Experimental Study On Ultrasonic Vibration Dressing CBN Grinding Wheel With Diamond Roller

With the extension of modern science and technology,grinding is widely used in various high-efficiency and precision machining of difficult to machine materials because of its excellent characteristics of high machining efficiency and high precision.At the same time,CBN grinding wheel plays an important role in the tool family of grinding because of its excellent properties of high hardness,high temperature resistance and no reaction with iron group elements.However,CBN grinding wheel is prone to wear or blockage when grinding difficult materials,resulting in the rise of grinding force and grinding temperature,chatter and thermal damage,which will eventually affect the surface integrity of the workpiece and even cause the fatigue failure of key structural parts.Therefore,the topography of grinding wheel is very important in the grinding process.Regular dressing is a common measure to solve the blockage of grinding wheel and the protrusion of abrasive particles.How to repair CBN grinding wheel with high efficiency and quality while ensuring the self sharpening of grinding particles is an important goal to improve the grinding process and realize high-performance manufacturing at this stage.Based on the excellent performance of ultrasonic vibration,this paper puts forward the ultrasonic vibration dressing technology of diamond roller.Combined with the advantages of efficient dressing of diamond roller and the characteristics of ultrasonic vibration,the dressing process is efficient and stable.Finally,the grinding wheel surface with ideal morphology is obtained and the grinding ability of CBN grinding wheel is improved.The specific research contents are as follows:(1)Based on the dressing mechanism of ultrasonic vibration of grinding wheel,the kinematics of a single abrasive particle in different dressing methods is analyzed,and the motion trajectories of multiple abrasive particles are simulated and analyzed by MATLAB.At the same time,it is found that the dressing method with additional ultrasonic vibration can obtain higher dressing efficiency compared with the ordinary grinding dressing method.At the same time,the characteristics of abrasive particle breaking and bond removal in the process of grinding wheel dressing are studied,and the geometric relationship model between abrasive particle cutting height and abrasive particle cutting area on the surface of grinding wheel after ultrasonic vibration dressing is established.(2)The experimental system of ultrasonic vibration diamond roller dressing CBN grinding wheel is designed and built.Firstly,the size of horn and roller is determined based on elastic theory and thin plate vibration theory.Secondly,the vibration of horn and roller is simulated and analyzed,and then the ultrasonic trimming acoustic system is built,and its impedance and vibration characteristics are tested and analyzed.The results show that the ultrasonic vibration system can meet the needs of ultrasonic vibration dressing test.Finally,the components of the designed ultrasonic trimming system are installed in the five axis machining center to complete the ultrasonic vibration trimming system.(3)In order to carry out real-time monitoring and feedback of dressing force in the grinding wheel dressing process,an acoustic emission system is built to complete the monitoring of grinding wheel dressing process.The transmitted signals in the dressing process are analyzed in frequency spectrum and time domain.A single factor test is designed to obtain the influence laws of grinding wheel particle size,dressing speed ratio,cutting depth and ultrasonic amplitude on acoustic emission voltage value.At the same time,the influence trend of dressing force in grinding wheel dressing is judged according to the change of acoustic emission signal.Further analysis shows that the dressing force increases with the increase of cutting depth.The dressing force decreases gradually with the increase of dressing speed ratio,and decreases first and then increases with the increase of ultrasonic vibration amplitude.(4)Through the vibration dressing of resin bonded CBN grinding wheel,the surface topography of CBN grinding wheel is observed by field emission scanning electron microscope,super depth of field microscope and confocal.The test results show that compared with ordinary dressing methods,ultrasonic vibration dressing method has the advantages of small dressing force,increased number of effective abrasive part.