Experiment Study Of Titanium Alloy In Electroplastic Turning

Since the 1950 s, the titanium alloy is widely used in the fields of the national defense industry, aerospace and biomedical, etc as an important strategic metal. Owing to its large number of advantages, especially high thermal strength, high specific strength, better resistance to corrosion and high reactivity, it established its superior position in many areas. However, due to highness and instability of the titanium alloy surface friction coefficient, the service performance and life of titanium alloy parts are seriously affected with poor wear resistance. These properties could give rise to the high cutting temperature, the severe rebound phenomenon, the large units cutting power during the processing, so that the high quality of the machined surface of workpiece is hard to achieve. The machining process of Titanium alloy shows great difficulties due to its low friction coefficient, high cutting temperature, large cutting force per unit area, serious cold hardening and tool wear, etc. These properties could give rise to the high cutting temperature, the severe rebound phenomenon, the large units cutting power during the processing, so that the high quality of the machined surface of workpiece is hard to achieve. In order to mitigate these limitations, especially to improve the surface roughness of titanium alloy, a new cutting method based on electroplastic effect is proposed- a pulse current assisted turning processing.Due to the process of electroplstic turning is done in the case of the workpiece is electrified, the corresponding electrode tooling fixture needs to be made. In this paper, based on the diameter, length and working environment of workpiece, three kind of fixture design plan were made.In this paper, we verify the advantages of this new cutting method by adopting the single-factor tests method and taguchi method where we compare the conventional turning(CT) with the electroplastic effect assisted turning(EET),and further prove the law of influence of the electroplastic parameters on TC4 Titanium alloy surface roughness、cutting forces and surface texture.1) The results show that, with the same cutting parameters, the electroplastic effect assisted turning outperforms the conventional turning in terms of the surface roughness,surface texture and the cutting forces. Moreover, the surface roughness is positively correlated with the charging voltage and independent of pulse current frequency. It turns out that the cutting force with the same charging voltage is proportional to the pulse current frequency.2) Through the Partial factorial method, the factors that have a significant effect on the surface roughness were acquired-the feed rate and the charging voltage.However the interaction between different cutting parameters and pulse current parameters have no effect on the surface roughness.The cutting forces were reduced significantly in the process of electroplstic turning. But with pulse current parameters changed, the cutting forces have no obvious variety.3) By range method, the law of influence of Signal-to-Noise Ratio of each factor in electroplastic turning effect was analyzed and the order of each process parameters which have a significant effect on the surface roughness was obtained:feed rate> charging voltage>machine speed>cutting depth>pulse frequency.4) In this paper, based on the trend of Signal-to-Noise Ratio of each process parameters, the optimal parameter combination of the surface roughness of TC4 Titanium alloy on electroplastic turning is obtained: the machine speed is 350 r·, the feed rate is 0.08 mm·, the cutting depth is 0.15 mm, the charging voltage is 70 V and athe pulse frequency is 200 Hz.