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Describe your issue:
Hi guys,
Recently rebuilt and klipperized a Prusa Bear clone running an SKR 2.0.
Printer was running fine with no skipped steps on any axes with the two Z motors controlled by a single TMC2209 driver at a current that barely warmed the motors.
I decided to try controlling the z motors independently as I had an unused driver and like the idea of using auto gantry levelling. I got a lot of binding and in order to get the z axis moving smoothly I needed to increase the stepper current to a level that got the motors uncomfortably hot, and was higher that what I had needed for both steppers on a single driver.
As a guess, I would say that the timing between the drivers cannot be guaranteed just due to how things are processed, i.e. they do not fire at exactly the same time, This sets up a stress at the threads, increasing friction. Slight timing variances between different axes are probably not an issue typically.
If this is not the actual reason, then I too would be interested in why this is occurring.
have you seen (and used) this feature and are using this in your config? This seems like it might effect what you’re experiencing. I was looking in the docs for something else and just stumbled on it. It seems very relevant.
Yep, that is how i had set it up when running the z motors on separate drivers.
Another odd thing that just came back to me; stepper buzz seemed fine when using separate steppers. Each motor would happily buzz with no issues, but buzzed and skipper when i homed or moved axis.