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Considering the relatively poor surface and subsurface quality of workpieces that are ground by coarse-grained grinding wheels, the nanosecond ultraviolet laser micro-structuring of coarse-grained diamond grinding wheels and the grinding performance of micro-structured grinding wheels were investigated in this study. In addition, the effect of two processing sequences on the topographical characteristics of the grooves and the effect of the groove angle ( α) on the surface roughness ( R ) of the ground workpiece were explored. Furthermore, the surface quality of workpieces that were ground by micro-structured (V-shaped and W-shaped patterns) and non-structured diamond grinding wheels and the grinding ratio ( G) of the grinding wheels were comparatively analyzed. The results demonstrate the following: Compared with the grinding wheel that was subjected to micro-structuring followed by sharpening, the surface of the grinding wheel that was subjected to sharpening followed by micro-structuring had a more integral groove structure. Neither an overly large α nor an overly small α was favorable for improving the surface quality of the workpiece that was ground by a micro-structured grinding wheel. When α = 60°, the minimum R of the workpiece was attained. The R of the workpieces that were ground by the grinding wheel with a V-shaped pattern (grinding wheel A) was 17-31% less than the R of the workpieces that were ground by the non-structured grinding wheel (grinding wheel C). The R of the workpieces that were ground by the grinding wheel with a W-shaped pattern (grinding wheel B) was 32-41% less than the R of the workpieces that were ground by grinding wheel C. The grinding performance of the micro-structured grinding wheels was related not only to the geometric parameters of the grooves but also to the micro-structure pattern. The W-shaped pattern was superior to the V-shaped pattern in terms of cooling and chip removal. Grinding wheel A and grinding wheel B had similar abrasion resistance, which were 26% less and 23% less than the abrasion resistance of grinding wheel C, respectively. [ABSTRACT FROM AUTHOR]

Coarse-grained bronze-bonded diamond grinding wheels dressed using lasers and silicon carbide dressing wheels were used to grind YG8-cemented carbide workpieces. The wear patterns and grinding ratios of the laser-dressed grinding wheels were investigated after different grinding stages. After grinding, the laser-dressed grinding wheel displayed superior surface topography compared to the silicon carbide wheel, and the surface quality of the workpiece also improved. The minimum surface roughness of the workpiece was 0.425 μm. In the initial wear regime, the primary mechanisms included abrasive wear and grain removal. The grinding ratio was approximately 205.4, and the surface roughness of the workpiece after grinding was 0.314 μm. In the steady-state wear regime, abrasive wear was the primary mechanism of wearing, while minor amounts of grain removal and bond wear were observed. The grinding ratio was approximately 405.1, and the surface roughness was 0.337 μm. In the accelerated wear regime, the primary mechanisms were grain removal, abrasive wear, and bond wear. The grinding ratio was approximately 96.0, and the surface roughness was 0.454 μm. [ABSTRACT FROM AUTHOR]

For the finishing of some difficult-to-machine materials, such as silicon carbide, diamond, and so on, a novel polishing technique named plasma-assisted polishing (PAP) was proposed, which combined with the irradiation of atmospheric pressure water vapor plasma and polishing using soft abrasives. In this article, application of PAP to 4H-SiC (0001) substrate was conducted. We used helium-based water vapor plasma to modify the mechanical and chemical properties of the SiC surface. The results of X-ray photoelectron spectroscopy measurements indicate that the surface was efficiently oxidized after plasma irradiation, and the main product was SiO. CeO was used as the abrasive material in PAP, the hardness of which was near to that of the oxidized surface. The scanning white light interferometer images of the PAP processed surface showed us that scratches disappeared and surface roughness also decreased from 4.410 nm p-v, 0.621 nm root mean square (rms) to 1.889 nm p-v, 0.280 nm rms. From the atomic force microscopy images, step and terrace structure was observed on the surface after PAP, which means an atomically flat surface was obtained. The PAP processed surface was observed using cross-sectional transmission electron microscope, which indicated that almost no crystallographical defects were introduced. [ABSTRACT FROM AUTHOR]

Electrochemical polishing (ECP) is widely used for scratch- and damage-free finishing of metal components. Though the polishing effect of ECP has been confirmed in many researches, the influence of polishing parameters on evolution of surface roughness is still ambiguous owing to the use of different ECP systems. In this paper, the universal factor determining the evolution of surface roughness during ECP is studied by theoretical analysis as well as experiments. Theoretical analysis based on viscous layer mechanism demonstrates that the material removal thickness is the key parameter governing the roughness evolution of the polished surface regardless of other parameters including the voltage and current and electrolyte concentration. A series of experiments were designed and carried out to verify the proposed hypothesis. Both the experimental results and already published researches proved the validity and universality of the newly developed hypothesis on surface roughness evolution. This work is of great significance for further understanding the finishing mechanism of ECP and process control for its practical applications. [ABSTRACT FROM AUTHOR]