A MEMS-based micro-electro-discharge machining technique that is enabled by the actuation of micromachined planar electrodes defined on the surfaces of the workpiece is developed that eliminates the need of numerical control machines. First, the planar electrodes actuated by hydrodynamic force is developed. The electrode structures are defined by patterning l8-µm-thick copper foil laminated on the stainless steel workpiece through an intermediate photoresist layer and released by sacrificial etching of the resist layer. The planer electrodes are constructed to be single layer structures without particular features underneath. All the patterning and sacrificial etching steps are performed using dry-film photoresists towards achieving high scalability of the machining technique to large-area applications. A DC voltage of 80-140 V is applied between the electrode and the workpiece through a resistance-capacitance circuit that controls the pulse energy and timing of spark discharges. The parasitic capacitance of the electrode structure is used to form a resistance capacitance circuit for the generation of pulsed spark discharge between the electrode and the workpiece. The suspended electrodes are actuated towards the workpiece using the downflow of dielectric machining fluid, initiating and sustaining the machining process. Micromachining of stainless steel is experimentally demonstrated with the machining voltage of 90V and continuous flow of the fluid at the velocity of 3.4-3.9 m/s, providing removal depth of 20 µm. The experimental results of the electrode actuation match well with the theoretical estimations. Second, the planar electrodes are electrostatically actuated towards workpiece for machining. In addition to the single-layer, this effort uses double-layer structures defined on the bottom surface of the electrode to create custom designed patterns on the workpiece material. The suspended electrode is electrostatically actuated towards the wafer based on the pull-in, resulting in a breakdown, or spark discharge. This instantly lowers the gap voltage, releasing the electrode, and the gap value recovers as the capacitor is charged up through the resistor. Sequential pulses are produced through the self-regulated discharging-charging cycle. Micromachining of the stainless-steel wafer is demonstrated using the electrodes with single-layer and double-layer structures. The experimental results of the dynamic built-capacitance and mechanical behavior of the electrode devices are also analyzed.

A tool path generation method for sculptured surfaces defined by triangular meshes is presented in this thesis along with an algorithm that helps determine the best type of cutter geometry to machine a specific surface. Existing tool path planning methods for sculptured surfaces defined by triangular meshes require extensive computer processing power and result in long processing times mainly since surface topology for triangular meshes is not provided. The method presented in this thesis avoids this problem by offsetting each triangular facet individually. The combination of all the individual offsets make up a cutter location surface. A single triangle offsetting results in many more triangles; many of these are redundant, increasing the time required for data handling in subsequent steps. To avoid the large number of triangles, the proposed method creates a bounding space to which the offset surface is limited. The original surface mesh describes the bounding surface of a solid, thus it is continuous with no gaps. Therefore, the resulting bounding spaces are also continuous and without gaps. Applying the boundary space limits the size of the offset surface resulting in a reduction in the number of triangular surfaces generated. The offset surface generation may result in unwanted intersecting triangles. The tool path planning strategy addresses this issue by applying hidden-surface removal algorithms. The cutter locations from the offset surface are obtained using the depth buffer. The simulation and machining results show that the tool paths generated by this process are correct. Furthermore, the time required to generate tool paths is less than the time required by other methods. The second part of this thesis presents a method for selecting an optimal cutter type. Extensive research has been carried out to determine the best cutter size for a given machining operation. However, cutter type selection has not been studied in-depth. This work presents a method for selecting the best cutter type based on the amount of material removed. By comparing the amount of material removed by two cutters at a given cutter location the best cutter can be selected. The results show that the optimal cutter is highly dependent on the surface geometry. For most complex surfaces it was found that a combination of cutters provides the best results.

One in eight women in America will develop breast cancer at some point in their lives. Breast cancer is the second deadliest form of cancer for women in the United States. When a suspicious region of the breast is detected, the tissue is diagnosed by removing a sample, preparing an H&E section, and performing histopathology. This procedure is expensive, invasive, and can take days to return a diagnosis. An alternative to excision biopsies is to instead perform an optical biopsy. This work details endomicroscopes intended to perform optical biopsies in breast tissue. The work address two issues limiting current optical biopsy systems: insufficient resolution and inability to reject out of focus light. To improve the resolution of current endomicroscopes, ultra-slim objectives are developed using optical plastics and zero alignment fabrication techniques. These objectives can outperform current alternative endomicroscope objectives in terms of performance across the field of view and chromatic aberration correction, while remaining as narrow as a biopsy needle. Next, an endomicroscope which utilizes structured illumination to perform optical section is designed, tested, and evaluated on ex vivo breast biopsies. The new endomicroscope provides high contrast images by reducing out of focus background light. Finally, an achromatic, ultra-slim objective and the structured illumination endomicroscope are integrated to form an optical biopsy system with improved lateral resolution and axial response. This integrated system is a step forward for in vivo microscopy and cancer diagnoses.

