Product Code: ICAL07_1201

The Influence of Pulse Parameters on the Laser Drilling of Hastelloy X
Authors:
Paul Jacobs, LFI, Inc.; Smithfield RI USA
Robin Bright, University of Connecticut Institute of Materials Science; Storrs CT USA
Harris Marcus, University of Connecticut Institute of Materials Science; Storrs CT USA
Mark Aindow, University of Connecticut Institute of Materials Science; Storrs CT USA
Presented at ICALEO 2007

Pulsed laser drilling has recently become of increasing importance to the aerospace industry as a method of creating cooling holes in a variety of high temperature gas turbine engine components. The potential for improved processing speed, accuracy, and reproducibility compared to conventional machining methods make laser drilling attractive from both an economic and product quality standpoint. In this research, a parametric study was performed investigating the molten material behavior of Hastelloy X during laser pulsed laser drilling. Pulse energies ranging from 1 10 J, pulse repetition frequencies ranging from 1.6 40 Hz, and pulse durations of 0.6 and 1.2 ms were employed using a DMG LASERTEC80 PowerDrill system and a 1.064 nm wavelength Nd:YAG laser. Characteristics of molten material generated during laser drilling and the behavior of material removal was studied for the above parameters as a function of number of laser pulses. Metallographic cross sections and quantitative image analysis were used to determine thickness of the recast layer on both the sidewalls and the bottom of partially drilled through holes. A clear relationship was established between laser pulse parameters and the amount of residual molten material. This relationship can be utilized to decrease recast layer thickness and variation and improve cooling hole quality.