There are a number of filament stowage solutions on Maker World, but none of them satisfy me: some go overboard with material savings and forgo strength. Some claim to print without support, but the quality is terrible.

So I designed this, which has the following benefits:

1. Material savings - only 130-140g filament per basic unit
2. High strength - even when subjected to tens of kilograms of pressure, the units don't deform significantly
3. High expandability - can expand any number of units in any direction and freely choose to place them horizontally or vertically
4. Easy to put together - each unit is connected by mortise and tenon joints without the need for any tools
5. High quality - the main part of the storage unit does not require any support, not even bridges. This means you get perfect print quality on printers like the A1
    

I print them using Bambu PETG-HF, which makes about 6 units per kilogram of filament. I have made about 30 units and have not had a print failure.

You can install optional doors for the storage rack units, which will prevent spool from accidentally rolling out. And the door can be fitted with a label to record the filament type. Two M2 flat top screws of any length are required to mount the door.

If the surface quality is not good when printing with PETG-HF, try reducing the wall speed to 100-200 mm/s.

Bambu PETG-HF is very susceptible to moisture, please dry it before printing.

This picture gives an example on how the edge cover works:

As shown in the picture, if you have a set that is 6 units wide and 3 units high, you will need 1 cover for each of the four corners, 2 horizontal covers (each cover is 2 units wide), and 1 vertical cover.

Warning: The profile I provided is specifically designed for Bambu PETG HF. If you are not experienced, do not attempt to use other materials. Otherwise, do not complain that my profile causes printing failures; this is not my fault.