Ender-2 3 Hotend Coupling mod

thingiverse

I discovered this innovative concept on Chep's/Elproducts YouTube channel, where he credits OneBadMarine for originating the idea.\r\nhttps://www.youtube.com/watch?v=Fb4XMbZ0iA4&feature=youtu.be\r\n\r\nInitially, I encountered difficulties slicing Cheps models in SLic3r, so I recreated them in Fusion 360 and made significant modifications to optimize it for Ender 2 and 3. After several test prints, the design performed well.\r\n\r\nThe changes include:\r\nExtended fitting by 5mm.\r\nDeepened cuts in the fitting for increased flexibility when compressed and reduced angle.\r\nDecreased inside diameter from 4.2 to 4.1mm and added a cylindrical taper outward to ensure gripping surfaces are parallel when compressed.\r\nSwitched from M10x1 to M10x0.9 thread with a 0.03mm negative offset for a slightly smaller tread.\r\nRepositioned the collar for improved functionality.\r\nCreated a flat surface for the collar to handle forces more effectively.\r\nReduced nut inside diameter by 0.4mm.\r\nCut out a section in the nut for the screw head on Ender printers.\r\n\r\nTube length:\r\nCropped the tube so it aligns with the top side of the cooling fin block, which measured 38.4mm in my case.\r\n\r\nTube compression:\r\nThe collar is positioned 1mm below the topside of the cooling fin block, resulting in a 1mm compression when the fitting is tightened. With a tube length of 38.4mm and compression to 37.4, a force of approximately 130N or 39LBs is required. You can adjust the tube placement to achieve a lower force.\r\nWhen compressing a 4x2x38.4mm tube by 1mm lengthwise, it transforms into a 4.05x2.02x37.4 shape. The inside diameter theoretically increases, which may seem counterintuitive. The bottom section likely undergoes greater changes due to higher temperatures.\r\n\r\nUse your fingers carefully when tightening the nut or risk compressing the Bowden tube excessively. Verify with a piece of filament. I'm uncertain about the compatibility of this design with 1.9mm tubes. My new Capricorn XS tube is significantly larger than the specified 1.98mm, likely around 2.05 (stated as 1.9±0.05). Therefore, don't rely on Capricorn maintaining their tolerances. The Capricorn Dy measured 4.00 and Creality 4.1. I designed this for an outside diameter of 4.0mm.\r\n\r\nSTL, STEP, and Fusion files are included. Note that M10x0.9 is not a default thread in Fusion 360, so you'll need to move the “ISOMetricprofile CUSTOM.xml” file to “%localappdata%\Autodesk\webdeploy\Production\\Fusion\Server\Fusion\Configuration\ThreadData.”\r\n\r\nUpdate 2020-01-15:\r\nEnsure the hole in the coupling is the same size or slightly larger than the Bowden tube. Otherwise, you may encounter difficulties with atomic pulls due to the filament end matching the inside diameter of the short tube inside the throat/heatsink. A diameter of 1.9 for the tube inside the throat/heatsink and 2.0 for the Bowden tube is probably optimal.\r\n\r\nUpdate 2020-10-26 (version 3):\r\nImplemented a barbed design for improved grip.\r\nEnhanced "blades" for even pressure distribution. This also makes it easier to verify that the Bowden tube is fully seated.\r\nAdded a through-hole version for the extruder, which can be used when the extruder fitting has been pushed out of your BMG and you have an M10x0.9 tap.\r\nIncreased nut inside dimension.\r\nSwitched from PLA to ABS material (PLA should still work).\r\nNote that Thingiverse refuses to update STL pictures for some reason.\r\n\r\nUpdate 2020-12-10 (version 3.1):\r\nIncreased compression from 0.5mm to 1.0mm for unknown reasons.\r\nRemoved the "dummy" part, as it was only for tube length verification anyway.\r\n\r\nPrint direction:\r\nCoupling is designed to be printed with M10x0.9 thread up. Raft with no support.