# Laser cutting/drilling of copper

In industry, it's common to cut steel using 50-200 W $\mathrm{CO}_2$ laser.

Meanwhile, for making holes in PCB (35 $\mu$m of Cu), DPSS 355 nm laser is usually used and secondary $\mathrm{CO}_2$ to drill through glass.

Why $CO_2$ cuts steel easily, but cannot be used to make holes in Copper?

UPDATE: Will it help to add thin layer of black paint + pre-heat to 200 °C to get through damn 0.035 mm of Cu?

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More to the point: Why does copper reflect CO2 laser light (8-10 µm) significantly better than steel? –  Nick T Jan 11 '11 at 17:34
Yes, this is what puzzled me too. Probably that's because DPSS works in pulsed mode, while CO2 is usually constant emission => worse hole quality probably. –  BarsMonster Jan 11 '11 at 17:53