Finally have mirror alignment sorted and air assist working well,
That looks really neat. What happens if it gets out of square? Will it destroy something?
That was my thought. You do NOT want to have a stepper motor come unplugged while that thing is going.
One of my clients is a sign shop that has a 40W and a 60W Epilog laser. They were doing maintenance on the 40W, and the beam was energized with one reflector out of alignment. One of the benches in the work area has a scorch mark about an inch around and about a quarter inch deep in a solid maple upright. Took less than a minute. Fortunately nobody was hurt, but it happened very fast. 40W doesn’t seem like a lot of power, but it will do a lot of damage pretty fast.
It looks to me that some of those pieces experienced a misaligned beam. Some of them look a little scorched around the edges. I imagine that the board behind the final reflector is to protect the Primo core. I can see the laser being unkind to that black PLA.
What amazes me with this is the use of so many rubber bands and zip ties holding this together. It looks both awesome and terrifying at the same time.
Hi Jeff, the new primo build is very stable , I have made the mirrors from an old hardrive at 30mm so plenty of scope for slight miss alignment
Hi Dan , this is still work in progress , and will be making a metal enclosure this will keep any stray beams in a safe way , the mirror alignment possess was a challenge and odd dots he the plastic parts
Wow you made the mirrors yourself?!? That’s impressive!
Do the spinning drive platters from the drives work as a mirror? I probably have 200 of those. I can get into all kinds of trouble with them. How powerful of a laser can they handle? Is that a valid question?
That’s the only part of a hard drive I can think of that would be reflective enough to work as a mirror. If I remember right they are aluminum or glass cores with a few layers doped titanium on top so they should be able to handle a lot of power before breaking down. I didn’t realize they where reflective enough to use as laser mirrors without a significant loss of power. But maybe (or should I say clearly?) I’m wrong.
I hear people have used them on 100w it’s solid aluminium alloy so can take it
They work very well , very reflective
Do you have any info on the optical power loss per mirror?
No official data but home tests show same or even better than China made cheaper mirrors , I can cut 3mm ply at 37% power in two passes so iam happy at 0 cost for the mirrors
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You’re a braver man then I.
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This is all my kind of MacGyvering. I was not trying to be the safety police (this time 
). I am curoius what kind of things you’ve done that have made you nervous, and what kind of mitigations you have that make sense. There was another CO2 laser build a few years ago, and it got taken apart. I think safety was one of the motivators. There are also people that say there shouldn’t be any lasers that don’t have enclosures, and I am not sure what to think.
I have always wanted a freaking laser beam in my shop. But I also know I don’t spend enough time to justify $5k for something really nice.
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Most of my old drives have had glass substrates for the platters. Made a secure erase a cinch. Hit it with a hammer and good luck getting anything off of the little glass cubes rattling around inside the case.
2 main reasons to enclose a laser.
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Vinyl and many other plastics generate cyanide gas when burned. My clients with the sign shop have a very cool filter on that 40W Epilog.
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Stray laser reflections are bad for your eyes. O.o
If you aren’t cutting vinyl, and don’t try to cut reflective stuff, probably ok. Acrylic not supposed to be as bad, but don’t breathe that smoke.
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Hi Jeff , going forward I will build at least side walls and an extractor , I have no regrets with this build and I love pushing the boundaries, I now have a 40w laser with a large cut area for less than ÂŁ200 uk , on the opposite side is a spindle and a diode laser so 3 in one machine the z axis can move up and down without effecting the laser set up . Setting the mirror alignment up was a challenge but after trying a few various mirror mounts the simpler the better with the larger mirrors , not sure if this would have been as successful with the older mpcnc , Ryan has made a massive improvements with the primo in my opinion.
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Dan all good advise , still work in progress , I know lots of people post pictures of builds that look like they are in a lab , I like to show how in the earlier stages its not like that .
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The aluminium stator plate cuts easy , take it slow to keep heat down
