MK3S+ smooth rolling parametric spool holder with optional bearings

prusaprinters

The original spool holder seemed to be rolling too uneven especially for flexible filaments such as Filaflex 40 or Flexfill 98A TPU. 2kg Prusament recycled spools also looked odd on the old holder. So I designed this one where the spool rolls on four plastic rollers or four 608 bearings with a plastic sleeve.You can adjust the position of both parts so that it fits for different spools easily.Pick the “608sleeve” version if you like to use bearings or the “dummy-roller” version for a complete print without the need for any additional parts.Slicing advice:use 100% infill modifiers for the hook which holds onto the printer framePrinting advice:use 0.6mm nozzle to reduce print time if possible, the accuracy is good enough on the MK3SAssembly:if you use 608 bearings press them in the roller sleeves, otherwise just use the dummy rollersmake sure the parts do not have any high spots (blobs of filament sticking out)put in the 2 rollers an then snap both parts togetheryou can of course use some glue to make it more permanent. FreeCAD advice:spool diameters can be set from approx. 150-300mm, though 200mm is the only one I actually printedwhen exporting select and export the bodies individually. You'll need “inner”, “outer”, “inner-mirrored”, “outer-mirrored” and either “608-ballbearing-sleeve” or “608-ballbearing-dummy”Word of warning: If your filament is somehow stuck on the spool there is a slight possibility that the printhead/extruder will pull the spool off the rollers so that it in the worst case might drop on the print bed. In 100+ hours of printing with these holders and loads of different spools I have not seen this happen or anything close to it. It is just a weakness of designs that do not utilize the center hole of the spool for holding it.