Spool holder to placed on top of the printer using the ‘roof’ details to stay in place.

This was designed as a prototype for printing with TPU/Flexible filament.

The goal is to make the shortest path to the extruder and reduce friction. You are supposed to remove the lid while printing with PLA/TPU so I tried to utilize all the top details to help stabilize the spool holder. Open end holder to make feeding easier. This mostly use the model+spool's weight to stay in place so be careful when using - I cannot guarantee it will stay put depending the printer head rapid/jerk movement. 

Sharing the design in case it helps someone or sparks an idea.

Added a small test piece so you can try this “bridging” on top of the printer.

As reference I printed in PETG, 0.2mm layers, 4 walls, 20% gyroid. (no supports needed in the provided orientation).

My spacing tolerances wasn't so good on my prototype but so far I've done about 7 small TPU prints without issues.

I've added electric tape on the model to help a bit with the friction of the spool's cardboard.

(Left the other roll in the PTFE tube to avoid turning off the run-out sensor)

Note: Current spool max width is ⁓70mm.

The idea sprang from a random video where the the creator made a spool holder going on top of his printer in order in order to remove as much “friction” as possible when printing with TPU. (I suppose credits to youtube/@JATdesign)

PS: This design might not even be needed for printing with TPU ; I haven't actually tried the normal filament routing with my TPU roll yet. I was curious about the concept and my model so I started using it right away.

Update 24h after: I've tried the standard filament routing for few more 95A TPU prints (⁓5h) with no issues. Small parts but I didn't notice any signs of under-extrusion which I suppose too much friction would cause. I don't have enough experience with flexible filament to judge other cosmetic appearance. YMMV but it does appear to not be needed for 95A and above on this printer.