Mechanism Research On In-process Dressing Of Grinding Wheel In Ultrasound-aided ELID Gringing

It is important for aerospace,national defense,precision instrument,microelectronics,optoelectronics and other advanced technology to develop the branch of ultra-precision machining,namely high efficiency mirror grinding with hard and brittle materials.Our workgroup proposes that the ultrasonic vibration and ELID grinding should be composited in order to create a new method of high efficiency mirror grinding with multiple-compound process,namely ultrasound-aided ELID grinding,by the virtue of ELID grinding and ultrasonic vibration grinding.This thesis analyzed ultrasonic parameters characterized in precision high-efficiency and electric parameter of ELID characterized in ultra-precision mirror,and the two sides influence on in-process dressing for fine diamond grinding wheel under ultrasound-aided ELID grinding,based on the study of nanocomposite ceramics,through which we can acquire the criterion of high efficiency,high quality in-process dressing for grinding wheel.First of all,combining with the current conditions of laboratory,the experimental platform of ultrasound-aided ELID inner grinding along with ultrasonic vibration tool has been completed on the basis of VMC850 E vertical CNC machining center,designing the vibration device and cathode device of ELID by analyzing the impedance of ultrasound-aided ELID acoustic system.Next,aiming at the in-process dressing problem for the fine diamond grinding wheel,the influence of electric parameters and ultrasonic parameters,especially ultrasonic cavitation and oxide film,on in-process dressing for grinding wheel were analyzed in ultrasound-aided ELID grinding.Then,we gained a good stability in-process truing effect for grinding wheel in the ultrasound-aided ELID grinding,by the contrast experiments with characteristic parameters and their evaluation methods on the truing effect such as the ground grain number per unit area,grain protrusion height,grits spacing,space,and 3D surface topography.Finally,according to the grindability of grinding wheel,the critical grinding depth was approximately 3.73 microns for nanocomposite ceramics in the ultrasound-aided ELID grinding,which was more than that in the ordinary grinding and ordinary ELID grinding on the same condition.The quality prediction model of ultrasound-aided ELID grinding was established on the ground of studying the processing quality of grinding wheel.In addition,we drew a conclusion that grinding wheel possesses high grinding capability and grinding efficiency based on the material removal rate and grinding ratio,and then established the machining efficiency prediction model of ultrasound-aided ELID grinding.Not only does the grinding wheel achieve better in-process dressing,but also has advantages of high grinding ability and efficiency in the ultrasound-aided ELID grinding,expands the scope of the ductility of the grinding wheel processing,and was susceptible to ultra-precision mirror processing nanocomposite ceramics.What has been discussed above further reveals the ultra-precision mirror processing mechanism for nanocomposite ceramics in the ultrasound-aided ELID grinding,makes great sense of enhancing the theory on high efficiency mirror processing for hard brittle material,and provides the guarantee for high efficiency super-smooth surface processing in advanced technology such as aerospace,national defense,etc.