Printrbot Simple Metal filament spool rack for small (25mm hole) center spools

thingiverse

Spool Rack for Printrbot Simple Metal Filament Spools - Smaller Diameter (25mm Hole) Holder with Mount-Screw Countersink to Prevent Spool Rib Snags I purchased Sainsmart flexible TPU from Amazon and was pleased to find that it included a spool, which was not mentioned in earlier reviews of the product. The spool has a small diameter of about 25mm, but it won't fit on the original rack provided by Printrbot. To solve this issue, I designed a replacement spool holder as a re-mix of their design with a smaller, rounded spool support arm and a thicker hanging base that keeps the mount screws recessed. THIS IS A WORK IN PROGRESS - I WILL POST AN UPDATE WHEN THE LATEST STL HAS BEEN TESTED (see details in Post-Printing section) Print Settings Printer Brand: Printrbot Printer: Simple Black Rafts: No Supports: Yes Resolution: 0.25 layer height Infill: 25% infill (recommended minimum 20%) Notes: This design was created in DesignSpark Mechanical and printed with Cura. I chose supports with the standard support size so the spool retaining flange will print properly. Post-Printing Post-printing finishing and fitting notes: Note: This is a work in progress. Changes have been made to the current version of this part to eliminate some of the steps it took to make this fit. The original test piece had to be re-shaped at the spool retaining flange end allow the support arm to fit through the back side of the spool. After removing the print support materials, I lightly sanded any major flashing left on the mount plate and filament spool rod. Fitting: The initial fit of this part was too tight. I drilled out the large holes at the bottom of the keyholes with a 7/64" drill bit so the cap screws would fit through as they should. I also had to do some minor filing to the keyhole slot sides so the part will slide down in place. How I Designed This Designing for Success Measure once, cut twice (is the old saying in shop environments). I try to plan things out and not take pot-shots at designing. I did want to get this done quickly, so I set up a small test to help me refine this design in stages. As a budding maker, I'm finding that this approach works best for now. I hope skills with design and compensation for materials/printing tolerances will improve with practice. I took caliper measurements on the Printrbot spool rack such as the base place size, the keyhole distance, the spool support arm, and the spool retaining flange. I checked the original base plate thickness and determined how much more I wanted to add in order to sink the cap screw heads. The filament spool support arm was re-designed as a half-round, taking into account the size needed for smaller center spools. Initially, I designed the base place with the keyholes and a short (20mm) spool stem. I did a quick print of this test part and checked the placement of the keyholes. Ugh... off by 1 mm. After moving the keyhole mounts apart, I finished out the design by extending the spool support arm and added a retaining flange at the end. The keyhole bottoms were enlarged to improve the install fit. At this stage, I modded the design with other finishing touches such as rounding edges, and the midpoint to back taper on the top edge. One portion of the design that was not pre-tested was the spool retaining flange. It was too long to fit through the back side of the spool, so I tapered the support arm below the flange by sanding it. I have built this taper into the current design and will post an update when the final test is complete.