Ender 3 X MGN12H Y MGW12 BMG Hemera

thingiverse

My total overhaul of the Ender 3 X rail is a big success. I'm using MGN12H on the X rail and MGW12 on the Y rail, and I didn't lose any build volume in either direction. No extension cables are needed. For my extruder, I chose to use a Chinese BMG with a Hemera-style cooling plate from Mellow Store on Aliexpress. My main goal was to keep the mass of the X rail as low as possible, so I removed the 2020 aluminum rail and designed my own custom rail brackets. I fastened these on the Z brackets using M4 brass hot-pressed nuts. The X limit switch is slightly adjusted. I used a 350mm rail. The Y belt has been moved to one side. I rotated the Y motor and the belt tensioner so that the belt is now on the left-hand side of the rail. I think a new, longer belt will be necessary. Unfortunately, I'm not entirely happy with my current belt fixing solution, so if anyone has a better idea, please share it. I've also modified the Y limit switch part by screwing in an M3 bolt to allow for Y home adjustments. My 350mm long rail was shortened to 325mm. The BMG extruder with Hemera plate is amazing. I printed TPU at 90mm/s with a retraction of 1/45 and no stringing occurred whatsoever. This is because there's no slack or space for the filament to bend out of line from the gears to the nozzle, making it possible to use retraction on soft filaments. To avoid using supports, I designed the bracket in multiple parts. My extruder comes with a 22mm stepper motor, which can get quite hot after lengthy prints. To address this issue, I glued a 10mm radiator onto it. I'm using the stock Prusa I3MK2s profiles, but I changed the bed size. In my filament custom settings, I've removed "If bowden blabla" and only inserted M900 K0.12. Everything that's screwed in is securely fastened with brass nuts. You can find the step file included. The filament used was ASA. To assemble this upgrade, you'll need: MGN12H 350mm MGW12 325 mm BMG extruder with Hemera plate from Aliexpress. A variety of M3 screws in different lengths. Brass hot-pressed nuts M3 in various lengths. Some M4 brass nuts for the X rail. Two M5 brass nuts with M5x20 screws for Y belt fixation. One M8x50 screw for Y belt tensioner. Y and X belts, about 10mm longer than stock. A 10mm 4040 radiator. Zip ties.