Extuder Idler Hanger

thingiverse

The bearings are 685 ZZ or RS, whatever you prefer. Just 5mm ID and 11mm OD will do. BONDTECH I tested some Chinese clone Bondtech gears, which came with a $15 kit. Needless to say, the kit had terrible plastic molds. Even without a stepper motor, it was rough to turn even one gear, let alone aligning and turning the second gear. The Bondtech gears are nice, though. Just throw away everything in the box except for the gears. Needle bearings are optional, but you can also use 685 bearings since I'm using a 5mm shaft, which works pretty much the same. It just needs to spin freely really, and we have 685 bearings for that. I'll add an alternative version later after I've tested it. I haven't tested any of this yet; I just played with some filament and pushed it through. I HAVE NOT YET TESTED THIS But it looks cool, though. Some weird kind of idler I came up with, and spent quite some time tweaking. There's another version as well, but I omitted it because it was too annoying to use. This one is nice, but I don't know if it works. Okay, background information: Classic extruders (technically filament pushers) use a spring to push an idler against the filament. And you just have to hope that your filament doesn't deform under this pressure or that your ExtruderMotor doesn't skip due to this added friction pressure on its shaft. So I came up with a filament-friendly extruder! That also needs a 5mm shaft, certain bearings, two MK8 extruder gears, and four bed leveling screws, springs, and nuts. Let me grab the actual parts and update this before Thingiverse destroys itself. BOM: Plastic, yeah Four M3 x 40mm (bed leveling kits) Four Thumb Nuts (bed leveling kits) Four Springs, 21mm long, 7.5mm wide (bed leveling kits) Two M3 x 8mm (m3 kits) Two 685 bearings, 5mm high, 11mm outer diameter, 5mm inner diameter Two MK8 extruder gears (the very small ones) One 5mm diameter shaft that's 21mm long. Can be longer. The plastic piece clamps itself down onto the bearings so that the extruder gears keep their position. Probably a cordless drill with M3 drills and a Dremel. M2.5, M1.5 allen keys -------------- Warning // Quirks -Movement The idler assembly moves slightly even when pushing filament through. Like a few micrometers, it can hardly be seen, but it can be felt. I'm just flabbergasted that I'm using four 21mm springs preloaded with 5-6mm compression (to 16-15mm). That's quite a lot of force to do by hand, let alone with one spring. -Friction The filament does grip on both sides, especially with Bondtech gears. This is noticeable because the friction increases. But it could also be my own feeling getting in the way since I'm freely moving a 17HS8401, 1.8-degree, 48mm stepper motor as well, and of course, two bearings and both gears. -Filament Loading Issues A flat End-Piece of filament won't get in that easily. Try to cut it at an angle! Or just force it in, I guess. Probably I'm just comparing it to normal filament extruders where you have to remove all idler pressure. Here the idler is already pressured and fixed onto a certain distance. It goes okay, though. Bet a Prusa MMU2 will be able to push it in just fine. -Filament pathway issues If your filament is bent, it will cause more friction against plastic and teflon. Or it will try to push against the flat side of the gears rather than in the hobbed grooves! Grab a piece of Teflon // PTFE tube, preferably 1.9mm ID or lower than 2.0mm ID (I use a Capricon clone; it's okay, not really 1.9mm, but 2.0mm tubes are not 2.0mm either). Cut it and make sure the PTFE follows the gears. Like a tip. I SHOULD MAKE A JIG FOR THIS. If I ever get to that.