Title: Pulsed laser machining of high-performance engineering and biomedical alloys

Authors: Asma Perveen; Adrian H.A. Lutey; Luca Romoli; Annamaria Cucinotta; Stefano Selleri

Addresses: Department of Mechanical Engineering, Nazarbayev University, Astana, 010000, Republic of Kazakhstan ' Dipartimento di Ingegneria e Architettura, Università degli Studi di Parma, Parma, 43124, Italy ' Dipartimento di Ingegneria e Architettura, Università degli Studi di Parma, Parma, 43124, Italy ' Dipartimento di Ingegneria e Architettura, Università degli Studi di Parma, Parma, 43124, Italy ' Dipartimento di Ingegneria e Architettura, Università degli Studi di Parma, Parma, 43124, Italy

Abstract: The exceptional mechanical and thermal properties of high-performance engineering and biomedical alloys lead to difficulties in machining with conventional processes. This work explores nanosecond pulsed laser machining as a flexible alternative to overcome manufacturing-related limitations associated with Ni Hastelloy, Ti-6Al-4V titanium alloy and Stellite 6K. An extensive experimental campaign was performed with a 1064 nm nanosecond pulsed fibre laser, quantifying the ablation threshold, penetration depth and material removal rate as functions of average laser power (2 to 20 W), repetition rate (20 to 80 kHz), scanning velocity (100 to 2,000 mm/s) and number of laser passes (1 to 20). Optimum conditions for machining were achieved for all alloys with 20 W average power, 20 kHz repetition rate and 1,000 mm/s scanning velocity due to strong ejection of the liquid phase with high pulse fluence (71 J/cm²), good process stability and material removal rates in the range 0.08 to 0.17 mm³/s.

Keywords: Ni Hastelloy; Ti-6Al-4V; stellite 6K; pulsed laser machining; nanosecond ablation; non-conventional machining; heat accumulation; ablation threshold; removal rate; penetration depth; machining quality.

DOI: 10.1504/IJMMM.2020.105664

International Journal of Machining and Machinability of Materials, 2020 Vol.22 No.2, pp.137 - 152

Received: 11 May 2018
Accepted: 16 Jan 2019
Published online: 09 Mar 2020 *

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