Adjust Belt Tension




Adjusting 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.  High belt tension will contribute to premature bearing wear.  Low belt tension can lead to reduced printing accuracy and/or dislocation.

Belt tension is adjusted at the factory using an expensive meter to measure the audio frequency of the belt when it is plucked.  There is a direct relationship of belt tension to frequency and this is a well established method.

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. 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.

To adjust the belt tension on your printer:

  1. Install and open the tuner app on your mobile device.
  2. Set the Tolerance to +/- 10 Cents.
  3. Turn off the printer; manually move the printhead to a position that allows space for plucking the belt underneath the Y-rail opposite of the printhead.

  4. Place your phone's microphone close to, but not touching the belt opposite of the printhead.  Pluck the belt, as if it were a guitar string. Use a 3mm hex wrench to adjust the belt tensioner until a frequency of 82Hz-84Hz is read by the app.


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Learn More About Adjusting Belt Tension

A few hints for best results:

  • Make measurements in quiet surroundings. If you cannot count on 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 of frequency.
  • 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 quickly die off and you are left with only the fundamental frequency. For this reason, ignore early readings that appear to be a multiple of your target. With a little practice you will obtain highly repeatable and accurate results in less than two minutes.

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