Dealing with VFA using TMC drivers in Klipper

VFA (vertical fine artifacts) is known to be a problem of imperfect matching between TMC drivers and steppers.

Klipper provides some low-level accesses directly to the registries in the IC chips via driver_xxx settings. Altering these timing values changes the shape of waveforms generated by TMC drivers and thus smooth the final prints.

Here is a sample setting by SK-Tank owner Jeffery Kilgore using TMC2209 and LDO-42STH48-1684MAC 0.9° XY steppers (the default stepper in SK-Tank). You'll have to know the technical meanings of these settings by checking TMC data sheets.

More settings will be available soon. (2021 Nov 6th)

Reference:

• Trinamic website for TMC data sheets

• Configuring driver_XXX settings in Klipper document

• TMC stepper driver configuration in Klipper document