Precision Micron Hole Drilling using a Frequency Doubled, Diode Pumped Solid State Laser

Friedman, H W ; Pierce, E L

Lawrence Livermore National Laboratory

关键词: Thermal Diffusion;    Solid State Lasers;    42 Engineering;    Drilling;    Laser Drilling;   

DOI  :  10.2172/15014643
RP-ID  :  UCRL-TR-208902
RP-ID  :  W-7405-ENG-48
RP-ID  :  15014643

美国|英语

来源: UNT Digital Library

【 摘 要 】

This work represents the second phase of a program to demonstrate precision laser drilling with minimal Heat Affected Zone. The technique uses a Diode Pumped Solid State Laser with two wavelengths and two modes of operation. The fundamental mode of the DPSSL at 1.06 microns is used to drill a hole with a diameter of a fraction of a millimeter diameter in a millimeter thick substrate quickly, but with low precision. This hole is then machined to precision dimensions using the second harmonic of the DPSSL Laser at 532 nm using a trepanning technique. Both lasers operate in the ablative mode with peak powers at or above a giga-watt per square centimeter and pulse durations in the 80 - 100 ns range. Under these conditions, the thermal diffusion distance is of the order of a micron or less and that fact coupled with the ablative nature of the process results in little or no HAZ (heat affected zone). With no HAZ, there isn't any change in the crystalline structure surrounding the hole and the strength of the substrate is maintained. Applications for these precision holes include cooling passages in turbine blades, ports for diesel injectors, suction holes for boundary layer control on wings and holes for dies in precision extrusion processes.