Research On The Prediction Model Of Surface Roughness Of ZTA Ceramics By Ultrasonic Vibration Assisted ELID Grindin

ZTA ceramics are materials with high hardness,heat and corrosion resistance,which are widely used in microelectronics,biomedicine and high-end machinery.In order to improve the grinding efficiency and surface quality of ZTA ceramics,ultrasonic vibration assisted on-line electrolytic wheel grinding technology has been applied to the grinding of ZTA ceramics in recent years.In order to understand the evolution law of grinding surface roughness and realize the adaptation of process parameters,the prediction model of ZTA ceramics surface roughness was studied in this study.UVAEG is a grinding technology composed of ultrasonic vibration grinding and on-line electrolytic grinding,which is expected to improve the machining efficiency and surface quality of ZTA ceramics.In this paper,the prediction model of ZTA ceramic surface roughness in UVAEG grinding is deduced theoretically and compared with the experimental results.Specific research contents are as follows:(1)A prediction model of surface roughness of ZTA ceramics grinding ELID was established.Firstly,by analyzing the formation principle of ELID grinding oxide film,the prediction model of oxide film thickness was established based on the literature.MATLAB software was used to analyze the variation rule of oxide film with time under different duty ratio and voltage.Secondly,the grain protrusion height under ELID oxide film was studied,and the effective grain protrusion height model of ELID grinding wheel surface was established.The simulation analysis was carried out using MATLAB.Under the condition that the average grain of grinding wheel was Gaussian distribution,the maximum number of effective grain was obtained when the grain protrusion height was 3-5μm and the thickness of oxide film was 4-6μm.Then,the ABAQUS simulation software was used to simulate the pressing of adjacent abrasive particles at different protrusion heights,and the regression model of synergistic effect between abrasive particles was established.Finally,a prediction model of ELID grinding surface roughness was established based on undeformed chip thickness parameters considering the synergistic effect between grains.(2)The surface roughness prediction model of UVAEG grinding ZTA ceramics was established,and the three-dimensional motion trajectory of grinding particles was simulated by ultrasonic vibration grinding.Firstly,the ultrasonic vibration grinding wheel topography detection map was fitted,the probability of the surface abrasive protrusion height was analyzed,and the simulation was carried out using MATLAB software.Secondly,the motion equation of UVG grinding particles was established,and the influence law of some motion equation parameters on the motion trajectory of grinding particles was analyzed,and the overlap effect principle of ultrasonic vibration interference was explained.Thirdly,UGNX software is used to simulate the three-dimensional motion trajectories of abrasive particles under different parameters.Finally,the prediction model of UVAEG grinding surface roughness considering the synergistic effect of grinding wheel grain protrusion height in the presence of electrolytic oxide film was established by introducing ultrasonic vibration interference effect and combining with ELID surface roughness prediction model.(3)ELID、UVG and UVAEG grinding experiments of ZTA ceramics were carried out,and the UVAEG prediction model and experimental results were compared.The comparative experiments of UVG,ELID and CG grinding under different grinding parameters were carried out.The results show that compared with CG grinding,the normal and tangential forces of ELID grinding decrease by 30-40 %,and the surface roughness decreases by 20-50 %,while the normal and tangential forces of UVG grinding decrease by about 20 %,and the surface roughness decreases by 20-50 %.The results of UVAEG grinding experiments at different grinding depths show that the grinding force and surface roughness of UVAEG are reduced by about 50 % compared with ELID and UVG grinding.The surface roughness of the UVAEG grinding experiment was compared with the results of the UVAEG surface roughness prediction model.The results of the UVAEG grinding prediction model were smaller than the experimental results.The reason may be that the idealized hypothesis in the model derivation and the error between the machine tool and the human operation in the experiment.The correction coefficient K is introduced to make the UVAEG grinding ZTA ceramic surface roughness prediction model better consistent with the experimental results.