High-quality laser microdrilling of metals and ceramics with maximum aspect ratio

Abstract

To meet the industry's demand for reducing machine cycle lengths concerning laser-drilling a Nd:YAG MasterOscillator Power-Amplifier (MOPA)-system was developed at the LMTB-laboratories that emits high-power peakpulses at excellent beam-quality. Presently, the output power of the oscillator (10W@1064nm) with a beam-quality of M²=1.3 is amplified to 95W@1064nm with M²=2.3 and a single pulse energy up to 500mJ. The pulse duration can be varied between 26 and 230ns. On account of the excellent beam quality, frequency conversion resulted in 49W@532nm and 4.8@266nm. The MOPA-System is used for laser micro drilling experiments into metals and ceramics where the influence of the beam quality on the geometrical shape of the hole is investigated and compared with applications conducted with similar laser systems. Additionally means in optimizing the drilling process such as burr-minimizing and melt-reduction were introduced. Furthermore, experiments using tapered drilling technique are undertaken. A maximum aspect ratio of 1:200 in stainless steel was obtained.

High power Nd:YAG laser with self-pumped phase-conjugate loop cavity and repetitive pulsed diode-matrix side-pumping

“…An importance to develop the powerful pulsed solid-state lasers with high spatial brightness is caused by many possibilities of its applications, for example, in the remote monitoring [1,2], the laser-induced breakdown spectroscopy [3,4], and the ultrahard material processing [5,6]. Use of diode pumping gives high laser efficiency, compactness, laser operation stability, and simplicity in exploitation.…”

“…One of well-known schemes of high-energy pulsed laser systems is master oscillator -power amplifier system. A master oscillator generates low-energy laser beam with high spatial and temporal quality [5,7]. A power amplifier (or many amplifiers) gives high energy laser output, but results in degradation of the beam quality.…”