TC4钛合金电火花高效铣削加工效率研究

钛合金材料以其优异的机械性能在航空航天工业中得到了广泛的应用，目前钛合金切削性能差的问题一直没有得到妥善解决，制约了钛合金工业应用范围的推广。以TC4钛合金加工效率为研究对象，通过使用长脉宽大电流脉冲电源，采用电火花铣削加工的方法实现了钛合金的高效加工。利用设计的正交实验对电火花铣削加工钛合金过程中主要加工参数，分别为脉宽、脉间、峰值电流、电极转速、冲液压力和切削深度等对加工效果的影响进行了实验研究。通过加工参数优选、极差分析及显著性分析等方法对加工参数对加工效率的影响进行了分析，使用加工效率预测公式对加工所能达到的最大加工效率进行了预测。最终在正交实验分析的基础上，通过进一步进行实验，采用脉宽为2 000 μs、脉间为100 μs、峰值电流为635 A、电极转速为800 r/min、冲液压力为1.5 MPa和切削深度为3 mm时，使得电火花铣削加工钛合金的加工效率最高可以达到9 000 mm³/min， 并使用电子扫描电镜对钛合金被加工表面的受热影响层进行了检测分析，验证了使用电火花铣削对钛合金进行高效加工的可行性。与传统切削方法相比，电火花铣削加工的加工精度有限，表面质量较差，但是由于采用石墨材料作为电极，相同体积钛合金的去除其电极损耗的成本只有刀具加工的10%左右，因此非常适合应用于航天航空工业制造中大量存在的需要大体积材料去除的钛合金等难加工材料的粗加工。

Research on Efficient Electrical Discharge Milling of TC4 Titanium Alloy

Titanium alloy has been widely used in the aerospace manufacturing industry due to its excellent mechanical properties. The application promotion of titanium alloy is limited because its poor cutting properties have not been solved. The efficient processing of titanium alloy was realized by using the electrical discharge milling. The influences of processing parameters, such as pulse-on time, pulse-off time, peak current, electrode rotating speed, flush pressure and depth of cut, on the processing efficiency of titanium alloy are studied through orthogonal experiment in which a power supply with long pulse-on time and high current is used. The processing parameter optimization, range analysis and significance analysis methods are used in this study. The maximum processing efficiency of electrical discharge milling is predicted using processing efficiency prediction formula. The processing efficient of titanium alloy reaches to 9 000 mm³/min with pulse duration of 2 000 μs, pulse interval of 100 μs, peak current of 635 A, electrode rotary speed of 800 rpm, flushing pressure of 1.5 MPa, and cutting depth of 3 mm based on the orthogonal experimental analysis. The heat-affected layer of titanium alloy processed surface was tested using SEM, and the feasibility of titanium alloy high efficiency machining using electrical discharge milling is verified. Although ED-milling of TC4 titanium alloy has a low machining precision and poor surface quality, it can reduce the cost of machining by 90% compared to traditional cutting method.