The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
C.f. Cheung - One of the best experts on this subject based on the ideXlab platform.
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A mesoplasticitiy analysis of cutting friction in ultra-precision machining
Journal of Materials Processing Technology, 2003Co-Authors: Bun Lee, C.f. CheungAbstract:Abstract The control and minimization of cutting Force Variation is of prime importance in obtaining a consistent surface finish and form accuracy of a machined workpiece in ultra-precision machining. However, most continuum theories do not take into account the effect of crystallographic anisotropy that causes Variation in the shear plane at the grain level and hence of the cutting Force. The periodicity of the fluctuation of cutting Forces is found to be dependent on the frictional condition during cutting. However, investigation of the in situ relationships among the cutting friction, the crystallographic orientation of workpiece and the periodic fluctuation of cutting Forces has received relatively little attention. In this paper, a mesoplasticity approach is proposed to access the crystallographic and frictional effect on the fluctuation of micro-cutting Forces in diamond turning of crystalline materials. The predictions were able to explain the experimental results based on the power spectrum analysis of the cutting Force Variation. The research findings throw light on the possibility of an indirect in situ assessment of the frictional condition in ultra-precision machining.
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A mesoplasticitiy analysis of cutting friction in ultra-precision machining
Journal of Materials Processing Technology, 2003Co-Authors: W B Lee, C.f. CheungAbstract:The control and minimization of cutting Force Variation is of prime importance in obtaining a consistent surface finish and form accuracy of a machined workpiece in ultra-precision machining. However, most continuum theories do not take into account the effect of crystallographic anisotropy that causes Variation in the shear plane at the grain level and hence of the cutting Force. The periodicity of the fluctuation of cutting Forces is found to be dependent on the frictional condition during cutting. However, investigation of the in situ relationships among the cutting friction, the crystallographic orientation of workpiece and the periodic fluctuation of cutting Forces has received relatively little attention. In this paper, a mesoplasticity approach is proposed to access the crystallographic and frictional effect on the fluctuation of micro-cutting Forces in diamond turning of crystalline materials. The predictions were able to explain the experimental results based on the power spectrum analysis of the cutting Force Variation. The research findings throw light on the possibility of an indirect in situ assessment of the frictional condition in ultra-precision machining.Department of Industrial and Systems Engineerin
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a microplasticity analysis of micro cutting Force Variation in ultra precision diamond turning
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2002Co-Authors: W B Lee, C.f. CheungAbstract:This paper describes a microplasticity model for analyzing the Variation of cutting Force in ultra-precision diamond turning. The model takes into account the effect of material anisotropy due to the changing crystallographic orientation of workpieces being cut. A spectrum analysis technique is deployed to extract the features of the cutting Force patterns. The model has been verified through a series of cutting experiments conducted on aluminum single crystals with different crystallographic cutting planes. The results indicate that the model can predict well the patterns of the cutting Force Variation. It is also found that there exists a fundamental cyclic frequency of Variation of cutting Force per revolution of the workpiece. Such a frequency is shown to be closely related to the crystallographic orientation of the materials being cut. The successful development of the microplasticity model provides a quantitative means for explaining periodic fluctuation of micro-cutting Force in diamond turning of crystalline materials.
W B Lee - One of the best experts on this subject based on the ideXlab platform.
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finite element modelling of shear angle and cutting Force Variation induced by material anisotropy in ultra precision diamond turning
International Journal of Machine Tools & Manufacture, 2013Co-Authors: W B Lee, Hao Wang, C Y ChanAbstract:Abstract This paper addresses a key theoretical problem in the mechanics of ultra-precision machining – shear angle prediction and cutting Force Variation induced by crystallographic anisotropy. The constitutive equation of crystal plasticity is implemented in the finite element modelling of the chip formation at micro-scale to take into account the effect of crystallographic orientations of the work piece to be cut. The theoretical prediction of shear angle and cutting Force Variation reveals two distinguished phases of pre-compression and steady-state cutting in ultra-precision diamond turning. The predicted patterns of cutting Force Variation are in good agreement with published experimental results.
