Tall print starts clean then Z banding kicks in

[GaiusWorzel]

I’m kind of nervous posting this because I feel like it should be obvious, but I’m stuck. I’m printing a tall part and the first half looks really clean, then around the mid point I start getting repeating ridges that look like Z banding. The weird part is it is not random, it is like a pattern that repeats, and it only shows up once the print gets taller.

A specific example is a tall bracket I ran this week where the bottom looked almost perfect, then the top half got those waves and it made the whole thing feel ruined. I’m happy the printer can at least get the first half right, but now I want to troubleshoot this the smart way instead of touching ten settings at once. If you had to check things in order, what would you look at first, lead screw, coupler, Z alignment, layer height choices, or belt tension?

 

[RufusAlbarea]

I’d try printing the same tall part rotated 90 degrees on the bed. If the banding stays tied to height, it points to Z motion. If it changes with orientation, it can be X or Y artifacts showing up more once the part gets tall and starts flexing.

 

[AcesClaudel]

A quick test is print the same tall part again but rotated 90 degrees on the bed. If the banding pattern rotates with the part, it can point to Z mechanics. If it stays on the same axis regardless, it might be frame/gantry or a wheel/rail issue. I’d also try lowering Z speed a bit just to see if it calms down without changing ten things.

 

[Alan]

Not obvious at all, this is a classic tall print problem. The first half looks good because the printer is stiff down low, then as the part gets taller it starts amplifying tiny wobbles and drag. Quick non setting checks are to make sure the spool feeds smoothly, the filament path is not tugging the toolhead, and the printer is on a solid surface. A simple fix that often helps is slowing the outer wall speed on tall parts and adding a bit more cooling consistency if your room temp is swinging.