Research On Ultrasonic Vibration Aided Milling Machining System Of Aramid Honeycomb Material

With the rapid development of economy,most parts begin to develop in the direction of lightweight,high hardness,high strength,wear resistance,heat resistance and corrosion resistance.Honeycomb core composites are widely used in all walks of life because of their excellent structural and mechanical properties.Because the aramid honeycomb material has a regular hexagonal structure and poor transverse cutting performance,the traditional processing method can not meet the current production and processing needs of high quality and high quantity.It is found that the longitudinal torsional ultrasonic vibration assisted milling can significantly reduce the milling force,improve the machining efficiency,improve the surface quality of the workpiece and reduce the tool wear,which can make up for the shortcomings of the traditional processing.Therefore,based on the methods of theoretical design,simulation analysis and experimental verification,this paper designs a longitudinal torsional ultrasonic vibration assisted milling device for aramid honeycomb materials,which has stable performance,can output large amplitude and reduce milling force.Based on the design frequency of 25 k Hz,the ultrasonic generator which can automatically track and follow the frequency is selected,the wireless power supply device is designed,and the disc knife is selected.The type of transducer,the shape of composite horn,the materials and connection mode of each component,as well as the quantity and arrangement mode of piezoelectric ceramics are determined.The transducer and ultrasonic horn are designed according to the analytical theory,and the frequency equations on both sides of the nodal plane are deduced,The theoretical design values of the transducer and the horn are obtained.The implementation mode and conversion mechanism of setting a chute structure in the exponential transition section of the horn to convert the single excitation longitudinal vibration into longitudinal torsional composite vibration are analyzed.The components are modeled and assembled.The modal analysis and harmonic response analysis of longitudinal vibration and longitudinal torsional composite vibration device are carried out through ANSYS finite element software,and the natural frequencies,vibration modes and longitudinal torsional amplitudes of the two structures are obtained.Orthogonal tests are carried out for the effects of different chute parameters on the natural frequencies,longitudinal amplitudes and torsional amplitudes of the system,and the optimal parameters of the chute structure are obtained.The performance,output amplitude,milling force and milling time of the longitudinal torsional ultrasonic composite vibration system were tested by using impedance analyzer,laser displacement sensor and Kister three component force sensor respectively.The comparative experiments of ultrasonic vibration assisted machining of aramid honeycomb and ordinary milling were designed.In the actual aramid processing experiment,the impedance test of the system shows that the system has stable performance and reasonable design and assembly;Through the amplitude test of the system,the longitudinal amplitude of the end face output of the disc cutter is 14.6 ? M and torsional amplitude of 6 ? m.The amplitude is large,which can meet the existing production and processing needs;Through the comparative experiment of ultrasonic vibration assisted machining and ordinary milling,it is concluded that the designed longitudinal torsional ultrasonic composite vibration system can effectively reduce the milling force,increase the effective machining time by about 25%,reduce the tool wear,and meet the design requirements.