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.