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    Pressure Advance Calibration

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    Tuning and tweaking
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    • Edgars Batnaundefined
      Edgars Batna
      last edited by

      Also found out about this script a few days ago and, man, was I wrong about the values I used. Turned out my Bowden setup runs best at 0.85, whereas I was using 0.2.

      Rightly noted that under-extrusion should be compensated by nonlinear extrusion, not presure advance. These two features in combination doubled my print speeds while keeping the quality. 😀

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      • briskspiritundefined
        briskspirit
        last edited by

        How should I choose min and max speed for calibration script? Max speed is the overal speed(70mm/s for me) or outline speed? (42mm/s). Min speed correlates with jerk speed or ..? Thanks!

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        • gnydickundefined
          gnydick
          last edited by

          Where is the link to the pressure advance test file?

          briskspiritundefined 1 Reply Last reply Reply Quote 0
          • briskspiritundefined
            briskspirit @gnydick
            last edited by

            @gnydick https://forum.duet3d.com/assets/uploads/files/1535998759071-advance_cal.py.txt

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            • gnydickundefined
              gnydick
              last edited by

              How do I read this result?0_1546069069917_IMG_20181228_233549.jpg

              wilrikerundefined 1 Reply Last reply Reply Quote 0
              • wilrikerundefined
                wilriker @gnydick
                last edited by

                @gnydick I would say that the range of PA values you used is still too low because it looks like none of the layers is continuously one thickness.

                Manuel
                Duet 3 6HC (v0.6) with RPi 4B on a custom Cartesian
                with probably always latest firmware/DWC (incl. betas or self-compiled)
                My Tool Collection

                gnydickundefined 1 Reply Last reply Reply Quote 0
                • gnydickundefined
                  gnydick @wilriker
                  last edited by

                  @wilriker ok, thanks. Strange I need so much. I have a direct extruder with zero slack.

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                  • JamesMundefined
                    JamesM
                    last edited by

                    How do you run the pressure advance test file? I see it's in python..Does it work similar to the linear advance website Marlin has where we can change the settings and it creates a .gcode file?

                    gnydickundefined 1 Reply Last reply Reply Quote 0
                    • gnydickundefined
                      gnydick @JamesM
                      last edited by

                      @jamesm

                      It's nearly identical. Instead of building up vertically, the linear advance creates a single extrusion on the bed for each setting and labels it.

                      You have to run the python program to generate the output.

                      JamesMundefined 1 Reply Last reply Reply Quote 0
                      • JamesMundefined
                        JamesM @gnydick
                        last edited by

                        @gnydick I just figured out how to run it. I changed the filament settings in the file before running it which I expect has to be done. I guess just edit the gcode to set the print temperature and turn on relative extrusion?

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                        • briskspiritundefined
                          briskspirit
                          last edited by

                          Will ask again... How should I choose min and max speed for calibration script? Max speed is the overal speed(70mm/s for me) or outline speed? (42mm/s). Min speed correlates with jerk speed or ..? Thanks!

                          Edgars Batnaundefined 1 Reply Last reply Reply Quote 0
                          • Edgars Batnaundefined
                            Edgars Batna @briskspirit
                            last edited by Edgars Batna

                            @briskspirit I'd simply go with minimum and maximum speed that I'd ever use on the printer. It's not so much about speed as pressure management in extruder. I ran the script at 60-120 first and 30-200 later once basic kinks were ironed out. The speed difference should be enough to cause significant pressure differences.

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                            • Cartolaundefined
                              Cartola
                              last edited by

                              Hi, I've been reading this thread for a long time and I noticed that a lot of people, like me, are having problems to identify the best PA in their tests. So I tried to create a similar script that tries to give clearer results. I am no sure if I achieved my goal 😄 , but I decided to share it anyway: https://www.thingiverse.com/thing:3442071

                              All the instructions are in the Thingverse link.

                              Here is one of my prints using PA from 0 to 3. Yeah, I need to use really high values. I didn't completely understood why but my Capricorn (original) bowden tube is big, so maybe I need to shorten it.

                              0_1550717752612_52b8e11a-eaf3-42c4-9790-d4f8008928ee.jpg

                              1 Reply Last reply Reply Quote 1
                              • tenjinundefined
                                tenjin
                                last edited by

                                i tried to print this, and nothing came out...

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                                • rs4raceundefined
                                  rs4race
                                  last edited by rs4race

                                  I want to share some of my experience tuning pressure advance. It was mentioned that you will need to recalibrate retraction.

