A comparative assessment in sequential μ-drilling of Hastelloy-X using laser in combination with μ-EDM and μ-ECM

• Published in: Journal of the Brazilian Society of Mechanical Sciences and Engineering Vol. 43; no. 7
• Main Authors: Sivaprasad, P. V., Panneerselvam, K., Noorul Haq, A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2021; Springer Nature B.V
• Subjects: Drilling; Electric discharge machining; Electrochemical machining; Engineering; Gas turbines; Hastelloy (trademark); Laser applications; Laser cooling; Laser processing; Lasers; Mechanical Engineering; Microholes; Nickel base alloys; Passageways; Productivity; Superalloys; Technical Paper; Thermal fatigue; Variance analysis; Hastelloy-X; Surface characterization; ECM; Laser; Sequential micro-drilling; EDM
• DOI: 10.1007/s40430-021-03068-4
• ISSN: 1678-5878

Hastelloy-X is a nickel-based superalloy predominantly using in engine combustion zone parts of gas turbines. Micro-holes are drilling to the surface of these parts for air-cooling passageways to improve part-life by reducing thermal fatigue. Laser, micro-electric discharge machining ( µ EDM), and micro electrochemical machining ( µ ECM) are the major processes for creating holes in superalloys. Yet, if used individually, these techniques could end up with faulty holes. The sequential application of multiple drilling methods for hole-making will eliminate the defects. In this work, micro-holes have drilled on Hastelloy-X by using a laser in sequence with μ EDM and laser in sequence with μ ECM. Holes produced by these two-hybrid approaches are later compared for productivity and quality features. Both form and productivity factors have been estimated, and optimal input combinations for each response have been identified from the mean analysis. The Pareto-Analysis of Variance has been used to determine the critical factors for each response. A detailed characterization study has been done to ensure the surface integrity of the holes. It has been found that micro-holes formed by sequential laser processing with μ EDM improve the responses compared to the individual μ EDM outputs. A similar improvement has also observed in laser combined with µ ECM holes concerning individual µ ECM. Both results collectively indicated that the novel sequential laser approach with µ EDM is more efficient than the sequential application of laser with the µ ECM. This study provides clear guidance for the sequential micro-drilling of Hastelloy-X using numerous non-traditional drilling approaches.