Laser nano-patterning with near-field optical microscope (NSOM) and the associated energy transport analysis are achieved in this study. Based on combined experimental/theoretical analyses, it is found that laser nano-patterning with a NSOM probes strongly depend on the laser conditions and material properties of the target: the energy transport from the NSOM probes to the targets changes from pure optical to a combination of thermal and optical transport when the pulse duration of laser is increased from femtosecond to nanosecond. As a result, the mechanisms of nano-pattern formation on targets changes from nano-ablation to nano-oxidation/ recrystallization when the laser pulse duration is increased from femtosecond to nanosecond. Also, with the laser nano-patterning experiments, thermal damage of NSOM probes is observed which can be attributed to the low transport efficiency (10-4 – 10-6) and associated heating of the metal cladding of NSOM probes. The heating of NSOM probes are studied with developed time harmonic and transient thermoreflectance (TR) imaging. From time harmonic TR when the NSOM probes are driven with continuous laser, it is found that the location of heating of NSOM probes is ~20-30µm away from the NSOM tip. The strength of the heating is determined by the laser power (linear dependence), wavelength of the laser (stronger with short A), and aperture size of NSOM probes (stronger when aperture size < A/2). From the transient TR imaging when the NSOM probes are driven with pulsed laser, it is found that the peak temperature of the NSOM probe shifts much closer to the tip. The possible reason for the change in the location of peak temperature when continuous laser is changed to pulsed laser can be attributed to the competition between the heat generation and dissipation rates at different location of the probe: the tip experiences highest temperature with pulsed heating as the entire heating processes is adiabatic. The tip also experiences highest heat dissipation rate due to its large surface-to-volume ratio which overcomes the heat generation at the tip under quasi-steady state resulting in shift of the hot spot. The knowledge obtained in this study can be important in the future design of more efficient NSOM probes and other nano-optic devices.

A simple model that includes energy and carbon dioxide (CO2) emissions in the economics of machining is proposed, which has been published in the highly respected and cited journal, Annals of CIRP (International Academy for Production Engineering). This is a timely analysis in current government discussions on a proposed carbon tax or a carbon cap and trade regime and greater energy efficiency. The new cost model is based on life cycle analysis methodology for the initial part production. An illustrative example is given showing that the cheapest electrical grid should not be chosen, if it also has the highest CO2 emissions. Accurate pricing is important, because the more expensive product was highly dependent on the carbon price. A comprehensive review of machining economic models is covered. However, there is a dearth of actual machining data in the literature. This work includes studies in milling and single point incremental forming (SPIF) which can be used by other manufacturing engineers in their machining economic model development. The first milling study involved simple straight cuts. In general, as feed rate (FD) increased (increasing the material removal rate, MRR), the energy consumed decreased as process time decreased. In contrast, as spindle speed (N) increased, energy consumed increased, since more power is drawn by the motor, without a process time reduction. Given the inverse power relationship observed for the time, energy, process CO2 and cost against MRR, the recommended parameters were the same at the highest FD and lowest N permissible. In the second milling study with constant N for a more complex part (sprocket), similar relationships were observed. However, for sprockets made at constant chip load (allowing FD and N to change together), there were varying prescribed MRRs for time, energy, process CO2 and cost minimization. The SPIF studies showed a similar relationship to the constant N milling, and, that results for a simple part can be extrapolated to improve efficiency in more complex parts. Finally, although the energy and carbon costs represented a small contribution to the final cost, their significance increased for higher efficiency parameters or user conditions, e.g. low labour rate. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2011-12-03 19:58:07.76

Modern trends in customer demand have resulted in the development of a class of manufacturing system known as Reconfigurable Manufacturing Systems (RMS). Reconfigurable systems are designed around the idea that they must be able to be reconfigured in both their production capacity as well as in the machining processes they perform. A subset of the RMS paradigm is a group of machines called Modular Reconfigurable Machines (MRMs). Modular machines are built up from different hardware modules. They offer the user the possibility of only purchasing the required tooling for the specific need at the time. As reconfigurable machines are able to offer flexibility in machining functions, their ability to have easy access to a variety of machine tools would greatly influence their effectiveness and production capacity. This project presents a machine tooling system that would provide MRMs with an efficient way to change tools. A major requirement of the unit was that it should automatically calibrate itself in terms of its position relative to the machine it was servicing. In order for the unit to realize this requirement, it needed a method that would provide it with real-time 3D tracking of the spindle with which it was interacting. Commercially available systems that offer this facility are very costly. A popular gaming controller, the Nintendo Wii remote, was used to provide the tool-changing unit with a very economical real-time 3D tracking capability. This dissertation details the design, implementation and testing of the positioning system for the tool-changing unit. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