                                  I'm using a bowden tube setup and at higher speeds (100mm/s) I was missing material at the start of extrusion. Increasing prime amount would fix the higher speed problems but leave blobs at lower speeds (25mm/s). To resolve this I had to reduce the retraction distance. I ended up with retractions similar to a direct drive and no extra prime amount. I ended up with the following retract and pressure advance settings:

                                  M207 S2.0 R0.0 F3600 T600
                                  M572 D0 S0.3

                                  This is with the following setup:
                                  E3D Volcano, 0.4mm nozzle
                                  550mm Capricorn XS Bowden tube
                                  Bondtech QR Extruder
                                  1.75mm Amazon Basics PETG

                                  Extruder config settings per request: (these are not necessarily limits of the extruder)

                                  M350 E32:32 ;microstepping
                                  M92 E953:953 ;steps/mm
                                  M906 E900:900 ;motor currents
                                  M201 E1000:1000 ;accelerations
                                  M203 E3600:3600 ;maximum speed
                                  M566 E900:900 ;maximum jerk speed

                                  Before Tuning these settings I was printing slower (50mm/s) with 6.5mm retraction distance.

                                  dc42undefined OBELIKSundefined 2 Replies Last reply Reply Quote 1
                                  • dc42undefined
                                    dc42 administrators @rs4race
                                    last edited by

                                    @rs4race said in Pressure Advance Calibration:

                                    I want to share some of my experience tuning pressure advance. It was mentioned that you will need to recalibrate retraction.

                                    I'm using a bowden tube setup and at higher speeds (100mm/s) I was missing material at the start of extrusion. Increasing prime amount would fix the higher speed problems but leave blobs at lower speeds (25mm/s). To resolve this I had to reduce the retraction distance. I ended up with retractions similar to a direct drive and no extra prime amount. I ended up with the following retract and pressure advance settings:

                                    M207 S2.0 R0.0 F3600 T600
                                    M572 D0 S0.3

                                    This is with the following setup:
                                    E3D Volcano, 0.4mm nozzle
                                    550mm Capricorn XS Bowden tube
                                    Bondtech QR Extruder
                                    1.75mm Amazon Basics PETG

                                    Before Tuning these settings I was printing slower (50mm/s) with 6.5mm retraction distance.

                                    Thanks for sharing this.

                                    Duet WiFi hardware designer and firmware engineer
                                    Please do not ask me for Duet support via PM or email, use the forum
                                    http://www.escher3d.com, https://miscsolutions.wordpress.com

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                                    • OBELIKSundefined
                                      OBELIKS @rs4race
                                      last edited by

                                      @rs4race Could you also post your speed, jerk and accelleration settings for the extruder?

                                      P3Steel Toolson mk2 - Duet 2 WiFi --> RatRig V-Core with Duet WiFi 1.03
                                      Original Prusa i3 MK3S

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                                      • jtroutt19undefined
                                        jtroutt19
                                        last edited by jtroutt19

                                        When running the python script changing the center of bed to 110,110

                                        This is a little snippet of the code it produces. Obviously X is off the charts. What am I doing wrong. Using python 3.7

                                        G1 X3853.750 Y126.800 E0.2910 F4200
                                        G1 X3858.750 Y126.800 E0.1663 F300
                                        G1 X3867.500 Y126.800 E0.2910 F4200
                                        G1 X3876.250 Y126.800 E0.2910 F4200
                                        G1 X3881.250 Y126.800 E0.1663 F300
                                        G1 X3890.000 Y126.800 E0.2910 F4200
                                        G1 X3898.750 Y126.800 E0.2910 F4200
                                        G1 X3903.750 Y126.800 E0.1663 F300
                                        G1 X3912.500 Y126.800 E0.2910 F4200
                                        G1 X3921.250 Y126.800 E0.2910 F4200
                                        G1 X3926.250 Y126.800 E0.1663 F300
                                        G1 X3935.000 Y126.800 E0.2910 F4200
                                        G1 X3935.000 Y127.200 E0.0133 F4200

                                        I should note that python is giving me Indentation errors.

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                                        • Jareryundefined
                                          Jarery
                                          last edited by Jarery

                                          Im still quite a newbie in this realm and i guess the amount of variables are getting to me 🙂

                                          Backstory is I have a zesty nimble, which worked amazing but had 2 issues I cannot solve

                                          1. Ripples in the surface finish - Company is still working on a fix
                                          2. blobs at the end of a layer creating terrible Z seam scars

                                          Tried all the ideas such as coast and wipe, but they have their own issues such as only available in some slicers, cannot be used with firmware retraction, etc.

