RE: Constantly recalibrating
Ok, I let it bang away for three minutes. It returned an error "Axis Measurement Failed" and then started printing. This is an insane amount of time to have any kind of machinery crashing around in it's boundaries trying to calibrate. And why would it start printing if the "axis measurement failed"?
The test keychain did print fine, with an overall print time of 15 minutes, 23 seconds, including the three minutes of crashing around in the corner.
RE: Constantly recalibrating
Just updated to the 6.3.1 firmware and my home calibration problem seems worse. The banging goes along for a long while, finally fails with multiple error messages including y calibration failure and collision detection (same as others have reported), but then still prints, and prints seem Ok. Running the y axis test manually also consistently fails, but all other tests succeed. Went through the belt tuning exercise (both sides at ~85hz). Prior to the firmware update, the banging would last no more than 20 seconds with no error messages (still annoying, but more tolerable than one it's doing now).
RE: Constantly recalibrating
Followup: Fiddled with belt tension again (84hz), and got y calibration test to finally succeed. Homing also seems back to normal. This seems to be a very finicky aspect of this printer (and perhaps all core xy printers, as this is my first). Some kind of auto belt tensioning mechanism would be a welcome improvement in future versions.
While the Core One is noticeably faster than my old MK3 once it gets going, it seems like a lot more time is spent getting ready to print.. absorbing heat (skip-able I know), 49 point calibrations, sometimes followed by another smaller count calibration, nozzle cleanings, etc... it sometimes feels a bit slower overall.
RE: Constantly recalibrating
So I let things sit for the evening. In the morning I re-ran the X, Y and Z calibrations. I've had two prints start correctly now, where there is a couple quick bounces on the right side of the x axis, a couple to the front on the Y, a few bounces diagonally between the two, and it's off to the races. The spatula from the USB drive printed well, and I just started a 5 hour print that started cleanly and has been running well for most of an hour.
I did not consider the pre-start time of letting the metal frame acclimate to the internal temp as well, but this is countered by the fact I can print more materials and significantly faster than my old MK3. Overall a big plus for me. Just wish I had room for another one.