Lately i bought a 4x beamexpander. My 60W CO2 lasertube emits a beam of 2.5mm.. At the head, this is still 2.5mm round.
While the hole in the head is 14mm, i thought i could expand the beam to 10mm.
I expected the focuspoint to become 4x smaller ad 16x more density of power.
Well... this point is smaller ( i haven't measured it yet..)
But ... when i engrave, i need much more power than before!
OK, i know i might have some losses in the expander but a max of 15-20% is considered acceptable..
I think the powerdrop is about 90%...
Is this normal or should i have to reduce my power when everything was normal (like i expected)
Who has experience with beamexpanders??
BTW i focus with a proximityswitch with high accuracy.. my focus is within 0.05mm..
Kees