| Titanium alloy material has high strength,light weight and high temperature resistance,corrosion resistance and other excellent characteristics are widely used.However,the intrinsic properties of titanium alloys such as large chemical activity,low thermal conductivity,small elastic modulus and large surface friction coefficient lead to large cutting forces during the cutting process,hard cutting heat dissipation,severe tool wear,and low surface quality and belong to typical hard-to-machine materials.Therefore,traditional cutting methods have proved to be uneconomical.In order to solve this problem,this paper proposes a novel titanium alloy turning technology based on the coupling of electro-plastic and ultrasonic-vibrations on the basis of traditional turning,combined with ultrasonic technology and electro-plastic processing technology.In order to carry out the experimental research of turning smoothly,the special electro-plastic auxiliary tooling was designed and manufactured to meet the need of introducing the pulse current in the turning process.At the same time,in order to facilitate the clamping of the ultrasonic vibration turning element,the corresponding tooling tooling was designed.In this paper,the single factor experiment and Taguchi experimental method are combined.Through comparative experiments,the surface roughness and cutting force of TC4 titanium alloy are selected as the research object,and the superiority of titanium alloy turning based on electro-plastic ultrasonic-vibration coupling is verified.The influence of electric plastic parameters and ultrasonic vibration parameters on the surface roughness and cutting force of the workpiece is analyzed.The main conclusions are as follows:1)Compared with common turning(CT),ultrasonic vibration assisted turning(UAT),Electro-plasticity ultrasonic-vibration coupling assisted turning(EUAT)can significantly reduce the cutting force and improve the surface quality.Compared with UAT,the cutting force of EUAT reduced in the same direction and decreased with the increase of the amount of back-eating knife.This shows that the greater the back of the knife to eat more can reflect the superiority of EUAT.2)During the EUAT process,with the discharge voltage increases,the three-direction cutting force decreases,but the decrease is smaller;surface roughness Ra value decreases,and the reduction rate is larger.As the discharge frequencyincreases,the three-direction cutting force decreases and the reduction rate is larger.The Ra value of the surface roughness decreases,but the reduction amplitude is smaller.As the ultrasonic power supply voltage increases,the cutting force is greatly reduced and the uniformity of the workpiece surface is getting better and better.During the EUAT process in order to reduce the cutting force to obtain better surface quality should be higher discharge voltage and higher discharge but the interaction between the ultrasonic vibration parameters and the pulse current parameters is not significant.The discharge frequency and the percentage of the output voltage of the ultrasonic power supply have a great effect on the triaxial cutting force.Discharge frequency and power supply voltage output percentage increases,three-direction cutting force is significantly reduced and the effect of discharge frequency is more significant.4)The range-to-noise method was used to analyze the signal to noise ratio of ultrasonic vibration parameters and pulse current parameters in Taguchi experiment.The order and rule of the primary and secondary processes on the response surface roughness(Ra): Discharge voltage has the greatest influence,followed by Percentage of supply voltage and Discharge frequency.As the discharge voltage increases,the surface roughness Ra decreases rapidly.With the increase of the output voltage,the surface roughness Ra increases slightly.5)According to the analysis of the signal-to-noise ratio under this experiment are discharge voltage 100 V,discharge frequency 200 Hz,and power supply voltage output percentage 30%. |
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