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Drilling Technology

Fundamentals and Recent Advances

Ed. by Davim, J. Paulo

Series:Advanced Mechanical Engineering

eBook (PDF)
Publication Date:
October 2018
Copyright year:
2018
ISBN
978-3-11-048120-4
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2 Deep hole gun drilling of nickel-based superalloys

Woon, Keng Soon / Tnay, Guan Leong / Yeo, Swee Hock

Abstract

Miniature deep holes with length to diameter ratios above 100 are commonly produced with mechanical gun drilling because of the efficiency of this process in meeting stringent straightness and finishing requirements. However, such superiority diminishes while drilling nickel-based superalloys such as Inconel 718. This chapter addresses the fundamental cause arising from a critical change in the generation of cutting force that induces adverse impacts on deflection of drills, burnishing along the hole and the eventual deterioration in straightness accuracy. The unique tool wear and failure modes are discussed in detail to provide insights into the underlying challenges, especially on the severe thermal-mechanical loading conditions. To improve tool life during the process, an effective methodology that increases coolant efficiency through strategic optimization of drill designs is presented. Besides this, a new approach in designing pilot holes for gun drilling based on pilot hole and gun drill design compatibility is described, as effective tool-work engagement enhances drilling stability that benefits tool life as well as straightness accuracy. Finally, exploratory solutions to the adverse impacts of re-sharpening gun drills with primitive manual grinding apparatus - a long-standing challenge in multiple-pass gun drilling are also duly addressed.

Citation Information

Keng Soon Woon, Guan Leong Tnay, Swee Hock Yeo (2018). 2 Deep hole gun drilling of nickel-based superalloys. In J. Paulo Davim (Editor), Drilling Technology: Fundamentals and Recent Advances (pp. 37–88). Berlin, Boston: De Gruyter. https://doi.org/10.1515/9783110481204-002

Book DOI: https://doi.org/10.1515/9783110481204

Online ISBN: 9783110481204

© 2018 Walter de Gruyter GmbH, Berlin/Munich/BostonGet Permission

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