Over-extrusion: when too much plastic is printed
Over-extrusion means more material is deposited than the toolpath requires. Surfaces can become rough, material can build up around edges and functional fits can become too tight. Before changing flow, verify the filament profile, filament diameter, nozzle and other relevant settings.
Typical symptoms
- excess material ridges
- rough top surfaces
- nozzle scraping over raised material
- outside dimensions too large
- inside dimensions too small
- mating parts become too tight
Extrusion multiplier
The extrusion multiplier or flow factor fine-tunes the amount of material extruded. For example: 1.00 = 100%, 0.95 = 95%. The right value depends on filament, printer and nozzle — there is no single universally correct value.
Check the filament profile first
Verify:
- material profile
- filament type
- nozzle size
- filament diameter
Why fits reveal over-extrusion
Extra material can enlarge outside dimensions, shrink openings and create uneven mating surfaces. A fit problem may therefore be a print-process problem rather than only a CAD-clearance problem.
Glue joints
An over-extruded top surface may become uneven and prevent two printed halves from sitting flat against each other.