Research On Electrochemical Micromachining Of Pure Titanium

Titanium and its alloys are widely used in aerospace, medical instrumentation. They can be used to make aviation metal screen and damping bushings of aeroengine. They can also be used on artificial bone and cardiovascular stent implants. At present, the pure titanium structures are made by laser processing and through-mask electrochemical micromachining. In the laser processing method, three-dimentiongal structure can be easily machined,but distortion or burr will appear on the workpiece surface. While in through-mask electrochemical micromachining, the depth can not be controlled exactly and the complex three-dimensional structure is difficult to be produced. According to the problems, a new method is proposed innovatively. It is the electrochemical micromachining on pure titanium.This paper analyses the mechanism and characteristic of titanium electrochemical micromachining theoretically. The relationship between the polarization voltage and current by polarization curve is also analyzed. A physical model for single electrode polarization voltage in electrochemical micromachining is established. The interelectrode electric field is simulated by the finite element software and the rule of the electric field is obtained. This provides theoretical basis for machining and designing micro-electrodes。Pure Titanium has a high passivation and is easy to be passivated in water-soluble electrolyte. The experiment shows that using pure methanol as electrolyte can solve the problem. According to the requirements of electrochemical micromachining, tungsten and copper are selected to make the micro-electrode. Using array-electrodes in the electrochemical micromachining can improve the efficiency. The influences on the result of the intereletrode distance, electric parameters and the feed rate are analyzed by the single factor optimized experiment. In the processing with ultrashort pulse power, it is difficult for the processing because the capacitance can not be controlled to be small enough. The electrochemical micromachining with low-voltage DC.Micropores is carried on to process micropores and micro-array-pits structure. The experiment result shows that the appropriate interelectrode gap is 8 to 15 micrometers, the voltage is 4 volt, and the feed rate is 0.04 micrometers per second. The experiment result lays a foundation for the further research of the pure titanium electrochemical machining in nanotechnology.