3D Printing: Cyclops NF 2-in-1 Printhead

Sourcing

After my bad experience with the “Cyclops/Chimera” clone (2-in-1 with mixing capability), I purchased (June 2019) the improved “Cyclops” which resembles the “Cyclops NF 2-in-1” or “LERDGE 2-in-1 V2” , so I name this variant “Cyclops NF 2-in-1“:

which can be ordered at AliExpress (affiliate links):

and uses E3D V6 nozzle (clone) and 30x10mm fan on top. The two mounting holes are 24mm apart and fit the Prusa i3 X-carriage.

Further, the two filaments cannot be mixed like the original Cyclops but either filament A or B can be fed into the nozzle, but not both at the same time. Also, one can print with one filament solely, a 2nd filament must not be present.

Pros:

  • affordable
  • simple setup
  • single filament printing possible without 2nd filament being present

Cons:

  • cannot mix colors
  • long retraction required for tool change (>34mm)
  • long transition purge (~55mm)
  • custom PTFE or nylon piece in the heatbreak (not easy to source)
  • uncoordinated retraction can cause one filament blocking another

Model & Part Cooler

I quickly modeled the heatsink in OpenSCAD:

so I was able to adapt my Parametric Part Cooler with following settings part_cooler(name="cyclops nf",m=30,wx=25,yoff=10):

and the printed assembly:

Download

https://www.thingiverse.com/thing:3680090

Full Assembly

I finally turned the heatblock around (from the default orientation), so I could see the nozzle better and the LED strip shining more direct on the nozzle and bed.

Operation

The long tool switching retraction of > 34mm imposes quite additional risk of jamming combined with temperature sensitivity: depending on the temperature the pulled back of end of filament changes shape, and may not able to re-enter at next tool switch – so I’m a bit skeptical on the reliability – time will tell.

As I use print3r solely (without GUI), I set following in the printer profile:

# -- slicer=slic3r, slic3r-pe and prusa only:
retract_length_toolchange = 36

and a small macro named e2-nf-t1.ini for my Ashtar C #1 (380x400x380) Core XY style:

prepend_gcode="G91\nT0\nG1 E20 F100\nG1 E-36 F3000\nT1\nG1 E36 F3000\nG1 E60 F100\nG90\nG92 E0\n"
end_gcode="G1 Y{$machine_depth-10} F6000\nG92 E0\nG91\nG1 E-2 F2000\nM104 S0\nG1 E-36 F3000\nT0\nG1 E36 F3000\nM84\nG90\n"

which I use as print3r @e2-nf-t1 ... in case I like to print with 2nd filament only:

  • start:
    • T0: purge 20mm
    • T0: retract -36mm
    • T1: forward 36mm
    • T1: purge 60mm
    • reset E meter and go back to absolute positioning/extruding
  • end:
    • go back to Y380 (absolute)
    • T1: retract extrusion -2mm
    • T1: retract -36mm quick
    • T0: forward 36mm quick
    • switch off heating and motors

This way I keep T0 as default, and on-demand switch to T1 only with @e2-nf-t1 macro in operations. One case is not covered: if I abort a print then T1 is still active in the printhead and manually needs to be retracted (future print3r version will resolve this).

print3r --device=tcp:printhub:0 --printer=ashtar-c-1-e2 --random-placement --scad --slicer=cura print 'for(i=[0:2]) translate([50*i,0,0]) cylinder(d=5,h=40)'

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

★★★★★

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

That’s it.