It's been a while since I have uploaded a thing. But this one is pretty cool! You might know me from my Proximity sensor mount if you have a Prusa i3. Which is quite popular, according to Thingiverse Analytics.

I came up at this idea, when I got interested in dual extrusion. At first I found the well known Extruder Merger. Later on I found a Direct drive dual extruder (single-nozzle and single-drive), which I like more. Because it is less bulky than using 2 stepper motors.

Problem

The single-nozzle single-drive dual extruder, is direct drive. Meaning the motor is attached on the axis. My 3D printer is upgraded to a bowden extrusion, so I could not use it.

Solution

I convert the single-nozzle single-drive dual extruder to Bowden. Seems simple right? So this is what I came up with after hours of recreating in Autodesk Fusion 360.
Now it's possible to combine this using a Extruder Y-merger:

• Extruder Merger by mokash770 (PC4-01 Push fittings)
• Y-piece for dual extrusion with one nozzle by 3Dator (PC4-M5 Push fittings)

If you want to switch between 4 filaments, you will only need 2 stepper motors. Instead of the regular 4, by using a 4-way Y-merger at the nozzle end. If someone gets this (quad) working, please share your Gcode for switching!
Like this one does: Original Prusa i3 MK2 Multi Material upgrade release - dual/quad extrusion

The STL files have been exported using the highest quality (lowest Surface Deviation) as possible, in order to achieve maximum Number of Triangles. In short, the prints should look smooth AF.

Assembly

• See this link for assembly instructions: Direct drive dual extruder (single-nozzle and single-drive).
• Requires 1 additional M3 washer where each idler mounts to the stepper motor. You can see the recessed hole for the M3 washer.
• Requires 2* PC4-M5 pneumatic fittings at the output side.
• Print the parts at 0.1mm layer height for best result.
• Print and assemble a Extruder Y merger. I might design one myself and add it to the files.
• Print the right body for your servomotor:
  • Original design requires the use of a metal gear Hitec HS-225MG mini servomotor. But wait!
  • The HS-225BB is essentially the same size, but has plastic gears and therefore costs less.
  • Another design made to fit the more affordable Hitec HS-422/HS-425BB standard size servomotor and others of similar size: body-hs422-hs425bb_repaired.stl.
  • Tamiya TSU-04 standard size servomotor confirmed to fit body-hs422-hs425bb_repaired.stl
• Cut one leg off of "regular" servo horn (arm) #12, that comes with your Hitec servomotor (says BigSteve). Or use a similar one if you want to use a different servomotor.
  

Mounting

• The mount has been designed to be in the proper direction of the layers, for maximum strength. Hole spacing is the same as a NEMA17 stepper motor. Allowing popular stepper motor brackets able to attach to the body using M3 hardware. Or some other way, be creative!
• Sandwich the popular 90 degree angled stepper motor bracket between the NEMA17 stepper motors and body. The mount will face downwards, towards the output side.

Good luck!

• Successfully printed dual color:
  • See video in gallery above!
  • Cura and Firmware settings released at my GitHub Repo
    • If you have a different firmware please let me add your configuration to the Repo. Let's help each other out :)
• I would love to see your prints! I Made One
• Status:
  • Prints:
    • Body printed successfully
    • Idler printed successfully
  • Preliminary test single extrusion, see video below
  • All mounting hardware ordered from eBay
    • Stainless Steel Fasteners: [1] [2] [3] [4] arrived (request combined shipping)
    • 624ZZ bearings arrived
    • PC4-M5 Pneumatic straight fittings and PTFE ID=2mm OD=3mm (same seller) arrived
    • MK8 Drive gear and 623ZZ bearing arrived
• Standard size servomotor:
  • Done! body-hs422-hs425bb_repaired.stl - I managed to fit a Tamiya TSU-04 as well.
  • "I will be working on a second body design to fit a standard size servo. Which is more friendly priced (€15/€25), such as the plastic gear Hitec HS-422/HS-425BB dual (ball-)bearing. Or similar size servomotor. I think this would make it easier on the wallet for anyone to test this thing."

Video of it working and Source files: https://3dprintingwithzahier.blogspot.nl/2016/12/its-working-bowden-dualquad-extrusion.html