Swivelling dual hotend mount for CoreXY (Hypercube mod)

Dual extruder/dual hotend mod. I've been working on it on and off for a few years and decided to share it once I understood that there is nothing else I can add :). I have managed to print hundreds of models meaning thousands of hotend switches. 

It is not an easy to print/assemble/configure mod, but for those of you who are into that kind of entertainment, may be worth it.  Dual colour/material is obviously a bonus, but simply having 2 different filaments or nozzle sizes available at any time is also nice.

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Servo used is MG996. Ball bearing 608. This version of the mount is designed for LM8LUU linear bearings. 

I recommend printing out of something stiff and temperature resistant such as Nylon or Polycarbonate. Due to the long iterative process my current assembly, as you can see in the photo, is a mix and match of all sorts of materials.

I recommend E3D Revo 6 extruders for the smaller weight, footprint, and of course, ease of swapping nozzles. It will work with the original V6, but the heatblocks end up very close to the blower duct and slowly warps it with heat (see photo.) I only switched to E3D's recently, this PETG duct is over a year old.

There is a 70 degrees angle between the hotends. I cannot give you the exact angles as they will vary depending on the servo position during mounting. It is not difficult to fine tune with M280/M281 commands. Use 

#define HOTEND_OFFSET_X { 0.0, 20.80 } // (mm) relative X-offset for each nozzle

#define HOTEND_OFFSET_Y { 0.0, 0.0}  // (mm) relative Y-offset for each nozzle

#define HOTEND_OFFSET_Z { 0.0, 0.0}  // (mm) relative Z-offset for each nozzle

and fine-tune (M218) later with any dual-print calibration model.

Glue the ball bearing_insert to the swivel to reduce wobble. Use 43mm partially threaded bolt and a metal washer for this connection. Same for the top blower fan (12V 5015) hole, with some 3d printed washers. 20mm M3's for the clamp sides, 5 and 10mm for the belt fixing parts and ooze shields. Brass inserts everywhere.

Initially I used this with BLTouch (clamp_BL.stl), but with swivelling extruder, setting the Z offset is problematic, therefore BD sensor is recommended, if you need one. This also allows to use a much easier to print clamp.

I glued the BDsensor mount to the flat surface on bottom right of the carriage. You can place it on the left if needed. I couldn't figure out where to mount the body of BDsensor, it can be glued to the side of the part cooling fan.

I will add a picture with BDsensor mounted, once the new one arrives. I managed to rip the cable off the old one :(

Finally, the ooze shields you'll have to DIY. I used aluminium PC slot covers - they have mounting holes already and are fairly easy to cut and bend.

Dual extruder/dual hotend. Bed sensor mount.