Abstract
Diffuser shaped film cooling holes are increasingly being applied in the turbine blades of advanced aeroengines. It is a difficult problem to machine this kind of cooling holes due to their complicated shape and superalloy material. Currently, die-sinking electrical discharge machining (EDM) is regarded as an available process for machining the diffuser holes. However, the change of tool electrode shape caused by the electrode wear and difficult renew of dielectric fluid affect the processing precision. The worn tool electrode has to be replaced with a fresh one after machining one or several holes. The replacing procedure is time consuming to break the machining process. In the previous work, a novel block divided EDM process was proposed to efficiently machine the diffuser holes, but the machining accuracy needs to be further improved. In this research, the block divided EDM process firstly is analyzed and simulated in detail to know the key factor affecting the machined accuracy. Furthermore, a self-repair method and a profile error compensation method of the tool electrode wear are proposed for improving the processing accuracy. The self-repair method is to plan and control the rotation motion of the tool electrode for maintaining its shape. The profile error compensation method is to modify the Z coordinate of the tool electrode for decreasing the machining error. Machining experiments verified that the proposed methods can meet the accuracy requirements of the film cooling holes with diffusion angle error < 0.1° and average profile error < 10 μm.
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References
Lee KD, Kim KY (2011) Surrogate based optimization of a laidback fan-shaped hole for film-cooling. Int J Heat Fluid Flow 32(1):226–238
Bunker RS (2005) A review of shaped hole turbine film-cooling technology. J Heat Trans-T ASME 127(4):441–453
Bunker RS (2009) The effects of manufacturing tolerances on gas turbine cooling. ASME Turbo Expo 2008: Power for Land, Sea, and Air 041018
Song MC, Liu Y, Li WM (2017) Fabricating micro-core by EDM with multi-station narrow slit electrode. Int J Adv Manuf Technol 88(9-12):3507–3514
Yu ZY, Li DP, Yang JF, Zeng ZJ, Yang XL, Li JZ (2019) Fabrication of micro punching mold for micro complex shape part by micro EDM. Int J Adv Manuf Technol 100(1-4):743–749
Zhang L, Tong H, Li Y (2015) Precision machining of micro tool electrodes in micro EDM for drilling array micro holes. Precis Eng 39:100–106
Cross JA, Jackson CM (1989) Method of forming electro-discharge machining electrode. United States patent US 4819325
Ball GE, Gleason MJ, Webb BJ (2007) Duplex electrical discharge machining. United States patent US 7214901
Yu ZY (1998) Micro-EDM for three-dimensional cavities-development of uniform wear method. CIRP Ann-Manuf Techn 47:169–172
Li JZ, **ao L, Wang H (2013) Tool wear compensation in 3D micro EDM based on the scanned area. Precis Eng 37(3):753–757
Tong H, Zhang L, Li Y (2014) Algorithms and machining experiments to reduce depth errors in servo scanning 3D micro EDM. Precis Eng 38(3):538–547
Nguyen VQ, Duong TH, Kim HC (2015) Precision micro EDM based on real-time monitoring and electrode wear compensation. Int J Adv Manuf Technol 79(9-12):1829–1838
Liang W, Li Y, Tong H, Kong QC (2018) A block divided EDM process for diffuser shaped film cooling holes. Procedia CIRP 68:415–419
Jeong YH, Min BK (2007) Geometry prediction of EDM-drilled holes and tool electrode shapes of micro-EDM process using simulation. Int J Mach Tool Manu 47(12):1817–1826
Zhang LN, Du JY, Zhuang XS, Wang ZL, Pei JY (2014) Geometric prediction of conic tool in micro-EDM milling with fix-length compensation using simulation. Int J Mach Tool Manu 89:86–89
Funding
This research is supported by the National Natural Science Foundation of China (Grant No. 51675302), Science and Technology Support Program of Jiangsu Province of China (Grant No. BY2016024-01), Tsinghua University Initiative Scientific Research Program (Grant No. 20131089209), and Independent Research Project of State Key Laboratory of Tribology of China (Grant No. SKLT2015B08).
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Liang, W., Tong, H., Li, Y. et al. Tool electrode wear compensation in block divided EDM process for improving accuracy of diffuser shaped film cooling holes. Int J Adv Manuf Technol 103, 1759–1767 (2019). https://doi.org/10.1007/s00170-019-03591-8
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DOI: https://doi.org/10.1007/s00170-019-03591-8