Filament spool cartridge

To print: 2×sides, 4×bearing mounts, 6×spacers.

BOM: 4×608 bearings (skate bearings).

The spacers accommodate spools down to 5mm narrower. For example, the 65mm spacers accepts spools from 60mm to 65mm. And the cartridge accommodates spool diameter from 185mm to 205mm.

De-grease the bearings and lube them lightly. Assemble like on the pictures.

To insert a spool, remove the two top spacers. Insert the spool, secure the filament into one of the 4 holes on the front/back of the cartridge. Replace the top spacers.

Designed to be printed in ABS. 70g to 80g per cartridge.

The width of the cartridge extends only 0.6mm past the maximum spool width it is designed to accommodate. For a 75mm spool, the total width will be 76.2mm. This helps packing as many spools into dry boxes as possible.

The spacers takes into account the thickness of the cartridge sides. A 70mm spacer is actually shorter than that. When installed, the room for the spool is exactly 70mm. It is fine to fit a 70mm width pool into a 70mm cartridge. There is very little friction on the spool flanges.

As mentioned above, a given width accepts down to 5mm narrower spools. Smaller, and there is a risk of falling off the 608 bearings.

The cartridge encloses the spools 5mm on both sides. Such that the filament shouldn't be able to pass around the flanges of the spool. And thanks to the spacers, the filament is also less likely to come out radially. This effectively acts as a buffer. I can get a meter of buffer easily on a brand new spool (65mm width, 195mm OD). The more the spool is consumed, the longer the buffer.