Papers by Keyword: Precision Finishing

Abstract: The abrasive jet finishing process with wheel as restraint is a kind of compound precision finishing process that combined grinding with abrasive jet machining, in which inject slurry of abrasive and liquid solvent to grinding zone between grinding wheel and work surface under no radial feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal finishing.In the paper,the finished surface morphology was studied using Scanning Electron Microscope (SEM) and microscope and microcosmic geometry parameters were measured with TALYSURF5 instrument respectively. According to the metrical results, the surface topographical characteristics were evaluated with correlation function and PSD (Power Spectral Density) of random process about machined surface before and after finishing. The results show that longitudinal geometry parameter values of finishing machining surface were diminished comparing with ground surface,and the mean ripple distance was decreased and, ripple and peak density were increased. Furthermore, the finished surface has little comparability compared to grinding machining surface.The isotropy surface and uniformity veins at parallel and perpendicular machining direction were attained by abrasive jet precision finishing with grinding wheel as restraint and the surface quality is improved obviously.

Abstract: The grinding hardening is a new surface heat treatment technology using grinding heat in which induce martensitic phase transformation in the surface layers of annealed or tempered steels to achieve surface strengthening processes and integrate the surface hardening process with the grinding precision machining. In the paper, a thermal model to describe this process has been presented from the thermal partition modeling and has been used to predict subsurface time–temperature profiles in the dry cylindrical grinding crankshaft using cubic boron nitride (CBN) wheels. The grinding hardening experiment was carried out in precision cylindrical grinder M1420E, using work-piece material 42CrMo4 and CBN grinding wheel under dry grinding condition. The experimental results showed the theoretical model is agreement with experimental results and the model can well forecast the grinding hardening depths.

Abstract: The process technique on abrasive jet finishing process with wheel as restrain was investigated by experimental. The effects of different particle size, abrasive concentration, machining cycles, the velocity of grinding wheel and medium type on surface quality were analyzed. Experiments were performed with plane grinder M7120 and workpiece material 40Cr steel. The machined surface morphology was studied using Scanning Electron Microscope (SEM) and microscope and microcosmic geometry parameters were measured with TALYSYURF5 instrument respectively. The experimental results under percentage 10 abrasive concentration, Al2O3 abrasive particle with W7 size and machining 20～30 circles showing the novelty process method, not only to attain higher surface form accuracy, to diminish grinding defects such as severely deformation, surface layer pollution and ground burnout, but also to can acquire efficiently free defects finishing surface with Ra0.15～1.6µm and finally achieve high efficiency, high precision and low roughness values. Furthermore, integrate grinding process and abrasive jet finishing process into one feature.

Abstract: The integration manufacturing technology is a kind of compound precision finishing process that combined grinding with abrasive jet finishing, in which inject slurry of abrasive and liquid solvent into grinding zone between grinding wheel and work surface under no radial feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal finishing. In the paper, the machining process validity was verified by experimental investigation. Experiments were performed with plane grinder M7120 and workpiece material 40Cr steel which was ground with the surface roughness mean values of Ra=0.6μm. The machined surface morphology was studied using Scanning Electron Microscope (SEM) and metallography microscope and microcosmic geometry parameters were measured with TALYSURF5 instrument respectively. The experimental results show the novelty process method, not only can obviously diminish longitudinal geometry parameter values of ground surface, but also can attain isotropy surface and uniformity veins at parallel and perpendicular machining direction. Furthermore, the finished surface has little comparability compared to grinding machining surface and the process validity was verified.

Abstract: Abrasive jet finishing process is a novel process whose objective is to remove surface defect layer and to diminish roughness and ripple after grinding. Experiments were performed with plane grinderM7120 and workpiece material 45# steel which was ground with the surface roughness values of Ra =0.2-0.6 μm . The machined surface morphology was studied using SEM and the microcosmic geometry parameters were measured with MICROMESVRE2 instrument. In this paper, with the fractal dimension, Ra , Rq and the supporting rate curve, the surfaces of grinding machining and abrasive jet finishing machining were researched. The result indicated that the machined surfaces changed from continuous parallel micro-groove and plough to randomly distributed discontinuous micro-pit could be observed with the increase of machining circles and surface roughness was obviously improved. Furthermore, the isotropy surface and uniformity veins both parallel and perpendicular machining direction were attained by abrasive jet precision finishing with grinding wheel as restraint. The supporting rate curve of the surface profile can be increased. This is favorable for the wearable capability of the workpiece.

