After Replacing Laser Tube, my laser still won't cut

I don’t really understand what I’ve done wrong. My mirrors and lens are clean. The beam itself is in perfect position. My air assist and power supply are both working as intended. But after one of my laser tubes started going out on my OMTech 150W laser, I decided to buy the same exact tube and replace it. But my cuts still aren’t what they should be. I can’t cut 1/8" Inch Acrylic at 85% and 15 m/s. My cuts look clean they just aren’t going through all the way. Any ideas?

  1. working tube
  2. clean and aligned optics
  3. proper focus

If they have these three, they work…

I always start at M1, while I’m there I check to see the TEM mode the tube is operating … Then I move down the line…


Can you post the m1 results?

This should be a real light burn… a target with a burnt hole is of no use…

:smile_cat:

I’m sorry how exactly would I check this? Is there a specific mode or am I missing something?

On the right is how I check the tube output…

A real light mark, not a hole…

This is from my tube as it started going out of the TEM00 mode of operation… The dot was in the exact center… had realign it multiple times before the replacement arrived in three days…

The more light the mark the easier it is to read… this one is a little hot, but it’s clearly failing.

:smile_cat:


I recently realigned my tube so im not sure why it’s off but does this image work?

The outer ring should be brown not dark… This is the power distribution of the output of the tube… TEM00 mode is much darker in the middle and gets lighter towards the outer edges…

You is not in the center of the mirror, so it’s clearly not aligned…

I’d contact the vendor with the photo and ask them why it doesn’t appear as TEM00 resonance…

Even with a good tube, being off that far on m1 may be enough…

Let us know…

:smile_cat:

I’m still not sure I quite understand this “TEM00” mode and “M1”, what you mind explaining it to me? I’ll contact my vendor for this tube as soon as possible.

The power desity of your tube is supposed to be as close to a Gaussian power distribution as possible.

The-distribution-Gaussian-of-laser-beam-profile-nb

The beam coming out should be dark in the center and become lighter as it nears the edge…

Yours is darker on the edges and lighter as it goes toward the center. Just the opposite of what’s expected…

Does this make sense?

:smile_cat:

Yes it does, thank you. While I’m waiting for my vendor to contact me back, could the power supply be at fault here? If so, do you know how many amps my PSU should be putting out?

It could be, but I really doubt it… It would have to be doing something pretty odd to cause anything like that…

It’s more likely the tube and I’d pressure the vendor for a good answer not a elusive type response.

One of my charts has <30mA for a 150W tube.

If you decide to buy an lps, I’d suggest something like this 180W model.… only 20% over the recommended but will undoubtedly have a quicker response time with your tube.

This is for a 180W tube… 35kV@38mA…

I’d like to hear what the vendor says… did you mention which vendor you purchased? OMTech?

:smile_cat:

After numerous emails, they’re sending a new one out lets hope this one actually work.