Post by Tjalling de Boer

🚗 ⚡ #autoenergy Mondays at Coherent Corp. ⚡️ The bottleneck in green hydrogen might be… hole drilling. 🛠️ In PEM water electrolysis, the microporous layer (MPL) sits between the porous transport layer and the catalyst-coated membrane — a small interface that can influence water distribution 💧, bubble release 🫧, and contact resistance 🔌. 📄 A recent Journal of Laser Applications paper looks at making ultrathin titanium MPLs via femtosecond laser microperforation — and the story is really about manufacturing tactics, not just “can we drill tiny holes?”. 📉 Thin looks great, until it has to be handled: 2 µm Ti: a single-pulse strategy delivers ~3 µm hole diameters and impressive porosity… but the foil becomes mechanically fragile and ultra-thin foil economics are tricky. ✅ So they move to 10 µm Ti and use multipulse on-the-fly percussion drilling: pulse-by-pulse control of breakthrough enables single-digit µm exit holes, even with production-friendly optics (f = 100 mm). Why I’m paying attention 👇 🌀 Quality window matters: higher fluence can lead to warping/wrinkling → lost perforations. 🧽 Oxidation nuance: the oxidised material is mainly the ablation debris, which can largely be removed by cleaning. ⏱️ Scale-up playbook: scan strategy + higher repetition rate + 1×9 DOE beam splitting takes cycle time from 37.0 s → 0.9 s per 20×20 mm² layer (>97% reduction), with throughput reported as 10.8 → 444 mm²/s. Where Coherent Corp. comes in 🔦 They used a Coherent Monaco ultrafast platform (1035 nm / 517 nm, <350 fs) — exactly the kind of source that supports precision drilling and parallel-beam scaling. 📌 Ref: 🙌 Alexander Wienke et al., “Laser micromachining strategies for high quality perforation of thin titanium foils to produce microporous layers for polymer electrolyte membrane electrolysis,” Journal of Laser Applications 37(4), 042019 (2025), Epub 6 Oct 2025, https://lnkd.in/eSutr-55 Leibniz Universität Hannover Laser Zentrum Hannover e.V. (LZH)