Experimental Study On Ultrasonic Vibration Assisted Milling Of Titanium Alloy

With the rapid development of the aerospace industry and the increasing demand for titanium alloy materials,high-quality processing of titanium alloy has been difficult to achieve by the traditional cutting technology.Ultrasonic vibration assisted machining is the combination of ultrasonic vibration and traditional machining,which translate electrical signal into mechanical vibration to realize intermittent machining.During the processing of ceramics and other materials,ultrasonic vibration aided processing has shown unique advantage,which can decrease the cutting force and temperature and improve processing efficiency and quality.To evaluate the influence of ultrasonic vibration and milling parameters on tool wear,milling force and surface integrity,study on ultrasonic vibration assisted milling(UVAM)of TC4 titanium alloy was conducted.Firstly,considering tool wear on UVAM of TC4 titanium alloy,experiments were conducted to analyze the mechanism.With the comparison of traditional milling and UVAM,obtaining that ultrasonic vibration can decrease tool wear and prolong tool life.Besides,the chip morphology of titanium alloy was found to be finely and evenly curved under ultrasonic vibration assisted milling.Secondly,the experimental research on the milling force in UVAM of titanium alloy was carried out.Then,the effects of milling parameters and ultrasonic vibration parameters on the milling force were analyzed.And the advantages of UVAM were analyzed by comparison with conventional milling.The experimental results showed that UVAM could effectively reduce the maximum milling force and average milling force during machining processing.And in a certain range,cutting force descend as ultrasonic current and spindle speed increase.It increased with the rise of feed rate and cutting depth,but the increase of milling force was relatively slow due to ultrasonic vibration.This paper also presented a index prediction model for milling force in UVAM of titanium alloy based on the experimental research,and the milling parameters of titanium alloy were optimized.The results showed that the predictive accuracy and stability of the model were relatively high.The optimized milling force was obviously reduced and the optimization effect was significant.Finally,the three-dimensional(3D)surface roughness of titanium alloy was measured by non-contact 3D topography instrument.Comparative analysis method was applied to evaluating 3D surface roughness,obtaining that ordered and uniform surface structure was achieved by the effect of high frequency vibrating.And,the increase of spindle speed was helpful to decrease the surface roughness,and the cutting depth has little effect on the surface roughness.Meanwhile,the edge quality of the two processing methods at different cutting depths was observed by stereomicroscope,showing that the edge quality of UVAM was obviously improved.And the edge burr increased in two machining modes with the cutting depth increase.In addition,the residual stress data was acquired by X-ray diffract meter.The measurement indicated that residual compressive stress was formed on the surface under UVAM,and high frequency vibration shock was helpful to enhance the residual compressive stress,and presented an increasing trend with the ultrasonic current increase.