Dual Extruder Advanced Usage

Hello all Dual Extruder users, both present and future!

I have had many questions about how to use the dual extruder to do specific things (sometimes basic things) that aren’t always straight forward. I thought I would post some of my findings here for the community to work on as well.

The most blatant thing that seems simple but at least in Cura is not straightforward (yet) is how to print a single material part using the front extruder instead of the back. So here goes the simple fix:

Front extruder only on Dual Extruder

In Full Settings in Cura, go to the “Start/End Gcode” tab, and add the following lines to your start Gcode, preferably right after the “G28” command(s):

G1 Y50					;move Y to new offset position
G92 Y0					;set new Y offset
T1						;activate E1

Now load your STL, place it where you want it on the bed, slice, breathe normally, and print.

You will notice one significant change during the beginning of your print, namely that after homing all axes (G28) the print head will move forward 50mm in Y. This is effectively positioning your front nozzle (E1) to where your back nozzle (E0) usually sits, and redefining that as your new Y=0 position. And yes, for all those who want to be even more accurate, you can substitute your actual Extruder 2 Y offset for the “50”, just to be more exact. And if you are really shooting for pinpoint accuracy you can also add your X offset in there, and then add “X0” to the G92 line.

So if you have a FlexyDually and want to print something big in Ninjaflex, here’s a simple and straightforward way to get it done. Oh, one final thought about this. You may notice that when slicing in Cura with a two-material print, Cura restricts your use of the back of the bed. This is because as far as it knows, your front extruder (E1) can’t travel back there. But if you disable your steppers and pull your bed forward, you will notice that your TAZ can just about make it. Doing the above fix will ignore this because Cura sort of thinks you are still using E0, so it will let you use the full bed, and the Gcode will override firmware limits in the Y-axis (PS, we didn’t lie, we just told Cura to do something without it really understanding what it is doing). Just note that if you call alllll the way to the very back, your bed may come forward enough to hit the frame, and without an endstop there, it will be noisy (shouldn’t hurt much though).

This leads me to one more simple fix, which is…

Using the full bed size with the Dual Extruder

This one is much more simple. Basically, in Cura go into “Machine Settings” and tell Cura that your bed is +50mm long, or 325mm in Y. This will allow you to print over the full Y-length of the bed with your two-material print. That one was easy, wasn’t it! (Okay, this time we lied to Cura. It should get over it once it sees how awesome your print is)

Let me know of other dual extruder functionality that would be good to delve into!

Ray, thanks so much for this post. I got the Flexydually for Christmas and for the life of me was struggling figuring out how to print a model JUST with ninjaflex (the front extruder).

Surely Lulzbot isn’t thinking that customers that want to print only in Ninjaflex, but that have a Flexydually, should have to buy a Flexystruder as well?? It really does seem like there should be a way to do it in Cura without having to deal with custom G-code.

Anyway, thanks again!

Ray, I’m wondering how to trick Cura into slicing with a Ninjaflex profile? (My guess is that a merged model uses E0 filament settings for the first-loaded model part, and e1 flex filament settings and nozzle size for the other model part?)

I used the T1 trick from the print control window, and while it definitely used E1, the result wasn’t all that great :confused: That might be because it’s my first actual Ninjaflex print, or it could be because Cura sliced the model for 0.5mm ABS? (I noticed a gaps between perimiter in some places, and the retraction commands didn’t seem to match the calibration test print)

Is there anything else I can do for having Cura target Ninjaflex profile, before using GCODE to configure Flexydually v2 for an E1-only print? Maybe I can hand-roll a Cura profile that does this?? Do folks use profiles for this kind of customisation?

I will try this myself sometime in the future, but can’t we select our toolhead as the Flexystruder before proceeding with this gcode?

On a seperate note; in concerns for wear of any one of the extruders. will it be of any harm or extra wear if I was to use my Flexydually as a single extruder for either just ABS or just Ninjaflex?

Great tips!