Hole geometry and surface integrity assessment in drilling of inconel 718 using laser texture filled solid lubricant tools

Abstract

Purpose

Inconel 718 is used in gas turbine engines for aerospace applications due to high creep resistance but generating a hole with good surface integrity is challenging because the γ′′ interface is very strong so that slip is difficult in the grain boundary. So, the purpose of this work is to enhance the performance of drilling using a micro texture drill tool filled with solid lubricant.

Design/methodology/approach

Three different micro textures such as star shaped with 6-sharp apex, rectangular slots parallel and perpendicular to drill axis are created using laser on the drill tool. Deep cryogenic treatment is done on the textured tool to improve the strength and wear resistance before it is filled with solid lubricant. A detailed experimental investigation is performed to analyse the hole geometry and surface integrity of the drilled hole.

Findings

The accuracy of the drilled holes is enhanced in the star shaped texture drill tool over other textured and non-textured tools. A significant improvement in surface finish and hardness are observed and moreover cylindricity error, burr height of the hole is less for the above condition. It is also inferred that, at lower feed rate and higher speed produce hole with an accuracy of 96%.

Originality/value

Aerospace industry is focussing on improving the hole geometry and surface in Inconel 718. This work demonstrates the novel technique to improve drilling of Inconel 718 using laser textured tool filled by the solid lubricant.

Citation

Mishra, P.K., Kalidas, P. and T., J. (2021), "Hole geometry and surface integrity assessment in drilling of inconel 718 using laser texture filled solid lubricant tools", Industrial Lubrication and Tribology, Vol. 73 No. 10, pp. 1267-1274. https://doi.org/10.1108/ILT-07-2021-0237