Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 94 for “"Material Removal"”.
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Face-up chemical mechanical polishing : kinematics and material removal rate
A working prototype face-up CMP tool has successfully been completed. Experiments conducted on the face-up CMP machine qualitatively correspond with the theoretical polishing model. Discrepancies in data from the theoretical model could potentially be caused by non-uniform loading of the polishing …
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Mechanisms of focused ion beam (FIB) material removal and rearrangement at high beam flux
Focused ion beam (FIB) is widely used as a material removal tool for applications ranging from electron microscope sample preparation to nanopore processing for DNA sequencing. Despite the wide spread use of FIB, the basic material removal mechanisms are not well understood and may depend upon FIB …
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Multi-physics modeling of plasma discharge and material removal in micro electro-discharge machining process
… is a machining process capable of removing material in sub-grain size range and machining a range of materials irrespective of their hardness. Due to the unique capabilities offered by micro-EDM process in manufacturing high accuracy micro-scale parts with complex geometries, it has …
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Computing the distribution of material removal rates to enable efficient customization of coaxial offset shoulder grinding
Thesis (S.M.)--Massachusetts Institute of Technology, System Design & Management Program, 2000.
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Multi-physics modeling of plasma discharge, material removal and debris ejection in electrical discharge machining with flowing dielectric film
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-12-01
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G-Code Based Toolpath Simulation for Predicting CNC Energy Consumption
… or accessible to CNC machining, where the material removal rate is variable. This thesis develops a G-code based simulation that uses a voxel mesh to virtually recreate material removal, approximating the material removal rate at discretized points in the machining process. Using an energy …
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Ablation of Steel by Microsecond Pulse Trains
Laser micromachining is an important material processing technique used in industry and medicine to produce parts with high precision. Control of the material removal process is imperative to obtain the desired part with minimal thermal damage to the surrounding material. Longer pulsed lasers, with …
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Multi-scale models for wafer surface evolution in chemical mechanical planarization
… pattern structure variation across a chip. The material removal rates are different for the regions with different pattern structure. Therefore, CMP obtains local planarization but generates global thickness variation. Two models, referred as Models I and II, are developed to investigate the …
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Rotary ultrasonic machining of ceramics: Characterization and extensions
… processes which are capable of achieving high material removal rate while maintaining the surface/subsurface damage to the machined parts at an acceptable level. Rotary Ultrasonic Machining (RUM), a hybrid machining process combining the material removal mechanisms of diamond grinding and …
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Micro-scale scratching by soft pad asperities in chemical-mechanical polishing
… force and motion to the abrasive particles for material removal. As the applied pressure is concentrated under few asperities, however, the asperities themselves, even though softer, may generate unintended micro-scratches on relatively hard surfaces under certain conditions. This thesis …
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Fundamental study of magnetic field-assisted micro-EDM for non-magnetic materials
… is a unique machining method capable of removing material in the sub-grain size range (0.1-10 µm) from materials irrespective of their hardness. This process is valuable in the manufacturing of miniaturized products where industry demand for increasingly hard materials has reached the limitations …
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The solid particle erosion of WC-Co alloys
… undertaken to determine the mechanism by which material is removed. For this purpose a simple particle-gas stream erosion apparatus was employed. The nineteen different WC-Co alloys studied were initially characterised according to mi crostructural and mechanical properties. An investigation of …
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Prediction of cutting forces and surface errors in face milling with generalized cutter and workpiece geometry
Face milling is a widely used material removal process in the automotive industry for machining the flat surface of components such as an engine block and cylinder head, etc. The surface flatness error of the machined workpiece is a key variable affecting the quality of the part and the …
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Cavitation erosion of WC-Co
… in order to determine the mechanisms of material removal. Nineteen grades of WC-Co alloys were studied. These alloys had been previously characterised according to microstructural and mechanical properties. Further characterisation by way of Young's modulus and density of the materials …
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Integrated process planning for a multi-axis hybrid manufacturing system
… layered manufacturing system, in which a laser material deposition and material removal system with more than 3-axis mobility are configured, a process planning to automatic define motion path for the integrated system is critical. The purpose of this research is to develop a robust system which …
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A Tool Wear Comparative Study in Turning Versus Computer Simulation in 1018 Steel
<p>The material removal process uses cutting tools in order to produce the desired shape of the workpiece. Tool wear has been a problem for cutting tools, since cutting tools wear and break. Research has been accomplished in the tool wear field for tool life and more recently tool wear. The …
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Vibration assisted machining: Modelling, simulation, optimization, control and applications
… precision components made of hard and brittle materials such as glasses, steel alloys and advanced ceramics, is such that conventional grinding and polishing techniques can no longer meet the requirements of today's precision manufacturing engineering. Particularly, in order to undertake …
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Experimental and numerical analysis of abrasive waterjet drilling of brittle materials
… between abrasive waterjet (AWJ) and brittle materials, as well as lated machining mechanisms, was studied using a hybrid experimental - numerical analysis approach. First, the machineability of ceramic materials, such as alumina, silicon nitride, silicon carbide, and titanium diboride, was …
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Surface texture enhancement of SLS processed turbine blades using a mix of flexible media and abrasives
… the fabrication of complex shapes with minimal material wastage. With the increased use of complex shapes, newer polishing technologies need to be developed to accommodate the fabrication technological advancements. This dissertation proposes a novel abrasive flow polishing technology that can …
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The erosion of ultrafine WC-Co
… through the spray conversion process. The materials have been characterised and subjected to slurry erosion and cavitation erosion. A further twelve WC-Co alloys of varying grain sizes and cobalt contents have been produced through conventional processes and subjected to the same tests in …
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