Hot End RTD Inspection

Model [X] AON-M2 [X] AON-M2 2020
Category [X] Preventive [ ] Corrective [ ] Troubleshooting


The procedure that follows explains how to inspect the PT100 resistance temperature detectors (RTDs).

A functional RTD prevents:

  • Inaccurate heating of the polymer(s).
  • Blockages in the hot end(s).
  • Damage to the filament feed system.

Estimated time: 30 minutes


None required.

Parts Information

None required.

Personal Protective Equipment

Qty Description Specification
1 Safety Eyewear N/A

Prepare the Machine

  1. Home XYZ.
  2. Lower the Z-axis by 300 mm.
  3. Wait until the build chamber, build plate and hot ends are at room temperature.

Hot End RTD Inspection

Allow all machine components to reach room temperature prior to proceeding further. Failure to allow components to cool down will result in thermal injury (burns) to personnel.

  1. On the user interface, select the terminal tab (1). Command Page
  2. Enter the M18 command. The M18 machine code (M-code) disables all stepper motors which prevents the axes from moving.

    Do not home any axes when maintenance is performed inside the build chamber. This will cause the axes to move, even with the M18 command is active. Failure to do so will lead to personal injury.

  3. On T0, make sure the connections that follow are correct:
    1. Heater plugs (2).
    2. RTD electrical plugs (3). Electrical Plugs
  4. Make sure that the RTD connects correctly in the hot end. Tighten by hand as necessary.
  5. Make sure that the RTD wires are in good condition.
  6. Do the steps that follow to test the RTD:
    1. Pinch the wires close to where they connect on the RTD,
    2. Carefully move the wires around to simulate X/Y-axes movement,
    3. On the user interface, select the temperature icon (4),
    4. Make sure the temperature does not change more than +/-5ºC on the user interface while carefully moving the wires.
  7. Close the build chamber door.
  8. Make sure that the T0 temperature (5) is the same as the ambient room temperature (+/-5ºC). T0 UI
  9. Set the T0 target temperature to 50ºC.
  10. After approximately 30 seconds, make sure that T0 temperature is 50ºC (+/-5ºC).
  11. Set the T0 temperature to the necessary operation temperature.

    Make sure to use the correct build chamber and/or hot end operation temperatures. The operation temperatures vary for all polymers. Failure to use the correct temperatures will damage the hot end and the filament feed system.

  12. After hot end temperature has been reached, make sure that T0 temperature reading on the user interface is at the preset operation temperature chosen in step 11 (+/-5ºC).
  13. If the temperature reading on the user interface is not in the satisfactory range, replace the RTD. Refer to replace hot end RTD.
  14. Do steps 1 to 13 with T1.

    Turn off the hot end heater(s) if the machine is not ready for operation. Leaving the hot end heater(s) on for extended periods of time without extruding can burn the polymer filament and cause clogs in the nozzle(s). The heater timeout feature can be enabled to automatically turn off the hot end after a period of inactivity.

Test and Return to Service

  1. Home XYZ.

Last modified: June 14, 2021