Re: HELP: Internal Solenoid Leaks Killed Us!
 

It could likely be that teams return non-working valves to the Spare Parts desk at a Regional and then they get handed out to the next person in line, or at the next Regional where the new parts person doesn't know there was a problem with them. Spare Parts may become a collecting point for malfunctioning parts. Spare Parts has no test rig to verify that teams didn't have something else wrong. Go for the ones in original, still sealed, boxes. They probably didn't have metal filings dropped into them at the last Regional.

Anecdotal reports are not statistically significant.
Think about how you'd conduct a real engineering study...

Re: HELP: Internal Solenoid Leaks Killed Us!
 

I dont know about IMR, but 1075 has found that the plastic festo valves dont last long, even if they DO work properly out of the box. They leak in relatively short order... I can however report that the one we got from Spare Parts at Waterloo was good to go.

Re: HELP: Internal Solenoid Leaks Killed Us!
 

I believe I stated earlier that the replacement valves were sealed, new-in-the-box units. My direct experience is that the 2008 KOP Festo values had a 100% failure rate, so I believe I was being somewhat conciliatory in estimating a 50% rate. If anything, I have relied on anecdotal evidence to refute rather than affirm my hypothesis. That said, I'm still very much open to the idea that we/I somehow damaged the valves or installed them incorrectly. All I can tell you is that we installed and attempted to use them in accordance with the technical documentation available from the 2008 Pneumatics Manual and the online installation instructions.

Since the spare parts process at a regional is based on exchanges, we don't have a statistically significant sample size of valves with which to do a proper investigation (nor do we have the financial resources, etc.). If Festo would like to have our lone remaining [apparently] defective valve for their own engineering evaluation, we'd be happy to sent it in for analysis.

Re: HELP: Internal Solenoid Leaks Killed Us!
 

I'll second that. We have a new valve they can have for evaluation also.

Re: HELP: Internal Solenoid Leaks Killed Us!
 

I know we totally disassembled one of our SMC valves before, when it jammed up, and found an aluminum shaving in it. We had to do this a few times, but it always fixed the valve... we've had many festos that just started leaking through the plastic casing, pouring air out the exhaust port, or any number of other issues... open relay coils... no led's... actually, the one with no led still functions fine, just no light. other ones get a light but dont actually switch, and we've wired/plumbed them all the same way.

Re: HELP: Internal Solenoid Leaks Killed Us!
 

fi: Here's some postmortum info on our SMC leaks

- only ever had one push-on plastic tube joint leak. Oddly enough, it was the very last push-on we did. All the leaks were from fittings using brass.

- high pressure leaks would be solved, then reappear again in the next day

- some leaks could not be solved by tightening the brass fitting or taking the brass fitting out, replacing the teflon tape and reinstalling. We had to put in a new fitting.

- the leak that killed us was solved by finally swapping out the manifold on one SMC solenoid valve. One port had a brass "stopper" installed and we never were able to solve leaks around it even with new stoppers. Close inspection showed aluminum shavings in the threads of the port and aluminum fused onto the thread of the brass stopper near the leading edge. Clearly either the teflon tape was not applied close enough to the leading edge of the thread to protect it from galling (students scared of tape fragments getting in the air system), or more tape was required. Tightening it just cut into the aluminum threads of the manifold.

My recommendations now are
1) apply 2 wraps of teflon to darn close to the start of the first thread but absolutely no overhanging tape
2) leave the complete air system at full pressure as long as possible with air cylinders both extended and then retracted to try to get leaks to occur sooner than later.
3) Check every single low and high pressure joint with soapy water (we used dollar store childrens bubble liquid) during the Thursday with the air cylinder both extended and retracted.
4) Buy some port plugs and pipe caps so you can isolate each pneumatic circuit for testing
5) You can see evidence of air leaks very quickly if you bypass the reserve tanks and watch the 120 psi gauge. It will drop very quickly with the slightest leak if there are no reserve tanks connected. But don't forget to test the reserve tanks. Ours leaked repeatedly.

By the end, we had a totally leak-proof robot. But we regularly left it energized and watched the 120 pSI gauge for 15 minutes every 3rd match anyway.