Research On Cutting Force Characteristics In Ultrasonic Vibration Milling Of Titanium Alloy Curved Thin-walled Parts

Titanium alloy curved thin-walled parts are widely used in modern aerospace,energy and other fields for their many advantages,and need to meet complex working conditions and high performance.Due to the small wall thickness,poor rigidity and difficult machining of titanium alloy parts,they have difficulties in processed and manufactured.Meanwhile the processing quality and processing efficiency are difficult to be guaranteed,which limits their application in related fields.Therefore the study of milling of titanium alloy curved thin-walled workpieces is a crucial challenge.It has great significance for titanium alloy workpieces by optimizing the cutting process,reducing cutting force and chatter and cutter relieving during the milling process for the economical and practicality of the overall processing and manufacturing were improved.In this article,the milling force characteristics of ultrasonic vibration milling titanium alloy thin-walled surface are studied through theory,simulation and experimental combined.By studying the kinematics of two-dimensional elliptical vibration milling,the theoretical for the reduction of cutting force during the ultrasonic cutting of the milling cutter is analyzed.A longitudinal torsional composite ultrasonic vibration assisted milling tool tip motion trajectory model is established to solve the characteristic points,the duty cycle and the spindle speed that affects the cutting state of the tool during the machining process.Finally,the conceptual parameters of reducing the average milling force in the ultrasonic vibration milling force model are proposed,and the change trend with the change of cutting amount is further studied in the subsequent research.A two-dimensional elliptical vibration cutting titanium alloy simulation model and a three-dimensional longitudinal torsion composite ultrasonic vibration milling titanium alloy thin-walled part cutting simulation model were established by using finite element cutting simulation technology.In the simulation,the theory of reducing the cutting force during ultrasonic vibration cutting of titanium alloy was verified and a phenomenon which high frequency vibration cutting between workpiece and tool was demonstrated.Furthermore,the coupling effects from ultrasonic parameters and cutting parameters for cutting force in ultrasonic vibration processing and the reduction ratio are analyzed.An ultrasonic vibration milling experimental platform was established,and the relevant experiments of ultrasonic vibration milling titanium alloy curved thin-walled parts were researched and analyzed.The results of orthogonal experiment and single factor experiment in semi-finishing show that compared with ordinary milling,with the radial depth of cut increased,the reduction ratio of average milling force caused by ultrasonic vibration milling decreased;the improvement of the average milling force reduction ratio will be highest at high speeds within the limit speed of the rotary cutting.The relevant conclusions from theoretical analysis and finite element cutting simulation are also verified.The analysis results of the semi-finishing experiment are used to guide the finishing.Finally,the machined workpieces were tested and analyzed.The results show that the milling force variation characteristics are consistent with the machining results.What's more,the accuracy of the milling force characteristics in ultrasonic vibration milling was verified.