Back to the Gcode Dictionary
M302: Allow cold extrudes
- This command can be used without any additional parameters.
- Pnnn Cold extrude allow state (RepRapFirmware)
- Snnn Minimum extrusion temperature (RepRapFirmware 2.02 and later)
- Rnnn Minimum retraction temperature (RepRapFirmware 2.02 and later)
- M302 ; Report current state
- M302 P1 ; Allow cold extrusion
- M302 S120 R110 ; Allow extrusion starting from 120°C and retractions already from 110°C
This tells the printer to only allow movement of the extruder motor above a certain temperature, or if disabled, to allow extruder movement when the hotend is below a safe printing temperature.
The minimum temperatures for extrusion can be set using the Snnn parameter with a default value of 160°C if unset. A minimum retraction temperature can be set with the Rnnn parameter. The default for this is 90°C.
M302 with no parameters it will report the current cold extrusion state.
Note: One limitation of M302 is that it requires a thermistor to be present for the temperature to be monitored. If your system does not have a thermistor or heater to be monitored, you can define your tool in M563 without a heater to disable cold extrusion protection on that tool. ex: M563 P0 S"Pump" D0 F0 Note the lack of H parameter.