Duet3D Logo Duet3D
    • Tags
    • Documentation
    • Order
    • Register
    • Login

    Mesh bed Levelling with BLTouch. Am I doing something wrong?

    Scheduled Pinned Locked Moved
    Tuning and tweaking
    14
    28
    5.8k
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • okerchoundefined
      okercho
      last edited by

      Hi,

      Thanks, I'll try to make it more simple so I can debug it, although checking the compensation and calibration in the GUI, it seems that mesh is being used (I'm executing G29 S1 in my gcode):
      e4d838b5-a046-4bde-98a6-67878e83fd27-image.png

      Regarding the homeAll, I'm not using it... Im doing the homing "manually" (First homing X, then Y, and then Z, one by one), after that, I do the G32 and G29, and then if everything was successful, I launch the print... I got used to do it in that way when I was using a non-very-reliable probe some time ago...

      Regards

      Okercho
      Custom Prusa i3 Hephestos with Duet Wi-Fi
      E3d V6 with Bondtech BMG DirectDrive and PrecisionPiezo Sensor
      Rebuilding Hypercube Evolution

      1 Reply Last reply Reply Quote 0
      • Phaedruxundefined
        Phaedrux Moderator
        last edited by

        What do you have in your slicer start gcode?

        Z-Bot CoreXY Build | Thingiverse Profile

        1 Reply Last reply Reply Quote 0
        • Thaliosundefined
          Thalios
          last edited by

          Seems to be the exact same problem I have. My IR Probe scans the bed, reports properly, but when printing, it ignores it.

          Railcore II 300ZL with lots of upgrades (Duet 3 6HC)
          Heavily modified Ender 3 Pro (Duet 3 6HC)
          Heavily modified Tronxy X5SA-500 Pro with Chimera+ and dual bondtech (Duet 3 6HC)
          CR-10S Pro V2 (Duet 3 Mini 5+)
          and a bunch of SLA printers..

          1 Reply Last reply Reply Quote 0
          • OwenDundefined
            OwenD
            last edited by OwenD

            @okercho
            What happens if you add to the start fo bed.g ?

            M290 R0 S0 ; clear baby stepping
            M561 ; clear any bed transform
            
            okerchoundefined 1 Reply Last reply Reply Quote 0
            • piperswundefined
              pipersw
              last edited by

              Same problem for me with bltouch.
              I follow the post

              1 Reply Last reply Reply Quote 0
              • okerchoundefined
                okercho
                last edited by

                Hi all,

                At least I'm not the only one so... we're all doing something weird 😛

                This is my start code, is based on the Prusa one (I'm using PrusaSlicer)

                G90 ; use absolute coordinates
                M83 ; extruder relative mode
                ;G32 ; Bed Level
                {if first_layer_bed_temperature[0] > 0}
                M140 S[first_layer_bed_temperature] ; set bed temp
                M190 S[first_layer_bed_temperature] ; wait for bed temp
                {endif}
                G29 S1; mesh bed leveling
                M104 S[first_layer_temperature] ; set extruder temp
                M109 S[first_layer_temperature] ; wait for extruder temp
                G1 X40 Y100 F5000
                G1 Y0 Z0.6 F3000.0 ; go outside print area
                G92 E0.0
                G1 Z0.2 X30.0 E9.0 F1000.0 ; intro line
                G1 X100.0 E12.5 F1000.0 ; intro line
                G92 E0.0
                M221 S{if layer_height<0.075}100{else}95{endif}
                

                Regards

                Okercho
                Custom Prusa i3 Hephestos with Duet Wi-Fi
                E3d V6 with Bondtech BMG DirectDrive and PrecisionPiezo Sensor
                Rebuilding Hypercube Evolution

                1 Reply Last reply Reply Quote 0
                • okerchoundefined
                  okercho @OwenD
                  last edited by

                  @OwenD said in Mesh bed Levelling with BLTouch. Am I doing something wrong?:

