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    Z- Probe consistency issue

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    • buzzby
      buzzby last edited by

      I am trying to configure my Micromake D1. Been running through the guide and checking my Z probe consistency. I am using the piezo probe. I am having an issue where the trigger height is increasing with ever probe.

      I have manually found Z=0 then run the following g code from a macro
      g1 Z5
      G30 s-1

      These are the results I got and I can replicate a similar pattern each time. I just cannot think what might be causing this. I think maybe that the g1 Z5 isn't being accurate somehow as there is definitely not 0.2+mm of play in the piezo probe.

      4:26:25 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.214 mm
      4:26:21 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.204 mm
      4:26:17 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.194 mm
      4:26:12 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.184 mm
      4:26:07 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.174 mm
      4:26:03 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.174 mm
      4:26:00 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.174 mm
      4:25:56 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.164 mm
      4:25:52 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.164 mm
      4:25:47 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.154 mm
      4:25:42 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.154 mm
      4:25:35 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.144 mm
      4:25:31 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.144 mm
      4:25:28 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.134 mm
      4:25:24 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.134 mm
      4:25:20 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.134 mm
      4:25:16 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.144 mm
      4:25:12 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.144 mm
      4:25:08 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.134 mm
      4:25:04 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.134 mm
      4:24:59 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.134 mm
      4:24:56 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.124 mm
      4:24:52 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.114 mm
      4:24:48 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.114 mm
      4:24:44 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.094 mm
      4:24:39 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.114 mm
      4:24:36 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.124 mm
      4:24:32 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.094 mm
      4:24:28 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.094 mm
      4:24:23 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.074 mm
      4:24:18 PMM98 P0:/macros/ProbeTest
      Stopped at height 0.064 mm
      4:23:35 PMG30 S-1
      Stopped at height 0.044 mm
      4:23:30 PMG1 Z5
      4:23:26 PMG30 S-1
      Stopped at height 0.024 mm

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      • dc42
        dc42 administrators last edited by

        It could be that your probing speed (F parameter in M558) is too high, so that when the probing move stops the nozzle overshoots and ends up lower than it should be. Then when you do the next G1 Z5 it ends up at slightly less than 5mm. Similarly, if your Z acceleration is set too high, it may be missing steps at the start of the G1 Z5 move.

        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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        • buzzby
          buzzby last edited by

          the probing speed is quite slow but when running G1 Z5 it does move very fast. How and where to i change the acceleration speeds?

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          • buzzby
            buzzby last edited by

            found the settings for acceleration and have halved all of the Z speeds as a test.

            Any thoughts?

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            • buzzby
              buzzby last edited by

              I was wrong. I don't get consistent results. the number always increases. Just did around 1000 probes and the trigger height went from 0.024 to 0.511.

              I cannot see anything mechanical that would account for this

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              • dc42
                dc42 administrators last edited by

                What speeds and accelerations are you using, what is your Z steps/mm, and what are the F and T parameters in your M558 command?

                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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                • buzzby
                  buzzby last edited by

                  Here is my config file

                  ; General preferences
                  M111 S0 ; Debugging off
                  G21 ; Work in millimetres
                  G90 ; Send absolute coordinates…
                  M83 ; ...but relative extruder moves
                  M555 P2 ; Set firmware compatibility to look like Marlin
                  ; Automatic saving after power loss is not enabled

                  M665 L244.000 R104 H235 B80.0 X0 Y0 Z0
                  M666 X0 Y0 Z0 A0 B0
                  M208 Z0 S1 ; Set minimum Z

                  ; Endstops
                  M574 X2 Y2 Z2 S0 ; Set active low endstops
                  ;M558 P5 H20 ; Set Z probe type to mode 5
                  M558 P5 R0.4 F300 X0 Y0 Z0 H20
                  G31 X0 Y0 Z-0.1 P200
                  ;https://www.duet3d.com/forum/thread.php?id=2769

