Anycubic Chiron Direct Drive - BMG

thingiverse

# Objectives I developed this light'ish weight direct drive extrusion system with the objective of matching or reducing the form factor of the stock print head assembly. I do a lot of sequential printing so I wanted minimal bulk around the nozzle. I also wanted nozzle height to replicate stock so there would be no need to change nozzle home position or Z height. Auto bed leveling is excatly the same as stock. I also wanted easy access to the fans, heatsink, and particularly the nozzle so that I could easily swap larger orificed nozzles taking advantage of the E3D Volcano hotend and the printer's massive format. # Parts - Dual drive extruder from Bondtech or the cost effective [Trianglelab Dual Drive Extruder](https://s.click.aliexpress.com/e/_dVw8vbw). - 24v Volcano hotend from E3D or the [Trianglelab Volcano Hotend](https://s.click.aliexpress.com/e/_d6BJewy). Be sure to get some [larger nozzles](https://s.click.aliexpress.com/e/_dWBl4nm) for faster prints. - Slim style Nema 17 stepper motor [like this one](https://s.click.aliexpress.com/e/_d9CFzzI). You coud attempt to use the original extruder stepper motor but it is very heavy and the 3:1 gear ratio of the BMG style extruder doesn't need much torque. Less weight, less ringing. - 24v [5015 Blower Fan](https://www.aliexpress.com/item/4000011565156.html) for the part cooler. I'm a big fan of Trianglelab because they ship fast and quality is very good. By the way, if you are having issues with adhesion on the Ultrabase, definitely going with an adhesive PEI sheet like this massive [405x405 PEI bed surface](https://s.click.aliexpress.com/e/_dZmU9B2) and say goodbye to warping. I also much prefer the smoother print quality on the bottom of the part. # Nuts & Bolts You'll be able to reuse most of the original M3 screws from the old hotend assembly but you will need M3 nuts and some longer M3's as well as 2 x M4 screws for the part cooler fan. I highly recommend getting a metric screw/nut set [like this one](https://s.click.aliexpress.com/e/_d6r9cGs) because let's face it, the 3d printing addiction will take hold if it hasn't already and you'll always need various size screws. # Printing Tips You can use PLA, PETG, etc. Plastic does not come in contact with anything hot. I recommend at least 20% infill and 3+ perimeters and top/bottom layers. More perimeters provide stronger holes for threading. As always, make sure your printer is dimensionally accurate to ensure correct tolerances. # Miscellaneous ## Print Head Wiring Harness The robot arm cable guide thingy had to go. It wasn't worth designing around and I actually think it negatively impacts print quality. See the print files for a cable guide that is used to keep the cable in a neutral postion that minimizes drag or weight on the print head assembly. ## Filament Routing I see a lot of direct drive systems that retain the Bowden tube for filament routing. This takes away one of the key benefits of a direct drive system which is easy filament loading and better yet... hot swapping filament while the printer is running. I suppose you could do it still with the PTFE tube but definitely not as easily. Check out the filament guide in the files list for an alternative routing strategy. Also allows you to get rid of the crappy metal arm that holds the filament roll. I also think that a heavy roll of filament moving and shaking on the frame of the printer impacts print quality. ## X Axis Endstop Needs to be flipped over so that the 2 wires have room to run under the extruder chassis.