This research examines the amount of heat transmitted to the workpiece during the end milling of aluminium alloys. The thesis covers the development of a mathematical model to predict the temperatures in the workpiece being machined by end milling. The model uses the proportion of the cutting energy that is transmitted to the workpiece as a major variable. The mathematical model was used to predict temperature distributions within the workpiece for a wide range of cutting speeds and feed rates. A technique for measuring the workpiece surface temperatures using an infrared thermometer mounted on the milling machine quill was developed. At present no commercial method for measuring temperatures while machining exists. The methods of machining temperature measuring temperatures while machining exists. The methods of machining temperature measurement that have been used in laboratories have been proof of concept and were not designed for industrial use. All this emphasises the need for a reliable method of measuring temperature at the required point, and a definition of that point. The method developed is capable of presenting data to the machine operator simply and accurately in real time.

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High-accuracy miniaturized components are increasingly in demand for various industries such as aerospace, biomedical, electronics, environmental, communication and automotive, and this coupled with new developments of High Speed Machining (HSM) has led to the emergence of a strong and viable technology in High Speed Micro Machining. This technology is very important in bridging the macro-domain and the nano- and micro- domains for making functional miniaturized components. High speed Micro Machining is a specific technology where high spindle speeds, high performances cutting tools and high accuracy control systems are used. The understanding of this technology is still not well established and theories are still under development. A major implication of the High Speed Micro Machining process is the relatively high machining forces with respect to the cutting tool's size, which often cause low process reliability and high costs, due to frequent tool failures and short tool life. The aim of this investigation is to contribute towards a fundamental understanding of the effects of increased spindle speed in High Speed Micro Machining.

This thesis has focused on three key areas of interest for femtosecond micromachining and inscription. The first area is micromachining where the work has focused on the ability to process highly repeatable, high precision machining with often extremely complex geometrical structures with little or no damage. High aspect ratio features have been demonstrated in transparent materials, metals and ceramics. Etch depth control was demonstrated especially in the work on phase mask fabrication. Practical chemical sensing and microfluidic devices were also fabricated to demonstrate the capability of the techniques developed during this work. The second area is femtosecond inscription. Here, the work has utilised the non-linear absorption mechanisms associated with femtosecond pulse-material interactions to create highly localised refractive index changes in transparent materials to create complex 3D structures. The techniques employed were then utilised in the fabrication of Phase masks and Optical Coherence Tomography (OCT) phantom calibration artefacts both of which show the potential to fill voids in the development of the fields. This especially the case for the OCT phantoms where there exists no previous artefacts of known shape, allowing for the initial specification of parameters associated with the quality of OCT machines that are being taken up across the world in industry and research. Finally the third area of focus was the combination of all of the techniques developed through work in planar samples to create a range of artefacts in optical fibres. The development of techniques and methods for compensating for the geometrical complexities associated with working with the cylindrical samples with varying refractive indices allowed for fundamental inscription parameters to be examined, structures for use as power monitors and polarisers with the optical fibres and finally the combination of femtosecond inscription and ablation techniques to create a magnetic field sensor with an optical fibre coated in Terfenol-D with directional capability. Through the development of understanding, practical techniques and equipment the work presented here demonstrates several novel pieces of research in the field of femtosecond micromachining and inscription that has provided a broad range of related fields with practical devices that were previously unavailable or that would take great cost and time to facilitate.

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The first part of this study involve an evaluation of the performance of recently developed nano-grain size ceramic tool materials when machining nickel base, Inconel 718, with conventional coolant flow in terms of tool life, tool failure modes and wear mechanisms as well as component forces generated under different roughing conditions. Comparison tests were carried out with commercially available ceramic tool materials of micron-grain composition. The test results show that the micron grain size commercially available tool materials generally gave the longest tool life. The dominant failure mode is nose wear, while some of the nano-ceramic tools were rejected mainly due to chipping at the cutting edge. It is also evident that chemical compositions of the tool materials played significant role in their failure. The alumina base ceramics performed better than the silicon nitride base ceramics. Severe abrasion wear was observed on both rake and flank faces of the cutting tools while cutting forces increased with increasing cutting speed when machining with the silicon nitride base nano-ceramic tools. This is probably due to the lower superplastic flow temperature of the nitride base nano-ceramics. The second part of this study involve turning of Inconel 718 with commercially available ceramic and PVD coated carbide tools with conventional and high-pressure coolant supplies at cutting speeds up to 300 and 60 m min" respectively. Increasing the coolant pressure results in shorter tool life when machining Inconel 718 with ceramic tools, suggesting that the high-pressure coolant supply reduces temperature at the cutting zone below a critical level where ceramic tools can perform satisfactorily. The inadequate fracture toughness of ceramic tools makes them more susceptible to failure by mechanical action such as notching at the depth of cut line and premature fracture. The notch wear rate increases with higher coolant supply pressure due to significant erosion of the tool material by the high-pressure coolant jet. Machining Inconel 718 with a triple PVD coated (TiCNI AI20iTiN) carbide tool at speeds up to 60 mlmin using conventional and various high coolant pressures, up to 203 bar was found to be encouraging. The test results show that acceptable surface finish and improved tool life can be achieved when machining Inconel 718 with high coolant pressures. Compared to conventional coolant supplies, tool life improved as much as 7 folds when machining at 203 bar coolant pressure at high speed conditions. Tool life generally increased with increasing coolant supply pressure due to the ability of the high-pressure coolant to lift the chip and gain access closer to the cutting interface. Chip breakability during machining is dependent on the depth of cut, feed rate and cutting speed employed as well as on the coolant pressure employed. Machining Inconel 718 with lower coolant pressures did not produce chip segmentation. Tool wear increased gradually with prolong machining with high coolant pressures. Nose wear was the dominating tool failure mode when machining with coated carbide tools due probably to a reduction in the chip-tool and tool-workpiece contact length/area. SEM micrographs of the machined surfaces show that micro-pits are the main damage to the machined surfaces. Microhardness analysis show evidence of hardening of the top machined surfaces. In most cases the microhardness readings tend to approach the hardness of the base material at 0.25 mm under rough and 0.2 mm under finish machining below the machined surface. This is due to the austenitic structure of Inconel 718 which promote work hardening when machining as a result of the high temperature generated at the cutting interfaces. The hardening effect decreased under finishing conditions and with increasing coolant pressures up to 203 bar as the coolant gain access closer to the cutting interfaces, thus minimising the cutting interface temperature. Analysis of the microstructure shows that severe plastic deformation occurred when machining with conventional coolant supply than with highpressure coolant supplies. There was also mild plastic deformation under finish machining. Surface damage or phase transformation was absent when machining Inconel 718 under highpressure coolant supplies. Generally the surface integrity of the finish machined surface is in accordance with CME 5043.

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There is no doubt that today manufacturing is more competitive and challenging than ever before in trying to respond to "production on demand". Companies from east and west and all over the world have changing rules of business and need to collaborate beyond geographic boundaries with the support of the rapid advancement of information technology associated with manufacturing technology. To satisfy customers' demands for product variety and the industrial need for high precision, numerically controlled machining with multiple axes and sophisticated machine tools are required. Due to the complexity of programming there is a need to model their process capability to improve the interoperable manufacturing capability of machines such as turning centres. This thesis focuses on the use of the new standard, ISO 14649 (STEP-NC), to address the process planning and machining of discrete turned components.