Inconsistent Extrusion

For accurate 3D printing, your printer must extrude plastic consistently. Variations in extrusion can significantly affect print quality. Inconsistent extrusion is often noticeable when observing the print process; for example, a straight line that appears uneven or bumpy may indicate this issue.

Common Causes and Solutions:

Filament Issues

First, inspect the filament spool feeding into your printer. Ensure the spool rotates freely and that the filament unwinds smoothly. Tangled filament or a spool with excessive resistance can disrupt even extrusion. If your printer has a Bowden tube (a tube through which the filament travels), ensure the filament moves through it without excessive resistance. Clean or lubricate the tube if needed.

Clogged Nozzle

Check the nozzle for clogs if the filament feeds properly but extrusion remains inconsistent. Debris or residual plastic in the nozzle can impede extrusion. If problems are detected, consult your manufacturer for proper nozzle cleaning procedures. For more information, refer to the ‘Clogged Extruder’ article.

Very Low Layer Height

Extremely low layer heights, such as 0.01mm, may limit the space for plastic to exit the nozzle, leading to inconsistent extrusion. Verify that you are using a reasonable layer height for your printer.

Incorrect Extrusion Width

Using your printing software, check the extrusion width setting to ensure it is appropriate for your nozzle size. The extrusion width should be within 100-150% of the nozzle diameter. For instance, a 0.2mm extrusion width with a 0.4mm nozzle may lead to inconsistent flow.

Poor Quality Filament

Low-quality filament can also cause inconsistent extrusion. Filaments with inconsistent diameters or additives can affect extrusion. Additionally, some filaments, such as PLA, can absorb moisture and degrade over time. If you suspect filament quality issues, try using a new, high-quality filament spool to see if the problem persists.

Mechanical Extruder Issues

If all other factors seem fine, check for mechanical issues with your extruder. Many extruders have a drive gear with sharp teeth that grip the filament. There may also be an adjustment for how tightly this gear presses into the filament. If this adjustment is too loose, it can impact extrusion consistency. Consult your printer’s manual or manufacturer for guidance on adjusting the extruder.