Slag on bottom of .125 Aluminum 10

[Barneylaser]

Is there a rule of thumb for aluminum cutting?
I'm getting a burr "slag" on the bottom of 1/8 and thicker.
I can push off the burr with my finger but would like to eliminate it.
I can find tons of info on stainless Like
(long sharp burr means focal point is too high. Small burr means focal point too low.)
and steel 02 cutting (not too much on Nitrogen cutting)
The main thing I'm looking for is
#1 Aluminum (Nitrogen cutting) and
#2 Steel (Nitrogen cutting)
I have the "cutting know how" paper
but it is not very descriptive and short on Aluminum.

 

[RPosty]

When we cut it, we are happy if it comes off with a finger. we don't actually try for better than that.

"I am stuck on Band-Aid brand, 'cause they are stuck on me"

 

[Barneylaser]

Thanks RPosty
I can get virtually burr free on .100 thick but as soon as I go to 1/8 I have problems.
I have tried to set parameters from example of my .100 settings but it doesn't seem to help.
Just looking for rule of thumb for aluminum cutting in general.
Some thing like the "cutting know how" paper.
It seems like cutting aluminum is a Secret society or Men in Black type of thing.

 

[GotSteel]

maybe this will help. this is the basics for our byst lasers

 

[Barneylaser]

Thank you "Gotsteel"
That is the most information I have found about how to go about fixing problems when cutting aluminum. When I get back to cutting 1/8 (or thicker) I'll try some of the solutions I see in the file.
I appreciate the information

 

[lasermate]

What type of lens are you using? Have you tried to turn up the gas pressure?

 

[Barneylaser]

Thanks "Lasermate"
7.5"lens from (IIVIinfrared) and yes I have tried turning up the pressure. I think some of it may be focal position. I have moved focus into the material some (up from the bottom) and it seems to have helped a little. Going to try and mess around with it some more next week.

 

[Foostrap]

How much power does your machine have? The more power, the thicker you can clean cut aluminum. Above a certain thickness, it is normal to have a burr; as long as it is soft.
With 4000W, I was able to cut 1/8 alu clean; no burr at all. Don't use too much gas pressure; I used around 10 bar.

 

[Barneylaser]

I have a 4000W machine.

 

[Foostrap]

Then you should be able to get it burr-free (assuming you cut 5052 or 6061 aluminum). Try to lower your gas pressure.

 

[Barneylaser]

Footstrap,
Where did you have your focal point set, what nozzle size were you using and at what speed.

 

[Foostrap]

Nozzle of 2.0mm conical.
Focus at -2.4mm (0 being top of the material; negative is below material surface)
Speed 125"/min

 

[Barneylaser]

Thank you everyone for all the help.
I thought with Aluminum you wanted to make sure you were always at the bottom of the material or deeper.
I found that if I moved my focal point to -.100
I had much better quality.(I was at -.125).
This forum is about the only place I have ever found information that was helpful.
I guess with the onslaught of cheap chinese "Laser engravers" it's hard to find an informative community on laser cutting.
What a great place this is.