Laser not marking at higher frequencies

I have an OMtech 30W Fiber laser and I am trying to mark copper coins. I have tried:

  • Power: 100%
  • Speed: 50
  • Frequency: 25
  • Hatch Spacing: 0.03
  • Passes: 2-3

At certain angles the image looks dark but, on inspection it looks greyish/white.

When I go to freq. 50 the laser seems to “sputter” and miss some areas similar to if the Lens was not at the correct height. Why is that?

What settings would help me achieve darker markings?

These are the settings I use for my 30w with a 110 lens.

However please make sure that it is focused precisely:

Is this for copper?

I’ve found there is quite a change going from brass to copper… I attribute it to copper being a great heat sink.

Do you know the laser source in your machine? Do you have a manual on it? Usually they will tell you at what frequency you get maximum power… I’ve found this nice to know. My JPT max power output is at 40kHz.

:smiley_cat:

Yes, it was for copper, however it was such along time ago when I used it, I believe that I was never really happy with the result, but that was the best I could achieve.

I have a Raycus 30w from Cloudray, I did get a manual of sorts, unfortunately however it didn’t tell me what frequency for maximum power. With a Raycus there isn’t really that many frequencies to play with, I now wish I had saved up more pennies and bought a Mopa.

You live and learn !