BondTech BMG Filament Tube Guide

thingiverse

This is a versatile printer filament tube guide that installs vertically, with the flare situated at the top. A 2mm hole on the bottom allows filament to feed directly into the guide. The guide securely holds a PTFE (Teflon) tube with an outside diameter of 6.36 mm and inside diameter of 3mm. The top is flared to prevent kinking of the PTFE tube. The second component mounts above your extruder on the X carriage, utilizing another piece of PTFE tube emerging from the top flange. You only need 150-250mm of the PTFE tube for each part. As the X carriage moves away from the side-mounted guide, the filament pulls the PTFE to a more horizontal position. Conversely, as the carriage approaches the side-mounted guide, the PTFE relaxes and lifts the filament up, pushing some back down the side-mounted tube outside of the printer. This clever setup has worked flawlessly for me. I've never encountered any issues with filament problems using this system. You can witness it in action by visiting the provided link. I utilize the BondTech BMG extruder on my X carriage. The extruder mount is crafted from 2mm thick 6061 aluminum. The edge of the extruder mount extends to the side of the NEMA 17 and rises above the extruder. Two Low Profile M5 screws, similar to those offered by OpenBuilds, attach the printed extruder tube guide to the extruder mount. The two M5 holes are centered 19mm apart horizontally and 25mm vertically above the M3 holes for the NEMA 17, but they do not align vertically with these holes. If you create your M5 holes exactly as described, the 2mm hole in the bottom tube guide will perfectly align with the opening of the BMG extruder. To facilitate effortless filament loading, I recommend placing a short piece (about 6mm long) of 4mm O.D. PTFE tube inside the top of the extruder, protruding only 1mm above it. Taper the interior of this short tube to prevent any curled filament from becoming stuck. The 2mm hole in the bottom of the extruder tube guide should be centered directly above the tapered short tube. This setup ensures smooth and hassle-free new filament loading every time, without requiring manual adjustment of the quick release.