The demand for carbon fiber reinforced plastics (CFRP), classified as functional resins, has increased for micromachined products that are manufactured using lathes and used in the medical field. However, the problems with machining CFRP include the occurrence of burrs and deterioration of the finished dimensions owing to the significant tool wear caused by the carbon fiber. To turn CFRP and maintain high dimensional accuracy, the authors proposed a novel combination of conventional turning and electrical discharge-assisted turning (EDAT). In this study, the capability to control the machinability of EDAT under low-voltage conditions was experimentally investigated. The relationship between the discharge voltage, frequency, and depth of discharge influence of the carbon fibers was clarified.

1. [1] M. A. Karataş and H. Gökkaya, “A review on machinability of carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) composite materials,” Defence Technology, Vol.14, No.4, pp. 318-326, 2018. https://doi.org/10.1016/j.dt.2018.02.001
2. [2] A. Kitano, “Characteristics of carbon-fiber-reinforced plastics (CFRP) and associated challenges – Focusing on carbon-fiber-reinforced thermosetting resins (CFRTS) for aircraft,” Int. J. Automation Technol., Vol.10, No.3, pp. 300-309, 2016. https://doi.org/10.20965/ijat.2016.p0300
3. [3] Y. Kondo and S. Sakamoto, “A damage-free machining method for CFRP without feedback control systems,” Int. J. Automation Technol., Vol.10, No.3, pp. 318-323, 2016. https://doi.org/10.20965/ijat.2016.p0318
4. [4] Y. Kojima, R. Tanaka, Y. Yamane, K. Sekiya, and K. Yamada, “Drilling of CFRP with an electrodeposited diamond core drill – Effects of air assistance and tool shape –,” Int. J. Automation Technol., Vol.10, No.3, pp. 310-317, 2016. https://doi.org/10.20965/ijat.2016.p0310
5. [5] S. Sakamoto, “Precision drilling of carbon fiber reinforced plastics with ball nose end mills,” Int. J. Automation Technol., Vol.10, No.3, pp. 334-340, 2016. https://doi.org/10.20965/ijat.2016.p0334
6. [6] M. Henerichs, R. Voß, H. Tanaka, F. Kuster, and K. Wegener, “Analysis of material weakening in CFRP after a drilling operation,” Procedia CIRP, Vol.24, pp. 44-48, 2014. https://doi.org/10.1016/j.procir.2014.07.145
7. [7] T. Inoue and M. Hagino, “Cutting characteristics of CFRP materials with carbon fiber distribution,” Int. J. Automation Technol., Vol.7, No.3, pp. 285-291, 2013. https://doi.org/10.20965/ijat.2013.p0285
8. [8] A. Hosokawa, N. Hirose, T. Ueda, T. Koyano, and T. Furumoto, “High-quality end milling of CFRP – Inclination milling with high-helix end mill –,” Int. J. Automation Technol., Vol.10, No.3, pp. 372-380, 2016. https://doi.org/10.20965/ijat.2016.p0372
9. [9] S. Maegawa, S. Hayakawa, F. Itoigawa, and T. Nakamura, “Two-layer tool with hardness distribution around tool edge for reducing cutting forces in CFRP machining,” Int. J. Automation Technol., Vol.10, No.3, pp. 364-371, 2016. https://doi.org/10.20965/ijat.2016.p0364
10. [10] T. Tashiro, J. Fujiwara, and N. Asahi, “Cutting characteristics in end-milling of CFRP with diamond-coated herringbone tool,” Int. J. Automation Technol., Vol.10, No.3, pp. 356-363, 2016. https://doi.org/10.20965/ijat.2016.p0356
11. [11] F. Muto et al., “Development of a forward-reverse rotating cBN electroplated end mill type tool for cutting and grinding CFRP,” Int. J. Automation Technol., Vol.15, No.1, pp. 41-48, 2021. https://doi.org/10.20965/ijat.2021.p0041
12. [12] H. Tanaka and M. Kitamura, “Machinability of thermo-plastic carbon fiber reinforced plastic in inclined planetary motion milling,” Int. J. of Automation Technol., Vol.12, No.5, pp. 750-759, 2018. https://doi.org/10.20965/ijat.2018.p0750
13. [13] H. Tanaka, M. Kitamura, and T. Sai, “An evaluation of cutting edge and machinability of inclined planetary motion milling for difficult-to-cut materials,” Procedia CIRP, Vol.35, pp. 96-100, 2015. https://doi.org/10.1016/j.procir.2015.08.072
14. [14] H. Tanaka and T. Yoshita, “Machinability evaluation of inclined planetary motion milling system for difficult-to-cut materials,” Key Engineering Marerials, Vol.656, pp. 320-327, 2015.
