When to use this guide
Use this page when the symptoms below match what you see on the printer. Work through the checks in order and avoid changing several variables at once.
- A vertical scar appears on one side of the print
- Random zits appear on curved surfaces
- Seam blobs are worse after increasing speed
- Retraction fixes strings but creates gaps or pockmarks
- PETG leaves little deposits at starts and stops
Most likely causes
These are the most common root causes. The correct fix depends on when the failure happens, which material is loaded, and whether the profile used to work before.
- Seam position is visible on curved geometry
- Pressure advance, retraction, wipe, and coast are not balanced
- Temperature is too high or filament is wet
- Flow is slightly high at starts/stops
- Travel path crosses visible surfaces
Safe fix order
This order is designed to prevent random tuning. Start with physical checks and material condition, then move into slicer changes.
- Move seam to the least visible corner where possible.
- Tune temperature and dry filament before aggressive retraction changes.
- Use pressure advance/linear advance only after flow is close.
- Use wipe/retract settings conservatively and test on a small cylinder.
- Avoid random seam placement on display models unless it looks better than one scar.
- For product renders/display items, orient the seam to the back.
Settings and decision notes
Seam positionAligned seam can be hidden; random seam can spread small zits.
RetractionToo much can cause gaps and under-extrusion after travel.
Wipe/coastUse small changes and inspect starts/stops.
Pressure advanceHelpful for corners and seams after base tuning is done.
Bench checklist
Use this short checklist beside the printer before reprinting the full model.
- Dry filament if needed.
- Tune temperature.
- Set seam location intentionally.
- Test retraction/wipe in small steps.
- Tune pressure advance after flow.
- Inspect a real display model.
What to do after it works
Print a small confirmation part before returning to a long print. Save the working material, temperature, cooling, speed, and support notes in Profile Vault so the same problem does not become a repeat mystery.