| Because of high grinding temperature, the traditional cylindrical grinding makes defects on the ground surface such as micro-crack、tensile residual stresse、burned layer and so on, and the roughness and ripple values are also greater. All of these would affect the fatigue strength, resistance corroding capability and contact rigidity of the ground surface. Therefore important parts require micro finishing in order to reduce the surface defects and diminish the surface roughness and ripple. A new method named abrasive jet precision machining of cylindrical grinding is to remove surface defect layer and diminish roughness and ripple. When the workpiece was after grinding the slurry of abrasive and liquid solvent was injected to the grinding zone under no depth of cut infeed condition. For the high speed of grinding wheel, when the abrasive slurry is injected to the grinding zone, hydrodynamic pressure has formed, pressure field and velocity field have also formed. The abrasives are driven and energized by the rotating grinding wheel and the surface of workpiece achieved micro removal machining process. The investigate shows that, not only the higher form accuracy of surface but also the no defect cylindrical surface with Ra0.19-0.6μm can be achieved efficiently. Furthermore, cylindrical grinding process and polishing method can be integrated together. This paper has done a lot of systemic research about the model building and simulation on the basic of theory and experiment, which kernel is fluid wedge field of grinding zone、pressure field、velocity field、removal theory and character surface. The purpose of the work is to offer the basis theory and experimental research for the new methord and the primary study work includes these several sides:(1) Analysis the sketch of the development of the finishing technique, the practical appliance and the newest achievement in and out country. The function, sorts, trait and development of the finishing technology were summarized and the important action of the finishing technique was also discussed. Especially, the loose abrasive finishing technique and the latest achievement of the domestic and international were especially analyzed. The intention and significance of the topic research was also introduced.(2) Based on Navier-Stokes and continuity equations, the 3D hydrodynamic pressure model of wedge-like zone between the grinding wheel and workpiece was established, combined hydrodynamics and simulation technology,3D hydrodynamic pressure field was simulated by using Matlab, and the distributing principle and affecting factor of the liquid hydrodynamic pressure were investigated. The simulation solution is close to the experiment’, which has provide the method for the simulation study of the fluid pressure field of grinding.(3) The velocity field model of wedge zone between the grinding wheel and cylindrical workpiece was established. The velocity field of liquid in 2D and 3D has been simulated in computer and investigated by using Fluent. The speed distributing principle and influencing factor of liquid velocity field in wedge zone was researched. Secondary the trace of single abrasive、group of abrasive and the effect of trace by different released position were research. Finally the distribution of abrasive by machining time and in different position of wedge were also researched.(4) Based on the size ratio of characteristic particle size to the thickness between grinding wheel and workpiece, the material removal mechanisms for abrasive jet machining with cylindrical grinding wheel as restraint were investigated. It can be suggested that the material removal mechanisms combined with two-body lapping and three-body erosion. According to the probability statistics method, the number of particles which can remove material actually was established. The model of material removal ratio was established according to the model of material removal by single abrasive and the number of useful abrasive. Experiments were performed on the cylindrical grinder for material removal of abrasive jet machining experiment, and the material removal rate model was found to give a good confirmation of the experimental results.(5) The microscopic morphology surface of abrasive jet machining process with cylindrical wheel as restrain was analyzed. The peak removal mechanism and homogenizing theory of workpiece surface were investigated. Experiments were performed on cylindrical grinder MB1332A and workpiece material 45. The mocro-parameters and microscopic morphology of workpiece surfaces before and after finishing process were measured respectively. The experimental results showing that the machined surfaces change from continuous and parallel micro-groove and plough to randomly discontinuous micro-pit can be observed with machining time increasing. Furthermore, the new process method can obviously diminish roughness values and cause the surfaces to be smooth.(6) The outline of the workpiece surface before and after abrasive jet machining process was evaluated by auto correlation function (ACF)、power spectral density (PSD)、cross correlation function (CCF) and Fourier.(7) The machined surface of abrasive jet machining with cylindrical grinding wheel as restraint was evaluated by physical performance. And the effect of frictional behaviour、wear behaviour、corrosion resistance and metallurgical structure of the workpiece surface were researched before and after abrasive jet machining process. Fractal dimension was used to analyse the workpiece surface as a assistant parameter.(8) From the contrast of pressure field、velocity field and surface quality between the wedge contact zone of plane grinding and cylindrical grinding, the difference between the plane surface and cylindrical surface was expounded. The method can be used to machine the surface of plane workpiece.(9) The research work was summarized and exploring suggestion was proposed. |
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