Title: Effect of deep cryogenic treatment on different graphite electrodes for EDM performance

Authors: Israa Dheyaa Khalaf Alrubaye; Gualtiero Fantoni; Davide Melis; Massimo Arcioni; Dario Clori; Francesco Grazzi; Leonardo del Rosso

Addresses: Department of Smart Industry, University of Pisa, Largo Lucio Lazzarino, 56122, Pisa, Italy ' Department of Civil and Industrial Engineering, University of Pisa, Largo Lucio Lazzarino, 56122, Pisa, Italy ' Baker Hughes Nuovo Pignone Tecnologie S.r.l., Felice Matteucci 2, 50127, Florence, Italy ' Baker Hughes Nuovo Pignone Tecnologie S.r.l., Felice Matteucci 2, 50127, Florence, Italy ' Baker Hughes Nuovo Pignone Tecnologie S.r.l., Felice Matteucci 2, 50127, Florence, Italy ' National Research Council, Institute of Applied Physics, Madonna del Piano 10, Sesto Fiorentino, Florence, Italy ' National Research Council, Institute of Applied Physics, Madonna del Piano 10, Sesto Fiorentino, Florence, Italy

Abstract: In the present investigation, cryogenic treatment (CT) has been used to enhance the efficiency of electrical discharge machining (EDM). Different cylindrical electrodes, made of high-quality (QG) and standard (SG) graphite have been cryogenically treated at temperatures of -185°C and -196°C with varying soaking durations using liquid nitrogen and helium gas as a cooling system. Raman spectroscopy has been employed to monitor the microstructural changes in the graphite material. The impact of cryogenic treatment on the graphite electrode microstructure has been investigated using a scanning electron microscope (SEM). While the microstructure of the machined workpiece has been investigated using optical microscopy (OM). The EDM experiments showed that cryogenically treated standard graphite electrode for 24 h (liquid nitrogen system) reduced the total machining time by 45% and machined surface roughness by 15%, compared to untreated electrode. These findings highlight the benefits of cryogenic treatment for enhancing EDM performance when using graphite electrodes.

Keywords: deep cryogenic treatment; electrical discharge machining; EDM; graphite electrode; cooling system; Raman spectroscopy; machined surface roughness.

DOI: 10.1504/IJMMM.2025.150055

International Journal of Machining and Machinability of Materials, 2025 Vol.27 No.4, pp.431 - 456

Received: 15 Oct 2024
Accepted: 01 Mar 2025
Published online: 28 Nov 2025 *

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