This is a rigid, compact, and light-weight carriage arrangement for a BMG extrder and other common accessories (like a BLTouch and a dual RJ-45 adaptor so that CAT6 cables can be used for easy wiring of the components on the carraige). It is based on my previous https://www.thingiverse.com/thing:3615464 . This improved version was done because I used PETG to print the previous version, and the PETG "plate" part had more flex than I liked. So this one adds upper walls for very good vertical stiffening even with less-stiff filaments. Doing this also gave a way to integrate the dual RJ45 breakout board mounting into the other parts, reducing printed parts count, and simplifying printing and assembly.
The design, done for a FT-5 printer, has the carriage mounted on an MG12H slider and horizontal 2020 extruded bar, with the extruder and motor above those pieces . Several other printers use a similar MG12H slider and 2020 arrangemtn (FT-6, and some others), so this design should be applicable to those.
Also included are textured clamps to securely hold 2mm belts instead of using tie-wraps. Te clamps allow belts to be removed and reinstalled without need for buying a new belt.
The RJ45 breakout board is available from (using the MDFLY dual RJ45 board w/screw terminals): https://www.amazon.com/gp/product/B01KHMFH1M/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
and of course it can be left off if desired.
The "Over the Top" placement of the extruder provides better stability since the nozzle sits much closer to the linear bearing (so less of a lever for it to jiggle around), but may cause another issue with some printers (like the FT-5) as it moves the nozzle up so high that the bed can't reach it. So, for the FT-5, the bed has to be raised some (about 48mm from the melamine bed platform with standard V6, about 40mm with a Volcano). That isn't hard to do with some pieces of wood or use this neat 3D printed bed riser:. https://www.thingiverse.com/thing:3719437
Some related designs used with this arrangement: (partially shown in the photos)
any PETG or ABS recommended, PLA acceptable
Print parts in orientation shown.
Various long (~45mm) and short (~12mm) 3mm screws and nuts required for assembly.