                                          Pressure advance by the sounds of it should eliminate the blobs at end of layer, but any attempt to use PA with a nimble due to its required low jerk values caused my prints to slow to about 3x the time. Was painful to watch.
                                          Although, with the nimble I was able to get a great calibration part from the above enclosed script.

                                          0_1555794438938_Nimble PA 1.jpg

                                          With the nimble, the calibration part has easily discernible reversing thick areas, and one can find the "best" setting of 0.12, but pressure advance was unusable for me in combination with the nimble.

                                          So I order a Bondtech BMG and use a capricorn bowden tube of about 650mm paired with an E3D 0.9 degree stepper.

                                          Now i get the Esteps all setup at E808, run some retraction calibration parts, and i still get blobs due to pressure at the end of a layer.
                                          Run the above scripts on a Pressure Advance test and..... The results do not make sense to me.

                                          0_1555794869096_BMG PA 1.jpg

                                          Before the extruded line ever gets to an optimal state, the extrusion is messed up. It gets to the point where nothing is coming out of the nozzle at all. I was at 5-100 print speed so ran again at 20-80 which is the speeds I actually print at (E3D volcano, 0.6mm X nozzle)
                                          And again the part never gets to the optimal PA value without the PA settings making the filament retract so much it doesn't print.

                                          What am i doing wrong? Any suggestions?

                                          Duet Wifi, Smart Effector, newest firmware, Delta printer based smilar to DC42's large kossel

                                          Config is as follows :
                                          M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
                                          M92 X200 Y200 Z200 E808; Set steps per mm original
                                          M566 X1200 Y1200 Z1200 E2000 ; Set maximum instantaneous speed changes (mm/min)
                                          M203 X18000 Y18000 Z18000 E3600 ; Set maximum speeds (mm/min)
                                          M201 X1000 Y1000 Z1000 E3000 ; Set accelerations (mm/s^2)
                                          M906 X1000 Y1000 Z1000 E900 I30 ; Set motor currents (mA) and motor idle factor in per cent

                                          1 Reply Last reply Reply Quote 1
                                          • coreZairundefined
                                            coreZair
                                            last edited by coreZair

                                            @jarery said in Pressure Advance Calibration:

                                            E2000

                                            Hi @Jarery

                                            I don't know if I can still help you, you asked that question way back in April. But I would try to decrease your extruder jerk dramatically. I got mine around 4-5mm/s, and because the values are in mm/min that translates to 240-300. Your extruder jerk is at 2000, meaning that your extruder doesn't try to accelerate in most cases and could loose steps easily, which seems plausible concerning your shown print results.

                                            And at all, and of course @DigitalVision I tried to improve your python script a little. Added some comments, a cooling fan speed parameter, start and end gcodes kind of parameters, and some small tweaks. If you want you can merge it to your script or link this one in your first post. 🙂

                                            For all the windows-python newbies:

                                            1. Install python3 or newer (or python2.7, also called python27, but it's getting unsupported by the end of the year, so install python3)
                                            2. navigate to the downloaded pressureadvance2.py script in your explorer
                                            3. open the file with a good editor (no not editor.exe! I mean a good one) and change the parameters to fit your printer. Be careful not overshooting the dimensions and bed center!
                                            4. hold down shif key and right click on and empty spot in the file list of the windows explorer
                                            5. choose "open terminal here" or "open command line here" or similar
                                            6. type in: python pressureadvance2.py > output.gcode

                                            the shell command simply means "use [python] with script [ pressureadvance2.py ] and redirect output [>] to the file [output.gcode]"

                                            1. Use calipers to measure the position of the best layer. Mine was at around 7mm of 20mm total height for having the parameters set to pressureadvance_min = 0.0 and pressureadvance_max = 0.2. Meaning you get a gradient from 0 to 0.2... Now simply use math to calculate your pressure advance value for your printed calibration wall. It's a good idea to reprint a version with refined parameters around your determined sweet spot. I reprinted one in 0.05 to 0.10 for my roughly measured 0.07 of my first version, finally sticked with 0.068

                                            For my direct extruder with hobb goblin ID 5mm with e3d volcano and 0.8mm nozzle I got round about 0.068
                                            Tests with my 0.4mm Volcano is up next.

                                            Have fun guys!

                                            pressureadvance2.py

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