prusa3d/Prusa-Firmware v3.12.0-RC2

3.12.0-RC2 Firmware for MK3, MK3S, MK3S+, MK2.5 and MK2.5S

on GitHub

Summary

• Thermal model protection updated
• Nozzle change menu
• XYZ calibration updates
• Bug fixes

This is the second release candidate of the upcoming firmware 3.12.0.

Thermal model protection updated

The thermal was first introduced in 3.12-beta1 and updated 3.12-RC1. This release brings further improvements and tweaks.

Protection is always active

The thermal model protection increases the overall security of the heating system and starting firmware 3.12.0, will be turned on by default. Since every printer is slightly different it is necessary to calibrate the printer first.

Modded printers

In case your printer is equipped with third-party components (heating or cooling), the thermal model might not be working properly. The developers are trying to expand support, but a large amount of data is needed to calibrate the model properly. Internally we have tested and analyzed over 150 000 OEM heaters and thermistors.

We are aware that third-party nozzle E3D REVO is not working correctly and we have an active GitHub issue where users reported their values. At this moment we don’t have enough data to analyze these, so please if you are a REVO user share your log files there.

Turning the thermal model protection off is not recommended, however, at your own risk it can be disabled via the serial line by sending G-code M310 S0 followed by M500 to make it permanent.

Calibrate the temp model on your printer

In case the printer is updated from any firmware prior to 3.12.0, or a factory reset is performed, the thermal calibration is considered invalid and must be executed again! If this process is skipped by the user, the printer will beep and possibly pause more often.

Temp model calibration is available in the LCD menu Calibration -> Temp model cal. as well in the initial setup Wizard.

• The calibration takes approximately 12 minutes and for the duration, you can’t give the printer any other commands.
• During the calibration the LCD status line shows which step it is going through at the moment.
• As soon as you see ”Original Prusa MK3S” on LCD, it is finished.

Please re-run the temp model calibration to ensure the best performance and minimize the temp model warnings,

• when you change:
  • the nozzle
  • heater block
  • the heater cartridge
  • the hotend thermistor
  • the print fan
  • fan shroud
  • complete hotend assembly
• When you add a silicone sock
• When you move the printer to a different environment (enclosure, etc.).

Printer behavior

While preheating:
In case the algorithm detects any issue, the printer starts beeping. If the problem persists for about 10 seconds, the heating is stopped and the message “Thermal anomaly” is displayed. The printer continues beeping (calls for user attention).

While printing:
Similar to preheating, a discrepancy between the model and thermistor readings causes the printer to first beep and display “Thermal anomaly” and after about 10 seconds, the print is paused. The nozzle is turned off and the printer continues beeping.

Please note, that once a “Thermal anomaly” is detected the printer “locks” itself to prevent any possible damage and it is necessary to perform certain actions. See more information below.

Added Clear TM error

To “unlock” the printer in case a “Thermal anomaly” is detected, there is a new option in the menu LCD menu -> Clear TM error to temporarily clear/acknowledge the issue. As this is only a “temporary” solution proper calibration is recommended. In case the temp model calibration doesn't solve this, please contact Prusa support or open a GitHub issue.

Feedback reporting

To give positive feedback, please use a ✔️ here below the release notes. In case of issues TM: warning or TM: error start a GitHub issue, which should contain at least the following information:

• Reproducible: Yes/No
• Printer: MK3/S/+ stock or modified
• Modifications: Example E3D Revo or Copper block or different Fan shroud (with a link)
• Specific print causes issues. Please attach the printed model
• Try to add a serial log of the print failing.

Nozzle change menu

We added the necessary Nozzle change menu option under Settings -> HW Setup which disables the temp model temporarily. Please read Changing or replacing the nozzle (MK2.5S/MK3S/MK3S+) before you start. Please also keep in mind that changing the nozzle will need the first layer adjusted, as you will never be able to tighten the nozzle at exactly the same height as the previous one. We made this change thanks to the feedback from our community testers (see #3719).

XYZ calibration updates

A message displayed on the screen has been updated from It will take up to 12 mins. to It will take up to 24 mins. as some users reported that their printer needed more time. We added some status information during the XYZ calibration to give visual feedback that the printer is still busy.

Bug fixes

• Fixed µm being shown incorrectly in languages other than English.