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A mesoplasticitiy analysis of cutting friction in ultra-precision machining
Journal of Materials Processing Technology, 2003Co-Authors: W B Lee, C.f. CheungAbstract:The control and minimization of cutting Force Variation is of prime importance in obtaining a consistent surface finish and form accuracy of a machined workpiece in ultra-precision machining. However, most continuum theories do not take into account the effect of crystallographic anisotropy that causes Variation in the shear plane at the grain level and hence of the cutting Force. The periodicity of the fluctuation of cutting Forces is found to be dependent on the frictional condition during cutting. However, investigation of the in situ relationships among the cutting friction, the crystallographic orientation of workpiece and the periodic fluctuation of cutting Forces has received relatively little attention. In this paper, a mesoplasticity approach is proposed to access the crystallographic and frictional effect on the fluctuation of micro-cutting Forces in diamond turning of crystalline materials. The predictions were able to explain the experimental results based on the power spectrum analysis of the cutting Force Variation. The research findings throw light on the possibility of an indirect in situ assessment of the frictional condition in ultra-precision machining.Department of Industrial and Systems Engineerin
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a microplasticity analysis of micro cutting Force Variation in ultra precision diamond turning
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2002Co-Authors: W B Lee, C.f. CheungAbstract:This paper describes a microplasticity model for analyzing the Variation of cutting Force in ultra-precision diamond turning. The model takes into account the effect of material anisotropy due to the changing crystallographic orientation of workpieces being cut. A spectrum analysis technique is deployed to extract the features of the cutting Force patterns. The model has been verified through a series of cutting experiments conducted on aluminum single crystals with different crystallographic cutting planes. The results indicate that the model can predict well the patterns of the cutting Force Variation. It is also found that there exists a fundamental cyclic frequency of Variation of cutting Force per revolution of the workpiece. Such a frequency is shown to be closely related to the crystallographic orientation of the materials being cut. The successful development of the microplasticity model provides a quantitative means for explaining periodic fluctuation of micro-cutting Force in diamond turning of crystalline materials.
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effect of crystallographic orientation on cutting Forces and surface quality in diamond cutting of single crystal
CIRP Annals, 1994Co-Authors: Z J Yuan, W B Lee, Yingxue Yao, M ZhouAbstract:Summary As the depth of cut in ultraprecision machining is usually less than the average grain size of a polycrystalline aggregate, cutting is performed within a grain. Single crystals are known to be highly anisotropic in their physical and mechanical properties. In this paper, the effect of crystallographic orientation of the substrate material on cutting Forces and surface quality in diamond cutting of single crystal copper and aluminium has been studied. Experimental results show that the crystallographic orientation of the workpiece material exerts a large influence on the cutting Force and surface roughness. The crystallographic nature of cutting Force Variation was analyzed based on a microplasticity model. Analytical results compare well with the experimental data. Measures for minimizing the cutting Force Variation and hence improving the machined surface quality were discussed.
Akira Nakajima - One of the best experts on this subject based on the ideXlab platform.
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Comparison of photocatalytic activity and surface friction Force Variation on Ti-doped hydroxyapatite and anatase under UV illumination
Journal of Photochemistry and Photobiology A: Chemistry, 2015Co-Authors: Ayumi Tsuruoka, Toshihiro Isobe, Sachiko Matsushita, Masato Wakamura, Akira NakajimaAbstract:Abstract Photocatalytic activity and surface friction Variation were evaluated on Ti-doped hydroxyapatite (Ti-HAp) and anatase-type TiO 2 powders under UV illumination. Although the adsorption capability of Ti-HAp against gaseous 2-propanol (IPA) in the dark was greater than that of anatase, photocatalytic decomposition activity and water adsorption capability of Ti-HAp under UV illumination were inferior to those of anatase. Experiments using powder/epoxy composites revealed that Ti-HAp does not exhibit photocatalytic wettability conversion to a hydrophilic state, which was confirmed on anatase. The surface friction Force Variation of anatase under UV illumination was similar to previously reported trend for rutile ceramics. That of Ti-HAp exhibited a different trend against anatase, suggesting that its surface was originally more hydrophobic than anatase or cantilever.
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Wettability conversion and surface friction Force Variation of polycrystalline rutile ceramics under UV illumination
Journal of Photochemistry and Photobiology A: Chemistry, 2011Co-Authors: Kenji Okudaira, Tomoya Kato, Toshihiro Isobe, Sachiko Matsushita, Toshihiro Kogure, Akira NakajimaAbstract:Abstract Photoinduced surface friction Variations of the polished surface of polycrystalline rutile ceramics under UV illumination in different atmospheres was evaluated using FFM. When UV was irradiated onto the rutile surface, the surface friction Force first increased and then decreased. Once the water contact angle of the rutile surface reached the lower limit, the surface friction Force increased gradually. Increased friction Force on the surface in the early stage of UV illumination was attributable to decomposition of the surface organic contaminant and the resultant increase of surface energy from the fitting of calculated contact angles to practical values. However, the friction Force decrease and gradual increase after a certain period of UV illumination are attributed to the lubrication effect and either a capillary effect or the increased adsorbed water layer by humidity control. From the Force curve measurement on the highly hydrophilic rutile single crystal (1 0 0), the repulsion Force was detected from 2 to 3 nm separation distance.
