Quick answer
The Z-seam is the small vertical scar left where every layer starts and stops. You can’t delete it, but you can hide it: set the seam position to Aligned/Back (or paint it onto a hidden edge), enable a scarf seam on the outer walls, and tune retraction and wipe so the nozzle stops oozing at the start/stop point. On Bambu Lab and OrcaSlicer, a scarf seam plus a small seam gap usually makes the line nearly invisible.
Why the Z-seam happens
Every perimeter loop has to begin and end somewhere. At that point the printer stops, retracts, then starts again, leaving a tiny blob, gap, or notch that stacks up layer over layer into a visible line. Oozing during the stop, leftover pressure in the nozzle, and the abrupt start/stop move all make it worse. The goal isn’t to remove the seam, but to move it somewhere you can’t see it or blend the ends together.
1. Set the seam position
In Bambu Studio / OrcaSlicer this is under Process, Quality, Seam. For a figurine or display piece with a clear front, use Back (Bambu Studio) or Aligned Back (OrcaSlicer) to tuck the seam behind the model. For parts with lots of corners, Nearest or Sharpest Corner hides the seam inside the geometry. Aligned stacks the seam in one straight line, which is easy to sand later.
2. Paint the seam onto a hidden edge
When automatic placement can’t find a good spot, paint the seam yourself. In Bambu Studio, select the model and click the Seam Painting brush in the left toolbar. Left-click enforces a seam and right-click forbids one, so you can drag the line down a back corner or an area that will never be seen.
3. Enable a scarf seam
A scarf seam replaces the abrupt start/stop with a long, shallow diagonal overlap so the two ends blend together. Bambu Studio added it in version 1.9. Apply it to Contour (outer walls) only, and keep the scarf speed at or below your outer-wall speed so flow stays precise. On a Bowden printer, a longer taper of around 15 mm at about 50% of outer-wall speed gives the cleanest result. Some scarf parameters require Develop Mode (Ctrl + P) to appear.
4. Tune retraction
A seam that oozes usually just needs better retraction. Start at roughly 5 to 7 mm for Bowden extruders or 0.5 to 1 mm for direct drive, with a retraction speed around 35 to 50 mm/s. Under-retraction leaves a blob at the seam; over-retraction leaves a gap or a hole, so adjust in small steps.
5. Turn on wipe and a little coasting
Wipe moves the nozzle back along the finished path while retracting, cleaning the tip so it doesn’t leave a zit. Try a wipe distance of 5 to 10 mm. A small coasting distance of 0.2 to 0.5 mm stops the extruder just before the layer ends and lets residual pressure finish the line. The Seam Gap setting (default 15% of nozzle diameter) controls how early extrusion stops at the seam point.
6. Slow down and cool the outer wall
Excess heat keeps plastic runny and worsens seam blobs. Dropping the print temperature by about 5 degrees C and slowing the outer-wall speed gives the nozzle time to start and stop cleanly. Good part cooling helps each seam point solidify before the next layer lands on it.
7. Rule out filament and mechanical causes
If the seam looks ragged no matter what you change, the cause may be upstream. Wet filament pops and oozes inconsistently, a worn or loose extruder skips at the start of a line, and Z-axis wobble or a bent lead screw can stack seam defects into a wavy stripe. Dry the filament, check extruder tension, and inspect the Z hardware before chasing slicer settings further.
Frequently asked questions
Can I remove the Z-seam completely? No. There is always a start and stop point on each layer, but a scarf seam or careful seam placement can make it nearly invisible.
Where should I put the seam on a figurine? Use Back / Aligned Back, or paint the seam onto the rear of the model so the front face stays clean.
Why does my scarf seam look worse than a normal seam? Scarf seams need enough time and flow to blend. Slow the scarf speed (about 50% of outer wall on Bowden machines) and apply it only to the outer contour.
Does a random seam hide the line? It scatters the seam so there’s no single stripe, but it adds small zits across the surface, so it suits organic models better than flat walls.