Just wondering if anyone has experienced an issue where the box for the 1000uL DiTis gets stuck on the tips when mounting? This is the new MCA that uses the original FCA tips. It seems like the tips actually don’t mount perfectly straight and due to the length, they are putting pressure on the tip holes when removing the tips and it causes the box to get stuck.
I’ve had them look at the issue and the solution was to tighten the nest positions to hold the box down, but this has resulted in the cassette being removed from the box and becoming stuck to the tips. Also it isn’t a good solution for us since we use the same positions for barcoded plates and the gripper can’t lift the plates correctly.
In the past, I’ve seen something similar with the FCA and mostly the last row of tips sometimes, when picking up 8 tips at a time. Some different severe crashes. This is one of the worst…
This occured first after maintenance where the FSE exchanged one channel. It was not completely reproduceable, but happened often enough to show our FSE.
He performed alignment tests again and again with no change of behaviour. He was in contact with manufacturing site to clearify if there is any adjustment possible. They told him that there is no adjustment needed/possible. However he did something and the issue was gone almost. I’m not aware what it was in the end.
In the time between we taped the racks onto the boxes to prevent lifting these off. And also taped the boxes to the table. But indeed, thats not a real solution.
So if anyone can share more insights about that I would appreciate it, too!
I’ve seen this a lot - especially after Tecan released a lighterweight version of the tip box,
I implemented a couple of approaches:
add spring clip to side of nest to apply pressure to tip box
add a counter weight to bottom of tip box to weigh it down
obviously, a more permanent attachment for the tip boxes to the nests would be advantageous - but if the nests are shared with plates too, our flexible options above might be more suitable
have you tried adding additional movement commands after tip pickup command to slowly move the tips out of the tip box, maybe with both X & Y movements
I have also struggled with this issue in the past with the FCA arm. And after the first crash like this, your arm may be misaligned and thus more prone to similar issues.
We managed to mitigate it with a service call and a very careful x-alignment of the tips, more stringent than the normal pass/fail criteria. They apparently cannot adjust the y-spacing between the tips, so if the pinching is primarily caused by this, you might need to replace the arm.
We also slightly adjusted the positioning of the nest tabs to keep the boxes more centered.
As mentioned, you can tape the box onto the deck and tape the grid-section at the top onto the box. We had a crash where the grid (the yellow part on the top of the diti box) came free from the rest of the box, so taping or weighing down the box itself is not 100% foolproof.
@Optimize How would you implement these X & Y movements if you are using the GetTips command? Would insert it between GetTips and subsequent operations, hoping that the box comes free and lands where it belongs? Or is it possible to insert some microscript commands into the GetTips command like a liquid class?