15. [15] H. Tanaka, Y. Fukada, and R. Kuboshima, “Feasibility study of EDM-assisted combined turning for unidirectional CFRP,” Int. J. Automation Technol., Vol.16, No.5, pp. 536-542, 2022. https://doi.org/10.20965/ijat.2022.p0536
16. [16] M. Henerichs, C. Dold, R. Voß, and K. Wegener, “Performance of lasered PCD- and CVD-diamond cutting inserts for machining carbon fiber reinforced plastics (CFRP),” Proc. of the ASME 2013 Int. Mechanical Engineering Congress and Exposition. Vol.2B: Advanced Manufacturing, Article No.V02BT02A064, 2013. https://doi.org/10.1115/IMECE2013-62675
17. [17] M. Henerichs, R. Voß, F. Kuster, and K. Wegener, “Machining of carbon fiber reinforced plastics: Influence of tool geometry and fiber orientation on the machining forces,” CIRP J. of Manufacturing Science and Technology, Vol.9, pp. 136-145, 2015. https://doi.org/10.1016/j.cirpj.2014.11.002
18. [18] K. Abhishek, S. Datta, S. Chatterjee, and S. S. Mahapatra, “Parametric optimization in turning of CFRP (epoxy) composites: A case experimental research with exploration of HS algorithm,” Applied Mechanics and Materials, Vol.619, pp. 54-57, 2014. https://doi.org/10.4028/www.scientific.net/AMM.619.54
19. [19] T. Rajasekaran, K. Palanikumar, and B. K. Vinayagam, “Experimental investigation and analysis in turning of CFRP composites,” J. of Composite Materials, Vol.46, No.7, pp. 809-821, 2012. https://doi.org/10.1177/0021998311410500
20. [20] T. Rajasekaran, K. Palanikumar, and B. K. Vinayagam, “Turning CFRP composites with ceramic tool for surface roughness analysis,” Procedia Engineering, Vol.38, pp. 2922-2929, 2012. https://doi.org/10.1016/j.proeng.2012.06.341
21. [21] T. Rajasekaran, K. Palanikumar, and S. Arunachalam, “Investigation on the turning parameters for surface roughness using Taguchi analysis,” Procedia Engineering, Vol.51, pp. 781-790, 2013. https://doi.org/10.1016/j.proeng.2013.01.112
22. [22] K. Sauer, M. Hertel, S. Fickert, M. Witt, and M. Putz, “Cutting parameter study of CFRP machining by turning and turn-milling,” Procedia CIRP, Vol.88, pp. 457-461, 2020. https://doi.org/10.1016/j.procir.2020.05.079
23. [23] A. Ito, S. Hayakawa, F. Itoigawa, and T. Nakamura, “Effect of short-circuiting in electrical discharge machining of carbon fiber reinforced plastics,” J. of Advanced Mechanical Design, Systems, and Manufacturing, Vol.6, No.6, pp. 808-814, 2012. https://doi.org/10.1299/jamdsm.6.808
24. [24] A. Ito, S. Hayakawa, F. Itoigawa, and T. Nakamura, “Effect of short-circuiting in electrical discharge machining of carbon fiber reinforced plastics,” Proc. of the 6th Int. Conf. on Leading Edge Manufacturing in 21st Century (LEM21 2011), Article No.3284, 2011. https://doi.org/10.1299/jsmelem.2011.6._3284-1_
25. [25] R. Kumar, A. Kumar, and I. Singh, “Electric discharge drilling of micro holes in CFRP laminates,” J. of Materials Processing Technology, Vol.259, pp. 150-158, 2018. https://doi.org/10.1016/j.jmatprotec.2018.04.031
26. [26] C. Wu et al., “Preheating assisted wire EDM of semi-conductive CFRPs: Principle and anisotropy,” J. of Materials Processing Technology, Vol.288, Article No.116915, 2021. https://doi.org/10.1016/j.jmatprotec.2020.116915
27. [27] M. M. Islam, C. P. Li, and T. J. Ko, “Dry electrical discharge machining for deburring drilled holes in CFRP composite,” Int. J. of Precision Engineering and Manufacturing-Green Technology, Vol.4, No.2, pp. 149-154, 2017. https://doi.org/10.1007/s40684-017-0018-x
28. [28] S. Ichii, A. Okada, Y. Okamoto, and Y. Uno, “Influence of carbon fiber direction on EDM characteristics of CFRP,” Proc. of the 6th Int. Conf. on Leading Edge Manufacturing in 21st Century (LEM21 2011), Article No.3247, 2011. https://doi.org/10.1299/jsmelem.2011.6._3247-1_
29. [29] R. Abdallah, S. L. Soo, and R. Hood, “A feasibility study on wire electrical discharge machining of carbon fibre reinforced plastic composites,” Procedia CIRP, Vol.77, pp. 195-198, 2018. https://doi.org/10.1016/j.procir.2018.08.284
30. [30] S. P. Bernix, S. Pradeep, R. Raviprasaath, and B. A. Saravanan, “Cutting characteristics of carbon fiber,” Int. J. of Research in Engineering, Science and Management, Vol.1, No.10, pp. 584-587, 2018.
31. [31] L. Babich and T. V. Loǐko, “Generalized Paschen’s law for overvoltage conditions,” IEEE Trans. on Plasma Science, Vol.44, No.12, pp. 3243-3248, 2016. https://doi.org/10.1109/TPS.2016.2629022