Filament feeder

My printer uses 3 mm filament. 1.75 mm filament is also available. A hot end can support only one diameter, so when you buy a hot end, you have to decide if you want to use 3 or 1.75 mm filament. Switching to another diameter means buying a new hot end. The filament I use is quite stiff and springy and has a strong tendency to tangle. This get worse to the end of the spool, where the diameter gets smaller and smaller. I can imagine this less of a problem if you have 1.75 mm filament. This makes feeding the filament to the printer a non trivial task. In my first setup, I had a spool with filament laying besides the printer. That was far from ideal, because I could not leave it alone. I constantly had to monitor the unwinding and every few minutes, I had to untangle the filament. It would be great, if I could start the system and leave it alone until the print is ready. In my current setup, I use a printed spool holder.

Printer and spool holder

The spool holder has bearings for optimal unwinding. To avoid tangling of the filament between the spool and the printer I use a PTFE-tube. To prevent the tube from getting pulled into the extruder, I have printed a washer which is placed at the end of the tube at the extruder. It lets the filament go through and blocks the tube from getting pulled into the extruder. Up till now I am very happy the results of this setup: now I can start a print that takes for example five hours and leave it alone until the print is ready. Mission accomplished!