Spool Rack for Prusa MK2/x Multi-Material

thingiverse

The Prusa I3 Multi-material upgrade comes with parts and directions to build a very nice and functional 4-spool tray. However, it is intended to be placed in the space behind the Prusa printer, or on a shelf above it. I had neither, so the Prusa rack was only useful for parts - like the 16 608 bearings. I took those bearings and a couple of lengths of 20mm V-slot extrusion, a handful of printed parts and built -- a shelf ! OK, it's a "spool holder rack", but that's just a particular kind of shelf, right? I liked that Prusa's design used the bearings as surfaces for the spool's rims. I'd been using that type of spool holder for several years and it works very well. I had seen similar designs on thingiverse, and have used this concept for the ones I designed for this rack. I have also liberally borrowed and remixed some parts from several makers here (listed below.) I designed the frame to take up very little table-space, since that's how much I had available. The rack's frame wraps tightly around the back and sides of the Prusa frame and positions the spools directly over the MM extruders' input. With the filament feeding off the back of the rack, it has an almost direct arc to the extruder while leaving plenty of room for the extra filament retracted during color changes. I've put slot guides on the bottoms of the spool/bearing holders and have left them unconnected to their matching bearing holder so any spool width can be quickly accommodated. The spools are very stable in use and can be re-positioned easily when desired. I used my spool rack for several weeks without any filament guides and had no problems - it looked a little messy, but worked fine. However, I couldn't leave it at that so I designed a fairly whimsical filament guide - and did it in multiple colors just for fun. I've included both single and multi-color versions, They look a little peculiar, but they work very well and can be easily positioned for each spool. When I finished the rack, I was reminded of a filling station pump area - especially with spools on top - so I came up with a little multi-color sign to add to that image. The name, "Catnap Motors", (slogan "The Purrfect Ride" -- [a division of "Catnap Industries"]), is that of a pseudo-company I created many years ago. This sign is totally optional, of course, and you can always make something yourself and glue a bit of slot-cover to the back to clip it to the slot. I have included a cut list for the extrusions, a parts list for the hardware, and a parts list for the printed parts. I've also made a stab at assembly instructions. (See the Thing Files for the .rtf file) Only two of the extrusion pieces must be cut precisely. For the others, a millimeter or two either way won't ruin anything. Note, however, that the pieces are dimensioned to fit the printer and to be cut from two 1500mm V-slot extrusions. I may have over-engineered the joints - the corner brackets are easy to print and can be decorative as well as functional so I've put one or two at every axis change. The "Suggested" links in the parts list are just that. You can use the link to see exactly what part I used, and then source the part wherever you want. I hope this design will inspire one of your own. Aluminum extrusion is easy to work with and is very strong. Lots of parts and accessories are designed for it. I also hope that this Summary is coherent. I've been playing (and losing) the Thingiverse Expiring Token game for the last few hours.) ------------------------------------------------------------- I gratefully acknowledge these makers for their designs that I've remixed or borrowed for this project. If the parts work for you, thank them. If they don't, blame me: V-slot corner bracket and T-bracket are originally from spauda01's D-Bot project: https://www.thingiverse.com/thing:1001065 V-slot covers resized from sheffdog's near perfect profile: https://www.thingiverse.com/thing:832077 Bolts and nuts were generated using mike_mattala's excellent Nut Job library: https://www.thingiverse.com/thing:193647 You'll also see in the photos a Raspberry Pi case (totally optional to this build) This is hofftari's Pi case for Prusa (I use the older design for Pi3 for all of my raspis): http://www.thingiverse.com/thing:1325370 I've made a simple v-slot mount for that case, but haven't published it, yet. When I do, I'll link to it, here. I used Simonarri's Miter Razor to clean up the ends of the slot cover strips: https://www.thingiverse.com/thing:912051 -- It's not really intended for cutting plastic, but it does.