The Experts below are selected from a list of 4575 Experts worldwide ranked by ideXlab platform
Paul Butlersmith - One of the best experts on this subject based on the ideXlab platform.
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profiled rotary dresser with controlled size and distribution of abrasive grits performance assessment
Cirp Annals-manufacturing Technology, 2019Co-Authors: Dragos Axinte, Alessio Spampinato, Paul ButlersmithAbstract:Abstract This paper reports on a novel proprietary profiled rotary dresser which, in contrast with conventional tools, enables a controlled arrangement of geometrically defined Abrasives over complex profiles. Output forces and Abrasives’ wear were investigated during dressing and grinding tests. This showed a significant reduction in radial dressing forces (˜37%) and volumetric loss of material per grit (˜21%) when compared with conventional tools, together with low grinding forces and workpiece surface roughness variability for different wear conditions. The novel dresser proves the ability to obtain uniform wear rates along complex profiles, while allowing abrasive segment replacement to restore the dressing conditions.
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an assessment of the wear characteristics of microcutting arrays produced from polycrystalline diamond and cubic boron nitride composites
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2016Co-Authors: Manuela Pacella, P H Shipway, Dragos Axinte, Paul Butlersmith, M Daine, C WortAbstract:The current methods for manufacturing super-abrasive elements result in a stochastic geometry of Abrasives with random three-dimensional abrasive locations. This paper focuses on the evaluation of wear progression/failure characteristics of micro-abrasive arrays made of ultrahard composites (polycrystalline diamond—PCD; polycrystalline cubic boron nitride—PCBN) in cutting/wear tests against silicon dioxide workpiece. Pulsed laser ablation (Nd:YAG laser) has been used to manufacture repeatable patterns of micro-abrasive edges onto microstructurally different PCD/PCBN composites. Opposing to these highly engineered micro-abrasive arrays, conventional electroplated abrasive pads containing diamond and CBN Abrasives, respectively, have been chosen as benchmarks and tested under the same conditions. Contact profiling, optical microscopy, and environmental scanning electron microscopy have been employed for the characterization of the abrasive arrays and electroplated tools before/during/after the wear/cutting tests. For the PCD abrasive micro-arrays, the type of grain and binder percentage proved to affect the wear performances due to the different extents of compressive stresses occurring at the grain boundaries. In this respect, the micro-arrays made of PCD with mixed diamond grain sizes have shown slower wear progression when compared to the electroplated diamond pads confirming the combination of the high wear resistance typical of the fine grain and the good shock resistance typical of the coarse grain structures. The micro-arrays made of fine grained diamond Abrasives have produced lower contact pressures with the workpiece shaft, confirming a possible application in polishing or grinding. As for the PCBN abrasive micro-arrays, the increase of metallic binder and the presence of metalloids in the medium content-CBN specimens have shown to produce higher contact pressure with the workpiece when compared to the electroplated specimen, causing fracturing as the main wear mechanism; while the PCBN micro-array with purely a metallic binder phase has shown slower wear and lower contact pressure in comparison to the electroplated CBN specimen. Among all of the tested arrays, the mixed grained PCD and the purely metallic binder phase PCBN micro-arrays have shown slower wear when benchmarked to the electroplated pads, giving a possible application of their use in the cutting tool industry.
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abrasive waterjet cutting of polycrystalline diamond a preliminary investigation
International Journal of Machine Tools & Manufacture, 2009Co-Authors: Dragos Axinte, D S Srinivasu, M C Kong, Paul ButlersmithAbstract:Abstract Although abrasive waterjet (AWJ) machining has been employed in different setups (e.g. through cutting, milling, turning, cleaning) to generate surfaces in various workpiece materials (e.g. metallic alloys, ceramics, composites), up to now there is scarce information on the use of this technology in cutting super-hard materials such as diamond-based materials. The paper reports for the first time on a preliminary study of the capability of AWJ cutting of polycrystalline diamond (PCD) using abrasive media with different hardness, i.e. aluminium oxide (Al 2 O 3 ), silicon carbide (SiC) and diamond. While keeping some operating parameters constant (pump pressure, stand-off distance and size of Abrasives) the feed speed has been adjusted to enable full jet penetration for each type of Abrasives. It was found that not only the material removal rates vary significantly with the employment of different types of Abrasives but also the nozzle wear ratios, with further implications on the kerf quality (width, taper angle) of diamond cut surfaces. Furthermore in-depth studies of the cut surfaces helped to reveal the material removal mechanism when different types of Abrasives are employed: Al 2 O 3 —low intensity erosion; SiC—medium erosion with undesired cracking; diamond—high intensity erosion. The experimental results showed that while Al 2 O 3 and SiC abrasive media yield modest material removal rates (comparable with those obtained by electro discharge machining-EDM) the use of diamond Abrasives can greatly increase (>200 times) the productivity of AWJ through cutting of PCD test pieces at acceptable roughness (Ra
S C Tjong - One of the best experts on this subject based on the ideXlab platform.
