Best way to handle tool changes with S3D and Duet wifi ?

[Mklein23]

I have a dual extrusion machine that I am trying to create a good tool change sequence for and could use some guidance. I'm using a combination of simplify3d's tool change retraction values and duet's tool change macros. What I have so far is pretty good but there's some room for improvement, specifically what happens at the end of the tool change. I use a wiper into a trashcan so my process is like this. abbreviated to save time, and I'm not at my machine to copy/paste the actual code ATM;

End of print segment, retraction. (E-5.000 F6000)

S3D calls a tool change in process;
Duet runs Tfree;

Go to position behind wiper (out side of printable volume);
large retraction to get filament out of hotzone (E-10.000 F6000);
set corresponding idle/active temperature;

Duet runs Tpre;

nothing here

Duet runs Tpost;

Extrude material to prime active tool, (E20.0000 F2000);
Retract filament to prevent ooze (E-5.000 F6000);

S3D takes it back to position and moves over wiper in the process

That last line is where I'm having troubles. S3D has a rudimentary canned cycle for tool changes as a "tool change retract distance." Here I can also state an "extra restart distance" that is any additional (positive or negative amount) it will do when calling up a new tool. I have this value set as a -5.0 so that it "un-does" my retraction pre-wipe. This is also where my problem is coming from.

The behavior I'm looking for at the end of the tool change is to retract filament, wipe across the wiper and move back to the part, THEN do the negative retraction to start printing again. What is happening now, is that S3D's putting that extra restart distance from a tool change in the same line as the movement so what I end up getting is:

Extrude behind wiper to purge/prime nozzle (duet value);
retract to prevent ooze (duet value);
move back to part to continue printing, while extruding and creating a nice ooze-stringer line connecting to wiper to the part;

I'd like to know if there's a way to split that last line into 2 moves. I want it to move back to the print in one move, then do the negative retract distance to get the filament where it should be in the nozzle.

Anyone else have luck running a dual extrusion machine with a wiper-trashcan tool change process?

The parts off the machine are great so far and having PLA-PVA models is such a game changer. I took just about all my inspiration from my machine from watching a stratysus fortus 250mc for probably hours on end.

[dc42]

Is there any reason why you don't do the wiping in the tpost file? The E3D tool changer does something similar. I think that after selecting a tool it extrudes some filament over a purge bin to endure that the nozzle is primed, then wipes the nozzle over a wire brush - probably with some retraction and re-priming around the wipe.

[bot]

I can't speak for the other user, but I wish to keep wipes and extruder moves out of the Tpre/free/post files because if I'm just jogging the axes around for one reason or another, I don't want the scripts to run when I change a tool.

Also, different filaments could use different wipe/extrude settings. I suppose firmware retraction will solve part of that, but it doesn't solve the wiping.

There is a way to select a tool without running the free/pre/post scripts, right? Is that the command that is sent when a new tool is selected in DWC/PanelDue?

[dc42]

@bot said in Best way to handle tool changes with S3D and Duet wifi ?:

There is a way to select a tool without running the free/pre/post scripts, right?

Yes, it's the T command with a P parameter to specify what scripts you want run. P0 means don't run any scripts.