A vertical line, or a row of little dots, running from top to bottom. It's where each wall loop starts and ends.
It happens on any FDM printer. Setting names are Bambu Studio's: in Orca Slicer almost all have the same name, and PrusaSlicer or Cura usually have an equivalent.
Where do I start?
Two questions to sort out what to check. It's a guide, not a sure fix: every printer and every filament is different.
Check in this order
- The printerIf it printed fine yesterday and not today, it's almost never the profile. Check the plate, the nozzle and the room: printing at 15 °C is not the same as at 30 °C.
- The filamentA spool that has soaked up moisture gives strings, bubbles and brittle parts. Dry it before changing settings, and pick that filament's profile in the program.Filament pages
- The quick checksThe “First” list below: it's the fastest to check.Go to “First”
- The slicerOnly now, the settings below, in order. Change one thing, print a small test and compare. If you change three at once and it gets fixed, you won't know which one did it.Go to the settings
Check in this order
- The quick checksThe “First” list below: it's the fastest to check.Go to “First”
- The filamentA spool that has soaked up moisture gives strings, bubbles and brittle parts. Dry it before changing settings, and pick that filament's profile in the program.Filament pages
- The testsCalibrate your filament with these tests:3Pressure advance
- The slicerOnly now, the settings below, in order. Change one thing, print a small test and compare. If you change three at once and it gets fixed, you won't know which one did it.Go to the settings
Check in this order
- The quick checksThe “First” list below: it's the fastest to check.Go to “First”
- The previewStep through the slicer preview layer by layer: that's where you spot missing supports and odd areas in this part.
- The slicerOnly now, the settings below, in order. Change one thing, print a small test and compare. If you change three at once and it gets fixed, you won't know which one did it.Go to the settings
First
- It can be hidden almost completely. It only disappears with “Spiral vase”, which works for single-wall parts with no infill and no top.
- If the seam bulges or leaves blobs, calibrate pressure first with Calibration › Pressure advance.
Then, in the slicer (in this order)
- Seam positionProcess › QualityOn parts with corners, “Aligned” hides it in a corner. On a cup or a vase, “Random” spreads the mark around. On a figure that faces forward, “Back”. You can also paint it.
- Scarf seamProcess › QualityThe scarf seam lays the end of the loop over its start, and on smooth, round parts the mark almost vanishes.
- Seam gapProcess › QualityIf a bump is left where the loop closes, the nozzle stops pushing plastic a little earlier. Only shown in developer mode.
- Number of wallsProcess › StrengthWith 3 walls the seam shows less: there's more plastic behind it to cover it.
- Spiral vaseProcess › OthersOn a vase, a cup or a single-wall lamp, the part climbs in a nonstop spiral and there is no seam.
Fixed by calibrating:3Pressure advance
Tried everything and it's still the same? Calibrate your filament with the 8 tests, or write to us with a photo.