Hesitations on the X and Y axis when using "Bed Mesh Compensation"



  • I have a Cartesian printer. There is a very slight multiple hesitations on the X and Y axis, extruder appears ok but is hard to see. At speeds less than 20mm/sec its really hard to visually see but can be seen as a little bit of extra extrusion causing a slight bulge in a long straight run where its building the wall of a box. At speeds above, lets say around 40mm/s to 100mm/s the hesitation is easily seen visually and heard, and can be felt by placing your finger on the carriages as they are moving. It only occurs when using "Bed Mesh Compensation". Works fine with "No Bed Compensation" and with "Auto Bed Compensation"

    https://youtu.be/t_yAEmRh_ig

    ; Configuration file for Duet WiFi (firmware version 1.17)
    ; executed by the firmware on start-up
    ;

    ; General preferences
    T0 ; Select first tool
    M111 S0 ; Debugging off
    G21 ; Work in millimeters
    G90 ; Send absolute coordinates…
    M82 ; Absolute Extruder moves (Cura)
    M555 P1 ; Set firmware compatibility to look like RepRapFirmare

    ; Axis - Config
    M208 X0 Y0 Z0 S1 ; Set axis minimum
    M208 X281 Y143 Z140 S0 ; Set axis maximum

    ; End-stops
    M574 X2 Y2 Z0 S0 ; Define active low and unused micro switches
    M558 P1 X0 Y0 Z1 H3 F200 T6000 ; Set Z probe type to un-modulated, the axes for which it is used and the probe + travel speeds

    ; Z - Probe
    G31 P500 X-16.6 Y-13.5 Z1.60 ; Set Z probe trigger value, Increase to move head closer to bed, offset and trigger height previous Z0.55

    ; Bed Compensation
    M557 X36.6:216 Y13:140 S20 ; Define mesh grid

    ; Drives
    M569 P0 S0 ; Drive 0 goes forwards
    M569 P1 S0 ; Drive 1 goes forwards
    M569 P2 S1 ; Drive 2 goes forwards
    M569 P3 S1 ; Drive 3 goes forwards
    ;M569 P4 S1 ; Drive 4 goes forwards
    M350 X16 Y16 Z16 E16 I1 ; Configure micro stepping with interpolation
    M92 X88.9 Y177.8 Z400 E400.0 ; Set steps per mm (Y is .9deg) (E is geared)
    M906 X800 Y1200 Z400 E800 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout

    ; Movement - Speeds
    M566 X600 Y600 Z10 E30 ; Jerk - Set maximum instantaneous speed changes (mm/min)
    M203 X15000 Y15000 Z600 E1200 ; Set maximum speeds (mm/min)
    M201 X1000 Y1000 Z150 E4000 ; Set accelerations (mm/s^2)

    ; Heaters
    M143 H0 S125 ; Set Maximum Bed Temperature
    M143 S260 ; Set maximum heater temperature to 260C
    M307 H0 A222.9 C886.5 D4.5 B0 ; Use PID on bed heater (may require further tuning)
    M307 H1 A655.3 C237.6 D7.5 B0 P1.0 ; Use PID on heater 1 (may require further tuning)
    M305 P0 T110000 B3988 C0 R4700 ; Set thermistor + ADC parameters for bed heater 0
    M305 P1 X200 ; Set PT100 Channel Heater 1
    M141 H2 ; heater 3 is the chamber heater
    M305 P2 R4700 T100000 B3950 ; heater 3 is monitored by a 100K thermistor with B=3950 and a 4.7K series resistor
    M301 H2 P-1 ; use bang-bang control for the chamber heater

    ; 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 PReplicator2x ; Set machine name
    M552 P0.0.0.0 S1 ; Enable network and acquire dynamic address via DHCP

    ; 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 H1 T45 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

    ;M106 P0 S0 H-1 F100 ; Set fan 0 , PWM signal inversion and frequency. Thermostatic control is turned off - FAN
    ;M106 P1 S1 H1 T50 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on - HS
    ;M106 P2 S1 H0 T60 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on - Motor

    ; Custom settings are not configured

    ; Miscellaneous
    M912 P0 S-8.5 ; CPU Temperature Calibration



  • This is interesting, I noticed this behavior too but did not link it to the mesh bed leveling.
    I have noticed this when printing a circle, I always get a "stitch line" when the printer hesitates, need to test your findings…



  • Perhaps your z-axis accelerations are holdign back X/Y movements while the Z-axis compensates?


  • administrators

    It's either the Z acceleration or Z jerk limit holding it back. Your Z jerk limit of 10mm/min does look very low.



  • DC,
    What settings would you suggest for Acc & Jerk?
    Thanks


  • administrators

    Try increasing Z jerk to 100.



  • Thanks DC, Changing Z Jerk to 100 fixed it

    Is there anything else in my config that you see that might be a problem now or in the future, maybe something is borderline and is working now but could cause a problem when printing something other than the simple box I'm doing now?

    Thanks


Locked
 

Looks like your connection to Duet3D was lost, please wait while we try to reconnect.