One of the best (and most unique!) features of the MOD-t is its simple calibration process. The MOD-t uses servo feedback to gracefully calibrate your MOD-t, regardless of your print plate’s starting location.

This means, you can place the print plate anywhere in the print bed and your MOD-t will still calibrate correctly. (Of course, you still need to make sure your plate is placed square on the pinion rods so that it can glide smoothly around the print bed! A good way to do this is by putting the plate against a corner or wall of the base.)buildplate

Your printer starts calibrating as soon as the file transfer is complete. There are currently three steps to the MOD-t calibration and we’ll keep you posted as we release more improvements to this process.

Update! We’ve changed our calibration process to make it faster and more accurate. Check out the new automatic calibration process below.

  • First, it will home the X and Y axes. We’ve made this step much faster and your MOD-t will now actively work to align your build plate as it homes.
  • Then, the carriage will lower the nozzle while the build plate moves side to side. Once the nozzle makes contact with the print surface plate, your MOD-t will have its rough Z position.
  • Your MOD-t’s nozzle will heat up.
  • Your MOD-t will repeat the second step two more times, with the MOD-t’s nozzle lightly touching the build plate to complete the high-accuracy homing. The entire process should take about 90 seconds.
  • You’ve probably noticed that every print begins with a vertical stripe on the right side of your print surface plate. That’s what we call priming, or, more informally, the “Nose Wipe.” It’s your MOD-t’s way of cleaning excess filament off the extruder and priming the nozzle so you get fresh filament for your new print.
The cleaning strip clears the nozzle after calibration.


Feeling nostalgic? The following is our old calibration process. This is the process for MOD-ts running on firmware versions before 0.12.0

(1) The carriage lowers so that the hot end touches the build surface and then rises back up.

MOD-t Calibration
One hop this time!

This is your MOD-t finding its rough Z-axis position.

This is done when the nozzle is at a lower temperature than when the printer is extruding. If the nozzle is hot (from a filament change or previous print job), the MOD-t will wait for the nozzle to cool before starting this step.

(2) The MOD-t moves the build surface.

This is the little dance your tray does in the print bed. (It moves right first, moves to the back next, moves left, then moves to the front.) This is how your MOD-t centers itself on the X-axis and Y-axis.

Cha-cha now, y’all.

At each point, two of the print surface plate’s legs (on the bottom of the tray) make contact with the pinion rods the plate returns to the middle. Then it continues to the next panel. If the MOD-t fails during this process, it will re-try up to three times. If the tray was not placed correctly (as mentioned above), you will hear a chatter. Sometimes, the MOD-t will automatically fix this, but it’s best to just place the tray correctly yourself!

(3) The carriage lowers while the build surface swipes left to right.

Sliiide to the left! Sliiide to the right!

(Note: There will be a pause before this step so the nozzle can warm up.)

This final step is when your MOD-t gets its most accurate reading of where the nozzle is in relation to your print surface plate. Your nozzle should not touch the build plate during this step. It should merely hover closely. Touching the build plate could cause inaccurate homing. You should also take care to keep your MOD-t base and pinion rods free of debris so homing is not affected during this final step.

Now that you understand how your printer calibrates, you can watch as your print surface and carriage do their little dances to help you keep making great things!


  1. Sahachai phiraphat

    My MOD -t does not touch the plate. It seems that it is too low and when the filament hot enough it melted down as a rubbish on the plate. How can I adjust it a little higher to receive and print at the right position level?

    • Madison

      The MOD-t will auto-calibrate before every print, so it should home (calibrate height) correctly next time you print. If your printer is consistently homing high or low, feel free to contact our customer support team! You can find their contact information on the Customer Support portal.

  2. Wm Steele

    I’m confused by what is actually happening on the third step, when it is bouncing left to right. It seems that the nozzle is actually touching, ever so lightly at the end. If it isn’t, I’m not sure what it is the system is looking for to indicate a good calibration. The nozzle starts higher up and on each pass lowers slightly until it touches it, or at least that’s what it appears to do. In fact, if I lightly touch the plate and let it drag once or twice under my finger, it will stop the process and proceed to print from that height.

    Am I missing something non obvious?

    • Madison

      Hello! In the current homing routine, the carriage moves down the z-axis while the plate is moved across the Y-axis. This is done so that the system can detect drag on the Y-axis by the Z-axis. Once the hot end just touches the plate, there is a significant change in Y-axis drag and we detect that to be Z0. It’s all just part of our feedback system. Hope that helps!

  3. Jim Watts

    Would you please add a verbose status to the desktop app that shows “Cooling hot end…”, “detecting rough z-axis position…”, “Warming up hot end…”, “Refining Z-Axis position…”, “Wiping my nose…”? Some times it takes longer than others and a thermal gauge (like you see when changing filaments) with a description of what it’s doing would be really nice to see. Thanks!

    • Madison

      Great suggestion, Jim. We’re actually working on updating our calibration process now. Our updated calibration process will be significantly faster, so it might not even be necessary to know what step your printer is on. I can’t say much more, but you’ll be pleasantly surprised by how much faster calibration will be!

  4. KyLee

    About how long should the calibration process take? Mine has been on Calibrating Carriage (step 2 of 2) for at least thirty minutes which seems extremely long without actually printing anything yet.

  5. Cicerone Family

    My printer “stuck” on the calibration phase. The tray itself is only going left and right. Some of the filament has also melted out of the nozzle in a line and now is touching the printing tray. The nozzle itself is still in it’s highest position and has not moved.
    I’ve ran successful test prints, but now I’m simply trying out to print out a ball.
    I have unloaded and reloaded the filament, and made sure the tray is resting on the correct grooves.

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