Adjust Belt Tension




  • 3mm hex key
  • Mobile device equipped with tuner app (see below)


Adjust the Belt Tension for Optimal Performance

The print head on your printer is moved using a system of motors, pulleys, and belts. For optimal operation, it is important that belt tension is maintained at the correct level. Excessive belt tension will contribute to premature bearing wear. Insufficient belt tension can lead to reduced printing accuracy and/or dislocation.

Belt tension is adjusted at the factory using a calibrated meter to measure the audio frequency of the belt when it is plucked, as there is a direct relationship between belt tension and frequency.

Since belts may stretch over time, it is recommended that users occasionally (every 100 prints) measure belt tension and adjust as necessary. This can be done with any device that allows you to measure audible frequencies in hertz (Hz). One inexpensive option is to use a mobile device equipped with the free version of either the Fine Tuner app (for iOS) or the Fine Chromatic Tuner app (for Android). These applications are designed to tune musical instruments, but they can also be used as accurate frequency meters.

Note: Some users have reported technical issues with Android tuner apps.

Note: To ensure accurate measurements, always take frequency adjustments in quiet surroundings.

  1. Install and open a tuner app on your mobile device.
    Note: If you are using the Fine Tuner app for iOS, you can disregard the lower of the two numbers on the main screen.
  2. Turn off the printer.
  3. Manually move the print head to the back left corner of the print chamber to more easily access the belt underneath the Y-rail opposite the print head.


  4. Place your phone’s microphone close to, but not touching, the belt opposite the print head. Pluck the belt as if it were a guitar string and use a 3mm hex key to adjust the belt tensioner until the app reads a frequency of 82Hz–84Hz. 



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Tips for Best Results

  • Make measurements in quiet surroundings. If you cannot secure a quiet environment, consider investing in a shotgun condenser microphone to plug into your mobile device.
  • Remove any protective case on your phone, if necessary, to get the most accurate reading.
  • Place your phone’s microphone close to, but not touching, the belt.
  • Do not over-pluck the belt such that it vibrates against the gantry plate.
  • When you initially pluck the belt, it will produce harmonics at multiples of the fundamental frequency. These will quickly die off and you will be left with only the fundamental frequency. For this reason, ignore early readings that appear to have measured a multiple of your target frequency. With a little practice, you will obtain highly repeatable and accurate results in under two minutes.


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