                  M557 R80 S20 ; Define mesh grid

                  ; Drives
                  M569 P0 S1 ; Drive 0 goes forward
                  M569 P1 S1 ; Drive 1 goes forward
                  M569 P2 S1 ; Drive 2 goes forward
                  M569 P3 S1 ; Drive 3 goes forward
                  M350 X16 Y16 Z16 E16 I1 ; Configure microstepping without interpolation
                  M92 X100 Y100 Z100 E98 ; Set steps per mm
                  M566 X300 Y300 Z300 E1200 ; Set maximum instantaneous speed changes (mm/min) was 1200
                  M203 X18000 Y18000 Z9000 E1200 ; Set maximum speeds (mm/min) was 18000
                  M201 X250 Y250 Z250 E1000 ; Set accelerations (mm/s^2) was 1000
                  M906 X1200 Y1200 Z1200 E1100 I10 ; Set motor currents (mA) and motor idle factor in per cent
                  M84 S30 ; Set idle timeout

                  ; Heaters
                  M301 H0 S1.00 P10 I0.1 D200 T0.4 W180 B30 ; Use PID on bed heater (may require further tuning)
                  M305 P0 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 0
                  M143 H0 S120 ; Set temperature limit for heater 0 to 120C
                  M305 P1 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 1
                  M143 H1 S280 ; Set temperature limit for heater 1 to 280C

                  ; Tools
                  M563 P0 D0 H1 ; Define tool 0
                  G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
                  G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

                  ; Network
                  M550 PMicroMake D1 ; Set machine name
                  M552 S1 ; Enable network

                  M586 P0 S1 ; Enable HTTP
                  M586 P1 S0 ; Disable FTP
                  M586 P2 S0 ; Disable Telnet

                  ; Fans
                  M106 P0 S0 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
                  M106 P1 S1 I0 F500 H1 T45 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
                  M106 P2 S1 I0 F500 H T45 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

                  ; Custom settings are not configured
                  M501

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                  • Dougal1957
                    Dougal1957 last edited by

                    shouldn't the max speeds for the X Y & Z in the M203 line be the same?

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                    • DjDemonD
                      DjDemonD last edited by

                      Apparently not, as RRF takes this to mean Z moves, rather than strictly Z axis (or back tower).

                      As such you can set Z acceleration low if you need to for your probe. It will only affect Z moves not XY moves. My understanding is that it does not potentially unbalance the delta kinematics. Marlin I believe does require X Y and Z to be the same, (or did).

                      Simon. Precision Piezo Z-Probe Technology
                      www.precisionpiezo.co.uk
                      PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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                      • DjDemonD
                        DjDemonD last edited by

                        buzzby try changing M558 H to 5 instead of 20… ALso set G31 P to 100, or consider changing to M558 P8 instead of P5 which eliminates any filtering on the z probe signal, and sharpens it up.

                        Not sure if it will help but 20 is only needed when your Z height is fairly unknown, or if you frequently change build plates of considerable difference in thickness.

                        Simon. Precision Piezo Z-Probe Technology
                        www.precisionpiezo.co.uk
                        PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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                        • buzzby
                          buzzby last edited by

                          Thanks for the input guys.

                          Here are my current settings

                          ; General preferences
                          M111 S0 ; Debugging off
                          G21 ; Work in millimetres
                          G90 ; Send absolute coordinates…
                          M83 ; ...but relative extruder moves
                          M555 P2 ; Set firmware compatibility to look like Marlin
                          ; Automatic saving after power loss is not enabled

                          M665 L244.000 R104 H235 B80.0 X0 Y0 Z0
                          M666 X0 Y0 Z0 A0 B0
                          M208 Z0 S1 ; Set minimum Z

                          ; Endstops
                          M574 X2 Y2 Z2 S0 ; Set active low endstops
                          ;M558 P5 H20 ; Set Z probe type to mode 5
                          M558 P8 R0.4 F300 X0 Y0 Z0 H5
                          G31 X0 Y0 Z-0.1 P100
                          ;https://www.duet3d.com/forum/thread.php?id=2769