                  M290 R0 S0 ; clear baby stepping M561 ; clear any bed transform

                  I've changed my bed.g for this and report back, although as I'm using G32 right after starting the printer, I don't think this will apply

                  M290 R0 S0 ; clear baby stepping
                  M561 ; clear any bed transform
                  
                  ;G28 X ; home X
                  ;G28 Y ; home Y
                  G28 Z ; home Z
                  G1 X5
                  G30 P0 X25 Y165 Z-99999 ; probe near a leadscrew, half way along Y axis
                  G30 P1 X290 Y160 Z-99999 S2 ; probe near a leadscrew and calibrate 2 motors
                  G28 Z ; home Z
                  G29 ; Mesh Bed Levelling
                  

                  Regards

                  Okercho
                  Custom Prusa i3 Hephestos with Duet Wi-Fi
                  E3d V6 with Bondtech BMG DirectDrive and PrecisionPiezo Sensor
                  Rebuilding Hypercube Evolution

                  1 Reply Last reply Reply Quote 0
                  • gloomyandyundefined
                    gloomyandy
                    last edited by

                    Is there a reason why your probe points for the lead-screws do not share the same Y values? One is 165 the other 160.

                    Also looking at the two meshes that you provided there is something odd going off. The first (lower resolution) mesh shows part of the bed to be "above zero" with the rest below, the second (higher resolution) mesh shows pretty much all of the mesh "below zero". That does not seem correct to me.

                    okerchoundefined 1 Reply Last reply Reply Quote 0
                    • mwolterundefined
                      mwolter
                      last edited by

                      One possible issue is that you are doing g32 and g29 before the printer is up to temp. Recommend moving the g32 after the nozzle and bed heating commands.

                      Most likely your printer and bed dimensions are slightly changing due to probing before everything up to temp. Try to probe as close as possible to printing so things don’t change from where the printer thinks thing are to where they actually are now.

                      okerchoundefined 1 Reply Last reply Reply Quote 0
                      • okerchoundefined
                        okercho @gloomyandy
                        last edited by

                        @gloomyandy said in Mesh bed Levelling with BLTouch. Am I doing something wrong?:

                        Is there a reason why your probe points for the lead-screws do not share the same Y values? One is 165 the other 160.

                        Also looking at the two meshes that you provided there is something odd going off. The first (lower resolution) mesh shows part of the bed to be "above zero" with the rest below, the second (higher resolution) mesh shows pretty much all of the mesh "below zero". That does not seem correct to me.

                        Regarding the different Y, the printer is a CoreXY with 2 lead-screws. When I checked for the Y position for the G32, I discovered that the motors were not perfectly aligned, and that's reflected in the bed file.

                        About the image, the bed is magnetic, is an aluminum heated bed, with a glass on top that has the magnets on it (Buildtak) and the steel sheet on top. I'm assuming that even though I put the sheet always the same way, the measurements changes. I'm doing always a G32 and a G29 after removing and installing the sheet, and if I repeat the G29 (without removing the sheet), results are consistent.

                        Regards

                        Okercho
                        Custom Prusa i3 Hephestos with Duet Wi-Fi
                        E3d V6 with Bondtech BMG DirectDrive and PrecisionPiezo Sensor
                        Rebuilding Hypercube Evolution

                        1 Reply Last reply Reply Quote 0
                        • okerchoundefined
                          okercho @mwolter
                          last edited by

                          @mwolter said in Mesh bed Levelling with BLTouch. Am I doing something wrong?:

                          One possible issue is that you are doing g32 and g29 before the printer is up to temp. Recommend moving the g32 after the nozzle and bed heating commands.

                          Most likely your printer and bed dimensions are slightly changing due to probing before everything up to temp. Try to probe as close as possible to printing so things don’t change from where the printer thinks thing are to where they actually are now.

