How to adjust the belt tension (Epsilon Series)





Allen key 2.5mm
Allen key 2mm
Socket wrench 5.5mm 



Here we will cover the procedure to adjust the tension of the belts in your BCN3D Epsilon. 

All printers are shipped with the belts adjusted from the factory. Unless you are experiencing layer shifting issues or your belts have lost tension overtime, there's no need to tighten them.



To set the belts to their right tension, you can use our printable tensioner as a reference. You can download the STL file and the instructions on how to use it from the following article:

BCN3D Belt tensioner.

Note: This tool is not updated and its precision may vary on each print, it should only be used as a reference point and to ensure that the tension is the same in all the belts from the X and Y axis.


1. With the X belts, make sure that both are adjusted equally. Once the tension is right, tighten the lower screws back.



2. With the belt Y belts, make sure that the external faces of the idler and the frame are parallel before finishing the adjustment.


Y motor belt adjustment


Note: The tensioner tool is not suitable for the adjustment of this particular belt.

1. Loosen the two nuts that hold the stepper to the printer’s structure without removing them. nut-iconx2 M3


2. Underneath the motor, there is a rectangular piece with two hollow screws in its lower part. Adjust them equally to increase/decrease the belt’s tension.

screw-iconx2 M4 10mm

adjust screws of Y motor tensioner

Note: It's very important that the belt is centered in the pulley, check it by giving a few turns to the Y motor and see if the belt moves to the sides or stays still. If it moves to a particular side of the pulley, tweak the alignment of the belt by adjusting the same hollow screws. 


3. Once the belt tension is set, tighten the two nuts that you loosened on the first step.

Note: When the nuts are screwed back, the belt gains some tension. Pay attention if the belt needs to be adjusted again to avoid damage to the motor or to the belt.




Check and adjust the belt's tension regularly to prevent issues like layer shiting or ghosting. It's recommended to do this process every 1000 printing hours or when you need to remove the belts or any component that is connected with them.

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Need more help? Check out our forum community for troubleshooting help.


It's important to keep your printer in good shape to make the most out of it. In this chart, you can find a list of the extruder maintenance procedures and how frequently these should be done. Maintenance Plan


bcn3d-recycle  Take your e-waste to a certified recycler. Check how we do it in BCN3D.



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