Across multiple STARlets, we’re seeing tip pickup/alignment issues—I’ve played with the tip racks and carriers a bit, and it seems like the tip rack frame (CO-RE II) isn’t clipping fully into some of our newer tip carriers, not even with extra pressure applied. There’s also been a few instances of fully seated tip racks and fully loaded tip carriers being multiple mm off-center when attempting to pick up tips, unsure if the two are related. All that said, the non-clipping tip rack appears to have been part of the issue here:
Main question, is there anything we can do to alleviate this? I’ve seen some of the tip rack adapters that seem to just raise the tip pickup height 10mm or so, would that be a viable workaround here? We haven’t found anything out of tolerance in the recent PMs so it’s difficult to troubleshoot without a good culprit.
The trace file for the run that ended in the above picture was riddled with this message every few milliseconds, starting right after the firmware version spiel at the beginning of the run:
Execute method - error; Either BOF or EOF is True, or the current record has been deleted. Requested operation requires a current record.,
However, it never made the operator aware of any error until it tried to aspirate from that trough with the whole rack of tips. What does this message actually mean? I will note that I only recently learned of the recommended LogFiles size of ≤ 2 GB, and some of ours were well, well past that. That has since been rectified, but may have been a contributing factor to some of that weirdness.
Another thought is to swap out the tip carrier. We see a lot of these left out in the sun do what we call ‘potato chipping’ where the twist slightly, causing position 1 or 5 top have poor preformance.
ALL (100%) of your carriers should be labeled with a silver sharpie. When you have problems, refernce that nubmer. “It was STAR H123, 2nd shift, Billy was the operator, Method XXXABC123, using carriers 14, 47 and 5.”
Lots of variables, but the labeling of the carriers helps point out easy to solve problems in a lot of cases.
Yes to maintenance (daily and weekly), and yes we’ve tried swapping carriers. It does seem a bit more prevalent in the newer carriers (appx 1y/o) but it happens on multiple carriers, new and old. Usually not to this extent, but this isn’t the first time it’s picked up a whole rack of tips frame and all.
I do agree that swapping carriers would potentially avoid this specific issue, but I’m more aiming for a way to work around this issue rather than sidelining 1/3 of our tip carrier inventory because it can’t hold the racks.
If it’s passing maintenance, then it shouldn’t be a positional issue with the instrument(s). So, it’s likely either a labware definition/teaching issue, carrier issue, or tip rack issue. If you could upload a method pkg along with a trace file in which a problem occurred, we can help assess.
For possible carrier or tip rack issues, I would recommend reaching out to your local Hamilton support team to help investigate - if there are quality issues, we’d want to report this. Let us know if you need help getting in contact with them.
Method and trace file uploaded, let me know if there are any issues with those.
Preface, this was months ago (right when we first used the newer carriers about a year back), so I may be misremembering things: I had brought up the carrier issues to our FSE when they were out for an install/PM, and at the time it seemed like the issue was that they were too new and needed to wear in a bit. That’s been true for the other issue we were seeing then (‘tight’ carrier loading, irrespective of the loading tray angle), but the tip racks not fully clipping in hasn’t really gotten better. It seems like the inner support spindles/plate aren’t fully seated, causing them to sit slightly higher than they ought to, but they’ve been reseated several times.
We recently had a new revision to many of our carriers. From the first image which is the new revision you can see that there is no longer a removable center plate that holds the two support bars. If you have the previous revision (second image) where the metal plate can be removed then I have seen cases where the metal edge can shave off the inner plastic of the carrier where the plate fits into place. These shavings can force the plate to sit higher than it should and if it sits high enough then perhaps tip wafers will no longer be able to snap correctly into place.