                          M557 R80 S20 ; Define mesh grid

                          ; Drives
                          M569 P0 S1 ; Drive 0 goes forward
                          M569 P1 S1 ; Drive 1 goes forward
                          M569 P2 S1 ; Drive 2 goes forward
                          M569 P3 S1 ; Drive 3 goes forward
                          M350 X16 Y16 Z16 E16 I1 ; Configure microstepping without interpolation
                          M92 X100 Y100 Z100 E98 ; Set steps per mm
                          M566 X150 Y150 Z150 E1200 ; Set maximum instantaneous speed changes (mm/min) was 1200
                          M203 X9000 Y9000 Z9000 E1200 ; Set maximum speeds (mm/min) was 18000
                          M201 X125 Y125 Z125 E1000 ; Set accelerations (mm/s^2) was 1000
                          M906 X1200 Y1200 Z1200 E1100 I10 ; Set motor currents (mA) and motor idle factor in per cent
                          M84 S30 ; Set idle timeout

                          Still seeing the probe activation height increase over time.

                          What is strange/consistent is that the value always increases by 0.0. Although not after every probe. X number of prob points will be the same height and then it will trigger 0.01 higher.

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                          • DjDemonD
                            DjDemonD last edited by

                            Something is odd there, can you post photos of machine and hotend + z-probe closeups?

                            Can you also try a much lower Z jerk (M566 Z10)?
                            Z never has to move fast.

                            While you're there (maybe later) change your X Y accelerations to 1000 (leave Z at 125) otherwise your printer will take forever to print anything. XY at 3000 isn't unreasonable, I've used 9000 before too.

                            Simon. Precision Piezo Z-Probe Technology
                            www.precisionpiezo.co.uk
                            PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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

                              I just ran a similar test on my delta:

                              18:22:39
                              Stopped at height -0.136 mm
                              Finished printing file TestProbeRepeatability.g, print time was 0h 1m
                              18:22:39
                              Stopped at height -0.131 mm
                              18:22:38
                              Stopped at height -0.136 mm
                              18:22:37
                              Stopped at height -0.136 mm
                              18:22:36
                              Stopped at height -0.131 mm
                              18:22:35
                              Stopped at height -0.131 mm
                              18:22:34
                              Stopped at height -0.136 mm
                              18:22:33
                              Stopped at height -0.131 mm
                              18:22:33
                              Stopped at height -0.136 mm
                              18:22:32
                              Stopped at height -0.131 mm
                              18:22:31
                              Stopped at height -0.136 mm
                              18:22:30
                              Stopped at height -0.136 mm
                              18:22:29
                              Stopped at height -0.136 mm
                              18:22:28
                              Stopped at height -0.136 mm
                              18:22:28
                              Stopped at height -0.136 mm
                              18:22:27
                              Stopped at height -0.136 mm
                              18:22:26
                              Stopped at height -0.136 mm
                              18:22:25
                              Stopped at height -0.136 mm
                              18:22:24
                              Stopped at height -0.136 mm
                              18:22:23
                              Stopped at height -0.136 mm
                              18:22:22
                              Stopped at height -0.136 mm
                              18:22:22
                              Stopped at height -0.136 mm
                              18:22:21
                              Stopped at height -0.136 mm
                              18:22:20
                              Stopped at height -0.136 mm
                              18:22:19
                              Stopped at height -0.136 mm
                              18:22:18
                              Stopped at height -0.136 mm
                              18:22:17
                              Stopped at height -0.136 mm
                              18:22:17
                              Stopped at height -0.136 mm
                              18:22:16
                              Stopped at height -0.136 mm
                              18:22:15
                              Stopped at height -0.136 mm
                              18:22:14
                              Stopped at height -0.136 mm
                              18:22:13
                              Stopped at height -0.136 mm
                              18:22:12
                              Stopped at height -0.131 mm
                              18:22:07
                              M32 TestProbeRepeatability.g
                              File TestProbeRepeatability.g selected for printing

                              So I don't see the same problem. I have these parameters:

                              M201 X3000 Y3000 Z3000 E1000:120 ; Accelerations (mm/s^2)
                              M203 X18000 Y18000 Z18000 E3600:3600 ; Maximum speeds (mm/min)
                              M566 X600 Y600 Z600 E600:40 ; Maximum instant speed changes
                              M558 P8 X0 Y0 Z0 H3 F1000 T10000 R0.4 S0.02 A4

                              Could it be as simple as a loose pulley?

