Frosty Acrylic And Flashback
FROM A CLIENT (Nova 35-80):
I cut through 3/4" acrylic (cast, i think) like butter with 4” lens, 4 speed, 95 power, and about a 7mm focal length. I didn’t have time or the material to get the perfect edge (it was a little frosty 1/4” down from the top edge), but for what it’s being used for, it’ll definitely work.
This is a sample of the frost. The lines you see are actually on the bottom edge and are cut marks from the supplier. Not sure what causes the frost. May have to adjust focal length. I do have some left over that I’m going to mess around with, and will update if I can dial it in nicely. It at least didn’t have the kerf on the bottom side. Even cut, and the majority has a glass like finish.
OUR OBSERVATIONS:
Assuming the orientation is correct, and the striations visible are due to the factory sawed edge, I see 2 things going on here:
1. The frosting, outlined in blue, is from using too much air. the air is solidifying it prematurely so you are not getting that flame polished edge. the reason the rest is smooth is because not much air made it that far into the kerf due to the aforementioned solidification as well as the thickness of the material. When cutting acrylic, you want just enough air to mitigate the flames and expel the resultant gasses.
2. The spawling, outlined in green, is likely from flashback off the honeycomb. if the reflected beam is strong enough to cause significant thermal insult, in a finite pattern, that can be indicative of using too much power. if the power isn't over the top, you can 'stand off' the material from the honeycomb with magnets, spacers, etc... or remove the honeycomb and use the blade system. either will mitigate any remaining flashback.
Link To OP's FB Global Thunder Laser Users Post:
https://www.facebook.com/groups/globalthunderlaserusers/permalink/1159690097788186/
How to cut smooth acrylics
Related Articles
Best Practices For Cutting/Engraving Acrylic
Acrylic is an awesome medium for C02 lasing. This article will cover the processing of acrylic. Types Of Acrylic There are 2 common variations of acrylic and while they are all chemically similar, they behave very differently from one another due to ...3D Relief Engraving on Acrylic
Here is a 3D Relief engraving workflow on acrylic. This is the same file we used on the wood 3d relief engraving: 3D Relief Engraving On Natural Wood The acrylic is 6"x 6" x0.75" cast. Thunder Nova 35-80, stock 2" lens, standard focus (6mm from ...Ray Artemus Wood & Acrylic Sample Test
Original demo sample with no reverse compensation settings active (Thunder Laser Scanning Offset Adjustment): Wood Workflow: Wood Resultant Output: Acrylic Workflow. This art was scaled down from 160mm square to 69.442mm square: Acrylic Resultant ...Best Practices For Engraving Glass
typically you want to use as little power as possible to make a mark... kinda like when doing edge lit acrylic... the laser beam doesn't actually ablate the glass, it creates microfractures in the glass when the water molecules are converted to ...4” laser head
4” laser head is the laser head of the laser cutting machine that installed a 4” focus lens. The standard laser head is mainly used to cutting material less than 10mm. But if you want to cut thicker material, such as 17mm foam, the cutting edge would ...