Experimental Study On The EDM For TC4 Titanium Alloy Workpiece Attaching To Ultrasonic Vibration

TC4 Titanium alloy is widely used in various fields because of its high strength-to-weight ratio, low density, good mechanical properties, strong ability to resist toughness and corrosion. In this experiment, we find an approach to efficiently process TC4 Titanium alloy, which makes the processing results have a faster processing speed, better surface accuracy and less electrode loss(known as process parameters).Firstly, the feasibility of conventional machining, conventional EDM and ultrasonic EDM compound machining is analyzed. Because of its poor thermal conductivity, large viscosity and poor machinability, the TC4 Titanium alloy processed by conventional machining often produces large deformation. By contrast, the EDM is only related to the thermal properties of materials, belonging to the non-contact processing in which there is no macro- force, no obvious scratches. But its efficiency is low, and its forming quality is poor. These problems can be improved obviously if the ultrasonic vibration with appropriate frequency and amplitude is introduced.Secondly, under the condition of positive and negative polarity, the TC4 titanium alloy has been carried out through the conventional EDM. We compare and contrast the data on how electrical parameters affect the above three process parameters, and obtain the best electrical parameter combination in rough and finish processing procedures. The conclusion is that the surface roughness of the positive electrode is better, and the removal rate of the negative electrode is higher.Thirdly, because of mainly emphasizing on the s urface roughness, we attach ultrasonic vibration of the horizontal and vertical directions to the TC4 Titanium alloy workpiece respectively. For this purpose,we also design the acoustic vibration system and its whole fixed installation fixture under the co ndition of positive polarity in conventional EDM, and prepare two programs: the one is to attach ultrasonic vibration with the definite frequency and amplitude to the basis of nine sets of parameters in the process of positive polarity processing.Finally,we analyze and compare that how the two ways of the ultrasonic loading affect the process parameters. The results shows that there were almost no differences between the horizontal ultrasonic way and vertical ultrasonic way in the electrode loss, and the former can get better surface roughness, and the later can obtain the high processing speed. The other is based on the optimal parameter group, attaching the ultrasonic vibration with the changing amplitude to discuss how it influences the spark discharge. The conclusion is that within a certain range, in the process of the horizontal ultrasonic vibration, the increase of amplitude can make the discharge point move around and improve the surface quality, while in another one, the amplitude increase can make the discharge point move up and down, save the establishment time of the discharge channel, and improve the processing efficiency.