Hairlock for Skelestruder MMU2

thingiverse

So, I got my MMU2 and hooked it up to my Skelestruder. Everything works perfectly, except I have a Volcano mounted instead of the standard V6 heat block. The great thing about Skelestruder is that it makes debugging and clearing issues fast and easy thanks to its quick connects and modular design. But the slic3r settings are tricky. The main issue to solve for MMU is to reduce stringing. The really fine strings, I call hairs, can build up and cause trouble in a number of places: jam the finda ball, plug the bowden, block the gears, etc. Prusa's solution for V6 is to do ramming, which purges the nozzle and pushes the melt zone to the bottom. The problem for Volcano is that it has much larger melt volume and also much higher heat transfer. For V6, it is easy to overwhelm the heater with high extrusion, but not so much on Volcano. So I decided to build a mechanical lock that acts to prevent the string from forming in the first place and keeps it out of the connecting bowden. With my prototype, I finally got my first successful print after weeks of trying. See it in action at https://imgur.com/a/7WjvZSo. This first version works with direct filament sensor. I plan to add an indirect option later. **Update 1/26/19** I updated the case to add an optional tension screw. Put a plate behind the spring and push it in with the screw to increase tension if needed. I added a step for those who want to adapt it to the stock extruder.