I am trying to etch some adhesive metal plaque plates. The markings at 60%-70% power look great. The problem is that the heat of the etch is bending the metal. I wanted to see if there was anything I could do to slow the etching process. So far I have changed the fill method to only etch in one direction. That helped a little, but still the material is bending.
Is there a way to pause between passes, or interleave the strokes?
For the record…
Since moving to LightBurn, life has been great.
Here is a solution that has worked for me:
strong magnets, or just really slowing it down to avoid heat build up - you can go fast and high power or low and slow, but do it in multiple passes.
Cheers 
Sas
What are you actually etching… Co2 doesn’t work well on metal. Are you removing the anodizing or ?
It might help come up with solution if we knew a bit more.
I’ve used an old heat sink as a base for some dog tags I did to suck off some of the heat…
Using a laser is using heat, so it’s one of those conundrums you have to figure out how to work around. I see it all the time with my fiber, especially with relatively thin material.
With a co2, you have a pair of options to work with, speed and power…
I’m sure something similar to this product.
https://www.jpplus.com/original-series-black-plaque-plate-gold-silver
Cheers
Sas
You’re etching off the black finish… do you know what the black finish it? Not that it really matters at this point.
I think I’d try slow speed at the lowest power I can use, multiple passes. If you run fast, even with low power, it will be back to the point of heating up… just want to delay heating up the same area, that’s why I’d try it at a slower speed.
Thanks for all responses. For background, I am using a 100w CO2 laser. I have messed with multiple passes and the speed, but it seems only over 60% does the etch ever show. The plaques are similar to what was posted above. They are broke/gold that turns black when hit with the laser.
Turns out the size I was using was too large, so it is back to the drawing board. I will select a better suited material.
What kind of minimum power will your machine lase?
The machine starts making marks at 6%. When I try multiple passes at lower power, it doesn’t seem to get any darker than the 1st pass. I will try again with something like 4 or 5 passes at 20% or 30%
Have you tried to de-focus it so the power is distributed over a larger area. You could lower the interval and that should reduce the heat.
Here is a video showing a plaque engraving using Lightburn.
There are a few great techniques that he shares.
One that I found useful is an alignment process (not a jig) by using a piece of cardboard that allows you an easier alignment of a plaque before engraving. This is also great if you have multiple plaques to engrave one after another like a whole sports team etc.
I also noticed that he uses some strong magnets to keep his plaque down. Maybe that will help with your warping.
His machine is a 60Watt and he does use it at 15% power which translates to 9Watts. Your Big boy laser may be too “hot” for this job.
Cheers and Good Luck 
Sas
Came across this video that uses double side stick tape to hold the piece down. This might help you as well
Cheers
Sas
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