Laser drilling of advanced materials: Effects of peak power, pulse format, and wavelength

Abstract

The quality of laser-drilled holes is significantly influenced by the laser peak power, pulse format, and wavelength. Three advanced materials are used to demonstrate the importance of choosing the correct laser parameters for a specific material. The materials are: (1) intermetallic single crystal nickel aluminide (NiAl) alloy; (2) N5, a single crystal nickel-based superalloy; and (3) a silicon carbide (SiC) ceramic matrix composite (CMC). The laser peak power is varied in terms of the pulse duration and format. For low peak powers, long pulse format (pulse lengths on the order of ms), conventional and also shaped-pulse (burst) commercial rod Nd:YAG laser systems were used. For high peak powers, a short pulse format was adopted for the laser used, namely a cw-pumped Q-switched or modelocked/Q-switched Nd:YAG oscillator followed by a cw-pumped multipass amplifier using a face-pumped, total internal reflection Nd:YAG slab as the gain medium. Finally, a KrF excimer laser operating at a 248 nm wavelength was used. The excimer wavelength was chosen to be close to the Nd:YAG fourth harmonic.

A Soft Strain Sensor Based on Ionic and Metal Liquids

“…After 30 minutes of curing at 65°C, the CO 2 laser was used at low power (30% of maximum speed, 22% of maximum power) to micro-machine the interfaces in order to remove the poorly conducting elastomer layer formed during curing and thereby expose the nanoparticles on the surfaces that will contact the fluids. This did not affect the nickel particles, since the laser wavelength (10.6 μm) was too long to be absorbed by this metal [42]. The resistance of the resulting interface was as low as 30 throughout its entire length (4 mm).…”

Wettability characteristics of an Al2O3/SiO2-based ceramic modified with CO2, Nd:YAG, excimer and high-power diode lasers

“…Similarly, from work investigating alternative routes to the laser ablation-deposition (LAD) of Al 2 O 3 and Ti:saphire using CO 2 and excimer radiation, Dyer et al [10] found that laser wavelength was a major influence in determining the likelihood of successful deposition. A study conducted by Chen et al [11] using Nd:YAG and excimer lasers found that the quality of laser drilled holes was significantly influenced by laser wavelength.…”

Wettability characteristics of a modified mild steel with CO2, Nd:YAG, excimer and high power diode lasers

“…Previously the main fundamental differences resulting from wavelength variations of CO, CO 2 , Nd:YAG and excimer lasers for a number of materials processing applications have been detailed [1][2][3][4]. Likewise, such practical comparisons between these traditional materials processing lasers and the more contemporary high power diode laser (HPDL) are even fewer in number.…”