Simplify3D User Forum

I prime both extruders prior to the start.

How do I make it so that when the Secondary Extruder does a retract as soon as the print is started? Otherwise it oozes all over the place since it's already primed and leaking out. By the time the primary is done, then the secondary loses all the filament and prints air so it makes a shitty prime pillar causing it not to adhere and destroying the pillar in the process.

Just add that command to your starting script

T1 ; select second extruder
G92 E0 ; zero the E-value
G1 E-10 F800 ; retract 10mm at 800mm/min

If you haven't written any gcode before, it's pretty simple and I would recommend starting here:
https://www.simplify3d.com/support/arti ... -tutorial/

ThanksI tried that and all it does is retract the extruder. The stupid thing does it's own G92 E0 after the start script making it pointless. I had to hack the gcode to remove those commands. There has to be a way so that I don't have to save the gcode and run the gcode each time.

I have fixed this issue by doing these 3/4 steps:

- in the G-code tab of your profile option disable "relative extrusion distances", so you will be using ABSOLUTE extrusion distances
-[optional depending on printer] deactivate the "allow zeroing of extrusion distances (i.e. G92 E0)"; this might sound counter intuitive as I will actually be using it, but it's the only way to make it work on my CTC Makerbot clone
- update your starting G-code with absolute numbers: e.g. an extrusion of 24mm followed by a 10mm retraction will look like .....E24 on the first line and then E14 (instead of E-10) on the following line
- adding a line at the end of your starting gcode: G92 B-10 (or B-11 if you want to add 1mm of extra restart distance and so on)

By doing this, the printer will be tricked to push the second extruder's filament 10mm more the first time it is used.