Abstract: The surface integrity finished by abrasive jet with grinding wheel as restraint was experimentally investigated. Experiments were performed with plane grinder M7120 equiped with abrasive jet finishing device and harded workpiece material 45 steel which was ground with the surface roughness values of Ra=0.6μm.The machined surface morphology was studied using Scanning Electron Microscope (SEM) and microscope and microcosmic geometry parameters were measured with TALYSURF5 instrument. The surface hardness for ground and finished surface was measured with HVS-1000 instrument and the phase structure was analyzed by X-ray energy dispersive spectram and residual stresses were measured by PW3208 X-ray diffraction. The Results show that longitudinal geometry parameter values were diminished and ripple was obviously improved comparing with ground surface. Furthermore, the finished surface has condensible residual stresses and high surface hardness comparability compared to grinding machining surface. As a result, life and precision consistency of finished workpiece were improved.

Abstract: The abrasive jet finishing process with wheel as restraint is a kind of compound precision finishing process that combined grinding with abrasive jet precision machining, in which inject slurry of abrasive and liquid solvent to grinding zone between grinding wheel and work surface under no depth of cut feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal machining. The micro removal machining with grinding wheel as restraint, not only to attain higher surface form accuracy but also to can efficiently acquire defect-free finishing surface with Ra0.15~1.6$m and finally achieve high efficiency, high precision and low roughness values, furthermore, integrating grinding process and abrasive jet finishing into one features. In the paper, surface topography finished by abrasive jet with grinding wheel as restraint was analyzed and evaluated with power spectral density function. Experiments were performed with plane grinder M7120 and workpiece material 45 steel. The machined surface morphology was studied using Scanning Electron Microscope (SEM) and the microscope and microcosmic geometry parameters were measured with TALYSURF5 instrument. The experimental results show that microcosmic geometry parameter values were diminished comparing with ground surface. Furthermore, the mean ripple peak distancing was decreased and, ripple and peak density were increased. The results indicate that surface qualities by machined with abrasive jet precision finishing were improved obviously.

Abstract: Surface microcosmic topography finished by abrasive jet with grinding wheel as restraint was analyzed and evaluated. Generating mechanism of surface morphology finished by abrasive jet with grinding wheel as restraint was investigated and surface topographical characteristics were also evaluated with cross correlation of random process. Experiments were performed with plane grinder M7120 and workpiece material 45# steel which was ground with the surface roughness values of Ra=0.2
0.6m. The machined surface morphology was studied using SEM and microscope and the microcosmic geometry parameters were measured with TALYSURF5 instrument. The experimental results shown that the machined surface change from continuous and parallel micro-groove and plough to randomly discontinuous micro-pit can be observed with machining circles increasing and surface roughness was obviously improved. Furthermore, The finished surface has little comparability compared to grinding machining surface.The isotropy surface and uniformity veins both parallel and perpendicular machining direction were attained by abrasive jet precision finishing with grinding wheel as restraint.

Abstract: The abrasive jet finishing process with wheel as restraint is a kind of compound precision finishing process that combined grinding with abrasive jet machining, in which inject slurry of abrasive and liquid solvent to grinding zone between grinding wheel and work surface under no radial feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal machining. The micro removal machining with grinding wheel as restraint, not only to attain higher surface form accuracy but also to can acquire efficiently defect-free finishing surface with Ra0.15～ 1.6μm and finally achieve high efficiency, high precision and low roughness values, furthermore, integrating grinding process and abrasive jet process into one features. In the paper, surface topography and tribological characteristics finished by abrasive jet with grinding wheel as restraint were analyzed. Experiments were performed with plane grinder M7120 and workpiece material Q235A. The machined surface morphology was studied using SEM and the microscope and microcosmic geometry parameters were measured with TALSURF5 instrument. The experimental results show that microcosmic geometry parameter values were diminished comparing with ground surface. The tribological characteristics of finished surface were also investigated with pin on disk wear tester of MG-2000. The experimental results show that the friction coefficient and wear amounts of finishing machining surface were obviously decreased comparing with ground surface. As a result, life and precision consistency of finished workpiece were improved.