Well,
I'm inclined to agree. But, the integrator has seen this error on multiple occasions across multiple arms all from the 2016-2018 vintage. This vendor only recently (past two years or so) switched to this arm, and have never seen anything like it with other arms (Denso, Staubli). 3 or 4 arm similar failures out of ~20 arms seems very high to me for industrial automation. I wondering if there is some greater issue with this arm, or the integrator use of it.
The integrator's response seems to default to replacing the entire arm -- which is very time consuming and disruptive -- mainly due to scheduling, arm lead times, and reteaching time. Can this model arm not be serviced in the field? When we (very rarely) have had issues with our Staubli arms (~20+ arms in all) -- or more often the controllers -- Staubli would typically fly someone in from somewhere in the USA or even France within a few business days to fix the issue onsite.
Kuka's response, thus far, has seemed rather lacking. As if any first line service / warranty claims fall to the integrator and they, the arm MFG, have little or no responsibility to end users. It's very possible/likely the 1yr "MFG warranty" has already expired -- but at this point we (or the integrator through our warranty with them) should be able to pay for service if that's what's needed.
I feel like there's some behind the scenes finger pointing going on where Kuka is blaming the integrator and the integrator is blaming Kuka and no one is taking the lead on diagnosing the real issue conclusively. Surely it would be very easy for Kuka to connect remotely to the Sunrise workstation and collect any necessary logging info, etc. via WebEx etc. But so far, after a month and two arms with the same issue, they've never tried. Similarly, given the frequency of the failures, I would expect Kuka would want the arm back ASAP so they could take it apart and get to the root cause. Crickets . . . (granted most of Europe is just coming back from Holiday).
At the moment, it could even be as simple as our arm firmware being out of data and this is a software bug that was already fixed in revised firmware. Who knows.
The arm ran perfectly for ~9 months completing 10's of thousands of moves and then developed the issue out of the blue (agree sounds like hardware). But then the replacement arm (originally supposed to be new, then ends up being supposedly repaired/re-manufactured) does the exact same thing? Now we're looking at another arm swap to replace the replacement. I guess it could be a coincidence. Or the integrator or Kuka passed us back an previously defective arm that was never really fixed.
One of the failures the integrator had -- for one of their other systems for another customer -- was supposedly a brand new arm right out of the box.
We're using this arm in a classic fashion to pick and place parts (~2kg payload total including end-effector) to different stations around a spherical workcell at the maximum rate of speed possible. Arm only transitions to collaborative mode if a human is detected within the safety zones. Movement / encoder / torque errors almost always occur when the arm is running at full speed.
Really missing my old TX90XL's which I had on prior systems from the same integrator.