Re-Revised BMG Carriage for V6/Volcano, BLTouch +RJ45, "Over the Top" Style

thingiverse

There's a newer version available at https://www.thingiverse.com/thing:3688067 that offers better rigidity and simplified printing and assembly, so I recommend using it instead. This older version is kept for reference purposes only.  _______________________________________________________________ This design features a single-piece attachment to the MGN12 rail, making assembly easier and more stable. The previous version held multiple parts together during installation, which was a bit tricky. This updated design also includes additional components for attaching and clamping the belt to the carriage, allowing users to remove and reuse the belt if desired. Tie-wraps can still be used as an alternative attachment method. The part cooling duct is fully height-adjustable, enabling it to accommodate V6 or Volcano hot ends with ease. The design incorporates a pattern for 2mm belt teeth on the bars that hold the belt, providing a tighter grip. This modification was made by revising d0ct0r's basic design, "Adjustable E3D V6 impr. fan adapter and modded Prusa MK3 Layer Cooling," found at https://www.thingiverse.com/thing:3512817. The carriage and BLTouch mount parts are designed to work with the cooling system, which can be downloaded from this page or used with a basic E3D V6 fan holder for the heatsink if not needed. This design was created with the Folgertech FT-5 in mind but may also work on other printers that use an MGN12H slider on a 2020 bar. The priorities are: 1. Keeping the nozzle close to the MG12H slider to minimize any effects from tipping of the bearing slider, which is why the BMG extruder and motor are placed above the 2020 bar. 2. Including a BLTouch mount that's adjustable in height over about 12mm with guides on the slider to keep it vertical. 3. Mounting an RJ45 socket board for simplified wiring using the MDFLY dual RJ45 board w/screw terminals, available at https://www.amazon.com/gp/product/B01KHMFH1M/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1. The two RJ45 jacks allow for up to 16 wires to be carried. However, the heater element wire should not be run through these connectors due to high current usage; a separate 2-terminal higher-current connector is recommended instead. The "Over the Top" mounting of the motor and extruder above the 2020 bar was chosen because it provides a more stable placement of the nozzle while still allowing for the benefits of the BMG's dual gear extruder. This design causes another issue, though: on the FT-5, with this new mounting, the bed won't reach up to the nozzle! The nozzle sits only 10mm below the 2020 bar, so the bed needs to be raised about 48mm from the melamine bed platform with a standard V6 hot end or about 40mm with a Volcano. You'll also need to lose the cable chains, but I don't consider this a loss at all – I hate those things! Instead, use spiral wrap on the cables and feed them from the top/back side of the chassis. If you encounter any issues with the cable dropping too low or running into other things mounted in your printer, my "Cable Dangler" design is an effective solution for that issue (and makes the printer look much more open than when using cable chains): https://www.thingiverse.com/thing:3613175. The carriage is compatible with any NEMA 17 motor you want to use with your BMG. The "Plate" and "Back" have insets for M3 Nylock nuts, which are highly recommended to simplify assembly with the BLTouch mount and use of the belt grips. The best way to install them is to use an M3 screw to draw the flat part of the Nylock nut into the insets before assembly, applying a high force.