3D Print Retraction Test

Sergio Peciña

Nov 14, 2022

The aim of the retraction test is to achieve a "cleaner" part without material residues in the movement areas of the hotend. The slicer parameters that influence this test are mainly speed and retraction distance.

How to proceed

Download the retraction test part

We download the following part (Retraccion_Test) and adjust the printing parameters as follows:

Temperature: The one obtained with the temperature tower test for the chosen material.
Flow: The one obtained with the flow test.
Layer height: 0.2 mm
Initial shrinkage:

Extrusion	Distance	Velocity	3D printer
Short Bowden	4 mm	40 mm/s	Ender 3 or similar
Long bowden	4 mm	40 mm/s	CR10, Tevo Tornado or similar
Direct	1 mm	35 mm/s	Prusa MK3s, Artillery X1 or similar

An image of a 3d printed part for retraction testing

Observe the finished part

With the finished, part we observe the amount of "hairs" that have been generated between the different shapes (next image). Next, we adjust the distance between the shapes:

If there is fuzz between the shapes, we increase the value by 1mm.
If there is no fuzz, we decrease the value by 0.5mm.

Printing the part again

We print the part again using the new shrinkage data and check. Next, we do this iteration several times until there is no link between the shapes of the part and the shrinkage values are as conservative as possible (the lower the better).

In the following example, after several iterations with a Prusa MK3S the following shrinkage parameters have been obtained: 35mm/s and 0.9mm with a temperature of 205 degrees and a nozzle of 0.4mm.