Beveling effect on 1/2" black acrylic

[GraphicsSource]

Hi,

I've been having trouble cutting 1/2" black acrylic in our GCC laser 120w...i can cut through the material just fine but i keep getting this beveling effect on the face around the edges (see photo). I've tried going faster with more passes, adjusting the power, adjusting the air etc. It is like this on both sides.

Anyone have any idea of the cause and possible solution? Help! Thanks!

 

[Devon19515]

my first thought would be to clean the mirrors and check the focus

 

[V-ENGRAVE]

Most probable cause for bevel effect when cutting thicker materials is due to beam alignment. If the beam is not hitting lens dead on it will cut angled. It will not be noticeable on less than 3/16" material.

 

[bjt140]

That's from your heat affected zone. What frequency and power and speed are you cutting at?

The other item that adds more to the ripple is the paper backing. The adhesive makes the ripple worse, try cutting without the top paper and see if it looks better that way.

 

[letterman7]

^ this. That's heat induced.

 

[GraphicsSource]

Thanks for the replies. I'm running at 100power at .5% speed and taking 2 passes...I think the issue may be that the 1/2" material is really getting towards the max capabilities of the machine and it just cant cut it fast enough and the heat builds up.

 

[GVP]

Refocus the beam half way through? At ½" thick, if you aligned to the top of the material, it will be out of focus by the time it gets to the bottom?

 

[rossmosh]

Thanks for the replies. I'm running at 100power at .5% speed and taking 2 passes...I think the issue may be that the 1/2" material is really getting towards the max capabilities of the machine and it just cant cut it fast enough and the heat builds up.

First thing to do is check the actual output of power from the laser. Mahoney makes a $100 analog power gauge that seems to work okay from what I've read.

The next thing you need to do is play with your focus. As GVP said, focusing into the material should help. On 1/2" material, you should probably focus about 1/8" into the material. I'd also try to go in 1 pass. 120W should be able to do 1/2" material in 1 pass.

Last thing you want to is play around with your air assist. Increasing the PSI could make the difference.