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abrasive wear behavior of tib2 particle reinforced copper matrix composites
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2000Co-Authors: S C TjongAbstract:Abstract Pure copper and its composites reinforced with TiB 2 particles were prepared by a hot isostatic pressing process. The two-body abrasive wear behavior of these specimens was investigated using pin-on-disk method where the sample slid against a SiC abrasive of 240-grit size. Pure copper exhibits a high abrasive wear loss because of its softness. The addition of only 5 vol.% TiB 2 particle to copper leads to a dramatic improvement in its wear resistance. The wear resistance increases by further increasing volume fraction of reinforcing particles that resist the microcutting action of SiC Abrasives.
Dragos Axinte - One of the best experts on this subject based on the ideXlab platform.
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profiled rotary dresser with controlled size and distribution of abrasive grits performance assessment
Cirp Annals-manufacturing Technology, 2019Co-Authors: Dragos Axinte, Alessio Spampinato, Paul ButlersmithAbstract:Abstract This paper reports on a novel proprietary profiled rotary dresser which, in contrast with conventional tools, enables a controlled arrangement of geometrically defined Abrasives over complex profiles. Output forces and Abrasives’ wear were investigated during dressing and grinding tests. This showed a significant reduction in radial dressing forces (˜37%) and volumetric loss of material per grit (˜21%) when compared with conventional tools, together with low grinding forces and workpiece surface roughness variability for different wear conditions. The novel dresser proves the ability to obtain uniform wear rates along complex profiles, while allowing abrasive segment replacement to restore the dressing conditions.
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an assessment of the wear characteristics of microcutting arrays produced from polycrystalline diamond and cubic boron nitride composites
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2016Co-Authors: Manuela Pacella, P H Shipway, Dragos Axinte, Paul Butlersmith, M Daine, C WortAbstract:The current methods for manufacturing super-abrasive elements result in a stochastic geometry of Abrasives with random three-dimensional abrasive locations. This paper focuses on the evaluation of wear progression/failure characteristics of micro-abrasive arrays made of ultrahard composites (polycrystalline diamond—PCD; polycrystalline cubic boron nitride—PCBN) in cutting/wear tests against silicon dioxide workpiece. Pulsed laser ablation (Nd:YAG laser) has been used to manufacture repeatable patterns of micro-abrasive edges onto microstructurally different PCD/PCBN composites. Opposing to these highly engineered micro-abrasive arrays, conventional electroplated abrasive pads containing diamond and CBN Abrasives, respectively, have been chosen as benchmarks and tested under the same conditions. Contact profiling, optical microscopy, and environmental scanning electron microscopy have been employed for the characterization of the abrasive arrays and electroplated tools before/during/after the wear/cutting tests. For the PCD abrasive micro-arrays, the type of grain and binder percentage proved to affect the wear performances due to the different extents of compressive stresses occurring at the grain boundaries. In this respect, the micro-arrays made of PCD with mixed diamond grain sizes have shown slower wear progression when compared to the electroplated diamond pads confirming the combination of the high wear resistance typical of the fine grain and the good shock resistance typical of the coarse grain structures. The micro-arrays made of fine grained diamond Abrasives have produced lower contact pressures with the workpiece shaft, confirming a possible application in polishing or grinding. As for the PCBN abrasive micro-arrays, the increase of metallic binder and the presence of metalloids in the medium content-CBN specimens have shown to produce higher contact pressure with the workpiece when compared to the electroplated specimen, causing fracturing as the main wear mechanism; while the PCBN micro-array with purely a metallic binder phase has shown slower wear and lower contact pressure in comparison to the electroplated CBN specimen. Among all of the tested arrays, the mixed grained PCD and the purely metallic binder phase PCBN micro-arrays have shown slower wear when benchmarked to the electroplated pads, giving a possible application of their use in the cutting tool industry.
