Cleaning the Nozzle¶
A partially clogged nozzle is a very common cause of under-extrusion, which results in weak, stringy, or incomplete prints. Before replacing a nozzle, it's often worth trying to clean it. This guide covers the two most effective methods.
Method 1: The "Cold Pull" (for Internal Cleaning)¶
This technique is excellent for removing stubborn bits of burnt plastic or debris from inside the nozzle's meltzone.
- Preheat: Heat the hotend to the normal printing temperature of the filament currently loaded (or the last filament used).
- Extrude: Manually push some filament through to ensure there is flow.
- Cool Down: Set the hotend temperature to a "soft" state, not fully molten. Good starting points are 90°C for PLA or 120°C for PETG/ABS.
- Pull: Once the temperature has stabilized, press the extruder's tensioner arm and use a firm, steady motion to pull the filament straight out of the hotend. It should require some force.
- Inspect: Look at the tip of the filament you removed. It should have a perfect impression of the inside of your nozzle. You may see the contaminant (e.g., a black speck of burnt plastic) embedded in the tip.
- Repeat: Snip off the dirty tip of the filament and repeat the process until the filament comes out clean.
Method 2: Acupuncture Needle (for Tip Blockages)¶
This method is best for clearing simple clogs located right at the very tip of the nozzle orifice.
Handle with Care
The nozzle will be hot and the needle is very sharp. Always work carefully.
- Preheat: Heat the hotend to its printing temperature.
- Clear Orifice: Carefully insert the fine acupuncture needle up into the nozzle tip by a few millimeters. Gently move it around to break up and dislodge the blockage.
- Purge: Manually extrude a small amount of filament to push out any loosened debris.