Amada FO3015 Fanuc C4000A/E Glass O-Rings

[RPosty]

Laser went down couple days ago, (Gas Controller & sometimes Power Down) they called me in yesterday and I took a look at it, massive leak, so I finally going to get to troubleshoot this leak it has had a while which just got much worse (see thread

http://www.eng-tips.com/viewthread.cfm?qid=366265

if your interested in the prequel).

So I built a vacuum rig from old vacuum pump I had so I could troubleshoot this without having to go through the tedious procedure Fanuc uses requiring power up, wait 9 minutes, power down, etc etc. plus this way I could isolate sections. So my leak was in the resonator. found it was an o-ring in the discharge tubes. Our laser for some reason has two different types used, the majority were white non jacketed o-rings that had a flat surface on the inside (unless time made it that way), the one that was leaking has a FEP encased red o-ring. I put in standard Buna 214's from grainger because it was only thing I could get right away today which worked. I do not want to keep them in because I don't think they will do well over time.

Ok to the point: Do you guys have a preference? I am not a fan of the FEP encased because on our 2000 they seem to fail also, they get rock hard on the inner surface, they are also obscenely expensive which is fine if they are really that much better. other lasers I worked on always used viton in similar setups, but those are oil cooled systems.

Cliffs: what do you like to use for orings on your glass? Do you also have a Vacuum Grease Preference? I use the 3M.


"I am stuck on Band-Aid brand, 'cause they are stuck on me"

 

[LASERNINJA]

The white are original, from Japan. I looked onece and I think they are about $100 each. The ones with the coating, $22.00. So you can see why there is a combination. I do not recommend Any grease on there at all. It will get all over and make a mess. The only grease I use is that apizeon stuff on the back of the mirrors.

Finally, come out to Portland sometime and I will show you how to do a positive pressure leak test. Not always super accurate but damn easy.

 

[RPosty]

i usually take a small amount of Dow Corning High vacuum grease (not 3M, my bad) and work it into the o ring so it is shiny but no globs, never tried dry o-rings before on any laser. I think I am going to use Viton FluoroMaster O-rings, they are reasonably priced and I have used them for years on other Lasers with great success, If price was no object, I'd like to try Kalrez Perfluorelastomer, but at close to $100 each, don't think I would get that approved. I have never actually seen a Vacuum o-ring fail until Fanuc and I have seen three of them FEP orings fail now. I don't think the silicone o-rings hold up very well to UV that Lasers create. On the other systems, the key to keeping the orings in good shape was to spin the glass a little ever so often when in there, not so easy in Fanuc.

found a lot of info here:

https://www.parker.com/literature/ORD 5700 Parker_O-Ring_Handbook.pdf

Has anyone ever tried other types of O-rings in Fanuc Resonators? How often do you pull the tubes out and clean them? Think I am going to try once a year so I never have this issue again, though I hate opening up a resonator.

I thought about applying about 5 PSI to the tubes to check for leaks, but decided to just take my time and check all the optic seals and glass since it was long overdue. I set my pump up with a filter and stone so I go release the vacuum without sucking too much crap in, I think I will modify it so I can have N2 regulated backfilling instead, which then could also be used to apply positive pressure too as you suggest. I could also use it as a purge when removing optics. How much PSI is safe to apply to the resonator do you think?

I like the Fanucs, but that Vacuum leak procedure is crazy IMO.

"I am stuck on Band-Aid brand, 'cause they are stuck on me"

 

[sparky4808]

I have installed Fanuc O-rings on the discharge tubes. at $32/ea they not too bad...if you consider a $32 o-ring "not bad". So far so good at 3000hr since changed.

 

[Foostrap]

Removing tubes should be avoided as much as possible as every time you take them out, you risk cracking the end. And those are not cheap. Once a year seems excessive. Tubes will usually last 36,000 hours. Then the quartz starts to generate white dust that goes on the optics. You can clean them, but it will come back faster and faster over time. If your tubes have 50,000 hours, then yes, you most likely will have to clean them once a year. Tube O-rings should be replaced every 18,000 to 24,000 hours as preventive measure.