RESUMEN
Electrochemical drill-grinding (ECDG) is a compound machining technology, which combines Electrochemical machining (ECM) with mechanical drill-grinding process. On this basis, a new method of machining small holes which called ultrasonic-assisted electrochemical drill-grinding (UAECDG) is proposed. First, the principle of UAECDG is analyzed through analysis of UAECDG process and electrochemical passivation behavior of materials. Second, the simulation of electrochemical drill-grinding process was studied to illustrate the effect of ball-end electrode on reducing the hole taper and improving the machining accuracy. Afterwards, several groups of experiments are conducted to analyze the influence of electrical parameters, ultrasonic amplitude and matching degree between electrolysis and mechanical grinding on the machining quality of small holes. Finally, small holes with diameter of 1.1 ± 0.01 mm, surface roughness of 0.31 µm and taper of less than 0.6 degree were machined by UAECDG, which revealed UAECDG is a promising compound machining technology to fabricate small holes with high quality and high efficiency.
RESUMEN
As one of the most promising micro-machining methods, electrochemical micro-machining is widely used in the field of metal micro-structures. The electrochemical micro-milling on Nickel-base superalloy by using high-speed spiral electrode was studied in detail. Firstly, the electric field and flow field models of micro-electrochemical milling are established and analyzed by the finite element method. Then, the milling profile was predicted and the effect of high-speed rotation of electrodes on electrolyte promotion and secondary electrolysis prevention were analyzed. Secondly, the influence of the main machining parameters, such as rotating speed, electrical parameters, and feed rate on machining precision and efficiency was analyzed experimentally. Finally, by optimizing the machining parameters, a series of micro-graphic structures with a width of about 150 µm were obtained on Nickel-base superalloy 718 by using the spiral electrode with a diameter of 100 µm. The experimental and simulation results show that the high-speed rotation of electrodes can greatly improve the machining efficiency and stability. It was proved that micro-electrochemical milling with the high-speed rotating electrode technique is an effective method for machining micro-metal parts.
RESUMEN
Micro electrochemical machining is becoming increasingly important in the microfabrication of metal parts. In this paper, the machining characteristics of micro electrochemical milling with nanosecond pulse were studied. Firstly, a mathematical model for the localization control of micro electrochemical milling with nanosecond pulse was established. Secondly, groups of experiments were conducted on nickel-based superalloy and the effects of parameters such as applied voltage, pulse on time, pulse period, electrolyte concentration and electrode diameter on machining localization and surface roughness were analyzed. Finally, by using the optimized machining parameters, some 2D complex shapes and 3D square cavity structures with good shape precision and good surface quality were successfully obtained. It was proved that the micro electrochemical milling with nanosecond pulse technique is an effective machining method to fabricate metal microstructures.