Different speeds for retraction speed vs restart speed

[PhillipM]

Just one I think that would help a lot of people with seam issues on S3D - I've noticed if I run a far faster retraction speed, say 60-80mm/s then the seams get much more like other slicers and almost disappear - unfortunately, if you're then running a sticky or flexible material like PET-G or TPU, then feeding back in at 80mm/s on a restart will make the extruder slip as it encounters residual filament in the nozzle from the retraction and the pressure builds just before smooth extrusion - meaning you end up slowing the setting down to 25-35mm/s and getting worse seams just to stop the slippage.

I'd like to see this setting split, into one setting for retraction speed, and another for restart speed, so I could then run say 80mm/s retraction with 30mm/s restart speed, giving much cleaner seems/line ends but without the chance of filament grinding on restart.

[S3D-Jake]

Phillip,

Great idea for a new retraction/prime speed setting. In the current software, have you tried using a REPLACE command to change the speed for the prime? If you know the retraction speed and the priming amount, the REPLACE command should be fairly simple to script.

example:

retraction amount = 1mm
retraction speed = 80mm/sec or 4800mm/min
extra restart distance set to 0mm

Your prime sequence in the g-code should look like this:
G1 E0.0000 F4800
G92 E0

so replace it with your own slower slip-free speed
{REPLACE "G1 E0.0000 F4800\nG92 E0\n" "G1 E0.0000 F1800\nG92 E0\n"}

[PhillipM]

Thanks, I'll give that a shot. Be nice to have it in the UI though as it's not really machine-specific?

[Ultrasonic2]

So ..to me having two speeds makes sense ..you want it fast pulled out but slow back in ... the slow back in is important to allow the firmament to re heat / Pressure to build .. It becomes a bigger necessity with super long distance traveled and long bowden tubes (big printers)

I managed to get a version of the script you posted to work..