Dual Extrusion settings explanation

[uneasymusic 0]

I am trying to dial my Idex printer with dual extrusion mode. I can;t get my head around Nozzle Switch retraction distance and extra prime amount after switch. 

No matter what I do I still can't get print started properly after nozzle switch. 

 

My assumption was that if my normal retraction is 0.8mm that's what I should put. and then it should retract it back when resuming print with that nozzle ?
But then that does not work at all as I thought. So I am trying to get extra prime amount set, but that also does not work as indented even with high values. 

What is the logic for those settings ? At which point it's doing that extra prime ? 

This is my current settings 

 

I was hoping I can get away with extra gcode in nozzle start, but it does not seem to be possible  with just those settings. I would like to understand those settings tho. 

[MariMakes 198]

Hey @uneasymusic,

 

Welcome to the Ultimaker Community 🎉

Sorry, it took us a while to get back to you 😞 

 

I don't have a lot of experience with IDEX printers, so I'm not sure I can help you with those details. 
I can tell you what the tooltips are for these settings:

 

Nozzle Switch Retraction Distance
The amount of retraction when switching extruders. Set to 0 for no retraction at all. This should generally be the same as the length of the heat zone.

Nozzle Switch Prime Speed
The speed at which the filament is pushed back after a nozzle switch retraction

Nozzle Switch Extra Prime Amount
Extra material to prime after nozzle switching

The Cura Settings Guide has a more elaborate explanation of the different settings:

You can download it from the marketplace here to see for yourself
https://marketplace.ultimaker.com/app/cura/plugins/Ghostkeeper/SettingsGuide2

Again, I don't know much about IDEX printers but in Cura 5.3 we introduced Per Object Retraction settings. 
Maybe they can be helpful to you. 

[Huds 0]

Hey @uneasymusic,

 

ive got an idex printer and am currently messing with these settings, im sure you got this all dialed in but for the 3 people who had idex printers, Cura 5.3.1, the extra prime value is used to put material back into the melt zone after it has leaked out due to heat. so the value IMO should be higher than your normal retraction value since it now has to re-prime the nozzle after every color switch. the downside to this is that it is priming the nozzle inside the skin of the print, in my case on an outer wall, if your extrusion value is too high. it will add surface defects to the print, i would much prefer if there was an option to purge before it moves the nozzle over the print, since i have custom nozzle wipe areas outside the print bed. 

 

I hope this made some sense, good luck!