Z banding with taller object

re banding - can be a few things. Slightly bent z-screw, which causes more pressure during rotations in particular directions - for this it will *usually* appear in the same place repetitively.. BUT...

The banding can also just be good old fashion bushings play on the z-table and the screw is behaving normally so to speak... For this, a good generous reapplication of lube along with trying to 'pack the bearings' with lube.. this will both free up movement and if using a decent viscous lube limit play slightly.

For similar reasons to the bent screw - bent z-axis rods can also cause the problem to amplify. Try rotating the rods 180° and see if the problem moves to the opposite side of the prints... Tall square columns are good test pieces for this

Its also worth checking that your extruder itself is tight - remember on stock carriages there needs to be a slight amount of pivot to prevent binding, but often the rear nylon block can become loose and cause wobbles in the print head that exhibit similar symptoms to z-banding. Also check the extruder/motor mounts.. smaller layers mean more rapid velocity changes (until it hits the slowdowns for cooling) with a higher frequency that can overlap other vibrations from previous moves..

For cleaning up the white bits - quite often a good wash with water will clean it up surprisingly well. Or Isopropyl Alcohol.

adrain said:
The banding can also just be good old fashion bushings play on the z-table and the screw is behaving normally so to speak... For this, a good generous reapplication of lube along with trying to 'pack the bearings' with lube.. this will both free up movement and if using a decent viscous lube limit play slightly.

I  had my SD3 about a year now.  noticed a lot of play in the Z rod bushing, I wonder if they are replaceable.,The  platform seems to have a constant downward tilt. because of that.