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abrasive waterjet cutting of polycrystalline diamond a preliminary investigation
International Journal of Machine Tools & Manufacture, 2009Co-Authors: Dragos Axinte, D S Srinivasu, M C Kong, Paul ButlersmithAbstract:Abstract Although abrasive waterjet (AWJ) machining has been employed in different setups (e.g. through cutting, milling, turning, cleaning) to generate surfaces in various workpiece materials (e.g. metallic alloys, ceramics, composites), up to now there is scarce information on the use of this technology in cutting super-hard materials such as diamond-based materials. The paper reports for the first time on a preliminary study of the capability of AWJ cutting of polycrystalline diamond (PCD) using abrasive media with different hardness, i.e. aluminium oxide (Al 2 O 3 ), silicon carbide (SiC) and diamond. While keeping some operating parameters constant (pump pressure, stand-off distance and size of Abrasives) the feed speed has been adjusted to enable full jet penetration for each type of Abrasives. It was found that not only the material removal rates vary significantly with the employment of different types of Abrasives but also the nozzle wear ratios, with further implications on the kerf quality (width, taper angle) of diamond cut surfaces. Furthermore in-depth studies of the cut surfaces helped to reveal the material removal mechanism when different types of Abrasives are employed: Al 2 O 3 —low intensity erosion; SiC—medium erosion with undesired cracking; diamond—high intensity erosion. The experimental results showed that while Al 2 O 3 and SiC abrasive media yield modest material removal rates (comparable with those obtained by electro discharge machining-EDM) the use of diamond Abrasives can greatly increase (>200 times) the productivity of AWJ through cutting of PCD test pieces at acceptable roughness (Ra
Eduardo Albertin - One of the best experts on this subject based on the ideXlab platform.
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mild and severe wear of steels and cast irons in sliding abrasion
Wear, 2009Co-Authors: Giuseppe Pintaude, F G Bernardes, M.m. Santos, Amilton Sinatora, Eduardo AlbertinAbstract:Abstract This paper presents the results obtained in pin-on-disk test apparatus using glass and alumina as abrasive materials, showing the rates and mechanisms of abrasive wear of 1070 and 52100 steels, and ductile and white cast irons. The test conditions were selected in order to obtain wear rates that correspond to mild and severe abrasion, using different metal hardness-to-abrasive hardness ratios ( H / H A ) and 0.2 or 0.06 mm abrasive grains. The use of bulk Vickers hardness, instead of microhardness, allows a better description of the different abrasion regions. Under severe abrasion, the microcutting mechanism of wear prevailed together with friction coefficients larger than 0.4. On the other hand, when relatively soft Abrasives are tested, indentation of abrasive particles followed by its fragmentation, and a creation of a thin deformed layer were the main damage mechanisms, with the friction coefficient lying below 0.4. The abrasive particle size under mild regime is able to change the wear rates in an order of magnitude.
Md Mohafizul Haque - One of the best experts on this subject based on the ideXlab platform.
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performance of different abrasive materials during abrasive water jet machining of glass
Journal of Materials Processing Technology, 2007Co-Authors: Ahsan Ali Khan, Md Mohafizul HaqueAbstract:Abstract Different types of Abrasives are used in abrasive water-jet machining like garnet, aluminum oxide, olivine, silica sand, silicon carbide, etc. The present work gives a comparative analysis of the performance of garnet, aluminum oxide and silicon oxide during abrasive water-jet machining of glass. The study showed that width of cut increases as the stand-off distance of the nozzle from the work is increased which is due to divergence shape of the abrasive water-jet. However, the garnet Abrasives produce the smallest width of cut followed by aluminum oxide and silicon carbide. This is because of higher hardness and cutting ability of silicon carbide followed by aluminum oxide and garnet. It was also noticed that width of cut reduces with the increase of feed rate. With the increase in work feed rate, the work is under the jet for a shorter time which causes a smaller width of the slots. Again, width of cut was found to be the smallest while using garnet Abrasives followed by aluminum oxide and silicon carbide. The taper of the cut slot was found to be higher at a greater stand-off distance and work feed rate, but smaller at a higher pressure. Since silicon carbide is very hard, it maintains its cutting ability as the Abrasives move down. As a result, the difference of the width at the jet entrance and the jet exit is not significant. This causes a smaller taper of the cut slots. The width of the cut slot was found to increase with increase in jet pressure. At a higher jet pressure the kinetic energy of the Abrasives increases, resulting an enhanced cutting ability of the Abrasives and causes widening of the cut slots. Due to higher hardness, silicon carbide produced the maximum width of cut followed by aluminum oxide and garnet.
