Melt plugs

A melt plug forms when melted plastic flows backward in the barrel of the extruder and solidifies. This creates a blockade, stopping plastic from moving down the barrel, effectively stopping any further extrusion.

A melt plug will form when

1. The auger is run in reverse
2. The extruder is left at temperature without the auger active
3. The auger is run when filament cannot be extruded, but the barrel is hot

How to remove a melt plug

1. Remove and the auger gearbox and stepper assembly by removing the four machine screws coupling the gearbox to the extruder.
2. Bring the extruder barrel up to 270 °C.
3. Using an electric drill or socket wrench, work the auger free and then reverse it out of the barrel. It is important not to apply too much force while doing this or the auger may break.
4. Let the auger and barrel cool.
5. Chip solidified plastic off of the auger.
6. When cool, drill out remaining plastic in the barrel with an unmodified 18 inch auger or similar bit. Now would be a good time to clean the breaker plate.
7. Check the grooves in the feed throat, as they must be free of any plastic or debris. If they are filled with melted plastic or debris, us a pointed tool like an awl to clean them out.
8. Replace the auger with socket attached
9. Reattach the gearbox to the auger, making sure the socket is firmly inside of the gearbox couple
10. Reinstall the four machine screws that hold the gearbox to the extruder.