Laser alignment issues confusing

using the method red dot led pointing at 3rd mirror . i have a 24"x40" 100 watt c02 laser .
with red dot led installed where lens assembly the red dot is adjusted with 3rd mirror screws to have red dot in centre of 2nd mirror . i have the x axis front far right . as i move x axis to front far left the red dot rises and will leave the 2nd mirror target area? if i adjust red dot with 3rd mirror screws so dot is in middle of 2nd mirror while X axis is front far left then move the X axis towards front far right the red dot falls to bottom of 2nd mirror and then out of target area.
i am confused what needs to be adjusted to prevent this dot moving while X axis is moving???

From the description, it sounds like the head is not 90 deg off the lens axes. The other option is that the m3 is not precisely 90 deg from the laser beam.

In a normal alignment, you mark the target at the closest position. Then move the the maximum (far) distance. You need to move the ‘far’ dot to the ‘close’ dot.

Are you sure the led is properly positioned?

I’ve had lots of people use this method and claim success, but I have never used it. There is no way to perfectly align that led with the actual tubes beam. To me it’s like adjust the rifle sights from the target …

Seems like a good idea from an initial alignment perspective, but I think you have to use the tubes beam for a confident alignment.

Alignments are ‘feared’ but they are relatively straight forward. The problem with the Chinese lasers is they are missing adjustments in places that would make it much more simple to align if they existed.

I’d suggest you follow a good alignment from the tube end. At least you would know what is going on.

Good luck


Many thanks . How important is it that beam from #1 mirror is parallel to y rail.
And beam from # 2 mirror if it isn’t travelling parallel to x rail could that give me this condition?

Since you are approaching this backwards, I’m going to have to think about what’s happening.

It’s mandatory if m2 runs on the Y rail it needs to be square.

I think any of these issues will be a problem.

You can’t change where the ‘dot’ on the target ends up. You can get an alignment where the ‘beams’ coincide far and near, but it may not be in the center of the mirror. You can’t change that by a mirror adjustment you have to move one of the mirrors.

Using the lens mounted laser and going backwards makes this very difficult to determine the issue.

If you move it all around and get to m1, you will have to adjust the tube…

If you are going to use that alignment laser, I don’t know if I can be of much help to you.


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