| Engineering ceramics is a special kind of advanced ceramic materials. At present, the application amount of engineering ceramic material accounts for 32% of the total amount of ceramic material every year. As engineering ceramic materials have great physical and chemical properties, they have been widely used in many fields such as the automobile industry, the aerospace, the electronic and electrical appliances, the petrochemical engineering and so on. But compared with the metal, the molding technology of hot pressing, sintering and vacuum extrusion of engineering ceramic material determines its poor machining performance. The machining cost of engineering ceramics parts usually accounts for 70%~90% of the cost of parts.In recent years, with the rapid development of the abrasive water jet(AWJ) technology, an enhanced form of pure water jet, and the advantages of low temperature processing, good quality of incision, high precision, low noise, non-selectivity of material, convenient processing and so on, the AWJ technology has been widely used in processing the materials of cemented carbide, glass, ceramics, composite material and others which are difficult to machined by traditional method. Nowadays the AWJ technology of cutting, milling, turning, drilling and polishing have developed very well. The grinding of AWJ expands its machining process, having a very high research value.This thesis uses the method of AWJ to research the grinding experiment of engineering ceramics. Combined with the traditional grinding process and AWJ machining process, a series of theoretical studies on AWJ grinding are made. The machining mechanism of grinding engineering ceramics by AWJ, the grinding model and the main factors effect on the surface roughness of material in grinding process are obtained through the research.In this thesis, the author made an experimental study on the six important factors of jet system pressure, nozzle feed rate, standoff distance, abrasive flow rate, transverse feed amount and abrasive particle size by using the single variable method. The experimental results indicate that with the increasing of the jet system pressure, the surface roughness value of material increases. When the nozzle feed rate increases, the surface roughness value of material decreases. With the increasing of the standoff distance, the surface roughness value of material decreases firstly and then increases, and there is an optimal standoff distance in the parameter scope. With the increasing of abrasive flow rate, the surface roughness value of material decreases significantly. The transverse feed amount increases, and the surface roughness value decreases slowly. The surface roughness value of alumina ceramic under the effect of grinding with 200 mesh silicon carbide is less than that of 80 mesh silicon carbide under the same conditions.The orthogonal experiment is designed for the four main parameters which influenced the grinding surface roughness in the thesis. And the experimental results are processed with the range analysis. The analysis results show that the jet system pressure has the greatest impact on the surface roughness, followed by the abrasive flow rate, the standoff distance in order, and the nozzle feed rate has the smallest impact. In the scope of the experimental factors, taking advantage of 80 MPa of jet pressure, 20mm/s of nozzle traverse speed, 30 mm of standoff distance, 90.6g/min of abrasive flow rate leads to the smallest surface roughness.In this thesis, a prediction model 0650.00102.01301.00084.1158.317???R? VmSPa of surface roughness value of AWJ grinding alumina ceramic is established by using multiple nonlinear regression analysis method and Matlab tool. The average error which validated by the experimental results of this model is only 5.49%. It is proved that this model has a high reliability and a certain practical significance. |
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