Study On Surface Generation Mechanism Of Tangential Ultrasonic Vibration Grinding

Hard and brittle materials are widely used in aerospace,nuclear power,ship,electronics,automobile,medical and other fields.The processing of materials is a major problem.Ultrasound vibration assisted machining(UVAM)is a kind of composite processing technology,which can be used to process ceramics,metals,alloys and other materials.More and more researchers have studied on it.At present,the commonly used methods of ultrasonic vibration assisted machining include ultrasonic vibration assisted turning,grinding,milling,drilling and so on.Ultrasonic assisted vibration machining has changed the traditional material removal method and processing mechanism and has a very broad application prospect.This paper mainly studies tangential ultrasonic vibration assisted grinding.This method applies ultrasonic vibration to the workpiece and combines with common grinding to make the workpiece do tangential motion relative to the tool.The kinematics of a single abrasive grain is analyzed,and the surface generation model of tangential ultrasonic vibration assisted grinding is established.The research content mainly includes the following aspects:(1)Research on the ultrasonic vibration worktable,mainly for the theoretical design of the vibration worktable,using the ANSYS Workbench software for modal analysis,and structural optimization to make the worktable have good working performance.(2)The kinematics analysis of tangential ultrasonic vibration assisted grinding was conducted,and the kinematics model,material removal rate model and grinding force model of single abrasive grain were established.Through analyzing the theoretical model,found that ultrasonic vibration assisted grinding single diamond grain tangential motion path length is greater than the common grinding,and the ultrasonic vibration assisted grinding material removal volume changes with the ultrasonic vibration frequency and amplitude.The magnitude of the grinding force decreases as the ultrasonic frequency and amplitude increase.The crack length and depth of the brittle material decreased,and the surface quality increased.(3)Research on the mechanism of the surface generation of the brittle material surface by tangential ultrasonic vibration assisted grinding.The introduction of ultrasonic vibration changes the motion state of a single abrasive grain,which changes from the original linear motion process to the reciprocating motion process.Therefore,the critical condition of the single abrasive particle motion trajectory is modeled to determine the critical frequency.When the ultrasonic vibration frequency is less than the critical frequency,there is no superposition of the trajectory of a single abrasive particle,and the machining process is similar to common grinding.When the ultrasonic vibration frequency is higher than the critical frequency,the motion trajectory of a single abrasive grain is superimposed,the workpiece surface is ironed repeatedly,and the workpiece surface quality is improved.(4)The quality of material surface machining is measured and evaluated.By measuring and analyzing the surface topography of grinding and comparing with the results of theoretical calculation,it is found that the quality of machining surface obtained by tangential ultrasonic vibration assisted grinding is better than that of common grinding.