Performance Improvement of High-speed Edm and Ecm Combined Process by Using a Helical Tube Electrode With Matched Internal and External Flushing

Micro-hole fabrication at a high speed and accuracy of machining while maintaining high surface quality is challenging. A core difficulty is the removal of the products of machining from extremely narrow gaps. To solve this problem, this study proposes an approach that combines high-speed electrical discharge machining (EDM) with electrochemical machining (ECM) by using a helical tube electrode with matched internal and external flushing. During high-speed electrical discharge drilling, matching the internal flushing with the clockwise rotation of the helical electrode can help remove debris from the bottom of the blind hole. During ECM, matching the external flushing with the anticlockwise rotation of the helical electrode can improve the flow of electrolyte in the gap. First, the flow field was simulated to show that matching the internal and external flushing of the helical electrode can enhance the flow of the medium and reduce particle concentration in extremely narrow gaps. Second, a series of experiments were conducted to verify that the taper of the hole and the surface quality of its wall can be improved by using the helical tube electrode. Finally, an experiment was carried out to optimize the machining parameters, and yielded a minimum taper of 0.008 at a speed of rotation of 460 rpm, and pressures of internal and external flushing of 9 MPa and 4 MPa, respectively.

Workpiece Vibration in Feed Direction Assisted Electrochemical Cutting Using Tube Electrode With Inclined Holes

Electrochemical cutting using tube electrode with inclined holes is a machining method that directly and obliquely injects electrolyte into the machining gap through inclined jet-flow holes on the sidewall of a tube electrode, allowing the electrochemical cutting of a workpiece. To improve the machining efficiency and accuracy of this cutting technique, a method of workpiece vibration in feed direction assisted electrochemical cutting is proposed in which workpiece vibration along the feed direction rapidly and periodically changes the machining gap. The near-instantaneous increases in the machining gap promotes the waste electrolyte containing electrolytic products to flow down the machining gap. At the same time, the electrochemical reaction time under the non-uniform flow field caused by the inclined downward injection of electrolyte is reduced. The flow field simulation of electrolyte in machining gap indicates that the near-instantaneous increases in the machining gap can improve the flow velocity of electrolyte. Experiment demonstrates that the average feed rate can be increased by 50% and the machining efficiency is superior to that of electrochemical cutting assisted by workpiece non-vibration in feed direction. The difference between the upper and lower slit widths is reduced and the machining accuracy is improved. The effect of the vibrational amplitude and frequency on the machining result is also investigated. Finally, an array slice structure is fabricated on a stainless steel block with a cross-section of 10 mm × 10 mm at average feed rate of 6 mm/s using a vibrational amplitude and frequency of 0.1 mm and 1.5 Hz, respectively.

Highly conductive Ni(OH)2 nano-sheets wrapped CuCo2S4 nano-tube electrode with a core-shell structure toward high performance supercapacitor

The design of microstructures and the optimum selection of electrode materials have substantial effects on the electrochemical performances for supercapacitors. A core-shell structured CuCo2S4@Ni(OH)2 electrode material was designed, in which...

Investigation of Circuit Parameters in Tube Electrode High-Speed Electrochemical Discharge Machining

Tube electrode high-speed electrochemical discharge machining (TSECDM) has been effectively used in the manufactures of micro holes with difficult-to-cut conductive materials in the field of aerospace industry. The design and parameters of circuit are critical for the machining performances of TSECDM. In this paper, the influences of circuit on the TSECDM performances are studied. Firstly, a relaxation type RLC generator is designed and analyzed by MATLAB simulation. Secondly, the effects of RLC circuit parameters such a resistor (R), capacitor (C) and inductor (L) on machining performances are investigated by experiments on the bulk of SS304 alloys by limiting factors changing. Finally, the analysis achievement indicated that the circuit selection parameters value R (15Ω); C (220nF); L (0.13mH) can be used to obtain a better machining performance.