Surface texture are widely used in key components of aero engines to help improve their heat dissipation and lubrication. Through-mask electrochemical machining is a highly efficient method for processing surface texture, despite some problems in processing such as uneven flow velocity of electrolyte, difficult to discharge the processed products and ensure the consistency of the surface texture, etc. Therefore, a new method of pulsed gas-assisted through-mask electrochemical machining was proposed, which could use the instantaneous impact force of the pulse gas to wash the electrolysis products in the machining area, thereby promoting the renewal of the electrolyte. In order to study the process law of pulsed gas-assisted through-mask electrochemical machining, under the fixed condition of a single nozzle, a multi-physics model of gas-liquid two-phase flow coupled with electric field was established based on COMSOL Multiphysics simulation software. Through theoretical analysis and experimental study, it was proved that this method has a strong disturbance effect on the fluid in the processing area. The simulation results show that the maximum fluid flow velocity at the bottom of the mask hole was about 3.5 mm/s at a jet velocity of 100 m/s. Traces of product dis-charge can be clearly observed on the surface of the processed mask. In addition, the effects of different process parameters on processing consistency and efficiency were studied. The experimental results show that with the increase of the pulse interval of the jet and the decrease of the gas injection speed, the processing consistency would increase and the processing efficiency would be less. In the experiment, the standard deviation of micro-pit depth could reach a mini-mum of 0.75 μm and the average depth could reach a maximum of 15.2 μm. Finally, the machining results with or without pulsed gas assist and the forming laws of simulation and experiment with pulsed gas assist were compared. Then, the array pits with the standard deviation of depth and the average depth of 1.06 μm and 10.7 μm were processed in the condition of nozzle scanning. Combining theoretical analysis and experimental research results, it was proved that this method had a strong disturbing effect on the fluid in the processing area, and could improve processing efficiency and consistency.
MA Shihe
,
LI Zhichao
,
LIU Guixian
,
ZHANG Yongjun
,
WANG Ruixiang
. Pulse gas-assisted through-mask electrochemical machining technology[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2022
, 43(4)
: 525646
-525646
.
DOI: 10.7527/S1000-6893.2021.25646
[1] SEN M H, SHAN H S. A review of electrochemical macro- to micro-hole drilling processes[J]. International Journal of Machine Tools and Manufacture, 2005, 45(2):137-152.
[2] LI L, DIVER C, ATKINSON J, et al. Sequential laser and EDM micro-drilling for next generation fuel injection nozzle manufacture[J]. CIRP Annals, 2006, 55(1):179-182.
[3] QIAN S Q, ZHU D, QU N S, et al. Generating micro-dimples array on the hard chrome-coated surface by modified through mask electrochemical micromachining[J]. The International Journal of Advanced Manufacturing Technology, 2010, 47(9-12):1121-1127.
[4] 戚宝运. 基于表面微织构刀具的钛合金绿色切削冷却润滑技术研究[D]. 南京:南京航空航天大学, 2011:5-11. QI B Y. Research on cooling/llubrication technology of green cutting of titanium alloy using surface micro-textured cutting tool[D]. Nanjing:Nanjing University of Aeronautics and Astronautics, 2011:5-11(in Chinese).
[5] BALDHOFF T, NOCK V, MARSHALL A T. Review-through-mask electrochemical micromachining[J]. Journal of the Electrochemical Society, 2018, 165(16):E841-E855.
[6] MCCRABB H, LOZANO-MORALES A, SNYDER S, et al. Through mask electrochemical machining[J]. ECS Transactions, 2009, 19(26):19-33.
[7] CHAUVY P F, HOFFMANN P, LANDOLT D. Electrochemical micromachining of titanium through a laser patterned oxide film[J]. Electrochemical and Solid-State Letters, 2001, 4(5):C31.
[8] CHAUVY P F, HOFFMANN P, LANDOLT D. Applications of laser lithography on oxide film to titanium micromachining[J]. Applied Surface Science, 2003, 208-209:165-170.
[9] COSTA H L, HUTCHINGS I M. Development of a maskless electrochemical texturing method[J]. Journal of Materials Processing Technology, 2009, 209(8):3869-3878.
[10] ZHU D, QU N S, LI H S, et al. Electrochemical micromachining of microstructures of micro hole and dimple array[J]. CIRP Annals, 2009, 58(1):177-180.
[11] ALKIRE R C, DELIGIANNI H, JU J B. Effect of fluid flow on convective transport in small cavities[J]. Journal of the Electrochemical Society, 1990, 137(3):818-824.
[12] ALKIRE R C, REISER D B, SANI R L. Effect of fluid flow on removal of dissolution products from small cavities[J]. Journal of the Electrochemical Society, 1984, 131(12):2795-2800.
[13] WANG G Q, LI H S, QU N S, et al. Improvement of electrolyte flow field during through-mask electrochemical machining by changing mask wall angle[J]. Journal of Manufacturing Processes, 2017, 25:246-252.
[14] LI H S, WANG G Q, QU N S, et al. Through-mask electrochemical machining of a large-area hole array in a serpentine flow channel[J]. The International Journal of Advanced Manufacturing Technology, 2017, 89(1-4):933-940.
[15] WANG G Q, LI H S, ZHANG C, et al. Improvement of machining consistency during through-mask electrochemical large-area machining[J]. Chinese Journal of Aeronautics, 2019, 32(4):1051-1058.
[16] CHEN X L, QU N S, LI H S, et al. Electrochemical micromachining of micro-dimple arrays using a polydimethylsiloxane (PDMS) mask[J]. Journal of Materials Processing Technology, 2016, 229:102-110.
[17] WU M, SAXENA K K, GUO Z N, et al. Fast fabrication of complex surficial micro-features using sequential lithography and jet electrochemical machining[J]. Micromachines, 2020, 11(10):948.
[18] WU M, LIU J W, HE J F, et al. Fabrication of surface microstructures by mask electrolyte jet machining[J]. International Journal of Machine Tools and Manufacture, 2020, 148:103471.
[19] ZHAI K, DU L Q, WEN Y K, et al. Fabrication of micro pits based on megasonic assisted through-mask electrochemical micromachining[J]. Ultrasonics, 2020, 100:105990.
[20] OLSSON E, KREISS G. A conservative level set method for two phase flow[J]. Journal of Computational Physics, 2005, 210(1):225-246.
[21] MAYANK G, KUNIEDA M. Two- phase simulation of electrochemical machining[J]. International Journal of Electrical Machining, 2017, 22:31.
[22] MCGEOUHG J A. Principles of electrochemical machining[M]. London:Chapman and Hall, 1974; 159-160.
CJA