EXPERIMENTAL STUDY OF PRODUCING NON-TAPERED HOLES USING A HIGH PEAK POWER PULSED ND:YAG LASER

摘要

Experiments of laser percussion drilling were carriedrnout on nickel-based superalloy using a modifiedrnpulsed Nd:YAG laser with adaptively collimatingrnoutput. Peak power, pulse energy and assist gasrnpressure were optimized experimentally.rnExperimental results demonstrated that combinationrnof pulses, focal position, the number of pulses in therncombination are the main factors of hole taper. Arnpulse combination with increasing pulse energy is anrneffective method to produce non-tapered holes. Evenrnnegative taper holes can be produced throughrnincreasing the number of pulses in the pulserncombination. And 1.1～1.7 mm above the surface ofrnthe sample helps reducing the taper of holes.rnNon-tapered holes with diameter of 480 μm and 510rnμm were drilled on nickel-based superalloy withrnthickness of 1.5 mm and 3 mm. Variation of holerndiameter was about 30μm, and hole taper was <1%.rnA feasible method of producing parallel holes and anrnapplied Nd:YAG laser have been presented for laserrnpercussion drilling, may also be used on otherrnmaterials.