3D Printing: Dual Nozzle Printhead

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Once I discovered the Micro Swiss Hotend clones aka CR10 hotends, I realized they had properties which were ideal for dual nozzle printheads:

  • the nozzle is vertically fastened with a single screw
  • 2 or more nozzles can be easily vertically calibrated to have the same distance to the printbed
  • CR10 Hotend: one worm screw to change distance
  • Dual CR10 hotends: equalize nozzles perfectly

The proper way includes two additional screws which stabilize the heatsink with the heatblock, but those are left out for this use-case.

Dual Hotend Mount

A very minimalistic lightweight mount with 40mm fan in mind:

The nozzle X offset is 24mm in the ideal case.

Part Cooler

Adapting my Parametric Part Cooler with part_cooler(name="dual swiss",wx=50)​:

Download

https://cults3d.com/en/3d-model/tool/dual-extrusion-with-2x-cr10-micro-swiss-hotends-with-part-cooler

https://www.thingiverse.com/thing:3633941

BOM

  • 2x M3x12 or 14 to mount to 30mm X carriage, possible 2x M3 nuts
  • 4x M3x20 (mount 2x “CR10 hotends”)
  • 4x M3 nuts
  • 4x M3x10 or M3x12 if you use part cooler too (mounting 40mm fan)
  • 1x 40×10 fan
  • 1x 50×15 fan blower (optional as part cooler)

Assembly

  1. assemble both hotends to the X carriage without PTFE inserted yet
  2. move Z down until one hotend reaches bed (truly touch)
  3. open worm screw of the other hotend so the nozzle drops to the bed as well
  4. close worm screw firmly
  5. move X carriage 2mm or more up
  6. insert PTFE and fasten firmly (I recommend https://www.thingiverse.com/thing:1993384 2x PC4-M10 = PTFE remains intact) and insert filament
  7. perform test print

X Offset

You can define X offset via Gcode (e.g. as start gcode):

M218 T0 X0
M218 T1 X24 Y0

given T0/Extruder 1 is left, and T1/Extruder 2 is on the right.

Since “CR10 hotends” are really cheap and not precisely machined, there is too much margin in the mounting 3mm holes – hence, you likely have more or less of 24mm X offset, and possible even Y offset as well. Use a 2-color calibration model to tune the offsets.

Usage

  • Dual CR10 hotends: different distance to bed
  • Dual CR10 hotends: equalize nozzles perfectly
  • Dual CR10 hotends: equal distance to bed
  • Dual CR10 hotends: 40mm fan mounted
  • Part cooler mounted
  • Complete setup attached to X carriage

Comparison Dual/Multi Color/Material Extrusions

blue = relevant positive
red = relevant negative

Independent Dual Extrusions (IDEX)

  • complex setup
  • moderate cost
  • non-mixing
  • dual nozzles
  • dual heatblocks
  • dual heatsinks
  • normal retraction
  • no purge block 1)
  • no oozing over print
  • no inactive nozzle traveling
  • reliable 2)

★★★★★

Dual Hotends 2-in-2

  • simple setup
  • low cost
  • non-mixing
  • dual nozzles
  • dual heatblocks
  • dual heatsinks
  • normal retraction
  • no purge block
  • inactive nozzle oozing over prints
  • inactive nozzle travels over print
  • moderate reliability

★★★★★

Chimera 2-in-2

  • simple setup
  • clone: low cost
  • original: high cost
  • non-mixing
  • dual nozzles
  • dual heatblocks
  • single heatsink
  • normal retraction
  • no purge block
  • oozing of inactive material
  • inactive nozzle travels over print
  • moderate reliability

★★★★★

Cyclops 2-in-1

  • simple setup
  • clone: low cost
  • original: high cost
  • mixing
  • single nozzle
  • single heatblock
  • single heatsink
  • normal retraction
  • purge block required
  • no oozing of inactive material
  • clone: unreliable

★★★★★ (clone)

Cyclops NF 2-in-1

  • simple setup
  • low cost
  • non-mixing
  • single nozzle
  • single heatblock
  • single heatsink
  • complex retraction
  • no oozing of inactive material
  • moderate reliability

★★★★★

Diamond Hotend 3-in-1

  • complex setup
  • clone: low cost
  • original: high cost
  • mixing
  • single nozzle
  • single heatblock
  • 3 heatsinks
  • tricky retraction
  • purge block required
  • no oozing of inactive material
  • moderate reliability

★★★★★

Multiple Switching Extrusions (MSE) 2-in-2, 3-in-3, 4-in-4

  • moderate complex setup
  • requires additional servo or motor
  • extendable 2, 3, or 4 colors/materials
  • low cost
  • non-mixing
  • multiple nozzles / heatblocks / heatsinks
  • normal retraction
  • no purge block 1)
  • no oozing of inactive material
  • no inactive nozzle touching print
  • reliable 2)

(rating comes later)

Y Splitter x-in-1

  • simple setup
  • extendable 2, 3, or 4 or more colors / materials
  • low cost
  • non-mixing
  • single nozzle
  • single heatblock
  • single heatsink
  • complex retraction
  • purge block required
  • no oozing of inactive material
  • moderate reliability

★★★★★

Tool Changer

  • complex setup
  • extendable to n-colors or materials
  • moderate cost
  • non-mixing
  • multiple nozzles / heatblocks / heatsinks
  • normal retraction
  • no oozing of inactive material
  • no inactive nozzle touching print
  • moderate reliability

(rating comes later)

Footnotes

  1. in theory no purge block, but if ooze shields are shared among switching extrusions (more than 2 extrusions) there may be cross-contamination between colors/materials
  2. the printheads individually are proven to be reliable

Hints:

  • single heatblock = same print temperature
  • dual heatblock = different print temperatures possible
  • dual nozzle = different nozzle sizes possible

See Also

That’s it.