BLV mgn cube Helmet Extruder

This is a complete direct drive print head assembly designed for the BLV mgn cube by Ben Levi. It takes inspiration from Ben's original Twin Blower but aims to make a few improvements.

My initial goal was to shorten the filament path from the extrusion gears to the nozzle but the problem is that if you want the extruder stepper motor on top of the rail (to reduce the moment force) then the original design pretty much has the extruder as close as it can be since the stepper motor cannot be lowered any further. Thus I created a completely new extruder design that flips the extruder gears below the motor gear as opposed to being position above it as in the original BMG. This brings the distance between extrusion gears and nozzle opening from ~118 mm down to ~79 mm. Whether this matters or not is up for discussion but anecdotally, I was at least able (or rather, forced) to lower my pressure advance from 0.09 to 0.06 for PETG.

Features:

• I'm biased but I think it looks pretty nice!
• Mounts for both V6 and Mosquito (or clones of them) hotends
• Optimized cooling fan ducts - I have spent a lot of time simulating and actually testing the design of the ducts in the real world
• Well thought out cable management - cables are routed hidden away up to a cable guide that can be angled to your preference. If you don't like this solution you can make your own and attach to the front plate.
• Improved belt paths to keep the belts parallel to the X axis
• Native support for BLtouch

What you need:

• Some PETG filament of your choice. Or whatever's hip these days.
• A BMG extruder to pick for parts or you can buy the spare parts from Bondtech, Triangle Lab or Mellow or whatever.
• Two 4010 blower fans for part cooling
• A 4010 axial fan for hotend cooling
• A PC4-01 pneumatic fitting for holding the end of a reverse Bowden tube. If you don't want reverse Bowden, you could leave this out.
• A piece of 3 mm nylon filament for the cable guide
• A textile sleeve (or similar) for the cable guide
• A BLtouch or clone - no other Z probe is supported at the moment
• A bunch of M3 screws and hex nuts
• The top and bottom plates from the original BLV mgn cube project. These are the same.

Use whatever print settings you feel is warranted. Also, print with supports according to your own judgement but here are a few guidelines:

• It's a pain to get supports out of deep horizontal holes, avoid where possible.
• Don't put support inside the filament path, it will be impossible to get out and it's designed to bridge fine without.
• DO put support right where the filament path crosses the gears, there's a bit of overhang there.
• Don't put support in the fan ducts, it will be impossible to get out and is designed to bridge.

I suggest you check out the online CAD viewer as a reference for how to assemble: https://a360.co/3cWstBm

I included some photos for reference of cable management.

For Z probe offsets, use X36.47 Y-4

Finally, I hope you enjoy it, give me feedback and remix it with the included STEP files.