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Re: beam exiting as line an not as dot

Posted: Mon Feb 10, 2020
by Jeffrey Aley
What does the beam look like when exiting the laser tube?
To check this - place a piece of adhesive tape (masking tape) over the entrance to Mirror 1. Set the laser to a very low power, and then do a very brief pulse.

I wonder if you have a cracked mirror.

Re: beam exiting as line an not as dot

Posted: Mon Feb 10, 2020
by Dave Vigness
I'll say ditto to Jeffery. You have a mirror / lens problem at best, a tube problem at worst.

Your diagonal points indicate a crack or aberration of some sort. As it has just started, a crack is the more likely. An aberration would have been visible from the start. Your only saving grace if it's one of the mirrors would be to move the offending mirror so the laser dot is no longer centered and not hitting the problem spot, but that is only temporary to get you up and running until you can replace the problem child. You could test #1 ans #2 simply by raising them up 3mm or so.

It is quite likely you will not be able to spot the imperfection with the naked eye. Getting most of your beam through would indicate the problem is physically very small.