LASER DRILLING NS PULSED FIBRE LASER: A VERSATILE


TOOL FOR DRILLING APPLICATIONS JACK GABZDYL, TRUMPF UK


Figure 1: Alternative techniques for laser drilling


Laser drilling has found applications in almost every industry sector, from medical and aerospace to automotive, electronics and semiconductors. Traditionally, holes have been produced by mechanical drilling or processes such as chemical etching. However, with the increasing pace of technological development, end-user requirements are being driven by higher quality, faster production rates, and lower costs. Lasers are proving to be one of the most appropriate tools for many of today’s drilling challenges.


The boom in photonics has created a diverse range of laser sources with different wavelengths, pulse durations, and pulse energies, making it challenging for end users to select the most suitable source


for a given application. As with many industrial processes, this decision must be driven by cost, quality, and productivity.


CAPABILITIES OF NS PULSED FIBRE LASERS


Pulsed nanosecond (ns) fibre lasers such as TRUMPF’s TruPulse nano range have been commercially available for around 25 years and have made a significant impact on global manufacturing. These short- pulse, high peak intensity laser sources are well known for marking, engraving, cutting, and even welding, but their use for drilling is often overlooked.


The pulse control offered by the Master Oscillator Power Amplifier (MOPA) design provides exceptional


parametric flexibility. Operating in the infrared at 1.06 µm, these lasers deliver pulse energies from a few microjoules to over 1 mJ, with pulse durations from 3 to 2,000 ns, peak powers exceeding 10 kW, and repetition rates up to 4 MHz. The ability to tailor temporal pulse characteristics is key to their industrial success and effectiveness as drilling tools capable of processing most metals, as well as some ceramics, semiconductors, and composites.


SCANNER-BASED DRILLING TECHNIQUES


A range of scanner-based drilling techniques can be implemented using ns pulsed fibre lasers (Figure 1). In the simplest case, a single pulse can be used to pierce very thin materials such as metallic foils. Although limited by pulse energy, the high repetition rates allow thousands of holes per second to be drilled in scanner-based “on-the-fly” processes.


For thicker materials, percussion drilling is commonly employed, where multiple pulses are delivered to a static location to increase hole depth. Hole diameter is largely governed by the focal spot size, which must provide sufficient energy density for material ablation. Aspect ratios of up to 10:1 are possible, although 6:1 is more typical for consistent, high-quality holes. Laser-drilled holes usually exhibit some taper, typically in the 3–5 degree range, which can be minimised through focal position adjustment and pulse optimisation.


Figure 2: Drilling blind holes in silicon - pulse duration and the corresponding impact on peak power shows significant impact, with 200 ns/low peak power pulses achieving 4x the depth of the 50 ns/high peak power pulses


20 | LASER USER 119 MARCH 2026


Pulse characteristics such as peak power, pulse energy, and pulse duration have a significant impact on drilling performance. In blind- hole drilling of silicon at constant pulse energy, longer pulse durations with lower peak power can achieve substantially greater depths than shorter, higher peak power pulses (Figure 2).


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