Start of print purging

[singhm29]

Hey everyone,

Was wondering if anyone had some tips on how to make a more effective startup gcode for clearing the nozzle

At the moment it extrudes 5mm but half the time it fails to break off and gets dragged into the print. I thought that maybe increasing the F value from F100 to F300 would make the printhead speed off faster and increase the chances of braeking off the extruded filament but im starting to think that im not using the F command correctly and their might be a different command to have a sudden move at the beginning.

Thanks!

[JoeJ]

There is a good explanation of the starting gcode purge sequence here: http://forum.simplify3d.com/viewtopic.p ... 7410#p7410

The F-parameter is the speed in mm/min. So yes, if you increase it to 300, it will extrude 3 times faster. You didn't mention what printer you have, but for many of my machines, I like to do the purge off to the side of the build platform so that I can then wipe off the extrusion on the edge of the plate.

[singhm29]

Thanks for pointing me to that reference its shown me what i was thinking of incorrectly.
Basically if F is used with an E command (ex. G1 E25 F300) it increases the filament feed speed BUT if its used without an E command and just a movement command it changes the speed of that movement (ex. G1 X300 F9000)

I have a Gigabot which seems to be rare in the wild will be starting a thread here for some help tuning simplify3d to work better with it. Thats exactly what I do too purge off to the side then move it so it wipes off on the edge of the plate

How would I end my startup code so it knows when it heads off to start the print it does it at a speed of like F5000? since the coordinates of the print vary how would that look?

[JoeJ]

Just change your XY movement speed to 5000 mm/min and it will do that automatically

[singhm29]

The problem with doing that is it will stay like that for the entire print, I just want it for that one initial movement