Long-Pulse Laser Micro-Hole Drilling of Titanium Foils for Hydrogen Components

The wider use of hydrogen is essential for sustainable energy storage, but the high cost of hydrogen components limits its adoption. The hydrogen sector seeks cost-effective methods to fabricate electrolyser parts, such as the porous transport layer (PTL), currently made of titanium felts. Laser drilling is a potential low-cost method to manufacture PTLs from titanium foils. Various pulsed lasers, from microsecond to femtosecond, can be used to produce such PTLs, with the former expected to be more cost-efficient. This paper investigates the fundamental characteristics of micro-hole drilling in 50 µm thick titanium foils using a microsecond pulsed single-mode fibre laser. Key laser drilling parameters, including peak power, pulse duration, and number of pulses (NoP), were studied. Results revealed that increasing energy input through longer pulse durations paradoxically reduced penetration depth. The underlying ablation mechanism were systematically investigated to optimise it for micro-hole drilling. Optimal percussion drilling of closely spaced, micro-holes (~35 µm) with a processing time of 6 ms per hole was achieved with 3 pulses of 25 µs duration and 10 mJ energy at 500 Hz.