Undo retraction from macro at the start of the actual print

Merlin246

Hello,

The E3D Toolchanger uses three macros for toolchanges, the tfreex.g, tpostx.g, and tprex.g. In which I have retractions, extrudes (undoing retractions), and other macros, such as initial purge, retract, and brush.

I'd like to keep these macros as they work well but I notice that the start of my print usually has a few mm before any plastic is extruded because of the retraction at the end of the tool picking so the hotend doesn't ooze anything on it's travel between the brushing area and the start of the print. Is there a way to get the printer (or slicer to have the printer) undo that final retraction and then actually start printing?

I'm not sure if this was a question for Duet or PrusaSlicer so I'm posting in both.

Thanks!

OwenD

@Merlin246
I'm pretty sure you could safely just put G11 in your start gcode.
It will only run if it is actually retracted.
However if you want to check you can use the object model

if tools[state.currentTool].isRetracted = true
   echo "Tool " ^ state.currentTool ^ " is retracted.  Performing in-retract"
   G11

Phaedrux

Is it a retraction or is it just lack of priming?

Merlin246

@Phaedrux it is an actual retraction, I do a prime, then retract for the move to the printing start point, however, the slicer doesn't have the retract undone before the actual print starts.

Merlin246

@OwenD I'm not sure if putting it in the start code will help. I want the process to look like the following:

Prime nozzle -> retract -> move to print starting coordinates -> deretract -> start the print.

The start gcode ends after the retract stage.

Phaedrux

Are you using slicer retraction or firmware retraction?

Merlin246

@Phaedrux slicer retraction.

deckingman

@Merlin246 I'm not sure how you've structured your tool change macros but I used to purge and wipe the nozzle at the end of tpost, then move the printhead from whence it started before the tool change using G1 R2, then do G11 (firmware un-retract) as the very last command of tpost.

Phaedrux

@Merlin246 said in Undo retraction from macro at the start of the actual print:

@Phaedrux slicer retraction.

I think you should transition to firmware retraction.

Merlin246

@Phaedrux I will experiment with it. I've never used it before though, can it support different retractions for different tools?

Also, can it be adjusted by the slicer based on the filament profile (if it requires more/less or faster/slower retractions)?

Phaedrux

Yes, you configure firmware retraction with M207

https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m207-set-retract-length

The slicer must be set to use firmware retraction as well, so that when a retraction is needed the slicer inserts a G10/G11 command.

To configure retraction for each tool, you can add an M207 command to your tool change files custom for each tool.

This also means that retraction state is tracked by the firmware, and it will un-retract when needed before starting to extrude.