12 Mar Discovering Felfil Evo: main components and open source files

Felfil Evo is a completely open source filament extruder for 3D printers: in fact, we strongly believe that this philosophy favors open exchange, collective participation and the free circulation of ideas. For this reason, Felfil Evo project files are available in free download, so anyone who wishes to modify them freely, or even to independently build their own extruder from a Basic Kit is able to do so.

The operating principle of Felfil Evo is relatively simple: once the plastic is inserted into the tank, the extruder heats up to reach the required temperature. At this point, the worm screw moves the material through the heated chamber, inside which it is melted; finally, the material comes out of a specially drilled nozzle as a filament.

To guarantee an optimal extrusion, the components of Felfil Evo are made ad hoc. Let’s see which are the main ones and how they are made:

• Nozzle: this is perhaps the most particular component of Felfil Evo. It is made of bronze because this is the material that provides the right compromise between mechanical strength, heat dissipation and gliding. Three “fins” allow passive cooling of the outgoing filament and thus guarantee the necessary tolerance without additional cooling sources.

• Chamber: here is where the transformation of the plastic material takes place: it goes from a solid state to semi-liquid. The chamber is made of aluminum, since it allows heat to be transmitted very quickly and therefore speed up the heating process. At the end there is a small “cockpit” that allows the flakes of larger material to be worked and lighten the pressure of the incoming material.

• Auger: made of K100 steel, the extrusion screw is the component that carries out the most precious work. It constantly pushes the material, blends it and compresses it. The core has a conical diameter, which causes the pressure inside the melting chamber to progressively increase.

In addition to these components, also the tank, the strip, the PCB, and the case are made specifically for Felfil Evo. More information is available in the project files, which can be freely downloaded.