                          I'm not always using the heated bed. When I do, I put the bed on, wait for it, and then home Z and perform the G29, as I´ve noticed, as you said, that bed expands (and as I've several "layers", it needs more time to reach the temp on top).
                          Regarding the nozzle temp, as I'm using a BLTouch, the nozzle temperature is not "important", I just have it into account for the G31 command.

                          The problem is that, checking the raft, it doesn't seems to be applying the compensation... even though as per the heightmap, the printer is aware of it :S.

                          Regards

                          Okercho
                          Custom Prusa i3 Hephestos with Duet Wi-Fi
                          E3d V6 with Bondtech BMG DirectDrive and PrecisionPiezo Sensor
                          Rebuilding Hypercube Evolution

                          1 Reply Last reply Reply Quote 0
                          • mwolterundefined
                            mwolter
                            last edited by

                            An easy way to check if the mesh is applied is to watch the z steppers for the first layer. They should move slightly if mesh compensation is enabled.

                            okerchoundefined 1 Reply Last reply Reply Quote 0
                            • okerchoundefined
                              okercho @mwolter
                              last edited by

                              @mwolter said in Mesh bed Levelling with BLTouch. Am I doing something wrong?:

                              An easy way to check if the mesh is applied is to watch the z steppers for the first layer. They should move slightly if mesh compensation is enabled.

                              I did... I can see the left side still more squashed and I cannot see the motor moving (I've put a bit of tape and I´ve been observing it, and I think it didn't move at all...)

                              Okercho
                              Custom Prusa i3 Hephestos with Duet Wi-Fi
                              E3d V6 with Bondtech BMG DirectDrive and PrecisionPiezo Sensor
                              Rebuilding Hypercube Evolution

                              1 Reply Last reply Reply Quote 0
                              • PaulHewundefined
                                PaulHew
                                last edited by

                                @okercho When you are printing, if you go to the 'Dashboard' and click the 'Compensation & Calibration' button, what does it say at the top of the dropdown?
                                If mesh compensation is enabled it should look like this.
                                f53e61fe-a6a8-4455-baec-eab383674f60-image.png
                                Compensation in use: mesh

                                P.

                                RailCore II - Duet Mini + 1LC, Voron V0.1 - Duet Mini
                                Voron 2.4 disassembled..... Waiting for the RailCore Mini....

                                okerchoundefined 1 Reply Last reply Reply Quote 1
                                • okerchoundefined
                                  okercho @PaulHew
                                  last edited by

                                  @PaulHew I posted before :), yes, it says "mesh" in use

                                  ![alt text](71bead44-5aad-4e96-8539-bfcaac8d9654-image.png image url)

                                  I'm thinking about doing the difference between left/right quite obvious on purpose, to see if it actually works or not, as I think mesh is applied even if you're not printing but moving the head around...

                                  Regards

                                  Okercho
                                  Custom Prusa i3 Hephestos with Duet Wi-Fi
                                  E3d V6 with Bondtech BMG DirectDrive and PrecisionPiezo Sensor
                                  Rebuilding Hypercube Evolution

                                  dc42undefined 1 Reply Last reply Reply Quote 0
                                  • Phaedruxundefined
                                    Phaedrux Moderator
                                    last edited by

                                    I find the best way to test the success of mesh compensation is to print a test file like this twice, once with it enabled and once without.

                                    bedlevel_nozzle_0.4_200x200-0.3-0.8.stl

                                    Also ensure that your taper height isn't set too low with M376

                                    https://duet3d.dozuki.com/Wiki/Gcode#Section_M376_Set_bed_compensation_taper

                                    Z-Bot CoreXY Build | Thingiverse Profile

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

                                      @okercho said in Mesh bed Levelling with BLTouch. Am I doing something wrong?:

                                      I'm thinking about doing the difference between left/right quite obvious on purpose, to see if it actually works or not, as I think mesh is applied even if you're not printing but moving the head around...

                                      You height map is actually very flat, so it will be difficult to see the Z axis moving due to bed compensation being active.

