New user cant figure out presure advance



  • So i have bin using my prusa mk3s for 10 month now and gone through 10000m of filament. I have started a business that sells mold made out of tpu. I needed a bit bigger print surface so got a CoreXY Hypercube Evo that was almost finished.
    I have now bin trying to configure a g-code for 5 hours and i still have no fucking clue how to do it right. No clue what to type where or anything. So i consider running no pressure advance but then my molds will look like shit.
    Why cant it be as easy as on marlin? i kinda thought this was superior firmware but so hard finding info and guides explaining stuff so a regular person like me can understand.

    I also cant understand how the pressure advance code should look like.
    "M572 D0 S0.1 ; set extruder 0 pressure advance to 0.1 seconds"
    "M572 D0:1:2 S0.2 ; set extruder 0, 1 and 2 pressure advance to 0.2 seconds (RepRapFirmware 1.20 and later)"

    If my pressure advance is say S0.025 should the code then say:

    M572 D0 S0.0.025 ; set extruder 0 pressure advance to 0.025 seconds"

    Can i add that line where in the config file?



  • Are you sure your problem is pressure advance? What kind of prints do you get with pressure advance set to 0? (pictures).

    Also, does you HEVO uses Bowden or direct drive extruder? I doubt if you will get reasonable TPU prints with ~600 mm Bowden tube, with or without pressure advance.

    BTW, duet is superior to Marlin. I used Marlin and Sailfish printers in the past, built my HEVO with duet and it's in a league on its own.



  • @Alucardi To answer your specific questions, the "D" parameter is the extruder drive number. If you only have one extruder then you only need to use D0. If you have multiple extruders, then you need to set the pressure advance for each one. In early firmware, you have to use a separate command for each extruder but in later firmwares, you can use a single command with each extruder number separated by a colon.
    The command can go anywhere in your config.g file.
    It's generally best to tune all other parameters such as speeds, accelerations and retraction first. Then introduce pressure advance. You can enter the command "on the fly" while a print is running. Then when you have found the best setting, add that to your configuration file so that it gets read in whenever you power up the printer.


  • Moderator



  • @Phaedrux, does that page discuss the dependency on jerk E parameter? May worth adding a short note.

    https://forum.duet3d.com/topic/14937/pressure-advance-with-s2-0/4?_=1584296267428

    This is also something that may be checked by linter that @danal is looking into.


  • Moderator

    @zapta said in New user cant figure out presure advance:

    does that page discuss the dependency on jerk E parameter? May worth adding a short note.

    Yes it does.

    When the extruder acceleration changes, the extruder velocity has to change instantaneously. If the configured extruder jerk is too low to permit this, the extruder acceleration will be restricted so as to honour the maximum configured extruder jerk, and this may in turn limit the printing acceleration. So if enabling pressure advance slows down printing, this may be a sign that the allowed extruder jerk configured in the M566 command is too low. This may prove problematic for remote direct drive extruders like the Zesty Nimble which use a high gear ratio and low jerk values.



  • @zapta my e-jerk is E3600:24 i am not sure what the ":24" means though. This is setup by previous owner so i have not actually changed it. Its a direct drive bondtech extruder aka prusa mk3s model.
    I did get it to work though. I use prusa slicer so added in a change after each 25 layers like in the link. But it really did not get that good looking on the seam. It ends good but the start after the seam gives me a bloob. Not sure if that is a slicer setting or pressure advance setting. I also for some reason thought i wanted this in the config file but i dont. I want it in start g-code since it will be different per filament type at least.


  • Moderator

    @Alucardi The 24 would be for a second extruder.



  • @Phaedrux, thanks for checking.