3mm White Acrylic Burn marks – Laser

[Simon Worrall]

did you try removing the protective paper first?

[Hussein Ibrahim]

Hi yes i tried that too. Its not the blue from the top cap liner which is what i thought at first.

[David McDonald]

Hi

What bed are you cutting on – do you have the ‘honeycomb’ type with the smaller holes, or the type with the open slats / tines? We’ve always found that that on our laser the slats work better than the honeycomb on acrylic – any melted residue seems to flame less as it drips away or vaporises. Might be worth switching that if you have both bed types?

Cheers

Dave

[David McDonald]

Also, have you got air assist on – this helps blowing smoke/vapour away from the cut edge so it gets less dirty, likewise your extraction switched on so get rid of smoke build up.

[Hussein Ibrahim]

Hi Dave

Ive tried it without the honeycomb bed too still the same results but i will add a stronger inline extraction fan into the mix in addition to the fan already with the unit and see if that solves the issue.

The air assist is on, Im also quite curious as to why its not visible on clear acrylic?

[David McDonald]

Hello again

We generally find that white/colours need a slightly higher power/slower speed to get a smooth cut edge – albeit you can never get a polished style finish. Overall clear is easier to cut and is more forgiving if things aren’t set up correctly – might help explain why your clear is OK but doesn’t solve your problem with white.

Finally as you suggest try a different brand of acrylic ?

Good luck

Dave

[Michael Cunney]

White acrylics are often tricky and the burn marks are a common complaint to acrylic many manufacturers, it’s due to the additives within the acrylic that makes White …White, rather than a problem with the laser.

Your acrylic supplier will have had the same issue previously and have gone through the process of adding / removing certain additives to get the White just right for fabricators, so I’d recommend speaking to them as they may say you need a particular colour code.

It’s typically the much thicker gauge materials where extraction can have a bigger effect due to the amount of material being cut through (but even then from my own experience it’s towards the bottom or top of the cut, I forget, rather than straight through).

[Hussein Ibrahim]

Hi Dave,

I had another mess about and managed to get the cuts without the burn marks and though still with some striations in the cuts.

Im not too concerned with the striations and trying to get a polished edge. The aim is to not see the burn marks.

So an update is that on the left hand side i managed to get cuts quite close to perfect or almost perfect should i say without burns but the right hand side wont cut through the material which now has given rise to a new issue of levelling the the working table as it looks off a tad and also doing a laser beam alignment to the mirrors.

@micheal – yes the factory in china originally said it was the material and it makes sense with your explanation as a few people said try a different brand after couple of discussions.

Im still open to trying other brands for the white once suppliers get back to me with a price list to see how they perform against each other in general more curiosity than anything else, but im quite confident now that my issue is the above with the working table level and mirror alignment which feels like a nightmare to get sorted.