Sanity check of my PA values



  • Hi all

    I've been calibrating PA on my large (320x320) CoreXY build and wondered if someone could look over my numbers and see what they think.
    My printer is using a 660mm bowden tube with a genuine Bondtech BMG extruder. Hotend is an E3D V6 with a 0.4mm nozzle.

    I've been using a combination of the python script that does fast and slow moves, and conditionals in Prusaslicer when slicing a 40mm cube with 2 walls and rear seams.

    I've come out with a PA value of 1.55 with Esun PLA+ at 225C which seems very high when compared to what other people are posting for bowden setups. If I drop the temperature to 205C which is more inline with the temperature I print on my other machines (running Marlin) I get values of well over 2.

    To sanity check my own findings I swapped the hotend out with another E3D V6 I had (a Lite 6) and got the same numbers more or less.

    Here are two tests. Both gradients start at 0.5 and end at 2.0:

    20200617_112708249_iOS.jpg 20200617_112636006_iOS.jpg

    I'm fairly new to RRF but very familiar with Marlin. On a slightly smaller printer running Marlin I get a LA value of 0.4 with a 400mm bowden tube. Are the numbers between PA and LA comparable or is that a red herring?

    This is the relevant section of my config.g:

    M566 X600 Y600 Z120 E1500                         	; Set maximum instantaneous speed changes (Jerk) (mm/min) 
    M203 X10000 Y10000 Z600 E3600                      	; Set maximum speeds (mm/min) 
    M201 X2500 Y2500 Z30 E8000			   	; Set accelerations (mm/s^2)
    M204 P500                                               ; Set print acceleration
    M906 X1600 Y1600 Z1600 E1600 I30                   	; Set motor currents (mA) and motor idle factor in per cent
    

    Any thoughts greatly appreciated.


  • Moderator

    @rilot said in Sanity check of my PA values:

    Are the numbers between PA and LA comparable

    Not really.

    Trust the tuning and then verify with actual prints.



  • @rilot said in Sanity check of my PA values:

    I've come out with a PA value of 1.55 with Esun PLA+ at 225C which seems very high when compared to what other people are posting

    I got similar PA numbers with my 600mm bowden, BMG and V6 configuration. Then I change to a direct configuration, PA went down to 0.08 and print results got much better.



  • Well, I just did the same. Ditched the Bowden and went to direct drive. 0.11 PA and much better prints. I should have done this ages ago rather than fighting with the bowden.

    Thanks.


Log in to reply