Creality K1 Max - Top Spool Holder w/ bearings (for printing TPU)

Top mounted filament spool holder. Used for printing TPU on a K1 MAX.

The adapter rings are a press fit into the original side supports to adapt them to fit standard cartridge bearings. The spool roller should be a slip fit into the inner bearing races so it can easily come apart to install the filament roll. 

Since the bearings are a slip fit, the structure is less rigid than the original design, so I added spring clamps to secure the the side supports to the printer frame. 

I recommend "cutting" the roller into 3 sections but leaving them assembled as one roller. Print each end that slides into the bearing race at 100% infill for strength. Print the middle section at lower infill to save time/filament.

I have adapter ring and spool roller files for the following bearing sizes:

6200 bearings (10 mm ID x 30mm OD x 9mm wide)

6002 bearings (15mm ID x 32mm OD x 9 mm wide)

608 bearings (8mm ID x 22mm OD x 7 mm wide)

I noticed when printing TPU on the original design, with a solid tube for the spool to rest on, there was a lot of friction between the roll and the tube, especially with a full roll and cardboard tube. 

This wouldn't really be a problem with a normal rigid filament, but given the entire point of a top mounted holder is to feed flexible TPU filaments directly into the print head, I was concerned the additional strain on the filament might result in slipping at the extruder rollers and therefore under extrude. 

I added bearings to reduce the strain on the filament. Uses two 608 or 6200 or 6002 bearings.