                                      It's not uncommon for the height map not to match what you see when printing, which may be the case here. This happens when you use a Z probe with a large offset from the nozzle, and the print head doesn't stay in exactly the same plane as it moves over the bed. For example, some printers have an X carriage that moves on 2 smooth rods. If there is a slight twist between those rods, then the print head will rotate slightly about the X axis as it moves in X. If the Z probe is offset from the nozzle in the Y direction, that will cause the relative heights of the nozzle and the Z probe to change.

                                      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

                                      okerchoundefined 1 Reply Last reply Reply Quote 2
                                      • Torroundefined
                                        Torro
                                        last edited by

                                        I tried bed leveling with different probes, ir probe and bltouch.

                                        My Problem was different trigger heights at different locations on the bed with both probes.

                                        Check that. Trigger height should be the same, no matter where you probe on the bed.

                                        I think the printhead is somehow twisting.

                                        Good luck!

                                        1 Reply Last reply Reply Quote 0
                                        • okerchoundefined
                                          okercho @dc42
                                          last edited by

                                          @dc42 said in Mesh bed Levelling with BLTouch. Am I doing something wrong?:

                                          @okercho said in Mesh bed Levelling with BLTouch. Am I doing something wrong?:

                                          I'm thinking about doing the difference between left/right quite obvious on purpose, to see if it actually works or not, as I think mesh is applied even if you're not printing but moving the head around...

                                          You height map is actually very flat, so it will be difficult to see the Z axis moving due to bed compensation being active.

                                          It's not uncommon for the height map not to match what you see when printing, which may be the case here. This happens when you use a Z probe with a large offset from the nozzle, and the print head doesn't stay in exactly the same plane as it moves over the bed. For example, some printers have an X carriage that moves on 2 smooth rods. If there is a slight twist between those rods, then the print head will rotate slightly about the X axis as it moves in X. If the Z probe is offset from the nozzle in the Y direction, that will cause the relative heights of the nozzle and the Z probe to change.

                                          Actually that makes a lot of sense... I'm using 8mm rods for a 300mm bed, and I was thinking that maybe is just not sturdy enough...

                                          e4b84f8b-5b38-4443-a677-a8cea9c421ef-image.png

                                          I'm gonna see how can I replace the 8mm rods by 10mm... wish me luck!

                                          I'll report back.

                                          Cheers

                                          Okercho
                                          Custom Prusa i3 Hephestos with Duet Wi-Fi
                                          E3d V6 with Bondtech BMG DirectDrive and PrecisionPiezo Sensor
                                          Rebuilding Hypercube Evolution

                                          1 Reply Last reply Reply Quote 0
                                          • RyanPundefined
                                            RyanP @Phaedrux
                                            last edited by

                                            I'm dealing with this same type of issue. I've been having problem with my z-offset floating around and having to constantly change it. So I with some advice from @Phaedrux im modifying my probe parameters and getting my BL Touch and nozzle tip closer for a smaller z-offset.

                                            @Phaedrux said in Mesh bed Levelling with BLTouch. Am I doing something wrong?:

                                            I find the best way to test the success of mesh compensation is to print a test file like this twice, once with it enabled and once without.

                                            bedlevel_nozzle_0.4_200x200-0.3-0.8.stl

                                            Also ensure that your taper height isn't set too low with M376

                                            https://duet3d.dozuki.com/Wiki/Gcode#Section_M376_Set_bed_compensation_taper

                                            Man. There is so much to learn when you take off your training wheels and start really learning about gcode, reprap firmware, and all the things you can do. Never even heard of taper height. Adding it to the list of things to learn.

                                            CR10S, August 2018
                                            Anycubic Photon S December 2019
                                            Ender 5 Feb 2020
                                            Ender 5 Plus May 2020
                                            Anycubic Photon Mono X Nov 2020
                                            ~
                                            https://3dimensiongames.com/

                                            1 Reply Last reply Reply Quote 0
                                            • First post
                                              Last post
                                            Unless otherwise noted, all forum content is licensed under CC-BY-SA