Mathematical modeling and experimental evaluation of superalloy EDM using cryogenically treated electrodes and transformer oil-based dielectrics: a correlation study

• Published in: International journal of advanced manufacturing technology 2023-11, Vol.129 (3-4), p.1649-1663
• Main Authors: Ishfaq, Kashif, Sana, Muhammad, Waseem, Muhammad Umair, Mahmood, Muhammad Arif, Anwar, Saqib
• Format: Article
• Language: English
• Subjects: Brasses; CAE) and Design; Computer-Aided Engineering (CAD; Copper; Cryogenic treatment; Dielectrics; EDM electrodes; Electric discharge machining; Electrodes; Engineering; Factorial design; Grain size; Industrial and Production Engineering; Mathematical analysis; Mechanical Engineering; Media Management; Nickel base alloys; Original Article; Simulation; Superalloys; Surfactants; Transformers
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-023-12398-7

Geometrical inaccuracy is one of the electric discharge machining (EDM) errors and is mainly influenced by the dielectric being used during the operation. The non-conventional machining processes are opted over traditional machining operations due to the greater strength of Ni-based superalloy, specially, Inconel 617 (IN617). But still, there is a need to upgrade the dielectric fluid to minimize the overcut. Therefore, this study uses a combination of surfactant-added dielectrics of transformer oil and cryogenically treated (CT) electrodes (copper and brass). One of the exceptional benefits of applying the cryogenic treatment on the electrodes is that it refines the grain size of the electrode which helped in the regular sparking and reduced the dimensional inaccuracy throughout the EDM operation. A set of 20 experiments under the full factorial design technique was implemented. The experimental results have been explained with process physics, and along with simulation to explore the mechanism of machining with mathematical expressions. The machining capabilities of CT electrodes provided greater dimensional accuracy by an average of 17.1% compared to non-CT electrodes. CT brass provided the minimum dimensional inaccuracy (0.023 mm) in T-20. However, the non-CT copper electrode showed the lowest overcut (0.134 mm) obtained transformer oil without the addition of surfactant. The modeling was also performed to measure the crater sizes produced during the machining of Ni-based superalloy. The simulation results revealed that the mean absolute divergence between the current simulation findings and the ones provided in the literature was approximately equal to 5–7%.