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    Issues with pressure advance since RRF 3.4

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    • Argoundefined
      Argo @jay_s_uk
      last edited by Argo

      @jay_s_uk

      Did you already have the time to print a comparison between RRF and Klipper on your setup?

      jay_s_ukundefined 1 Reply Last reply Reply Quote 0
      • Adrian52undefined
        Adrian52 @jens55
        last edited by

        @jens55 I was stimulated by your post to try again a gcode script I use to calibrate PA, adapted from a previous post. For me, this seems to work as expected:

        alt text

        It does 4 lines at 20mm/sec, then 4 lines speeding up from 20mm/sec to 100mm/sec and back for each PA setting - I have pictured to speeding up section, where you can clearly see the effect of PA, and confirming the .04 I usually use.

        My system is pretty basic - duet2wifi with no SBC running 3.4.4, with mzv IS, single nozzle, direct drive orbiter 2.

        Adrian52undefined 1 Reply Last reply Reply Quote 0
        • Adrian52undefined
          Adrian52 @Adrian52
          last edited by

          @Adrian52 should add that the script is adapted from that posted by DonStauffer (https://forum.duet3d.com/user/donstauffer) here

          https://forum.duet3d.com/post/250961

          I found it quicker without a raft, so made an anchor piece to start the test strips . Apologies to DonStauffer for mangling your script.

          ;	set variables
          
          var StartX = -70
          var StartY = -25
          var LinesPerTest = 4
          var LinesBetweenTests = 4
          var AnchorLines = 10
          var TempBed = 60
          var TempTool = 195
          var ToolNum = 0
          var Ext1 = 0
          var Ext2 = 1
          var Width = 0.55
          var Height = 0.2
          var ExFactor = 1.0
          var Retract = 1.0
          var Prime = 0	;	Before Raft
          
          var PALow = 0.0
          var PAHigh = 0.07
          var PAIncrement = 0.01
          
          var SpeedRaft = 400
          var SpeedSlow = 1200
          var SpeedFast = 6000
          var SpeedTravelXY = 9000
          var SpeedTravelZ = 1200
          var SpeedRetract = 7200
          
          ;	Calculated and Utility Variables
          
          var TestCount = 1 + floor((var.PAHigh - var.PALow) / var.PAIncrement + 0.5)
          
          var FilFactor = var.ExFactor * var.Width * var.Height / (pi * 1.75 * 1.75 / 4)
          
          var PA = var.PALow - var.PAIncrement
          
          var Dist = 0
          
          ;	PREPARE
          
          T{var.ToolNum}
          
          M82	;	Extruder Absolute Mode
          
          ;	Heat Bed and set Hot Ends to Standby
          
          M400
          
          M117 "Heat"
          
          M140 S{var.TempBed}				;	set Bed Temp
          
          M568 P{var.ToolNum} S{var.TempTool} A2	;	set Tool Temp
          
          M116 H{var.ToolNum + 1} S1			;	Wait for temp
          
          G4 S12					;	Delay to Allow for Overshoot
          
          M116 H{var.ToolNum + 1} S1		;	Wait for Recovery
          
          M116 H0 S1					;	Wait for Bed
          
          M400
          
          M117 "Home"
          
          
          G1 Z30 F3000
          G30
          
          M400
          
          ;M117 "Anchor"
          
          ;	Go to StartX - Width *5, StartY
          
          G90	;	Absolute
          
          G92 E0
          
          G0 E{-var.Retract} F{var.SpeedRetract}
          
          G1 X{var.StartX - var.Width * (var.AnchorLines-4) } Y{var.StartY} F{var.SpeedTravelXY}
          
          G1 Z{var.Height} F{var.SpeedTravelZ}
          
          G91	;	Relative
          
          
          set var.Dist = (2 * var.TestCount * var.LinesPerTest + var.LinesBetweenTests * (var.TestCount - 1)) * var.Width
          
          M221 S110 ;set extrusion factor to 110% for anchor
          
          while iterations < var.AnchorLines
          
          	;	Draw anchor Line
          
          	G0 Y{var.Dist} E{abs(var.Dist) * var.FilFactor} F{var.SpeedRaft}
          
          	G92 E0
          
          	;	Break here if last time
          
          	if iterations + 1 >= var.AnchorLines
          
          		break
          
          
          
          	;	Move Over
          
          
          
          	G0 X{var.Width} E{var.Width * var.FilFactor} F{var.SpeedRaft}
          
          	G92 E0
          
          
          
          	set var.Dist = -var.Dist
          
          
          
          G0 E{-var.Retract} F{var.SpeedRetract}	;	Retract
          
          
          
          ;	BEGIN TEST PATTERN
          
          
          M400
          
          M117 "Test Pattern"
          
          
          
