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 33 for “"material removal rate"”.
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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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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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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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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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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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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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Control of wafer-scale non-uniformity in chemical-mechanical planarization by face-up polishing
… in the manufacture of ultra-large-scale-integrated (ULSI) semiconductor devices. A major concern in CMP is non-uniform planarization, or polishing, at the wafer-scale - primarily as interconnect metal dishing and dielectric erosion. In conventional face-down CMP, the pad is much larger than …
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Micro-scale scratching by soft pad asperities in chemical-mechanical polishing
In the manufacture of integrated circuits (IC) and micro-electromechanical systems (MEMS), chemical-mechanical polishing (CMP) is widely used for providing local and global planarization. In the CMP process, polishing pads, typically made of polyurethanes, play a key role. Due to the random, rough …
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BioLaser: Establishing a High-Resolution Laser Ablation Tomography Platform for UK Bioimaging Research
… 3D tomographic imaging of botanical materials can provide enormous insight into questions regarding relationships between structure and function. The National Institute for Agricultural Botany (NIAB) sponsored this body of work to meet an unfilled imaging niche for a tomographic …
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Vision-based localization for robot-CNC hybrid manufacturing
… large scale parts with higher deposition rates than other additive processes. WAAM is often combined with subtractive machining to form a hybrid manufacturing process. This hybrid process can be realized by retrofitting Computer Numerical Control (CNC) machines with deposition heads, …
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Design and analysis of the internally cooled smart cutting tools with the applications to adaptive machining
… such as contamination free machining (CFM), high material removal rate, low tool wear and better surface integrity. The absence of cutting fluid in CFM causes the cutting tool and the workpiece subject to great thermal loads owing to higher friction and adhesion, and as a result may increase the …
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Machinability Study on Silicon Carbide Particle-Reinforced Aluminum Alloy Composite with CVD Diamond Coated Tools
… optimal cutting parameters for machining AlSiC material containing high silicon carbide particle reinforcement (>25%). The optimal cutting parameters are determined by investigating the relationship between cutting forces, tool wear, burr formation, surface roughness, and material removal rate …
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Study of Pulse Electrochemical Micromachining using Cryogenically Treated Tungsten Microtools
… range of electrically conductive engineering materials such as metals, semiconductors, and metal matrix composites. Absence of tool wear is a major advantage expected of PECMM. However, tools are often chemically corroded by certain electrolytes used in PECMM. In this thesis a novel approach …
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Process characterization of Electrical Discharge Machining of highly doped silicon
… is an advanced machining process that removes material via thermal erosion through a plasma arc. The machining process is accomplished through the application of high frequency current (typically through a fine wire or some other electrode) to a conductive workpiece. The electrode is physically …
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Effects of chromium powder mixed in electrical discharge machining of AISI D2 hardened steels
… that has been used extensively in machining hard material that is commonly used in mold and die industry but the limitations of EDM will cause lower productivity and poor surface quality. EDM becomes most apparent by using powder metallurgy electrode together with chromium (Cr) powder suspension …
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Influence of agglomeration phenomenon in machining of AISI D2 hardened steel using nano chromium powder mixed-EDM
… pilot procedure, to avoid the collapse of the removal operation. Digital Balance, SJ400 Mitutoyo, Shimadzu Vickers's tester, and SEM/EDS-Hitachi SU-1510 were invested to specify the Material Removal Rate (MRR), Tool Wear Rate (TWR), average surface roughness (Ra), Microhardness (MH), Recast …
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Investigation on removal mechanism in catalytic aided electrical discharge machining of polycrystalline diamond
… for aerospace and automotive industries as the material has high hardness (~80GPa) and strength (~60Gpa). However, low electrical conductivity (~10−13 S/m) and high melting temperature (3400oC) of PCD has caused slower EDM process. This investigation is purposely designed to investigate the EDM …
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Virtual three-axis milling process simulation and optimization
… conditions which result in high productivity rates without violating accuracy throughout the part production process. This thesis presents generalized virtual simulation and optimization strategies to predict and optimize performance of milling processes up to 3-axis. Computationally efficient …
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Non-lithographic and scalable manufacturing of silicon micro & nanomaterials
In the last decade, accelerated discovery of novel processing schemes has enabled rapid prototyping and large volume production of parts with extended and programmable functionality - such as biodegradable electronics, high-emissivity surfaces, optoelectronics circuits, fast-discharging batteries, …
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A Study of Energy, Carbon Dioxide Emissions and Economics in Machining: Milling and Single Point Incremental Forming
… 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 …
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