Loss of accuracy and position.

I hope this is the correct forum for my problem. Please point me in the right direction if not. :confused:

Hello AnyCubic RAMPS/TMC 2208 users, :slight_smile:

I'm running my original RAMPS board (Motherboard 33) in my AnyCubic Delta Plus using TMC2208s in Standalone mode @1.2V on the Vref pins. Anything lower and the motors lose steps and go out of calibration. Their temperatures are only 42 deg. C with good fan blast to keep them happy.
I just don't understand how this seemingly-random loss of steps can develop out of the blue.

The upload seems to be okay and the printer works reasonably well when making relatively small calibration blocks, 40 x 40 mm or so and is consistent at this size. Trying to print towards the edge of the 240mm dia glass plate brings on these problems. The item I'm trying to print is only about 160L x 100W x 40H so it should be okay.

Has anyone had similar problems?

I might try to replace the 2208s with the original DRV 8825s but this would defeat the purpose of the upgrade.
The 2208s are really quiet and run the steppers very smoothly when they work at all.

I have looked in various forum pages but so far there's nothing relevant to my problem.
All suggestions will be very welcome.

Thanks,

Scintilla.

Datasheet for your drivers is lacking. No idea what 1.2V on the Vref means without that. What microstepping
and current were you using with the DRV8825's and what are you using now?

Have you change top speed or acceleration settings?

scintilla:
Anything lower and the motors lose steps and go out of calibration. Their temperatures are only 42 deg. C with good fan blast to keep them happy.
I just don't understand how this seemingly-random loss of steps can develop out of the blue.

The first of those sentences suggests that at 1.2v Vref the motor does not miss steps. The second sentence suggests that it is missing steps? Which is correct?

I suspect that your problem is more appropriate to the Reprap Forum where they specialise in 3D printing.

...R

You are correct, :slight_smile:

I have posted my question on the Reprap forum where an answer is more likely to be found.
Many thanks for setting me in the right direction. Your forbearance is appreciated.
Scintilla.