Motor issue….but why?

  • I'm confused, my printer worked pretty well, so I took it apart (because it was a mess) and built it more accurately and more carefully, cleaned up the wiring, and swapped in motors with shorter cables. I added linear rails from robotdigg, and that's about it.

    I have not touched the software, config, speeds…It was all hardware. The motors are a few mm shorter, it worked with these exact motors a few months ago. These motors might be cheaper made because they are the original ones that came with the FLSun Kossel Mini kit.

    Here is my entire config

    ; Configuration file for Mini Kossel kit from Think3DPrint3D

    ; Communication and general
    M111 S0 ; Debug off
    M550 PKosselMini ; Machine name and Netbios name (can be anything you like)
    M551 Preprap ; Machine password (used for FTP)
    M552 S1 ; Enable WiFi
    M540 P0xBE:0xEF:0xDE:0xAD:0xFE:0xED ; MAC Address
    ;*** Adjust the IP address and gateway in the following 2 lines to suit your network
    M552 P192.168.1.10 ; IP address (0 = use DHCP)
    M554 P192.168.1.1 ; Gateway
    M553 P255.255.255.0 ; Netmask
    M555 P2 ; Set output to look like Marlin
    M575 P1 B57600 S1 ; Comms parameters for PanelDue

    G21 ; Work in millimetres
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    ; Axis and motor configuration
    M569 P0 S1 ; Drive 0 goes forwards
    M569 P1 S1 ; 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
    M574 X2 Y2 Z2 S1 ; set endstop configuration (all endstops at high end, active high)
    ;*** The homed height is deliberately set too high in the following - you will adjust it during calibration
    ;M665 L231.330 R113.370 H278.919 B70.0 ; diagonal rod length, set delta radius, homed height and printable radius
    ;Diagonal 231.330, delta radius 113.370, homed height 279.274, bed radius 70.0
    ;M666 X-0.52 Y2.15 Z-1.62 ; put your endstop adjustments here, or let auto calibration find them
    ;Endstop adjustments X-0.52 Y2.15 Z-1.62, tilt X0.37% Y-2.16%
    M665 L231.330 R113.413 H278.774 B70.0 X-0.431 Y0.677 Z0.000
    M666 X-0.50 Y2.10 Z-1.60 A0.37 B-2.16
    M350 X16 Y16 Z16 E16
    M92 X100 Y100 Z100 ; Set axis steps/mm
    ;M92 X800 Y800 Z800
    M906 X1000 Y1000 Z1000 E800 I60 ; Set motor currents (mA) and increase idle current to 60%
    M201 X2000 Y2000 Z2000 E2000 ; Accelerations (mm/s^2)
    ;M201 X300 Y300 Z300 E300
    M203 X25000 Y25000 Z25000 E3600 ; Maximum speeds (mm/min)
    ;M203 X3000 Y3000 Z3000 E400
    M566 X1200 Y1200 Z1200 E1200 ; Maximum instant speed changes mm/minute
    ;M566 X300 Y300 Z300 E100

    ; Thermistors or Thermocouples
    ;*** If you have a Duet board stickered "4.7K", change R1000 to R4700 to the following M305 commands
    M305 P0 T100000 B3950 R4700 H30 L0 ; Put your own H and/or L values here to set the bed thermistor ADC correction
    ;M305 P1 T100000 B3974 R4700 H30 L0 ; Put your own H and/or L values here to set the first nozzle thermistor ADC correction
    M305 P1 X200
    M305 P2 T100000 B3974 R4700 H30 L0 ; Put your own H and/or L values here to set the second nozzle thermistor ADC correction
    M570 S180 ; Hot end may be a little slow to heat up so allow it 180 seconds

    ;M305 P1 X200 ; X200 = PT100 Thermocouple

    ; Tool definitions
    M563 P0 D0 H1 ; Define tool 0
    G10 P0 S0 R0 ; Set tool 0 operating and standby temperatures
    ;*** If you have a dual-nozzle build, un-comment the next 2 lines
    ;M563 P1 D1 H2 ; Define tool 1
    ;G10 P1 S0 R0 ; Set tool 1 operating and standby temperatures
    ;M92 E416.898 ; Set extruder steps per mm
    ;M92 E412 ;Calibrated Titan Extruder
    ;M92 E418.5 ;Titan Extruder
    M92 E504.90 ;Geared OMC stepper 16x microstepping
    ;M92 E4039.3 ;x128
    ;M92 E2019.6 ;x64
    ; Z probe and compensation definition
    ;*** If you have an IR zprobe instead of a switch, change P4 to P1 in the following M558 command
    M558 P1 X0 Y0 Z0 H3 ; Z probe is a switch and is not used for homing any axes
    G31 X0 Y0 Z2.516 P500 ; Set the zprobe height and threshold (put your own values here)

    ;*** If you are using axis compensation, put the figures in the following command
    M556 S78 X0 Y0 Z0 ; Axis compensation here
    ;M556 S78 X1.121 Y1.196 Z0
    ;X0.893 Y1.064 Z0

    M208 S1 Z-2 ; set minimum Z
    T0 ; select first hot end


    The motor number is either:


    They are slightly smaller than 40 mm, I think.

    Are my acceleration speeds too high? My feedrate for my home file is was 5000, I lowered it to 3000 and did nothing, so I am thinking acceleration. I hesitate changing settings because they seemed pretty good with the last motors and the older roller ball carriages that rolled on the outside of the extrusion. These almost seem like more friction because I have to oil them but I didn't think it would prevent it from homing.

    What should I do? I need it for Monday or Tuesday, so I got the weekend to fix it.

    Also, anything in my config that may not be relevant that could still be improved?

    Thank you in advance.

  • What issue are you experiencing specifically?

  • This is a link to a video I recorded rather than attempt to explain.

  • Sounds/looks like a motor not connected right, maybe a plug only connecting 3 pins of a 4 pin connector?

  • yep agree

  • Hmm that's interesting. I'll check the wiring.

  • How to you check which wires are which coil? Continuity?? Resistence? What should I check on a multimeter?

  • administrators

    Each pair should have a low resistance, there should connection between the coils

  • Each motor appears to be wired the same as the others, black green blue red…black being the side with the power mosfets. Each coil is 1.9 ohms, with the exception of just one coil that was 2.9 ohms.

    I disconnected the cables and the previous motors ran perfectly, swapping the motors out would be extremely inconvenient, is there anything I can change to make the motors not vibrate when they move?

  • administrators

    And which colour wires do you get continuity between?

    The 2.9 ohms reading is not right if the other coil on the same motor reads 1.9 ohms.

  • administrators

    If the motor is a "20160631169" then I have no idea, could not find that on the internet. If its a "SL42STH40-1684A" that is a fairly standard stepper motor with 4 wires, so there should be only two coils, both of which should read the same resistance in the region of 1.65R your meter will also have the lead resistance so 1.9R would be in the right region).

  • I swapped out the motor with the bad coil, calibrated and printing. Note to self: check motors before installing!

    Thank you very much! 🙂


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