          ;	Go to StartX, StartY
          
          G90	;	Absolute
          
          G1 Z{var.Height} F{var.SpeedTravelZ}
          
          G1 X{var.StartX} Y{var.StartY} F{var.SpeedTravelXY}
          
          G91	;	Relative
          
          while iterations < var.TestCount
          
          	;	set PA
          
          	set var.PA = var.PA + var.PAIncrement
          
          	M572 D{var.Ext1} S{var.PA}
          	M572 D{var.Ext2} S{var.PA}
          
          	echo "PA=",{var.PA}
          
          	;	Draw Reference Lines
          
          	while iterations < var.LinesPerTest
          
          		G0 E0 F{var.SpeedRetract}		;	Unretract
          
          		G0 X140 F{var.SpeedSlow} E{140 * var.FilFactor}
          
          		G92 E0
          
          		G0 E{-var.Retract} F{var.SpeedRetract}	;	Retract
          
          		G1 Y{var.Width} F{var.SpeedTravelXY}
          
          		G1 X-140 F{var.SpeedTravelXY}
          
          
          
          	;	Draw Test Lines
          
          	while iterations < var.LinesPerTest
          
          		G0 E0 F{var.SpeedRetract}		;	Unretract
          
          		G0 X35 F{var.SpeedSlow} E{35 * var.FilFactor}
          
          		G0 X70 F{var.SpeedFast} E{105 * var.FilFactor}
          
          		G0 X35 F{var.SpeedSlow} E{140 * var.FilFactor}
          
          		G92 E0
          
          		G0 E{-var.Retract} F{var.SpeedRetract}	;	Retract
          
          
          		G1 Y{var.Width} F{var.SpeedTravelXY}
          
          		G1 X-140 F{var.SpeedTravelXY}
          
          
          
          	;	Move to start of next comparison
          
          
          
          	G1 Y{var.LinesBetweenTests * var.Width} F{var.SpeedTravelXY}
          
          
          
          ;	Finish up
          
          
          
          M400
          
          M117 "Done"
          
          G10 P0 S0 ; turn off temperature
          M140 S0  ;turn off bed heater
          G28  ; home
          
          
          
          jens55undefined 1 Reply Last reply Reply Quote 0
          • jay_s_ukundefined
            jay_s_uk @Argo
            last edited by

            @Argo I have but I'm awaiting some feedback for I post anything

            Owns various duet boards and is the main wiki maintainer for the Teamgloomy LPC/STM32 port of RRF. Assume I'm running whatever the latest beta/stable build is

            1 Reply Last reply Reply Quote 1
            • jens55undefined
              jens55 @Adrian52
              last edited by

              @Adrian52, thanks for posting the script and the results. I will see if I can get that working here!

              1 Reply Last reply Reply Quote 0
              • jens55undefined
                jens55
                last edited by

                I went back to the original script posted by DonStauffer with the raft and I did see the ever so subtle change in the printout. Interpretation of the test print is difficult but it works better than what my previous script was able to do.
                I kept the raft so I could remove the finished print in one piece and examine it clearly. I did have adhesion problems because it's a single line and I am working on adjusting my bed temperature to fix that.
                Final verdict: I didn't know what I was doing and pressure advance does in fact work on the CR10 printer. I have not yet tried this on the Jubilee where the extruder is driven off a tool board. Note that this only speaks to PA changing and not necessarily to how effective the PA is in an actual print.
                Tests are ongoing ......

                1 Reply Last reply Reply Quote 1
                • gnydickundefined
                  gnydick
                  last edited by

                  This post is deleted!
                  1 Reply Last reply Reply Quote 0
                  • Heartleander81undefined
                    Heartleander81
                    last edited by

                    Update on my conversion to Klipper.
                    At first the corners didn't look any better than with RRF until I came across a post today that refers to extruder smooth time.
                    The standard is with Klipper 0.04, which I also use.
                    Switched to 0.01 and the corners look awesome.
                    In the article it was said that some extruders can not cope with the smooth time and then you have to get smaller. see my pictures.

                    20221121_171555.jpg

                    With smooth time 0.04

                    20221128_153229.jpg 20221128_153233.jpg 20221128_153236.jpg

                    With smooth time 0.01

                    R4ffersundefined Argoundefined 2 Replies Last reply Reply Quote 2
                    • R4ffersundefined
                      R4ffers @Heartleander81
                      last edited by

                      @Heartleander81 wow mate what a difference

                      Mb6hc + 3hc + 1lc on Voron V2.4, Mini 5+ exp 2+ on Vzbot 235 AWD, Duet 2 wifi on Ox CNC and Mini 5+ on Millennium Milo v1.5 mini mill.

                      Heartleander81undefined 1 Reply Last reply Reply Quote 0
                      • Heartleander81undefined
                        Heartleander81 @R4ffers
                        last edited by

                        @R4ffers oh yes.

                        @dc42 is there also something like pressure advance smooth time under RRF? A few clippers have the problem with the high smooth time, but those who have problems are mostly DirectDrive extruder users. Maybe that's an approach you can follow.

                        Phaedruxundefined dc42undefined 2 Replies Last reply Reply Quote 0
                        • Phaedruxundefined
                          Phaedrux Moderator @Heartleander81
                          last edited by

                          @Heartleander81 Can you link that article you mention?

