Effect of pulse duty cycle on laser electrochemical hybrid machining microstructure

Abstract

To mitigate the adverse effects of stray corrosion on the machining accuracy of microstructures in electrochemical machining, a corrosion-resistant remelted layer is fabricated on the substrate surface utilizing laser surface remelting technology. Subsequently, selective material removal is achieved through electrochemical machining. Building upon this foundation, mathematical and geometric models of laser electrochemical hybrid machining for microstructures were developed to systematically investigate the influence of pulse duty cycle on the distribution of temperature, hydrogen volume fraction, electrolyte conductivity and current density. The correctness of the simulation results is verified by experiments. Both simulation and experimental results demonstrate that the temperature and hydrogen volume fraction exhibit a gradual increase with the duty cycle, whereas the electrolyte conductivity and current density show a corresponding decrease. The depth, width and taper of the microstructures initially increase and subsequently decrease as the pulse duty cycle varies. At a duty cycle of 20%, the microstructure depth reaches 36.6 μm, with an overcut of 5.001 μm and a taper of 7.78°, indicating favourable machining accuracy but relatively low machining efficiency. When the duty cycle is increased to 50%, the microstructure depth extends to 38.01 μm, with an overcut of 7.26 μm and a taper of 10.82°, resulting in reduced machining accuracy but enhanced machining efficiency. These findings provide critical insights into the optimization of machining parameters for achieving a balance between accuracy and efficiency in laser electrochemical hybrid machining.