Recycling SLS prints into FDM filament? Here is our experiment

In recent years, 3D printing technology has diversified. The most popular to date is the FDM or Fused Deposition Modelling printer, but you will certainly be familiar with SLS technology, which uses a high-power laser to sinter polymer powder particles and turn them into a solid object.

What all 3D printers have in common is that they produce a final object but the underlying technologies usually never meet.


But is the match between FDM and SLS printers really impossible?

We have received many requests about the possibility of recycling SLS print waste and because we love our customers, the environment and challenges, we are ready to share the results of our SLS print recycling test!

Before we start the experiment, let us introduce the star material of today’s recycling process: Nylon PA12. The starting objects in the recycling process are scraps of SLS prints in Nylon PA12

As you know, the recycling of 3D print waste has always been one of the central pillars of our philosophy, and adding more materials to the list of recyclable prints is always a source of pride and satisfaction.

Opening the possibility of recycling also to prints of other technologies, such as SLS, would be a huge opportunity for all of us and our experiment started with great excitement.


SLS prints before shredding process SLS prints after shredding process How did we carry out the experiment?

After receiving the material for the test, the first step is, as always, shredding. To be sure of obtaining small scales of Nylon PA12, it is best to run two shredding cycles in order to obtain a homogenous shredded material.

Before being extruded, the material needs to be dried; waste materials often accumulate a lot of moisture but a few hours inside a dryer will make them ready for recycling.



The first extrusion of a new material is always a source of great excitement, but it often requires time for trial and error. The right parameters are found by testing different combinations and analysing the results until we arrive at one that satisfies us (remembering that environmental parameters can also affect the result of the test). For this experiment we use our Felfil Evo and after a few attempts we found very good results by setting 225°C temperature and 6 rpm speed.

The recycled Nylon filament obtained from SLS print had the standard characteristics of a classic commercially available filament. 


The print test

Now the print test is a must to test the recycled material. After the extrusion of a new material, it is necessary to check the characteristics obtained during printing to confirm that the recycling process has not compromised or changed its typical qualities. For the print of recycled Nylon SLS, we used a standard ABS print profile, with a 250°C nozzle and plate heated to 110°C, and applied a raft.

The print test passed successfully with results comparable to new Nylon prints.

We can therefore confirm the success of this experiment, which proves to be of fundamental importance for both the world of recycling and 3D printing. The convergence and mixture of several 3D printing technologies is not something you see every day, and we are happy to have demonstrated how these worlds so far apart are actually more closer than we think.
Certainly recycling from SLS waste objects has different characteristics to recycling from SLS waste powders but don’t worry about that, experiments with powders are already in progress, all you have to do is keep following us so you don’t miss the next updates.


Do you have any questions?