Bondtech BMG direct drive extruder for GRR Neo

–UPDATE 2: I have added a new part „adapter_extruder_re_anguliert.stl“ which allows usage of a bigger and more powerful extruder stepper without losing build volume - see last picture. The only drawback of that one is that you need a printer that can handle a separate/soluble support material in order to print that on an FDM printer.

--UPDATE 1: I had completely forgot that I had changed the distance of the mounting holes on my print head relative to the original from Kakadu. I have now enclosed the changed parts as well, so this is now a complete print head set.

This is an updated version of Kakadu's ingenious Reprap Neo e3d v6 hotend upgrade (Reprap Neo e3d v6 UPGRADE), together with an adapter for the GRR Neo to mount a lefthanded Bondtech BMG as a direct drive extruder onto it.

In addition to one printout of each part you will need:

• 1x M3x16 screw for screwing the two pieces of the adapter_extruder together
• 3x M3x25 screw and
• 3x M3 hexagon nut for mounting adapter_extruder onto the base
• 2 M4x10 screws for the filament guide
• a small piece of bowden (a little more if you use the E3D v6 lite)
• a Bondtech BMG lefthanded extruder
• a small sized NEMA 17 stepper (I took one with 42x42x20mm from omc-stepperonline.com/nema-17-bipolar-18deg-13ncm-184ozin-1a-35v-42x42x20mm-4-wires-17hs08-1004s.html?search=42x42x2 )
• enough cable to connect the stepper
• two Ø10 x Ø3 x 4mm ball bearings
• two pieces of 3mm metal or plastic round material as axis for the bearings
• two neodym permanent magnets Ø5 x 7mm for the part cooler holder
• one piece of magnetic metal, 1mm thick, 7 x ca.18mm long
• other screws etc. identical to the original from Kakadu.

Assembly of the head should be pretty straightforward, I hope. Just take care to press in the two magnets with opposite magnetic poles facing outwards, so that the metal piece in the blower can close the "mangetic flow".

You need to take care about the bowden length though; it has to protrude ca. 6mm into the extruder, so do not cut it off flat to the surface of the adapter.

At least on my printer, this upgrade did wonders to print quality relative to the original bowden design. Happy printing!

Print Settings

• Resolution: 0.1 mm
• Infill: 60%

Notes: 
I suggest 4-5 perimeters and top/bottom layers for maximum stability