Pressure advance questions



  • I'm trying to dial in my dual extrusion, and while I have the filament swap down, it did do some funky things with my usual retractions. Part of it is definitely because I need to print a tad hotter due to friction in the bowden (going to test geared extrusion, to see if that is easily resolved), I want to play with pressure advance and see if it will help.

    I put in:
    M572 D0 S0.1
    M572 D1 S0.1

    Before my print, and can see some affect - can this be changed during a print so I can test different values? I tried lowering it and raising it, but didn't see much change in the print.

    I've seen values for the S parameter from 0.05 to 0.15, is this a typical range, with 0.15 being on the "more effect" side of it? Do people use higher or lower values than those?


  • administrators

    Yes you can change pressure advance during a print. Changes won't take effect for a few moves.



  • If inserting it directly into the gcode I assume it should take effect before the next gcode line?


  • administrators

    @Alexander:

    If inserting it directly into the gcode I assume it should take effect before the next gcode line?

    That's a good point. Currently it will take place earlier than that, because the pressure advance values are not queued.



  • So if I manually insert M572 into the gcode like this what happens? Sorry, I'm a little confused.

    M572 D0 S0
    <gcode lines="" to="" print="" a="" few="" layers="">M572 D0 S0.05
    <gcode lines="" to="" print="" a="" few="" layers="">M572 D0 S0.1
    <gcode lines="" to="" print="" a="" few="" layers="">M572 D0 S0.15</gcode></gcode></gcode>


  • administrators

    Unless you insert M400 before each M572 command or do something else that causes the move queue to be emptied such as pause the print, each M572 command is likely to be applied to existing moves in the move queue that have not already had their parameters frozen. Parameters get frozen about 0.5 seconds + 1 move earlier than they are due to be started.


Log in to reply