                          Z-Bot CoreXY Build | Thingiverse Profile

                          sebkritikelundefined 1 Reply Last reply Reply Quote 0
                          • sebkritikelundefined
                            sebkritikel @Phaedrux
                            last edited by

                            @Phaedrux I see some discussions on it at the bottom of Klipper's Kinematics page
                            https://www.klipper3d.org/Kinematics.html

                            Some other pages of interest
                            https://klipper.discourse.group/t/pressure-advance-smooth-time-on-direct-extruders-with-short-filament-path/1971
                            https://github.com/Klipper3d/klipper/issues/4442

                            richfelker created this issue in Klipper3d/klipper

                            closed Pressure advance smoothing induces e-axis position swings that scale with acceleration #4442

                            Large(ish?) IDEX - 6HC, 1HCL
                            Stratasys Dimension 1200es to 6HC Conversion

                            1 Reply Last reply Reply Quote 0
                            • dc42undefined
                              dc42 administrators @Heartleander81
                              last edited by dc42

                              @Heartleander81 said in Issues with pressure advance since RRF 3.4:

                              @R4ffers oh yes.

                              @dc42 is there also something like pressure advance smooth time under RRF? A few clippers have the problem with the high smooth time, but those who have problems are mostly DirectDrive extruder users. Maybe that's an approach you can follow.

                              No, there isn't anything similar. I will look into that Klipper feature.

                              The reason I have made no progress on this is that while a number of users seem to think that pressure advance doesn't work as well in RRF 3.4 as it did in 3.3, and I am prepared to believe that there may be a difference because the relevant code had to be rewritten to accommodate input shaping, nobody has been able to provide a simple GCode script and machine settings that demonstrate a difference when input shaping is disabled. That includes me - I have compared RRF 3.3 and RRF 3.4 prints.

                              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

                              Heartleander81undefined petriheinoundefined CR3Dundefined gnydickundefined camnewnhamundefined 5 Replies Last reply Reply Quote 0
                              • Heartleander81undefined
                                Heartleander81 @dc42
                                last edited by Heartleander81

                                @dc42
                                @Phaedrux

                                I couldn't find any differences between 3.3 and 3.4.x, but I still have a picture of a test where the corners became nice with PA. As now with klipper. The Artikel from sebkritel is that who I read.

                                1 Reply Last reply Reply Quote 0
                                • Argoundefined
                                  Argo @Heartleander81
                                  last edited by Argo

                                  @Heartleander81

                                  So altering the smooth time value did improve your corners and PA alone did not?

                                  Heartleander81undefined 1 Reply Last reply Reply Quote 0
                                  • petriheinoundefined
                                    petriheino @dc42
                                    last edited by

                                    Hi folks, my guess is OP simply did finer calibrations after update and found out underlying RRF issues regarding PA, Retraction, Extruder steps and acceleration relation... I got similar results (improvements) with Klipper conversion. I did some testing and posted it here earlier.

                                    1 Reply Last reply Reply Quote 0
                                    • Heartleander81undefined
                                      Heartleander81 @Argo
                                      last edited by

                                      @Argo said in Issues with pressure advance since RRF 3.4:

                                      So altering the smooth time value did improve your corners and PA alone did not?

                                      PA alone didn't make the whole corner look nice. See the picture with the corner sticking out in the direction of travel. Only with the change of smooth time and renewed PA, which was then higher, did the corners become so clean.

                                      Argoundefined 1 Reply Last reply Reply Quote 1
                                      • Argoundefined
                                        Argo @Heartleander81
                                        last edited by

                                        @Heartleander81

                                        I see.

                                        I know from another Klipper user that he also only could get nice corners by playing around with the smooth time setting. Pressure advance alone did not help much.

                                        Maybe extruders / hotends are so particular nowadays that we need this setting to get nice corners?

                                        Here is the example from the user I'm talking about:

                                        unknown.png

                                        He has a bowden setup and needed to increase the smooth time in order to get nice corners. PA alone did not the trick.

                                        @dc42
                                        How high are the chances we might get this feature for RRF? I think this might very much help those who are having problems with PA at the moment.

                                        Heartleander81undefined 1 Reply Last reply Reply Quote 1
                                        • Heartleander81undefined
                                          Heartleander81 @Argo
                                          last edited by

                                          @Argo ok. Nice test from him. I find for my Hevort 0.02 smooth time and 0.044 PA. Worked nice. I hope my Info can help Duet.

                                          1 Reply Last reply Reply Quote 0
                                          • CR3Dundefined
                                            CR3D @dc42
                                            last edited by

                                            @dc42 Hi David,

                                            I have to join this conversation because through my contact to @Heartleander81 i noticed this effect with "round corners" at some of our machines to.

                                            I think this comes with newer firmware and if you made some changes into PA there would be an issue. But how can we test it that it would be helpfull for you?

                                            one of our customers has now contacted us explicitly about this effect and is looking for a solution. I can't compensate for it by increasing the PA value. We've tested a lot here.

                                            Thank you 🙂 Regards Christian from @CR3D

                                            Christian from CR-3D
                                            Homepage:
                                            www.cr-3d.de

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                                            dc42undefined 1 Reply Last reply Reply Quote 1
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