Design And Process Research Of Ultrasonic Elliptical Vibration Turning System

With the increasing application of difficult-to-machine materials in aerospace,aviation,military and civil fields and the requirements for processing accuracy,surface quality and service life are getting higher and higher,traditional machining methods have become more and more difficult.Ultrasonic elliptical vibration cutting processing Due to the elliptical movement of the tool tip can make the tool workpiece periodically separated,this periodic separation characteristics can effectively reduce the cutting force,reduce the cutting heat,improve the surface quality of the workpiece,and has become an effective method for precision machining of difficult materials.This study designed a symmetrical ultrasonic elliptical vibration cutting device,which has a simple structure,compactness and convenient tool change.The main research contents are as follows:(1)Based on the principle of ultrasonic elliptical vibration turning,a set of ultrasonic elliptical vibration turning device with a frequency of 60 k Hz is designed.The specific resonance length and node position of the luffing rod are calculated by using the frequency equation of the conical luffing rod.According to the design requirements of the bending vibration luffing rod,the size of the symmetrical tool shaft is determined,and the modal simulation is carried out using COMSOL software,and the tool holder size is optimized in combination with the quadrature analysis table.(2)Use COMSOL software to conduct modal simulation of the entire set of ultrasonic elliptical vibration system,optimize the position of the flange,and simulate the vibration pattern of the ultrasonic elliptical oscillator under powered conditions through harmonic response analysis to find the optimal frequency mode.The displacement curve of the tool tip point with time is extracted by transient simulation analysis,and the motion trajectory of the synthetic tool tip point is elliptical motion to meet the design requirements.(3)The impedance analyzer is used to test the impedance parameters of the ultrasonic elliptical vibration system,explore the influence of the bolt preload torque on the ultrasonic oscillator resonance frequency and dynamic resistance at the connection between the tool holder and the luffing rod,and find that the bolt preload torque has a greater impact on the dynamic resistance of the oscillator,the impact on the resonance frequency is small,and the bolt preload torque is 10N·m The oscillator dynamic resistance is the smallest and the electromechanical conversion efficiency is the highest.The frontal and lateral displacement of the elliptical vibration is measured by the laser displacement sensor,and the positive displacement of the oscillator tip point is 4?m and the lateral displacement is 1.5?m.And by applying a long-term load to the tip point,the stability of the oscillator is judged,which provides a guarantee for subsequent process tests.(4)Through four sets of one-factor tests,the influence of different cutting speeds,cutting depths,feeds and ultrasonic voltages on the surface morphology and surface roughness of 304 stainless steel materials was explored.Comparing the results of ordinary turning with ultrasonic elliptical vibration turning test results,it is found that the elliptical vibration cutting effect is significantly better than that of ordinary turning,and under low cutting speed,small cutting depth and small feed,the elliptical vibration cutting effect is better,indicating that elliptical vibration turning is more suitable for finishing.When elliptical vibration turning,the surface roughness is minimal under the action of 70 V ultrasonic voltage.