4z axis 4 independent motors. Bed Levering



  • Hello, I read your forum and I did not find anywhere solved problem of 4 engines on the Z axis.

    Someone can write the instructions

    what to enter in config.g
    and in bed.g

    and where it is needed.

    Instructions on how it should work.



  • My config

    onfig.g

    M584 X2 Y1:9 Z5:6:7:8 E3;

    M671 X500:10:500:10 Y500:500:10:10 S0,5;

    bed.g

    ; bed.g

    ; called to perform automatic bed compensation via G32

    ;

    ; generated by RepRapFirmware Configuration Tool v2 on Mon Mar 04 2019 09:57:20 GMT+0100 (czas środkowoeuropejski standardowy)

    G28; Dom

    M401; wdrożyć sondę Z (pomiń, jeśli używasz bltouch)

    G30 P0 X500 Y0 Z-99999; sonda w pobliżu śruby pociągowej

    G30 P1 X500 Y500 Z-99999; sonda w pobliżu śruby pociągowej

    G30 P2 X0 Y500 Z-99999 ; sondować w pobliżu śruby pociągowej

    G30 P3 X10 Y10 Z-99999 S4; sondować w pobliżu śruby pociągowej i skalibrować 4 silniki

    M402; wycofaj sondę (pomiń, jeśli używasz bltouch)



  • You are using M671 incorrectly. This should define where the 4x leadscrews are, not where the bed is probed. I would expect the leadscrews to be outside the bed area. You must also state the leadscrew position in the order you defined the motors in M584, Z5:6:7:8, so the firmware knows which motor to adjust. So if, for example, Z5 is at -20,20, Z6 is at -20:480, Z7 is at 520,20 and Z8 is at 520,480, M561 would be X-20:-20:520:520 Y20:480:20:480

    See https://duet3d.dozuki.com/Wiki/Gcode#Section_M671_Define_positions_of_Z_leadscrews_or_bed_levelling_screws
    And from https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors#Section_Prerequisites

    You must use the M671 command to define the X and Y coordinates of the leadscrews. The M671 command must come after the M584 command and must specify the same number of X and Y coordinates as the number of motors assigned to the Z axis in the M584 command; and these coordinates must be in the same order as the driver numbers of the associated motors in the M584 command. The M671 command must also come after any M667 or M669 command.

    Also, the S value is used for the maximum amount of adjustment, which you have set to 0.5mm. If the bed is more than 0.5mm in error, it will fail. Increase this.

    Finally, you don't need M401 and M402 in your bed.g to deploy BL Touch, if you have defined it correctly in config.g; the firmware will deploy and retract probe.

    Ian



  • alt text



  • I cant put picture here.

    Thank you very much for the hint.

    I will do as you say



  • I have something like that

    Leadscrew adjustments made: 4.442 3.913 0.827 -0.424, points used 4, deviation before 3.011 after 0.000

    What this give me?



  • A recent forum software update has caused a problem uploading pictures, hopefully it will be back soon!

    @raf said in 4z axis 4 independent motors. Bed Levering:

    I have something like that

    Leadscrew adjustments made: 4.442 3.913 0.827 -0.424, points used 4, deviation before 3.011 after 0.000

    What this give me?

    Hopefully a flat bed? Run the levelling macro repeatedly to check.

    Be aware that if you're using 4 leadscrews, and either there is an error in how you have defined them, or an error in the probing measurement, the leadscrews may fight each other trying to get the bed level. 3 leadscrews is recommended, as 3 points describe a flat plane better than 4.

    Ian



  • My table consists of 4 plates 800x800 and it seems that they are not perfectly arranged relative to each other. But the hauler itself is heavy and the engines have to lift it up hard. Therefore, they must be 4. already have the voltage raised to 2.4A. And leveling G31 warms the drivers terribly. That's why I wanted to try leveling the table without constantly changing up and down while printing overloads the drivers

    i have something like that o z probe

    ; Z-Probe
    M574 Z2 S0 ; Set endstops controlled by probe
    M558 P5 H5 F120 T800 I1 ; Set Z probe type to unmodulated and the dive height + speeds
    G31 P500 X-5 Y-5 Z0 ; Set Z probe trigger value, offset and trigger height
    M557 X1:1200 Y1:1200 S50 ; Define mesh grid


  • administrators

    That's a large table! What is the rated current of the Z stepper motors? Perhaps a Duet 3 would be more suitable.

    The Duet WiFi/Ethernet is OK at 2.4A provided you have a good airflow from a fan, along the line of drivers on both sides of the PCB. With 4 Z drivers I presume you also have a DueX5. The DueX5 need similar cooling at high currents, but as it has a larger PCB area per driver, the cooling is better. Therefore, it is best to connect the stepper motors needing the highest currents to the DueX5.



  • Current is 2,2A And the controlers have radiators and cooling. BUt when i give 2,4A after 1 hour of working there is a statement that the drivers are to hot.



  • Does duet3d fit duex2?



  • @raf said in 4z axis 4 independent motors. Bed Levering:

    Does duet3d fit duex2?

    presumably you mean if the DueX expansion can be used with the Duet 3 board? No, the Duet 3 range has its own expansion boards that are not compatible.



  • Is the g32 command remembered by the system?

    Because I have the impression that the factorials are falling apart, they don't go up well



  • @raf said in 4z axis 4 independent motors. Bed Levering:

    Is the g32 command remembered by the system?

    only until the next restart unless you save them

    see: Saving the calibration results
    https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer


  • administrators

    @raf said in 4z axis 4 independent motors. Bed Levering:

    Current is 2,2A And the controlers have radiators and cooling. BUt when i give 2,4A after 1 hour of working there is a statement that the drivers are to hot.

    Have you followed the cooling recommendations at https://duet3d.dozuki.com/Wiki/Mounting_and_cooling_the_board#Section_Cooling ?

    Heatsinks on the stepper driver chips might actually make things worse, because they disturb the flow of air along the line of driver chips, and the plastic case of the chips does not conduct heat to the heatsinks very well.


Log in to reply