hotend
ES
ES

3D printing troubleshooting

Z-banding / z-wobble (horizontal bands)

Also known as: regular lines or rings on the walls, a repeating layer pattern.

The symptom

Walls show regular horizontal bands — rings repeating every few millimetres at a constant rhythm, sometimes alternating fatter and thinner layers.

Sources for this page: Prusa Knowledge Base · Manufacturer Simplify3D · Technical guide Simplify3D · Technical guide

Causes and fixes, ranked by likelihood

  1. 1

    Layer height that isn't a multiple of the Z motor's full step ('magic numbers'): the axis rounds each layer differently.

    Fix: Use layer heights that are multiples of your Z full step (most T8 leadscrews: multiples of 0.04 mm → 0.12/0.16/0.20/0.24). Avoid values like 0.15 on those machines.

    Source: Simplify3D — Print Quality Guide: Lines on the Side of Print ↗
  2. 2

    Bent or misaligned Z leadscrew (mechanical z-wobble): the screw pushes the nozzle in a circle every turn.

    Fix: Check the leadscrew spins without wobbling (watch the coupler). The screw must NOT be constrained sideways: loosen the nut mount, run the axis up/down, retighten without side load.

    Source: Simplify3D — Print Quality Guide: Lines on the Side of Print ↗
  3. 3

    Oscillating temperature or flow: alternating fat/thin layers without a fixed mechanical rhythm (inconsistent extrusion).

    Fix: Check the temperature doesn't swing more than ±2 °C (PID-tune if it dances) and rule out inconsistent filament diameter with calipers.

    Source: Simplify3D — Print Quality Guide: Inconsistent Extrusion ↗
  4. 4

    Dry or dirty leadscrew: dust and old grease make the nut advance in jerks at specific points of every turn.

    Fix: Wipe the leadscrew clean with a rag until the gunk is gone and re-grease with a light grease (PTFE ones work well). Never lubricate over the dirt: clean first, grease after.

The material factor

Z-banding is mechanical and shows up the same with any material; what changes is the shop window. Glossy or silky filaments (silk, PETG) amplify every band with their reflections, while matte ones hide them. The exception is banding from inconsistent extrusion: there, wet or uneven-diameter filament IS the direct culprit — and PETG and nylon soak up moisture within days.

hotend tools that help here

Printer comparator → Leadscrew or belts on Z? What structure does each model use? The comparator shows each printer's mechanics before you buy.

Related

FAQ

Z-banding or ghosting?
Z-banding is HORIZONTAL and rhythmic (repeats with height regardless of shape); ghosting is an echo trailing corners and details along the travel direction. Rotate the part: if the marks ring the whole part at the same heights, it's Z.
Is a new leadscrew worth it?
Before spending: 80% of z-wobble cases are fixed by relieving side tension (a screw fighting its nut) and using step-multiple layer heights. A truly bent screw is visible to the naked eye when spun.
How do I tell mechanical from extrusion banding? Measure the bands.
With calipers: if the band spacing matches your leadscrew's travel per turn (8 mm on typical T8s) or a divisor of it, it's mechanical. If the spacing is irregular, suspect extrusion: temperature, filament diameter or moisture.
Does z-banding weaken the part?
Almost never: in most cases it's purely cosmetic. Only when it comes from inconsistent extrusion do the 'thin' layers carry less plastic and bond slightly worse — but you'll have seen it all over the surface long before you feel it in strength.

Sources & references

This page is cross-checked against public manufacturer documentation and reference technical guides:

Still stuck? Back to the quick diagnosis or check which materials your printer can handle.