| As a kind of high quality metal structure material,titanium alloy has many excellent characteristics such as high strength,low density and corrosion resistance,etc.It is widely used in aerospace,chemical industry,medical treatment,automobile energy and other fields,but it is also a typical refractory material.This paper will be introduced to the axial ultrasonic vibration milling TC4 titanium alloy,through the combination of theory,simulation and experiment,the method of comparison analysis of ultrasonic vibration milling and ordinary milling processing in TC4 titanium alloy,the difference between the characteristics of ultrasonic vibration milling cutting parameters on the milling force,the influence law of chip morphology,surface roughness,the concrete research content is as follows:Firstly,the cutting principle of ultrasonic vibration milling is analyzed,and the difference between axial ultrasonic milling and ordinary milling tool tip motion trajectory is compared.It is concluded that the instantaneous cutting thickness of axial ultrasonic milling and ordinary milling is the same,but the cutting depth is different.The cutting force source of titanium alloy was analyzed,and the mathematical model of milling force was established by semi-analytical method,which can provide reference for the research of cutting force.Then,the axial ultrasonic vibration milling titanium alloy was built based on ABAQUS,a simulation model of three dimensional finite element through post-processing analysis of the characteristics,the size of the cutting force and chip results show that applying ultrasonic vibration can effectively reduce the direction of the cutting force size,and the chip is more short,lower crimpness,not easily around cutter groove;By analyzing the characteristics of the cutting force curve in the two machining modes,it is found that the application of ultrasonic vibration will make the cutting force curve more volatile.With the increase of the ultrasonic amplitude,the cutting force becomes lower and lower,but at the same time,it will lead to the greater fluctuation of the cutting force,which has an adverse effect on the cutter.The paper analyzes the cloud diagram of tool temperature distribution and the curve of tool tip temperature change under two kinds of machining methods,and finds that the tool temperature distribution gradually shifts from the tip to the middle of the cutting edge as the cutter cuts into and out,and the ultrasonic vibration assisted milling is beneficial to reduce the tip temperature,the larger the amplitude,the higher the degree of reduction.Then through the orthogonal experiment compared the cutting force value and cutting force curve characteristics under the two machining methods,the variance analysis of the orthogonal experiment results,it is concluded that each tooth feed and radial cutting depth are the main factors affecting the milling force,the effect of spindle speed is the second.In addition,the influence law of cutting parameters on milling force is studied,and it is concluded that the cutting force decreases first and then increases with the increase of spindle speed,increases with the increase of feed per tooth and radial cutting depth,and slows down when the feed is greater than 0.06 mm.Finally,the surface roughness and 3d morphology under different cutting parameters of the two machining modes were measured by VK-X100 laser microscope.The results showed that axial ultrasonic vibration could effectively reduce the side surface roughness,and the surface of ultrasonic milling showed a regular "fish scale" texture by observing the 3D morphology.The prediction model of surface roughness is established based on experiments,and its significance is tested.Finally,the surface roughness and cutting efficiency were optimized based on the genetic algorithm,and the optimal process parameters were obtained as follows: spindle speed 1200r/min,feed rate 0.089 mm per tooth,and radial cutting depth0.17 mm. |
PDF Full Text Request