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Dependence of photoinduced surface friction Force Variation on UV intensity and atmosphere in polycrystalline TiO2 thin films
Journal of Photochemistry and Photobiology A-chemistry, 2009Co-Authors: Naoki Arimitsu, Akira Nakajima, Toshiya Watanabe, Yoshikazu Kameshima, Kiyoshi OkadaAbstract:Abstract Anatase polycrystalline thin films and a plasma crystallization process were used to investigate the dependence of the photoinduced friction Force Variation for a TiO 2 surface on the UV intensity and atmosphere. Photoinduced friction Force Variation for UV illumination time was divisible into two stages, decreasing and increasing, where the switching time between these two stages and the degree of Variation depended on the UV intensity and atmosphere. The decreasing stage was attributable to the photocatalytic decomposition of organic compound adsorbed onto the surface, whereas the increasing stage was attributed to the capillary effect or an increase in the adsorbed water layer. Results demonstrated that UV intensity and atmosphere controlled the friction Force.
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Effect of atmosphere on photo-induced friction Force Variation on (001) rutile
Materials Letters, 2008Co-Authors: Akira Nakajima, Naoki Arimitsu, Yoshikazu Kameshima, Aya Nakada, Kiyoshi OkadaAbstract:Variations of friction Force and surface potential were evaluated using friction Force microscopy (FFM) and Kelvin Force microscopy (KFM) on (100) and (001) faces of rutile single crystals under UV illumination in three different atmospheres: dry nitrogen, dry air, and ambient air. Friction Force and surface roughness for the (100) face did not exhibit remarkable dependence on either UV illumination or on the atmosphere. However, the friction Force of the (001) face increased by UV illumination in dry air without roughness Variation. The surface potential of the (001) face changed negatively and more remarkably than that of the (100) face by UV illumination.
C Y Chan - One of the best experts on this subject based on the ideXlab platform.
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finite element modelling of shear angle and cutting Force Variation induced by material anisotropy in ultra precision diamond turning
International Journal of Machine Tools & Manufacture, 2013Co-Authors: W B Lee, Hao Wang, C Y ChanAbstract:Abstract This paper addresses a key theoretical problem in the mechanics of ultra-precision machining – shear angle prediction and cutting Force Variation induced by crystallographic anisotropy. The constitutive equation of crystal plasticity is implemented in the finite element modelling of the chip formation at micro-scale to take into account the effect of crystallographic orientations of the work piece to be cut. The theoretical prediction of shear angle and cutting Force Variation reveals two distinguished phases of pre-compression and steady-state cutting in ultra-precision diamond turning. The predicted patterns of cutting Force Variation are in good agreement with published experimental results.
Bun Lee - One of the best experts on this subject based on the ideXlab platform.
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A mesoplasticitiy analysis of cutting friction in ultra-precision machining
Journal of Materials Processing Technology, 2003Co-Authors: Bun Lee, C.f. CheungAbstract:Abstract The control and minimization of cutting Force Variation is of prime importance in obtaining a consistent surface finish and form accuracy of a machined workpiece in ultra-precision machining. However, most continuum theories do not take into account the effect of crystallographic anisotropy that causes Variation in the shear plane at the grain level and hence of the cutting Force. The periodicity of the fluctuation of cutting Forces is found to be dependent on the frictional condition during cutting. However, investigation of the in situ relationships among the cutting friction, the crystallographic orientation of workpiece and the periodic fluctuation of cutting Forces has received relatively little attention. In this paper, a mesoplasticity approach is proposed to access the crystallographic and frictional effect on the fluctuation of micro-cutting Forces in diamond turning of crystalline materials. The predictions were able to explain the experimental results based on the power spectrum analysis of the cutting Force Variation. The research findings throw light on the possibility of an indirect in situ assessment of the frictional condition in ultra-precision machining.
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CHARACTERISTICS OF MICROCUTTING Force Variation IN ULTRAPRECISION DIAMOND TURNING
Materials and Manufacturing Processes, 2001Co-Authors: Bun Lee, Chi Fai CheungAbstract:An investigation of the characteristics of microcutting Forces in diamond turning of crystalline materials is presented. The characteristics of the cutting Forces were extracted and analyzed using statistical and spectrum analysis methods. A series of cutting experiments were done on a copper alloy and copper single crystals with different crystallographic orientations. Experimental results indicate that there exists a dominant frequency component and a periodicity of fluctuation of the cutting Forces per workpiece revolution in the diamond turning of a single crystal material. The periodicity is closely related to the crystallographic orientation of the material being cut. As the depth of cut increases, the influence of crystallographic orientation of the single-crystal materials on microcutting Forces is found to be more pronounced. Moreover, the cutting Force ratio between the mean thrust Force and the mean cutting Force is found to vary with the depth of cut, and a large ratio was observed at a small ...
