... when CNC-engraving with a 445nm-diode and around 40mm focal distance I'll get around 0.05mm spot size ... when XY-scanning with 200mm distance, the 'spot' gets a line with roughly 0.4x0.1mm.
With the fiberlaser it's much better -- when engraving with 60mm distance, the spot is around 0.02mm wide ... when XY-scanning with maybe 300mm distance, it stays round and gets maybe 3x bigger. But when using a beam-expander, this could be halved in size - so around 0.01mm engraving, 0.03mm XY-scanning ...
Viktor