2 in 1 out - two approches

Hi,

I working to get some multicolor action going on my printer. I dont need a mixing nozzle for now, so I found these mechanisms:

1) Prometheus system style Y-splitter: https://www.aliexpress.com/item/3D-printer-E3DV6-Cyclops-dualhead-upgrade-kit-2WAY-in-1WAY-out-TL-Feeder-Prusa-bowden-splitter/32770576556.html
This comes with a 1,75mm special bowden tube to avoid the plug that form on retract in the 2mm heatbreak but still has a problem with stringing on PLA. Some recommed only printing PETG with that.

2) "Cyclops" Y splitter https://www.aliexpress.com/item/Hot-12v-24v-Cyclops-and-Chimera-Extruder-2-In-1-Out-2-colors-Hotend-Bowden-with/32796885685.html
Its says cyclops but its clearly not a mixing nozzle. It looks like a standard heater block and the splitting action happens inside the heatsink. They didnt want to tell me how the internal geometry looks like but i assume its a simple drilled 1,75-1.8mm Y shape.

What im asking myself is, if having the Y channels inside the heatinks helps against the stringing and the blob? any opinions from you?

This is just my personal opinion based on 3 years of printing.

I think is best to have the Y in the heater block like in the diamond system and in the Cyclops than in the cold side of the hotend like in the Prometheus, short retraction distances are easier to control an less prone to printing errors. Stringing and blobs are more related to multiple nozzles than single ones due to the fact that unused filament gets melted without any back pressure to control oozing.

true short distances are easier to control, but when i think about it the strings from retraction are sometimes 3-5cm so even if you have short switching retraction like in nr2 you still need to pull them out quite a bit to make sure the strings are not in the way of the 2nd color moving in.

and of course mixing nozzles are a whole different issue to be discussed

Edited 1 time(s). Last edit at 03/17/2017 08:03PM by sungod3k.

Agreed that certain retraction distance is needed to clear the path but if you switch filaments in a single hotend unit you will always going to have about 5 to 10mm of mixed color/material because no matter what you do (retract extremely fast as the Prometheus), melted material will stick to the walls of the nozzle and pipe and will mix with the incoming filament, a sacrificial tower is always needed in all of the systems and as such I prefer to go with the simplest one.