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;
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.