Its me again with another laser cutter woe.
I was having issues with the laser not cutting accurate last night. I put it down to my material being a little wonky, but when I went to clean the lems I noticed (see attached photo) @lasertechs is this an issue?
That looks nasty. Please put an out of order sign on the cutter and unplug it. I’ll have a quick look at it on my way home.
I will have time to diagnose, but not to fix this. It looks like someone/thing whacked the cutter hard enough to knock the mirrors out of alignment.
Sorry just seeing this - it’s all good. Someone else cut no issues, I etched no issues. I did give a clean but couldn’t get the visible burn off.
The mirrors can’t be out of alignment then…
I’m confused, is this machine out of order or still working and someone has partially destroyed the lens?
I checked the machine over and it is well aligned. The lens however is a write off. Someone has managed to actually melt a divot in the edge of it, and a crack has started propagating from there. The central part is still ok, hence the good cutting, but we can’t use a cracked lens. Zinc Selenide is poisonous so we don’t want the crack to turn into a shatter and have to pick tiny shards of poison out of the machine.
**Until a new lens arrives, the cutter is out of order. **
I think this was me. I’m awfully sorry.
I cleaned the machine as per the induction and I don’t believe I tightened the lens well enough. It moved when I tried to cut again - and I switched the emergency switch above the machine to stop it.
I then sought the guidance of another person who was laser inducted - I can’t recall who. They helped to ensure it was tightened properly, I tested the machine worked by cutting a simple piece, cleaned the area I was working in, and I left for the evening.
Thanks for owning up, and don’t worry you won’t be billed 
Just a thought … maybe only laser techs should clean the lens? I was planning on doing some cutting tomorrow for a Workshop I’m organising. Any idea how long it takes to receive and install a new lens? Thanks!
Lens cleaning needs doing during the course of use. You should have been told that in your induction?
It’s got a lock off point on the switch
Of course!
I’m out of town for the weekend, but if someone could put a bolt or something through the lock hole, just as a deterrent, I’d be very grateful.
Ideally folks in an emergency just open the lid and the machine will stop.
It’s not ideal to do a hard power off at the mains when the machine is running. We were specifically advised against it.
I’ve added a note to the machine referring them to this post.
Cheers
I believe this document on the cleanup of broken ZnSe optics comes from the manufacturer of the lens:
http://www.iiviinfrared.com/pdfs/Cleanup_instructions-071806.pdf
The first and second sentences read
“Toxicity studies to determine the risks of handling or ingesting ZnSe have show that this material is not toxic. However, long-term effects of ZnSe dust inhalation are unknown.”
I have heard it repeated before on Discourse and at the space that zinc selenide is toxic. I am not sure where this information is coming from, as it would appear to be refuted by the manufacturer.
Thank you for this Andrew. I had a nagging suspicion that we’d convinced ourselves this was more dangerous than it is.
Unless someone can find other evidence…
If your desperate you can be my guest at Hackney?
