure are predicted, and the films generated by hydrodynamic action are extremely thin. Under the most severe conditions transitory direct "dry" contact is predicted.

Increasing demands from end users in the fields of optics, defence, automotive, medical, aerospace, etc. for high precision 3D miniaturized components and microstructures from a range of materials have driven the development in micro and nano machining and changed the manufacturing realm. Conventional manufacturing processes such as chemical etching and LIGA are found unfavourable or limited due to production time required and have led mechanical micro machining to grow further. Mechanical micro machining is an ideal method to produce high accuracy micro components and micro milling is the most flexible enabling process and is thus able to generate a wider variety of complex micro components and microstructures. Ultraprecision micromilling machine tools are required so as to meet the accuracy, surface finish and geometrical complexity of components and parts. Typical manufacturing requirements are high dimensional accuracy being better than 1 micron, flatness and roundness better than 50 nm and surface finish ranging between 10 and 50 nm. Manufacture of high precision components and parts require very intricate material removal procedure. There are five key components that include machine tools, cutting tools, material properties, operation variables and environmental conditions, which constitute in manufacturing high quality components and parts. End users assess the performance of a machine tool based on the dimensional accuracy and surface quality of machined parts including the machining time. In this thesis, the emphasis is on the design and development of a control system for a 5-axis bench-type ultraprecision micromilling machine- Ultra-Mill. On the one hand, the developed control system is able to offer high motion and positioning accuracy, dynamic stiffness and thermal stability for motion control, which are essential for achieving the machining accuracy and surface finish desired. On the other hand, the control system is able to undertake in-process inspection and condition monitoring of the machine tool and process. The control of multi-axis precision machines with high-speed and high-accuracy motions and positioning are desirable to manufacture components with high accuracy and complex features to increase productivity and maintain machine stability, etc. The development of the control system has focused on fast, accurate and robust positioning requirements at the machine system design stage. Apart from the mechanical design, the performance of the entire precision systems is greatly dependent on diverse electrical and electronics subsystems, controllers, drive instruments, feedback devices, inspection and monitoring system and software. There are some variables that dynamically alter the system behaviour and sensitivity to disturbance that are not ignorable in the micro and nano machining realm. In this research, a structured framework has been developed and integrated to aid the design and development of the control system. The framework includes critically reviewing the state of the art of ultraprecision machining tools, understanding the control system technologies involved, highlighting the advantages and disadvantages of various control system methods for ultraprecision machines, understanding what is required by end-users and formulating what actually makes a machine tool be an ultraprecision machine particularly from the control system perspective. In the design and development stage, the possession of mechatronic know-how is essential as the design and development of the Ultra-Mill is a multidisciplinary field. Simulation and modelling tool such as Matlab/Simulink is used to model the most suitable control system design. The developed control system was validated through machining trials to observe the achievable accuracy, experiments and testing of subsystems individually (slide system, tooling system, monitoring system, etc.). This thesis has successfully demonstrated the design and development of the control system for a 5-axis ultraprecision machine tool- Ultra-Mill, with high performance characteristics, fast, accurate, precise, etc. for motion and positioning, high dynamic stiffness, robustness and thermal stability, whereby was provided and maintained by the control system.

Calculations of the thermal deformations of complex structures such as machine tool frames are insufficiently reliable due to the large differences in the heat transfer coefficients. Therefore, the underlying theme presented in this work is a thorough experimental investigation of the thermal deformations of a cylindrical grinding machine in an effort to present simple equations that will provide the engineer with a few simple rules and ideas in order to minimise the problem. The cylindrical grinding machine chosen and the characteristics of the experimental procedure adopted have been related to the present industrial scene. The amount of heat generated is a function of operating conditions of the machine and therefore investigations have been carried out for the complete speed ranges both for the stable and unstable operating conditions. The machine has been thermally segmented and as a result not only has the relative grinding wheel/work axis movement been determined but the influence on this caused by either the grinding wheel movement or the work axis movement has been shown. In addition, the effect of the major machine elements on either the work or wheel axis movement has also been established.

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