Zhaolong Li* and Bingren Cao
Background: High-temperature alloy such as nickel-based alloy has become the main material for core components such as aero engines due to their high strength and good toughness. Therefore, it is of great significance to study how to improve the machining accuracy and stability of electrochemical machining (ECM) of deep small holes on the nickel-based alloy. The instantaneous high-density current during the pulse width of pulse ECM is beneficial to the dissolution of metal workpieces. Many experts and scholars have studied the pulse ECM of deep small holes.
Objective: The purpose of this article is to propose and design a Positive And Negative Pulse (PANP) power supply to study the accuracy and stability of ECM of deep small holes on nickel-based alloys.
Methods: First of all, an H-bridge composed of four MOSFET switches is designed to achieve PANP output in the main circuit of the power supply. Then, this paper studies the influence of the ratio of positive and negative pulses on short circuits, the influence of the ratio of positive and negative pulses on the mass removal rate, and the influence of the electrolyte concentration and pulse width on the mass removal rate. Finally, according to the obtained optimal parameters, the influence of electrolyte pressure on the average radial overcut of hole depth is analyzed.
Results: The experimental results showed that the short-circuit frequency is reduced by more than 50% compared with non-negative pulse power supply; the ratio of positive and negative pulses, pulse width and electrolyte concentration and pressure were optimized by experiments to improve the mass removal rate of the workpiece and the average radial overcut of hole depth.
Conclusion: The designed PANP power supply can improve the machining accuracy and stability of ECM of deep small holes on nickel-based alloys.
Positive and negative pulse, electrochemical machining, machining accuracy, machining stability, mass removal rate, pulse width, average radial overcut
School of Mechanical and Power Engineering, Harbin University of Science and Technology, Harbin, Heilongjiang Province 150080, School of Mechanical and Power Engineering, Harbin University of Science and Technology, Harbin, Heilongjiang Province 150080