Simple Filament Fuser

This is a small and simple device that can be used to fuse filament together. You can finally take all those end of the spool pieces and samples of filament and combine them into enough of a roll to print something.

There are two parts, a top and bottom, and they get assembled using four 3mm x 14mm bolts (or longer) and four 3mm nuts. (You can change the hardware used in the OpenSCAD file if you wish, as well as change the size of the device.)

The nut pockets on the bottom part use the "sequential bridging" technique so (depending on your printer) you can probably print without supports. You can also opt to use supports, or print two top parts and skip the embedded nuts altogether. (We recommend printing at 0.2 layer height or lower for the sequential bridging to work without supports.

You'll also need a piece of PTFE tubing approximately 1.775mm ID / 2.5mm OD. (We use this one from Amazon.)

We've written up a blog post (and illustrated guide) to how the device works: https://rasterweb.net/raster/2023/10/25/fusing-3d-printer-filament/ 

We've had great success fusing filament so far, but if you have improvements or tips for doing it better, please let us know!