Blobs and Zits
Medium to Fix
Small bumps, blobs, or pimples appear on the outer surface of prints.
What Does It Look Like?
Small bumps on outer walls
Pimples or zits on surface
Usually at layer start/end points
More visible on solid colors
Common Causes
Retraction settings
Inconsistent extrusion
Seam placement
Over-extrusion
Solutions (Try in Order)
Start with Priority 1 solutions. Make one change at a time and test between changes.
1
Optimize Retraction
Prevent oozing at layer changes
Enable retraction on layer change, tune distance/speed
1
Change Seam Placement
Hide seam in corner or rear
Seam position: Rear or sharpest corner
2
Enable Coasting
Stop extruding slightly before end of perimeter
Coasting distance: 0.2-0.5mm
2
Reduce Extrusion Multiplier
Slight over-extrusion causes blobs
Decrease flow by 2-5%
3
Lower Print Temperature
Cooler plastic is less runny
Decrease by 5°C
Prevention Tips
- Save working settings for each filament type
- Perform regular printer maintenance
- Keep filament dry and stored properly
- Re-level bed before important prints
- Start with manufacturer-recommended settings
At a Glance
Severity:
LOW
Difficulty:
Medium
Category:
Surface Quality
Solutions:
5