Filament Extruder Build


filament extruder recycling 3d printer

What is an extruder? #

entire extruder assembled

Artme MK3 filament extruder I assembled

This filament extruder is a machine that produces plastic filament, specifically for use by 3d printers. To do this, it melts granules and pushes on them to produce pressure.

Plastic is a polymer that does not have a precise melting point, rather a melting range. When the granules are under pressure and heated, the temperature does not need to be as high to get them liquid. Just fusing them together into a viscous consistency like honey, is enough.

extrusion screw and funnel below it

The extrusion screw, before going into the core of the machine

Here the extrusion screw of the machine. It will be pushing granules at the top, and at the bottom the plastic will be under pressure from the screw’s rotation and molten from the applied heat.

Then, the plastic mass is pushed out of a nozzle which will shape it into the final round filament (simply by being round). The still hot plastic is cooled in an air current and then wound up on the filament spool, for storage because the 3d printer cannot print “continuously” off of the extruder.

The difficulty #

difficulty, consistent filament diameter

Filament exits the nozzle. The wire bending around it is a sensor to help with controlling diameter precisely

Filament for 3d printers needs to have a 1.75mm diameter filament precisely, and usual commercial spools claim a precision of +- 0.05mm. That means the filament diameter is between 1.70 and 1.80mm, just 0.1mm total wiggle room! This is a challenge to achieve with this machine, but possible. See future developments! For now though, I proceed with a test run to check how everything works, without worrying too much about perfection.

production process, from granules to winding onto spool
Here, the full process of the machine. It starts with granules and at the end, the produced filament is wound up on the spool, ready for 3d printer use (after drying for best results).

Preliminary Results #

first printed object
The first object I ever printed with the recycled filament. I was surprised that even though the filament diameter was inconsistent (+- 0.2mm in some places), it printed without crashing!

I do expect the process to improve and produce parts that are more comparable to commercial filament. They would have less noticeable and more consistent layer lines, and less stringing (those small whisps).

Read about future developments

This recycling project is supported by