How to install the Shims (BCN3D Sigma)

Install the shims to correct the Z offset between both nozzle tips


Shims are elements that mechanically correct the Z offset when printing in Mirror or Duplication mode. These printing modes are available for the Sigma R19. Those Sigma users who have previous versions must update their firmware to 2.0.0 or higher and buy the shims to be able to use these features on their printer.


In these modes both toolheads work simultaneously, so it is key to make sure both nozzle tips are exactly at the same height. Due to manufacturing and assembly tolerances, the Z offset between tips can be up to 0.5mm. BCN3D printers automatically correct the offsets when printing in Mirror/Duplication Modes.

However, this correction distorts the first layer of the model by repeating it as many time as needed. To avoid such distortion there are different options:

  1. Enable raft in BCN3D Cura: The offset will be corrected in the first layers of the raft, so the model won’t be affected by any Z offset.
  2. Install shims to mechanically correct the Z offset: Printing a raft takes time and spends material. For those users planning to use  Mirror or Duplication modes frequently, it is highly recommended to install the shims when it is suggested during the Printer Calibration process.

To install the shims follow these steps:

During the Printer Calibration process or before printing a job in Duplication or Mirror mode, the Sigma may suggest you to install shims to correct the Z offset
between nozzle tips.
Once you confirm you want to install the shims, remember de number of shims to install on which hotend and then follow the screen instructions:


Wait until the printer cools down to avoid any dangerous manipulation. Once it has cooled down, turn off the printer.

Unscrew the 2 bolts at the specified hotend and install as many shims as previously  indicated in the screen.

2-hotend-shimsOnce the shims are installed, Screw the bolts, turn on the machine and follow the instructions on the screen.


Forum community 


Need more tips? 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.



replace hotend eng


clean hotend eng


You can help improve the BCN3D Knowledge Base.

If you feel there are guides that we are missing or you found any error, please use this form to report it. Report form :)