MK7 NinaFlex Adaptor

thingiverse

I've got a Prusa I3 with an MK7 extruder, and I wanted to use it to print Ninjaflex. If you've ever tried printing this stuff, you know it's like trying to push a wet noodle through the extruder! The filament is super flexible, and the distance between the gear and barrel causes it to go anywhere but through the nozzle. I decided to see if I could do something about that, so I came up with the Wet Noodle Adaptor. Okay, this thing looks pretty simple, but the tolerances are really tight, so before you tackle this, make sure your bed level is spot on - don't skip this part! Slice the STL file with a layer height of .15mm and support enabled. Bring your bed up to temperature; I use 115C on PEI. After that, set your Z axis so it's just touching the bed and nozzle, with a sheet of paper slipping easily underneath. First-layer height is crucial for this part! Heat your extruder to 210C and load ABS filament - don't even think about using PLA. After printing the part, remove the extra plastic covering the top hole and clean out the rest of the filament hole with a manual drill bit. Remove the fan from your MK7 extruder; I've got mine set up with a connector and spacers glued in place, so it's easy to swap out. Slip the Wet Noodle Adapter under the gear and idler, with the long side facing down. You might have clearance issues with your grub screws - just file a little flat spot on the shaft and turn the gear around. The adapter should fit snugly under the gear and idler, with the idler aligned with the filament hole. You might need to add a larger washer behind the idler; its center must line up with the filament hole in both the adapter and barrel. While pressing on the adapter, make sure you can insert filament down through it into the barrel. Put the fan back on and test-extrude some filament. If you've made it this far, you're ready to print Ninjaflex! I found it prints best at 10mm/s or 600mm/min - slow is good. Use 240C extruder temp and reduce your flow rate to 95% for a nice shiny finish. Before starting the print, let about 15mm of ninjaflex extrude; then start the print while it's still oozing and stringy. Remove any excess filament after the print gets underway. If you wait too long, the filament will blob up inside the nozzle - that's why I start printing while it's still flowing! Anyway, hope this helps some of you who've tried and failed to print Ninjaflex on your Prusa I3. Check out the Wet Noodle Adaptor in action: https://youtu.be/2pkTmWo1C0w & https://youtu.be/2c8DDbqSJDQ