2nd Mirror Alignment

Discussions on optics for laser cutter/engravers

2nd Mirror Alignment

Postby dwessels » Sun Sep 25, 2011 7:01 am

I have really been enjoying building the 2.x engraver.

I have most everything done, just have a few gremlins to work out.
One of the more major ones is the alignment of the optics. I have it most of the way there, but am having a problem with the second mirror reflecting to the flying optic. Let me see if I can explain the issue.

With the head (flying optic) all the way to the left, the laser lines up perfectly. When I move the head all the way to the right, the laser is about .25-.33" low.

It looks like the mirror is higher than the head so the laser has to be reflected at a downward angle. I have tried to put spacers underneath the laser head mounting plate to raise it, but it does not make enough of a difference.

Anyone have an ideas?

Thanks
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Re: 2nd Mirror Alignment

Postby StigOE » Sun Sep 25, 2011 9:13 am

Aren't you able to adjust the second mirror so that it reflects the beam a little higher when the carriage is all the way over to the right? This shouldn't really affect where you hit the head when it's all the way to the left.
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Re: 2nd Mirror Alignment

Postby dwessels » Sun Sep 25, 2011 9:20 am

StigOE wrote:Aren't you able to adjust the second mirror so that it reflects the beam a little higher when the carriage is all the way over to the right? This shouldn't really affect where you hit the head when it's all the way to the left.


I tried that, but what happens is that the beam hits the head in the correct spot when it is all the way to the right, but when you move the head all the way to the left, the beam is hitting above the hole for the mirror in the head. It is about .25" too high.
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Re: 2nd Mirror Alignment

Postby bdring » Sun Sep 25, 2011 12:28 pm

Everything on laser must be on the same plane. Mirrors cannot correct for that problem.

Some people have had to shim the final mirror/lens assembly off the carriage a little with some washers. Mine was fine as is.

I did not have any drawings or 3D models for these parts. I just measured them and put them into the design. It is possible that there is some variability on these parts. If there is, we probably got lucky on the direction. It is easier to add material than subtract it.

On my first laser you had to shim just about every mirror.
Bart
"If you didn't build it, you will never own it."
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Re: 2nd Mirror Alignment

Postby dwessels » Wed Sep 28, 2011 5:49 am

Well, I have all the optics aligned. I just started again from mirror 1 and redid everything and it worked perfectly!

Now that I have this thing working, has quickly become one of my favorite machines. I am so used to machining everything with all of the headaches of work holding. The laser is just ridiculously simple.

Thanks everyone for all the help.
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