Simulation And Experimental Study On Precision Grinding Of Silicon Nitride Ceramics

Engineering ceramics with high strength in high temperature,high hardness,anti-oxidation,anti abrasion,corrosion resistance,line expansion coefficient and excellent dielectric properties and toughening modification of advantage,in important areas of the industry,modern medicine,national defense and aerospace are widely used.In order to meet the requirements of high quality,high efficiency and low cost,it is the most mature,practical and widely used in the engineering ceramics processing.Grinding essence can be regarded as a large discrete distribution on the surface of the grinding wheel grinding grain and processed materials interaction between the material removal process,and each abrasive are a lot of grinding,in a certain extent similar to cutting,namely each abrasive can be regarded as a combination of a number of tools.But grinding and turning complex many,because of participating in grinding grinding grain number more,grinding grain cutting edge shape,size and location of the random diverse and grinding process parameters,such as a variety of factors influence each other,makes the grinding material removal mechanism is extremely difficult.For the in-depth study of the grinding mechanism,from the single abrasive grit cutting processing research of,the single grinding grain machining results in grinding area are effectively integrated,and then explain the various physical phenomena in the grinding process,so a single grinding research on the mechanism of the grain cutting become aware of the complex grinding mechanism is a kind of important means.The silicon nitride ceramic precision grinding as the research object,in morphology and particle silicon nitride workpiece surface and sub surface structure on the surface of the grinding wheel in grinding were detected on the basis,the establishment of single grinding particle model and workpiece model,and on this basis were single grit cutting simulation,the single grinding grain cutting experiment is verified and the experimental results are discussed.Specific research work includes:1)Using a combination of random point in spherical coordinate space plane segmentation entity and truncated polyhedra method established truncated polyhedra virtual grinding grain(section with three to hexagonal)and contains(open type)of type I and type II(slide)typical crack damage of workpiece model simulation,and then in the NC plane grinder of single grit cutting experiment,the simulation results are verified.2)Through there may exist cutting scallop height tests and verifies a single abrasive grain cutting machining of silicon nitride orthogonal experiment in the superdepth of field three-dimensional shape measuring instrument,and the residual height formation process was observed and analyzed.3)Combined with the relationship between the machining parameters and cutting force,the establishment of various processing parameters and the force between the fitting function of,and in accordance with the fitting function of slope size are derived in this paper set processing range,impact of feed rate on cutting force,speed of the workpiece on cutting force influence minimum.4)Based on the virtual abrasive particles,the optimized grinding wheel model is established,and the simulation of the subsurface damage depth is carried out according to the first strength theory.Established by regression analysis of silicon nitride ceramic spherical grinding subsurface damage depth prediction model,by angle polishing method detection of subsurface damage components and depth,this paper puts forward a method for the optimum light damage measurement method of new strength to measure the depth of damage,and analyzes the influence of wheel speed,grinding depth,feed speed the subsurface damage depth,the regression analysis model of unknown quantities and verify the accuracy of the predictive model.