Understanding the retractions - BCN3D Stratos


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configuring the retraction


Retractions play a key role when printing pieces with small details. The perfect adjustment of this group of parameters allows obtaining clean prints, with very defined details.



Note:  Before modifying the retraction settings, verify that your filament is in good conditions and free of  humidity: Problems related to humidity


Table of Contents:

General tips
Retraction distance
Retraction speed
Minimum retraction travel
Maximum retraction count and Minimum extrusion distance window
Prevent filament grinding

General tips


Before modifying the retraction settings, it is necessary to keep in mind the following tips to avoid problems derived from an excess of retraction.

  • Retractions depend on the print speed. Printing slower allows you to reduce the retraction distance and speed.
  • Control the ambient temperature around your printer. High temperatures can cause that the filament leaves more threads.
  • Check that the extruder motors are clean and without rests of filament between the gears. This will improve the traction of the filament during retractions.
checking extruders dirty extruder bcn3d


Retraction distance and speed

configuring retraction distance and speed

Retraction distance

retraction distance

It is the length of the filament that will be retracted. By increasing the distance, to prevent filament threads from remaining in the piece generating more stress placed on the material, which can end up blocking it.




As it is a flexible material, it has a high possibility of getting stuck, the best thing to do is to avoid retracting the filament too much.


This material tends to leave threads during prints, to avoid this you can increase the distance.

Speed retraction

retraction speed

This parameter is divided in 2 option that allows you to configure the speed retraction and prepare the filament. Increasing the speed helps prevent threads in the piece but can degrade the filament until is clogged.

  • Retraction speed
  • Retraction prime speed



TPU To avoid jamming with this material due to shrinkcage, it is ideal to reduce the retraction speed. 
PET-G Being a very viscous material, it requires that the retractions be made more slowly to avoid leaving strands of material. 


Adjust the distance and speed of rectification

info-icon BCN3D Stratos contains recommended profiles with standard retraction parameters for each of BCN3D's materials, printers, and hotends. 


Setting the retraction distance and speed is usually sufficient to achieve good surface finishes on the print. For this, it is recommended to carry out retraction test in order to achieve the best balance of these parameters for the material you use and then make a fine adjustment on the piece you want to print.


retraction test piece

In BNC3D we have created the following quick test to adjust the retractions, which consists of two thin towers of 4mm in diameter. You can download the STL below.   

download button


Points to keep in mind during testing

  • Use the recommended profile as a base and vary the retraction distance in 1mm steps and the speed by 5mm / s.
  • Make 5 measurements of the diameter of the piece and obtain the average. If more than 0.3mm diameter is missing, you should reduce the retraction distance and speed. 
  • In case of having an excess or defect of material that cannot be adjusted with the retractions, you can reduce or increase the printing temperature by 5ºC. 


Minimum retraction travel

This option indicates the minimum length of the travel that the extruder must take before performing a retraction.

example of travel with and without retraction

The smaller this value is, the more retractions will be made in those models that have many details, however, the filament will be susceptible to obstruction.


Maximum retraction count and minimum extrusion window

The following parameters define the number of retractions that can be performed in the length of the filament. Its correct adjustment allows printing parts that require more retractions without losing quality.


maximum retraction chart


Maximum retraction count

It is the maximum amount of retractions that will take place within the minimum extrusion distance window.
When this value is exceeded, the rest of the retractions will not be considered. This prevents a small area of ​​the material from being under constant stress.


Minimum extrusion distance window

It is the length of the filament to which the maximum retraction count is applied.
For example, if you have a maximum of 10 retractions and a minimum distance window of 2mm, the printer will perform only 10 retractions for every 2mm of printed filament.

Prevent filament grinding

Activating this option will cause the head to be parked to perform a purge once the maximum retractions have been reached. This allows doing more retractions on the same layer at the cost of increasing print time.


Forum community 

Need more tips? Check out our forum community for 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 (Epsilon Series)

Maintenance Plan (Sigma Series)

Maintenance Plan (BCN3D Sigmax)

Maintenance Plan (BCN3D Sigma)


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



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