Delta printer dimensional error only in x

Hi,
I got an Anycubic Kossel Plus.I added TMC2130, printed corner brackets. Also I upgraded the arms to ones with less backlash and an even length.
As firmware I use MK4duo with the auto calibration algorithm from DC42. When calibrating, I use only 6 Factors. The strange problem is that I get -2.8% dimensional error in the x axis. Y and Z are perfectly ok. I don't understand the reason for that. If I would have an error in steps_per_mm or in diagonal_rod_length, the error should be also present in y.


Currently I compensate the error in the slicer. It works, but is annoying. Do you have any idea?

There is a checklist in the DuetWiki, for things that should be OK before calibrating.
One thing is :rods must be parallel to each other. Meaning the rods distance at the carrier has to be the same as at the effector.
I've seen effectors at thingiverse, which seem to be designed from apes. Neither the 60° angles were right, nor the rod-distance...

Edited 1 time(s). Last edit at 02/19/2018 04:07AM by o_lampe.

Do you have a link?