The effects of surface modification using an electrical discharge coating are investigated. The electrode used for the machining process is a Ti-type semi-sintered compact electrode. A thin and hard layer is formed on the machining surface. In this paper, the change in surface roughness during electrical discharge coating is described. The accretion layer surface became coarse after 10 min of machining. The peak height also increased. After 30 min of machining, the height of the accretion layer was lower than the original surface level, and the peak height decreased. Furthermore, the core roughness value increased. The surface roughness increased within several minutes from the start of electrical discharge coating using a Ti-type semi-sintered compact electrode. In this paper, we report on the temporal change of surface roughness during electrical discharge coating.

1. [1] T. Shinonaga, Y. Iida, R. Toshimitsu, and A. Okada, “Fundamental Study on Addition of Osteoconductivity to Titanium Alloy Surface by EDM,” Int. J. Automation Technol., Vol.11, No.6, pp. 869-877, 2017.
2. [2] K. Masui, K. Demizu, Y. Sato, and T. Sone, “Surface Modification of Tool Steel by Alloy in Method Using EDM Process,” Proc. of Int. Symp. on Electro Machining, Lausanne, Switzerland, pp. 419-426, 1995.
3. [3] N. Mohri, N. Saito, and Y. Tsunekawa, “Metal Surface Modification by Electrical Discharge Machining with Composite Electrode,” Annals of the CIRP, Vol.42, No.1, pp. 219-222, 1993.
4. [4] A. Goto, T. Magara, T. Moro, H. Miyake, N. Saito, and N. Mohri, “Formation of hard layer on metallic material by EDM,” Proc. of Int. Symp. on Electro-Machining XII, pp. 271-278, 1998.
5. [5] H. Miyake, Y. Imai, A. Goto, T. Magara, N. Saito, and N. Mohri, “Improvement of Tool Life through Surface Modification by Electrical Discharge Machining,” Proc. of Int. Symp. for Electromachining (ISEM), pp. 261-270, 1998.
6. [6] A. Goto, T. Moro, K. Matsukawa, M. Akiyoshi, N. Saito, and N. Mohri, “Development of electrical discharge coating method,” Proc. of Int. Symp. on Electro-Machining XIII, Bilbao, Spain, pp. 581-588, 2001.
7. [7] T. Moro, A. Goto, N. Mohri, N. Saito, K. Matsukawa, and H. Miyake, “Surface Modification Process by Electrical Discharge Machining with TiC Semi-sintered Electrode,” J. of the Japan Society for Precision Engineering, Vol.67, No.1, pp. 114-118, 2001 (in Japanese).
8. [8] N. Sumi, A. Goto, H. Teramoto, Y. Yasunaga, and Y. Nakano, “Study of Si-containing amorphous layer by electrical discharge coating,” Int. J. of Electrical Machining, Vol.16, pp. 27-32, 2011.
9. [9] N. Sumi, A. Goto, H. Teramoto, Y. Yasunaga, and Y. Nakano, “Study of the Si-Containing Amorphous Layer by Electrical Discharge Coating – Wettability and Erosion Resistance of the Si-Containing Amorphous Layer for Lead-Solder –,” J. of the Japan Society for Precision Engineering, Vol.78, No.11, pp. 970-974, 2012 (in Japanese).
10. [10] K. Furutani, “Proposal for Abrasive Layer Fabrication on Thin Wire by Electrical Discharge Machining,” Int. J. Automation Technol., Vol.4, No.4, pp. 394-398, 2010.
11. [11] M. Kosuge, N. Mohri, H. Takezawa, and K. Furutani, “Surface Treatment of Feeding Wire and Its Application to Combined Machining,” J. of Japan Society of Electrical Machining Engineer., Vol.39, No.91, pp. 9-15, 2005 (in Japanese).
12. [12] D. K. Aspinwall, R. C. Dewes, H. G. Lee, J. M. T. Simao, and P. McKeown, “Electrical discharge surface alloying of Ti and Fe workpiece materials using refractory powder compact electrodes and Cu wire,” Annals of the CIRP, Vol.52, No.1, pp. 151-156, 2003.
13. [13] Y. Uno, A. Okada, Y. Hayashi, and Y. Tabuchi, “Surface Modification by EDM with Nickel Powder Mixed Fluid,” Int. J. of Electrical Machining, Vol.4, pp. 47-52, 1999.
14. [14] M. L. Jeswani, “Effect of The Addition of Graphite Powder to Kerosene Used as The Dielectric Fluid in Electrical Discharge Machining,” Wear, Vol.70, pp. 133-139, 1981.
15. [15] B. Nowicki, R. Pierzynowski, and S. Spadlo, “The electrodischarge-based surface alloying process using brush electrode,” Proc. of Int. Symp. on Electro-Machining XII, pp. 289-298, 1998.
16. [16] T. Moro, A. Goto, N. Mohri, N. Saito, K. Matsukawa, and Y. Fukushima, “Study on a Piling Mechanisms in a High-Speed Surface Modification Process by EDM,” Trans. of the Japan Society of Mechanical Engineers, Series C, Vol.69, No.638, pp. 38-42, 2003 (in Japanese).
17. [17] P. V. Ramarao and M. A. Faruqi, “Characteristics of the surfaces obtained in electro-discharge machining,” Precision Engineering, Vol.4, No.2, pp. 111-113, 1982.
18. [18] N. Mohri, N. Saito, and M. Higashi, “A New Process of Finish Machining on Free surface by EDM Methods,” Annals of the CIRP, Vol.40, No.1, pp. 207-210, 1991.
19. [19] J. P. Kruth et al., “In-process alloying of the white layer of a workpiece machined by die-sinking EDM,” Int. J. of Electrical Machining, Vol.3, pp. 33-38, 1998.
20. [20] A. Goto, T. Moro, and K. Matsukawa, “Development of Electrical Discharge Coating Machine (EDCOAT),” J. of Japan Society of Electrical Machining Engineers, Vol.34, No.75, pp. 38-43, 2000 (in Japanese).
21. [21] N. Mohri, Y. Fukushima, Y. Fukuzawa, T. Tani, and N. Saito, “Layer Generation Process on Work-Piece in Electrical Discharge Machining,” Annals of the CIRP, Vol.52, No.1, pp. 157-160, 2003.