Research On Ultrasonic Vibration Milling Force And Surface Topography For Titanium Alloy Materials

Titanium alloys are widely used in aerospace,nuclear energy,biomedicine,optics and other fields due to their excellent material properties(high strength-to-weight ratio,good corrosion resistance,and good biocompatibility).However,as a typical difficult-to-process material,due to the inherent characteristics of the material,such as low thermal conductivity,high chemical reactivity,and low modulus of elasticity,which has severely affected its processing performance and production efficiency and the improvement of surface quality.How to improve the processing quality of titanium alloys has always been a hot issue studied by scholars at home and abroad.As an emerging special processing method,ultrasonic vibration-assisted milling technology combines traditional milling processing with high-frequency ultrasonic vibration,and has been widely used in the processing of difficult-to-machine materials.Aiming at the difficult-to-machine material titanium alloy as the research object The method of ultrasonic vibration-assisted milling were used in this articles to improve the processing performance of titanium alloy.The key core issues such as the material removal mechanism,kinematics characteristics,cutting force of ultrasonic vibration milling,milling tool wear and ultrasonic vibration milling surface morphology have been analyzed in detail theoretically and experimentally,which provides certain theoretical guidance for ultrasonic vibration milling in the processing of difficult-to-machine materials.The specific research content of this topic is as follows:(1)A kinematic model of the feed direction and two-dimensional elliptical ultrasonic vibration is established.The separation characteristics of ultrasonic vibration-assisted milling are studied through the analysis of the ultrasonic vibration milling processing trajectory,speed and acceleration.The contact rate model of two-dimensional elliptical ultrasonic vibration has studied the influence of machining parameters and ultrasonic vibration parameters on the contact rate;In the separation condition of type II,the parameter matching problem of the interrupted cutting of ultrasonic machining in the feed direction is studied,and the corresponding The conditions of intersection,tangency,and separation of the tool tip trajectories of two adj acent teeth.(2)Firstly,a cutting force model for ordinary milling was established,including flat-end milling cutters and more complex ball-end milling cutters.In view of the continuous changes in the cutting thickness of the ball-end milling cutter multi-axis machining and the length and position of the cutting edge involved in the cutting,a simplified cutting thickness model and a tool-workpiece contact area model were established.The simulation shows that the model has greater computational efficiency.For the modeling of the cutting force of two-dimensional elliptical ultrasonic vibration milling,this article mainly considers the dynamic cutting thickness and the interrupted cutting mechanism,and establishes the cutting force model of the two-dimensional elliptical ultrasonic vibration.Finally,an ultrasonic vibration machining experiment was carried out and the influence of machining parameters and vibration parameters on the cutting force of ultrasonic vibration milling was analyzed.(3)The tool wear of ordinary milling and two-dimensional elliptical ultrasonic vibrationassisted milling was studied experimentally.Through the analysis of the dynamic wear process of ordinary milling and two-dimensional elliptical ultrasonic vibration milling tools,the typical wear patterns of ordinary milling and two-dimensional elliptical ultrasonic vibration milling tools are obtained.(4)The theoretical models of surface topography of one-dimensional and two-dimensional ultrasonic vibrations were established,and the influence of processing parameters and vibration parameters on the surface topography of ultrasonic machining was studied.Then an experiment was carried out to verify the correctness of the theoretical model.Finally,using ultrasonic amplitude,spindle speed,feed per tooth,and cutting depth as input variables,and surface roughness as output variables,a prediction model of ultrasonic vibration surface topography based on response surface method was established,and certain parameters were obtained.Obtain the best surface roughness processing parameters within the range.