My laser accidently made a few great cuts and now I can't duplicate it

[Al Stewart]

My laser: 40W ULS VersaLaser with 2" lens
Laser settings: power=90%, speed=3.6%, PPI=300, z=.110" With and without air assist.
The material: 3/16" cast acrylic, with 8mil photo print and 3mil poly lamination film. The paper mask still on the underside of the acrylic.
The problem: laser burns/melts the lamination film at point of the cut


I have tried for years to solve the above problem, and a few days ago I tried lowering the focal point from .177" to .110" and I got absolutely perfect cuts!

The next day I used the SAME piece of scrap, the SAME settings and I got the SAME old terrible cuts.

It seems my laser accidently made a few marvelous cuts.

I would be forever grateful if someone would help me solve this mystery. Any ideas? Maybe erratic power output? Global warming?:) ??? Stock prices?

Thanks!
Al

[Mike Null]

Al

Are you using a cutting grid in your machine?

[Al Stewart]

Al

Are you using a cutting grid in your machine?

Hi Mike, I have tried it both ways: Honeycomb and the flat engraving table.

I thought I was on to something tonight when I noticed very little air flow in the air assist. But, I fixed that, and it didn't help.

FWIW, to cut 3/16 black cast acrylic (nothing laminated, with only the paper mask on the bottom) I have always had to use 100% power, 1.8% speed--when the machine was new, as well as after replacing the tube. Does that sound right for a 40W system??

Al

[Mike Null]

Al
It's difficult to judge a "norm" for various systems because of all the variables involved. I would advise using a cutting grid whenever you are in the cutting mode. Since your air assist appears not to be working consistently. that may be a problem. I would double check the mirrors and lens for cleanliness. There is a good chance that a malfunctioning air assist could cause issues with both and clean mirrors and lens are essential to good cuts.

A malfunction while cutting can damage the lens so that would be my first check.

[John Bion]

As Mike said above: Is your cone a bit blocked with detritus? Poor airflow will physically restrict the cone, cause filthy/burned lens and even mirror. I would check those first. What is your source of compressed air? Does it contain condensation that may also have oils, etc in it? Kind Regards, John

[Al Stewart]

Thank you, fellas, for all the great brainstorming! I was never able to get good cuts on laminated photos on acrylic, since the laser was new 17 years ago. After spending hundreds of hours, I gave up and simply used the laser for other things. Until a couple of weeks ago, when I was shocked to see it make perfect cuts! The next day it was back to making the same old terrible cuts, even with the same settings and the same sample piece. I have now been doing the same things I did 17 years ago, with the same results.

It's time to abort the mission. With the new lasers on the market selling for 1/3rd of what I paid in 2006, I look forward to using the incredible features available. I think I will be getting the XTool P2.

Thanks again for all the ideas! This is a great forum!!

[Richard Coers]

Thank you, fellas, for all the great brainstorming! I was never able to get good cuts on laminated photos on acrylic, since the laser was new 17 years ago. After spending hundreds of hours, I gave up and simply used the laser for other things. Until a couple of weeks ago, when I was shocked to see it make perfect cuts! The next day it was back to making the same old terrible cuts, even with the same settings and the same sample piece. I have now been doing the same things I did 17 years ago, with the same results.

It's time to abort the mission. With the new lasers on the market selling for 1/3rd of what I paid in 2006, I look forward to using the incredible features available. I think I will be getting the XTool P2.

Thanks again for all the ideas! This is a great forum!!
You sure you want to drop down to a diode laser? That's a huge drop in specifications! By the way, you are working with a robot. It can't produce accidents, YET

[Al Stewart]

Hi Richard!
Actually the xTool P2 is a 55W CO2 laser.
Al