The present study investigated the effect of dilute polymer solutions on the size, shape, and roughness of channels and holes, machined in metal and glass using a novel abrasive slurry-jet micro-machining (ASJM) apparatus. The apparatus consisted of a slurry pump and a pulsation damper connected to an open reservoir tank to generate a 140-micron turbulent jet containing 1 wt% 10-micron alumina particles. With the addition of 50 wppm of 8-M (million) molecular weight polyethylene oxide (PEO), the widths of the channels and diameters of holes machined in glass decreased by an average amount of 25%. These changes were accompanied by approximately a 20% decrease in depth and more V-shaped profiles compared with the U-shape of the reference channels and holes machined without additives. The present results demonstrate that a small amount of a high-molecular-weight polymer can significantly decrease the size of machined channels and holes for a given jet diameter.

The present study investigated the effect of dilute polymer solutions on the size, shape, and roughness of channels and holes, machined in metal and glass using a novel abrasive slurry-jet micro-machining (ASJM) apparatus. The apparatus consisted of a slurry pump and a pulsation damper connected to an open reservoir tank to generate a 140-micron turbulent jet containing 1 wt% 10-micron alumina particles. With the addition of 50 wppm of 8-M (million) molecular weight polyethylene oxide (PEO), the widths of the channels and diameters of holes machined in glass decreased by an average amount of 25%. These changes were accompanied by approximately a 20% decrease in depth and more V-shaped profiles compared with the U-shape of the reference channels and holes machined without additives. The present results demonstrate that a small amount of a high-molecular-weight polymer can significantly decrease the size of machined channels and holes for a given jet diameter.

This research describes the process of manufacturing and machining of wire and arc additive manufactured (WAAM) thin wall structures on integrated and non¬integrated WAAM systems. The overall aim of this thesis is to obtain a better understanding of deposition and machining of WAAM wall parts through an integrated system. This research includes the study of the comparison of deposition of WAAM wall structures on different WAAM platforms, namely an Integrated SAM Edgetek grinding machine, an ABB robot and a Friction Stir Welding (FSW) machine. The result shows that WAAM is a robustly transferable technique that can be implemented across a variety of different platforms typically available in industry. For WAAM deposition, a rise in output repeatedly involves high welding travel speed that usually leads to an undesired humping effect. As part of the objectives of this thesis was to study the travel speed limit for humping. The findings from this research show that the travel speed limit falls within a certain region at which humping starts to occur. One of the objectives of this thesis was to study the effect of lubricants during sequential and non-sequential machining/deposition of the WAAM parts. Conventional fluid lubricants and solid lubricants were used. In addition, the effect of cleaning of deposited wall samples with acetone was also studied. A systematic study shows that a significant amount of solid lubricant contamination can be found in the deposited material. Furthermore, the results indicate that even cleaning of the wire and arc additive manufactured surfaces with acetone prior to the weld deposition can affect the microstructure of the deposited material.

The development of a sustainable manufacturing process requires a comprehensive evaluation method and fundamental understanding of the processes. Coolant application is a critical sustainability concern in the widely used machining process. Cryogenic machining is considered a candidate for sustainable coolant application. However, the lack of comprehensive evaluation methods leaves significant uncertainties about the overall sustainability performance of cryogenic machining. Also, the lack of practical application guidelines based on scientific understanding of the heat transfer mechanism in cryogenic machining limits the process optimization from achieving the most sustainable performance. In this dissertation, based on a proposed Process Sustainability Index (ProcSI) methodology, the sustainability performance of the cryogenic machining process is optimized with application guidelines established by scientific modeling of the heat transfer mechanism in the process. Based on the experimental results, the process optimization is carried out with Genetic Algorithm (GA). The metrics-based ProcSI method considers all three major aspects of sustainable manufacturing, namely economy, environment and society, based on the 6R concept and the total life-cycle aspect. There are sixty five metrics, categorized into six major clusters. Data for all relavant metrics are collected, normalized, weighted, and then aggregated to form the ProcSI score, as an overall judgment for the sustainability performance of the process. The ProcSI method focuses on the process design as a manufacturer’s aspect, hoping to improve the sustainability performance of the manufactured products and the manufacturing system. A heat transfer analysis of cryogenic machining for a flank-side liquid nitrogen jet delivery is carried out. This is performed by micro-scale high-speed temperature measurement experiments. The experimental results are processed with an innovative inverse heat transfer solution method to calculate the surface heat transfer coefficient at various locations throughout a wide temperature range. Based on the results, the application guidelines, including suggestions of a minimal, but sufficient, coolant flow rate are established. Cryogenic machining experiments are carried out, and ProcSI evaluation is applied to the experimental scenario. Based on the ProcSI evaluation, the optimization process implemented with GA provides optimal machining process parameters for minimum manufacturing cost, minimal energy consumption, or the best sustainability performance.