                              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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                              • buzzby
                                buzzby last edited by

                                Here you go







                                1 Reply Last reply Reply Quote 0
                                • buzzby
                                  buzzby last edited by

                                  It might not be obvious from the pictures but YES the nozzle is the lowest point.

                                  1 Reply Last reply Reply Quote 0
                                  • DjDemonD
                                    DjDemonD last edited by

                                    If the suggested movement settings did not improve this problem then I would definitely make sure the drive pulley grubscrews are tight. Do your motors have flats on the shafts? If not take them off and grind flats into them.

                                    Next stop is the belts. They sometime wear in just one place. So quick check for that is to raise the bed up (or just put something on top of the bed which is 70+mm thick like a biscuit tin. Change your z height in M665 (in config.g and config_override.g to avoid a head crash), and repeat the test. If it performs better replace all of the belts.

                                    How well does it calibrate? Especially if you repeat the calibration over and over, the dev. value should get smaller with each iteration then stabilise after 1-3 tries. If it doesn't follow this pattern I'd still say mechanical issue.

                                    Simon. Precision Piezo Z-Probe Technology
                                    www.precisionpiezo.co.uk
                                    PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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                                    • DjDemonD
                                      DjDemonD last edited by

                                      If the suggested movement settings did not improve this problem then I would definitely make sure the drive pulley grubscrews are tight. Do your motors have flats on the shafts? If not take them off and grind flats into them.

                                      Next stop is the belts. They sometimes wear in just one place. So quick check for that is to raise the bed up (or just put something on top of the bed which is 70+mm thick like a biscuit tin. Change your z height in M665 (in config.g and config_override.g to avoid a head crash), and repeat the test. If it performs better replace all of the belts.

                                      How well does it calibrate? Especially if you repeat the calibration over and over, the dev. value should get smaller with each iteration then stabilise after 1-3 tries. If it doesn't follow this pattern I'd still say mechanical issue.

                                      I'm assuming the probe was a kit and you have assembled it? I can't think of an assembly error that would cause this drift, but you can send the assembled probe to me I'll check it on my test rig to rule it out,adjust it if needed and send it back.

                                      Simon. Precision Piezo Z-Probe Technology
                                      www.precisionpiezo.co.uk
                                      PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

                                      1 Reply Last reply Reply Quote 0
                                      • buzzby
                                        buzzby last edited by

                                        So it appears that I am an idiot. 2 of my pulley set screws were lose but the belt was so tight I could see it till I released the tension. They have flats on the shaft so have retightened all 6 sets screws.

                                        Ran the prob test again for 100 cycles and get a difference of 0.01.

                                        Ran the auto calibrate and have that down to 0.04

                                        ran bed mesh and get the following
                                        Number of probe points: 45

                                        Probe area: 201.1 cm²

                                        Maximum deviations: -0.071 / 0.106 mm

                                        Mean error: 0.004 mm

                                        RMS error: 0.038 mm

                                        About to repeat everything with the bed at temp and then try a print.

                                        Thank you everyone for you help. I will need some more soon.

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                                        • DjDemonD
                                          DjDemonD last edited by

                                          Glad its working, as I learned at university, common things occur commonly.

                                          Simon. Precision Piezo Z-Probe Technology
                                          www.precisionpiezo.co.uk
                                          PT1000 cartridge sensors NOW IN, just attach to your Duet board directly!

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