Study On Micro Mechanism Of Ultrasonic Assisted Magnetic Abrasive Finishing Of Titanium Alloy

As a new type of combined processing technology,ultrasonic assisted magnetic abrasive finishing(UAMAF)can achieve high quality and high efficiency finishing of difficult to machine materials such as titanium alloy.The processing of UAMAF includes the elastic-plastic deformation process of work-piece and the complex micro-mechanical interaction between abrasive particles and work-piece.Therefore,in order to truly and effectively use the technology,it is urgent to conduct in-depth and systematic research on its processing mechanism and guide the actual production with more perfect theory.In this paper,the theoretical models of cutting force and micro material removal in UAMAF of titanium alloy are established,and the micro mechanism between abrasive particles and work-piece is studied.The main research work and conclusions are as follows:(1)According to the principle of UAMAF,the micro cutting process between single diamond abrasive and work-piece is analyzed.Considering the influence of elastic-plastic deformation of work-piece,edge radius of abrasive and ultrasonic vibration,the micro cutting mechanical model of single diamond abrasive is established;Combined with the distribution model of the bottom layer of magnetic abrasive brush and the geometric model and distribution model of diamond particles,the cutting force and torque model of UAMAF of titanium alloy are established.The force measurement experiment of UAMAF of titanium alloy is carried out,and the cutting force model is verified.The maximum error between the theoretical value and the experimental value is 6.69%.(2)Combined with the theoretical model of cutting force and torque of UAMAF of titanium alloy,the influence of important process parameters such as diamond edge radius on cutting force and torque is studied.The results show that the maximum normal cutting force is positively correlated with the edge radius,ultrasonic amplitude and ultrasonic vibration frequency,and negatively correlated with the machining clearance.The maximum torque of magnetic abrasive brush is positively correlated with ultrasonic amplitude and vibration frequency,and negatively correlated with machining clearance and abrasive edge radius.(3)Based on the J-C constitutive model and J-C shear failure model,the micro cutting process simulation model of UAMAF of titanium alloy is established considering the motion relationship between abrasive and work-piece.The distribution and variation of stress field,strain field and temperature field in the contact area of single diamond abrasive and work-piece in a single ultrasonic vibration period are analyzed,and chip formation and separation.The simulation model is verified by force test,and the maximum error between simulation value and test value is 9.98%.(4)Based on the elastic-plastic interaction and micro cutting process between the abrasive and the work-piece,a micro material removal model for UAMAF of titanium alloy is established.The model is verified by observing the micro morphology of the work-piece surface.The maximum error between the theoretical value and the experimental value is10.7%.The results show that the material removal rate of single abrasive is positively correlated with spindle speed,ultrasonic amplitude,ultrasonic vibration frequency and track radius,and negatively correlated with abrasive edge radius,machining clearance and abrasive pose angle.