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Extruder Motor will not Turn

Cold Extrusion Prevention

If you are having issues with your extruder motor not turning when you tell it to extrude or retract, you may be having a safety feature in Marlin and our Unified firmware preventing it. The firmware is setup to not let the extruder motor turn until the hotend is at 170C or higher. Heat your hotend to 170C or higher and try to extrude or retract again.

This feature is present to prevent pushing filament into a cold hotend or trying to retract from a cold hotend. Trying to push in or pull out filament without the hotend heated can lead to stripping the filament and requiring disassembly of the extruder and/or hotend assembly to remove the filament.


Serial Monitor Output

If you look at your printer’s serial output (if connected over serial with something like Pronterface) you will see a message that says “cold extrusion prevented” in the output if this is preventing it from moving.


Disabling Cold Extrusion Prevention

If you are an advanced user who wants this feature disabled, you can remove it from the firmware. It is not recommended for most people because you can cause issues with the machine if you forget that it is off and try to extrude or retract filament with a cold hotend.

Marlin – In the Configuration.h file, search for “PREVENT_COLD_EXTRUSION”. Add 2 // in front of the #define PREVENT_COLD_EXTRUSION line and then flash your board with the new firmware.

Unified 2 – In the Configuration_backend.h file, search for “PREVENT_COLD_EXTRUSION”. Add 2 // in front of the #define PREVENT_COLD_EXTRUSION line and then flash your board with the new firmware.

WARNING: Disabling this feature may cause firmware issues or failure to compile. We do not test our firmware with this feature disabled. This information is provided AS-IS and is not supported by TH3D Studio LLC.

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