3rd mirror displacement in k40

that’s my k40 head, and this is the problem:


When the beam points to the center of the mirror the reflection is not going down through the head tube center, so in order to make it pass through the tube end I need to align the mirror in a wrong way and make the beam to goes down forming a diagonal:


This is not desired.
Another solution is to move up the laser tube so the beam ends up hitting upper in the 3rd mirror.
Unfortunately, the head design reaches its limit in the circumference entry before the beam reaches the tube center


So. what can I do?

I read somewhere in this forum about an acrylic header model. I’d like to try it. Where can I find that design?

I changed the head on mine out with something I can adjust in the Z direction.

Once you setup your machines beam, you have to catch it with m3. It’s nice to have it centered on m3, but it’s more important to get it down the center of the tube… if not the resultant cut will be at an angle.

The head adjustment problem is one of the major issues in doing a good alignment with many of these machines, not only the K40… this is my original head… notice the center of the mirror is not aligned with the center of the hole…

There’s really no way, other than mechanical changes to the optical path will correctly fix this, besides an adjustable head. As the beam leaves m1, it has to be 3d square with the other mirrors/lens/table for the machine to operate correctly.

Raise/lower the tube, beam impact point will raise/lower the same amount on all mirrors.

Might have to pick the best of the options…

Usually these are not that far off or the manufacturer couldn’t adjust it … is this a new machine or ? I’m wondering if you really have it aligned properly or was something changed causing this?

I replaced the head on mine with this one


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I’d like to purchase that head. Where can I get it?