How to Fix Over Extrusion in 3D Printing: Simple Solutions

Over extrusion in 3D printing happens when too much filament is pushed through the nozzle, causing blobs and rough surfaces. To fix it, reduce the flow rate or extrusion multiplier in your slicer settings and check your filament diameter calibration.

Why This Happens

Over extrusion occurs when the printer pushes more filament than needed through the nozzle. This causes excess plastic to build up, making prints look messy with blobs, stringing, or thick layers. Common causes include incorrect flow rate settings, wrong filament diameter input, or too high nozzle temperature.

ini

; Example slicer setting causing over extrusion
flow_rate = 120  ; 120% flow rate means 20% too much filament
extrusion_multiplier = 1.2  ; multiplier set too high
filament_diameter = 1.75  ; but actual filament diameter is 1.75 mm

Output

Print shows blobs, rough surfaces, and stringing due to excess filament.

The Fix

To fix over extrusion, lower the flow rate or extrusion multiplier to 95-100% or less depending on your printer. Also, measure your filament diameter accurately with calipers and enter the correct value in your slicer. Reducing nozzle temperature slightly can help filament flow better and reduce excess extrusion.

ini

; Corrected slicer settings
flow_rate = 95  ; reduce flow rate to 95%
extrusion_multiplier = 0.95  ; reduce multiplier
filament_diameter = 1.75  ; accurate filament diameter measurement

Output

Print layers are smooth and consistent with no blobs or stringing.

Prevention

Prevent over extrusion by regularly calibrating your printer's extrusion settings. Measure filament diameter often and update slicer settings accordingly. Use test prints like extrusion calibration cubes to fine-tune flow rate. Keep nozzle temperature within recommended ranges for your filament type. Avoid changing multiple settings at once to isolate issues.

Related Errors

Under extrusion is the opposite problem where too little filament is pushed, causing gaps and weak prints. It can be fixed by increasing flow rate or checking for clogs. Stringing can also occur with over extrusion but is often helped by adjusting retraction settings.

Key Takeaways

Reduce flow rate or extrusion multiplier to fix over extrusion.

Measure filament diameter accurately and update slicer settings.

Lower nozzle temperature slightly if filament flows too fast.

Calibrate extrusion regularly using test prints.

Avoid changing multiple settings at once to identify causes.