Recycling with Felfil Evo: from plastic caps to 3D printing filament

Have you ever thought that even plastic bottles caps can be transformed into filament for 3D printers? And thanks to Felfil Evo, it is not that difficult.

Although it is now widely known how much the abuse and the dispersion of plastic impact negatively on the environment, not everyone acts accordingly. It is true that the habit of buying steel water bottles has been spreading for some time, yet plastic bottles are still too many.

How to solve the problem of disposal and start recycling them? Felfil Evo can be an excellent solution.

In fact, after some tests in our laboratory we were able to get printable filament from empty plastic bottles with a minimal effort. Provided that some simple tips are respected: the first and most important is to separate the two parts of the bottles, made up of different materials. The body is PET, while the cap is in HDPE. For extrusion we can only use caps.

After collecting caps, we cut them into smaller pieces, as the extrusion process requires. To do this, we used a normal kitchen blender: nothing different from what we do to transform the waste of our 3D prints into a new filament. The minced caps were the raw material of the extrusion.

Once we had the necessary material, we finally started extruding. We used the HDPE extrusion settings for the extrusion, which are shown in the table below. You can find the values of the most common materials in the materials guide on our website.

These are the settings that we used:

Temperature: 200°C
Rpm: 9
Motor duty: 0,5 A
Drying needed: no


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After the extrusion was completed, we managed to get about 100g of filament with a constant diameter (1.75 mm) from the plastic caps: perfect size for the vast majority of 3D printers. The experiment proved to be a great success, because we managed to give new life to the caps that we would otherwise have thrown away. All while respecting the basic principles of Felfil’s philosophy: recycling and experimentation.

If you want to see more, have a look at the video above. And by the way, HDPE is a very common material: we used bottle caps for the extrusion, but you can replicate our experiment using detergent bottles or milk bottles!