Experimental study of producing non-tapered holes using a high peak power pulsed Nd:YAG laser

Abstract

Experiments of laser percussion drilling were carried out on nickel-based superalloy using a modified pulsed Nd:YAG laser with adaptively collimating output. Peak power, pulse energy and assist gas pressure were optimized experimentally. Experimental results demonstrated that combination of pulses, focal position, the number of pulses in the combination are the main factors of hole taper. A pulse combination with increasing pulse energy is an effective method to produce non-tapered holes. Even negative taper holes can be produced through increasing the number of pulses in the pulse combination. And 1.1∼1.7 mm above the surface of the sample helps reducing the taper of holes. Non-tapered holes with diameter of 480 µm and 510 µm were drilled on nickel-based superalloy with thickness of 1.5 mm and 3 mm. Variation of hole diameter was about 30 µm, and hole taper was <1%. A feasible method of producing parallel holes and an applied Nd:YAG laser have been presented for laser percussion drilling, may also be used on other materials.Experiments of laser percussion drilling were carried out on nickel-based superalloy using a modified pulsed Nd:YAG laser with adaptively collimating output. Peak power, pulse energy and assist gas pressure were optimized experimentally. Experimental results demonstrated that combination of pulses, focal position, the number of pulses in the combination are the main factors of hole taper. A pulse combination with increasing pulse energy is an effective method to produce non-tapered holes. Even negative taper holes can be produced through increasing the number of pulses in the pulse combination. And 1.1∼1.7 mm above the surface of the sample helps reducing the taper of holes. Non-tapered holes with diameter of 480 µm and 510 µm were drilled on nickel-based superalloy with thickness of 1.5 mm and 3 mm. Variation of hole diameter was about 30 µm, and hole taper was <1%. A feasible method of producing parallel holes and an applied Nd:YAG laser have been presented for laser percussion drilling, may also be use...