| With the rapid development of modern science and technology,there is an increasing demand for high performance new materials and complex parts,Therefore,people put forward higher requirements to the processing technology and cost control.Because its excellent characteristics,titanium alloy,as a kind of new metal alloy,has been widely used in the fields of Aeronautics and Astronautics, shipbuilding, military industry, metallurgy,light industry, seawater desalination, medical equipment, environmental protection and so on,and has created enormous economic and social benefits,which plays an important role in the development of national economy and national defense industry.With the increasing application of titanium alloy, it is urgent to solve the problem of processing difficulty and control cost.Titanium alloy products are been widely used,but their prices are generally much more expensive, the reasons are various, one of the important reason is that titanium alloy parts' processing costs are usually high.The traditional ways for machining titanium alloy is mainly machine work,Because of the high hardness of titanium alloy materials,the large friction when cutting titanium alloy will produce high temperature during processing,the wear of cutting tool is very serious.In addition, the surface modification of the machined titanium alloy is affected by the high temperature, which will affect its application performance,also the machining is usually be used to manufacture the ordinary titanium alloy work-pieces. It is more difficult and more expensive to manufacture the thin-walled parts.In order to solve the problem of titanium alloy processing technology, this paper put forward a ECM (Electrochemical Machining) method of machining titanium alloy TC4 thin-wall abnormal cavity.Electrochemical machining rapidly remove materials through "ionization",because its processing has the advantages such as non-contact, no cutting force,the tool will not be wear, the processing cost is greatly reduced,and electrochemical machining has its unique advantages of machining titanium alloy abnormal counterbore cavity.This paper is a study on the processing technology of thin-walled abnormal cavity of titanium alloy. Firstly, the difficult problems of machining titanium alloy TC4 thin-walled cavity are analyzed. Based on this, the electrochemical machining technology is proposed.The paper summarizes and analyzes the characteristics of TC4 titanium alloy electrolysis processing,namely in electrochemical machining, titanium alloy easily on the surface formation passivation film, so that the machining difficult, especially in the low current density prone to pitting corrosion, which lead to a worse quality of the machined surface.Combined with the experiment phenomenons such as the short circuit burn, long drum type and non - processed surface erosion ,analyze the mechanism of electrochemical machining of titanium alloy TC4 was analyzed,choose the suitable electrolyte and build mathematical model of electrochemical machining.By using Comsol to simulation the flow field distribution during the process,based on the simulation results and summarized the influence of cathode structure on the flow field in the process,in this paper we optimize tool cathode structure and design a positive flow and a counter flow cathode structure.Based on positive flow cathode structure,we have done a series single factor experiment including voltage,duty cycle and electrolyte concentration to find the influence law to titanium alloy TC4 work-pieces by changing such processing parameters.Through a series of orthogonal experiments, we analyzed and selected the optimal process parameters,then we verified the results by experiments.In the end, we do a comparison experiments by using counter flow cathode, and compared the differences between the two processing methods. Then finally make a result that machining TC4 titanium alloy may better to choose counter-flow cathode. |
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