Structural design and verification of ring-shaped laser-guiding tubular electrodes with sidewall-insulating functions for laser-electrochemical hybrid machining

Abstract

Laser-electrochemical hybrid machining (LECM) with a tubular electrode displays potential for use in the high-efficiency machining of deep small holes in difficult-to-machine superalloy materials. The tool electrode serves as the key component in coupling and transmitting the laser energy, electrical power, and electrolyte into the machining gap, thereby facilitating the hybrid machining process under the interaction of multi-energy fields. This study proposes a ring-shaped laser-guiding tubular electrode with a sidewall-insulating function for application in LECM. The novel electrode consists of an inner metal tube for electrical conduction and electrolyte transportation and an outer quartz tube functioning as a laser waveguide for efficient laser transmission while ensuring reliable sidewall insulation. The retraction distance of the sidewall-insulating laser waveguide is optimized via multiphysics simulations, and the optical modulation structure of the electrode tip is analyzed to regulate the spatial distribution of the laser within the machining gap. A tool electrode and machining head were fabricated and assembled. Performance tests show that the newly designed electrode achieves a numerical aperture above 0.24, a laser transmittance exceeding 80%, and a maximum flow rate of 100 mL/min at an inlet pressure of 3.5 MPa. LECM experiments conducted on Inconel 738 superalloy verify the feasibility of the proposed tubular electrode. Small holes with diameters of 1.22 mm and depths of 5 mm are successfully machined, realizing a machining speed of 1.1 mm/min.

Keywords

Laser-electrochemical hybrid machining (LECM) / Tubular electrode / Annular laser spot / Multiphysics simulation / Structure optimization / Deep small hole machining

References

[1] Reed RC. The superalloys: fundamentals and applications, 2006, Cambridge, UK, Cambridge University Press

[2] Chandar JB, Nagarajan L, Kumar MS. Recent research progress in deep hole drilling process: a review. Surf Rev Lett, 2021, 28(11): 2130003

[3] Soo SL, Hood R, Aspinwall DK, et al.. Machinability and surface integrity of RR1000 nickel based superalloy. CIRP Ann, 2011, 60: 89-92

[4] Imran M, Mativenga PT, Gholinia A, et al.. Assessment of surface integrity of Ni superalloy after electrical-discharge, laser and mechanical micro-drilling processes. Int J Adv Manuf Technol, 2015, 79: 1303-1311

[5] Lu CS, Duan WQ, Wang KD, et al.. Experiments of drilling micro-holes on superalloy with thermal barrier coatings by using femtosecond laser. Ferroelectrics, 2020, 564(1): 37-51

[6] Burger M, Koll L, Werner EA, et al.. Electrochemical machining characteristics and resulting surface quality of the nickel-base single-crystalline material LEK94. J Manuf Processes, 2012, 14(1): 62-70

[7] Zhang Q, Sun SF, Zhang FY, et al.. A study on film hole drilling of IN718 superalloy via laser machining combined with high temperature chemical etching. Int J Adv Manuf Technol, 2020, 106: 155-162

[8] Malik A, Manna A. Investigation on the laser-assisted jet electrochemical machining process for improvement in machining performance. Int J Adv Manuf Technol, 2018, 96: 3917-3932

[9] Sahu AK, Malhotra J, Jha S. Laser-based hybrid micromachining processes: a review. Opt Laser Technol, 2022, 146 107554

[10] Zhang H, Xu JW, Wang JM. Investigation of a novel hybrid process of laser drilling assisted with jet electrochemical machining. Opt Lasers Eng, 2009, 47(11): 1242-1249

[11] Zhang H, Gao P, Xu JW, et al.. Effect of electrochemical dissolving in laser drilling assisted with jet electrochemical machining. Int J Electrochem Sci, 2021, 16(5): 21056

[12] Sun AX, Chang YB, Liu HJ. Metal micro-hole formation without recast layer by laser machining and electrochemical machining. Optik, 2018, 171: 694-705

[13] Duan WQ, Mei XS, Fan ZJ, et al.. Electrochemical corrosion assisted laser drilling of micro-hole without recast layer. Optik, 2020, 202 163577

[14] Wang SW, Xie WD, Ding Y, et al.. Investigations on the water-jet guided laser drilling film cooling holes on the 8.5 mm-thick TBC superalloy. J Manuf Processes, 2024, 125: 374-388

[15] Saxena KK, Qian J, Reynaerts D. A tool-based hybrid laser-electrochemical micromachining process: experimental investigations and synergistic effects. Int J Mach Tools Manuf, 2020, 155 103569

[16] Saxena KK, Qian J, Reynaerts D. Development and investigations on a hybrid tooling concept for coaxial and concurrent application of electrochemical and laser micromachining processes. Precis Eng, 2020, 65: 171-184

[17] Wang YF, Yang F, Zhang W. Development of laser and electrochemical machining based on internal total reflection. J Electrochem Soc, 2019, 166(14): E481

[18] Wang YF, Yang F, Zhang GY, et al.. Fabrication of deep and small holes by synchronized laser and shaped tube electrochemical machining (laser-STEM) hybrid process. Int J Adv Manuf Technol, 2019, 105: 2721-2731

[19] Wang YF, Yang Y, Li YL, et al.. Profile characteristics and evolution in combined laser and electrochemical machining. J Electrochem Soc, 2022, 169(9 093505

[20] Yang Y, Wang YF, Gui YJ, et al.. Improving performance of laser and shaped tube electrochemical machining by using retracted hybrid tubular tool electrode. Int J Adv Manuf Technol, 2022, 118: 1779-1791

[21] Sogandares FM, Fry ES. Absorption spectrum (340–640 nm) of pure water I. Photothermal measurements. Appl Opt, 1997, 36(33): 8699-8709

[22] Semak VV, Gerakis A, Shneider MN. Measurement of temperature dependent absorption coefficient of water at 1064 nm wavelength. AIP Adv, 2019, 9(8 085016

[23] Yang X, Yang CJ, Tong H, et al.. Theoretical analysis and experimental research on tubular electrode-coupled laser and electrochemical hybrid machining. Chin J Lasers, 2024, 51(16): 1602402

[24] Stephen A, Vollertsen F. Mechanisms and processing limits in laser thermochemical machining. CIRP Ann Manuf Technol, 2010, 59(1): 251-254

[25] Yang Y, Wang YF, Jiang WM, et al.. Effects of synchronous laser irradiation on anodic dissolution behavior. Electrochim Acta, 2025, 535 146713

[26] Lin L, Liu Y, Xue W, et al.. Multi-energy field simulation and experimental research on laser composite machining of micro-holes. J Appl Phys, 2024, 135(23 233101

[27] Yang X, Yao Y, Yang CJ, et al.. Laser-electrochemical hybrid machining process based on novel dual-cathode and dual-channel tube electrodes inserted with optical fibers. J Manuf Process, 2025, 155: 775-791

[28] Yang Y, Wang YF, Gui YJ, et al.. Fabrication of microgrooves by synchronous hybrid laser and shaped tube electrochemical milling. Materials, 2021, 14(24): 7714

Funding

National Key Research and Development Program of China(2021YFF0500200)

Rights & permissions

Shanghai University and Periodicals Agency of Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature

Just Accepted

This article has successfully passed peer review and final editorial review, and will soon enter typesetting, proofreading and other publishing processes. The currently displayed version is the accepted final manuscript. The officially published version will be updated with format, DOI and citation information upon launch. We recommend that you pay attention to subsequent journal notifications and preferentially cite the officially published version. Thank you for your support and cooperation.