Study of the influence of conical guide on laser coupling stability in laser and electrochemical machining by optical simulation

Laser and shaped tube electrochemical machining (Laser-STEM) has been proposed to process small holes with high efficiency and surface quality. In Laser-STEM the laser energy is transmitted to the machining zone with high efficiency by total internal reflection confined in the inner hole of the tool electrode. Coupling between the laser and the tool electrode is of importance to guarantee the stability and accuracy of the Laser-STEM process. The previous studied focuses the laser beam to the entrance of the tool electrode utilizing a focusing lens. However, the method was easily affected by the focal length, spot size, and installation error, which would influence laser coupling stability and transmission efficiency. This paper focuses on the research of a novel laser coupling method based on the conical optical guide to improve the coupling robustness. Mathematical model of the laser propagation through the conical guide has been derived. The maximum coupling angle of the conical guide with different sizes was obtained. The effect of laserliquid- core fiber tool electrode coupling error on laser energy coupling efficiency is investigated by optical simulation, and the feasibility of conical light-guiding devices for efficient conduction of laser energy was verified experimentally. Results showed that the conical optical guide could improve the laser axial incidence range by about 3 times, the radial range by 2 times, and the angular coupling range by 1.9 times, with the laser coupling efficiency of 90%. The introduction of the conical guide remarkably improved the coupling efficiency and stability of the laser and tool electrode, which is of great significance for improving the stability of Laser-STEM.

[1]  Yufeng Wang,et al.  Improving performance of laser and shaped tube electrochemical machining by using retracted hybrid tubular tool electrode , 2021, The International Journal of Advanced Manufacturing Technology.

[2]  Yufeng Wang,et al.  Theoretical and experimental study on hybrid laser and shaped tube electrochemical machining (Laser-STEM) process , 2021 .

[3]  Zhengyang Xu,et al.  Machining of a film-cooling hole in a single-crystal superalloy by high-speed electrochemical discharge drilling , 2016 .

[4]  Xichun Luo,et al.  Hybrid micro-machining processes: a review , 2015 .

[5]  R. Patwa,et al.  Laser drilling of micro-hole arrays in tantalum , 2015 .

[6]  Hongyu Zhang,et al.  An investigation on the hole quality during picosecond laser helical drilling of stainless steel 304 , 2015 .

[7]  Xiangzhi Wang,et al.  Deep-type hole machining by inner jetted aerosol dielectric ablation , 2015 .

[8]  Altab Hossain,et al.  A review of modeling and simulation of laser beam machining , 2014 .

[9]  Urs Eppelt,et al.  Review on laser drilling I. Fundamentals, modeling, and simulation , 2013 .

[10]  Rosemary L. Smith,et al.  The electron beam hole drilling of silicon nitride thin films , 2008 .

[11]  H. S. Shan,et al.  Electro jet drilling using hybrid NNGA approach , 2007 .

[12]  R. T. Hodgson,et al.  Laser enhanced etching in KOH , 1982 .

[13]  C. Baumgart,et al.  Efficient machining of complex-shaped seal slots for turbomachinery , 2018 .

[14]  A. Loktionov,et al.  Role of laser radiation in activating anodic dissolution under electrochemical machining of metals and alloys , 2017 .

[15]  Gideon Levy,et al.  Turbomachinery component manufacture by application of electrochemical, electro-physical and photonic processes , 2014 .

[16]  A. Erman Tekkaya,et al.  Hybrid processes in manufacturing , 2014 .

[17]  Michael Schmidt,et al.  Numerical Simulation of Drilling with Pulsed Beams , 2012 .

[18]  K. Rajurkar,et al.  Influence of debris accumulation on material removal and surface roughness in micro ultrasonic machining of silicon , 2006 .

[19]  J. McGeough,et al.  Modelling and experimental investigation of laser assisted jet electrochemical machining , 2004 .