Upgrade your printer: Smart fan (BCN3D Sigma)

Save energy and avoid some noise during the pre-heat with this upgrade


Allen key 2mm
Allen key 2.5mm
Crosshead screwdriver


This upgrade is only for the early Sigma units that don't have the new extruder board and cooler fan that only turns on when the hotend has a temperature over 90ºC.


Before starting the upgrade, turn off and disconnect the printer.

sigma-turn-off-1 sigma-turn-off-2


1. Remove the four Allen screws from the hotend and the printed cover.

screw-iconx2 M3 6mm

screw-iconx2 M3 8mm


2. Remove and slide the cover-up. You can hold the cover like in the following picture.

3. Cut the zip-tie and remove it.

4. Disconnect the cable from the hotend pressing de connector.

bcn3d-sigma-upgrade-2 bcn3d-sigma-upgrade-3


5. Take the hotend out of the tool head.

6. Remove the flat cable holder unscrewing its Allen screw. screw-iconx1 M3 10mm


7. Gently release the latch, first one side and then the other. Remove the flat cable.

bcn3d-sigma-upgrade-5 bcn3d-sigma-upgrade-6


8. Remove the other cables holder unscrewing the Allen screw. Disconnect the cables of the endstop and the two fans.

bcn3d-sigma-upgrade-7 bcn3d-sigma-upgrade-8


9. Unscrew the two Phillip screws from the cooler fan and the Allen screw from the toolhead cover. Then, remove the cooler fan. screw-iconx2 M3.2 9.5mm
bcn3d-sigma-upgrade-9 bcn3d-sigma-upgrade-10


10. Take the new fan and make sure its cable is out of the locking tab

bcn3d-sigma-upgrade-11-2 bcn3d-sigma-upgrade-11


11. Insert the fan cable through the hole of the corner as the following pictures.

bcn3d-sigma-upgrade-12 bcn3d-sigma-upgrade-13


12. Make sure to put the fan in the correct position, with the sticker inwards and the cable as the following picture.


13. Screw halfway the two Phillip screws of the cooler fan. screw-iconx2 M3.2 9.5mm


14. Remove the two Allen screws and the four nylon washers of the old connection board.

screw-iconx2 M3 6mm




Take the new connection board with the same screws and washers and screw them on the same metal sheet. The washers have to be on both sides of the connection board.


new-extruder-board-bcn3d old-extruder-board-bcn3d
R16 Older Extruder board R17 | R19 Extruder board


16. Connect the two fans and the endstop. Look closely where each one is connected.


Position this assembly in its place and screw the holder with the cables well positioned.

Connect the flat cable. First, pull the latch-up gently, then insert de the flat cable in the connector carefully, and finally push the latch down. Make sure the latch is really tight.

bcn3d-sigma-upgrade-17 bcn3d-sigma-upgrade-18



This upgrade will make your printer make less noise when it is printing and save energy when it is on standby.

It's important to check the connections of the flat cables before powering the printer back up, you will find more information about this here:  How to check flat cable connections

Forum Community

Need more tips? Check out our forum community for more info about this


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.




Buy these parts

cooler-fan-bcn3d Sigma / Sigmax - R17 | R19 Cooler Fan SKU 11034
Sigma / Sigmax - R17 | R19 Extruder Board SKU 16100



upgrade printer sigma EN


upgrade printer driver EN


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