Monoprice Select Mini extruder cap to replace new OEM design

cults3d

Update - 4 Feb 2019: This update comes after I remodeled the design in Fusion 360, a parametric software that allowed me to refine my initial SketchUp model based on user comments. The new STL file is called "MPSMv2 threaded insert v2," and I've successfully printed it out with impressive results. I've also included a GCODE file sliced at a 0.219mm layer height in Cura, which takes just four minutes to print - a brief wait that might be tolerable if your collet is already broken. Additionally, I've provided an F3D file for anyone interested in examining or modifying my design. Note: While I'm thrilled with how my design turned out and it does work well, I acknowledge that it's not a long-term solution. For a more reliable fix, consider checking out the MPSM V2 Improved Extruder. My creation is meant as a temporary bridge to help you get back up and running if your stock top collet breaks, and then you can use my design to print the better one. Older Monoprice Mini printers featured a sturdy brass locking collet at both ends of the PTFE tube, whereas newer models have a minimal, cheaply made one at the top that's prone to breaking. My own printer suffered from this issue, so I exchanged it for a new one and collaborated with Bigben2 to find a suitable replacement. I present two alternatives to address this problem: 1. Threaded insert: This printable piece replaces the original top collet with an M6 thread, allowing you to secure a brass collet in place. To install it, remove the screws holding the black plastic cap on the extruder motor, take out the original collet, and thread the printed piece onto a brass collet. Be cautious when handling the small piece, as it might require pliers for threading. 2. Replacement top cap: This piece replaces both the original collet and the top cap. Currently, I haven't added threads to this design, but it's sized to accommodate an M6 brass collet without needing additional parts. Both options work well, as I've printed and tested them myself. Some important notes: 1. Thingiverse has issues with Amazon links, so here's the direct URL for the brass collets I purchased: https://amazon.com/gp/product/B019RQ5EYE/ - simply copy and paste this link. 2. When searching for brass collets, ensure you use "quick connect 4mm PTFE fitting M6" to find the correct item. This specification is crucial for a proper fit with your printer's components. 3. The bowden tube on my printer was initially too long, and adding the brass collet made it even longer. You may want to shorten your bowden tube after installing this modification to avoid any issues. 4. If you prefer to have a spare of the original part, here's a link to a store that carries it: https://gigdigit.com/bowden-coupling-connector-for-the-updated-extruder-feeder-mechanism/ 5. Apologies if the orange hand spinner in the photos offends anyone - but if you'd like to print your own, I've included the design here. Thanks to McMaster-Carr for providing a 3D STEP model of the M6 nut that I used for the threads, as I had difficulty sourcing one from Nut Job. Other options: MPSM V2 Improved Extruder: This design replaces the entire extruder base plate, block, and arm with new parts. I considered creating something similar next but opted to let this design shine instead. The use of an M6 steel nut should make it more durable in the long term. If your original part broke, you can use my design to print out this one. Updates: 2018-02-15: I realized I was missing a crucial piece from the extruder top cap, which led to air space that made feeding filament challenging. I removed the original piece and uploaded an updated version, which I've since printed and am currently using.