Drive chatter



  • Gentle people; I have built a 3d printer. No surprise, I have a problem I can't resolve.
    Back ground: Cartesian, VERY solid industrial 8020 frame.
    8mm rod ways,GT2 belting 16tooth drive pulleys,84oz.in nema17 2A.
    z axis dual leadscrew 8mm pitch anti-backlash, 1 drive motor ,2.25:1 drive ratio.
    Piezo Z limit and probe, laser filament monitor. Modified MK10 head(80W & PT100).
    MicroSwiss all metal hot end and extruder drive.
    And best of all: Duet WiFi W/ 7" touchscreen.
    Now the problem, The axis motors are surging, pulsing, vibrating or whatever you want to call it.
    It can be seen, heard and shows up in the print.
    It's also strong enough to shake the table slightly.
    Originally thought it was the way bearings...super junk. replaced with plastic bushings, super smooth.
    still have the surging. To eliminate the carriage I ran just the motor. Felt the surging in the shaft rotation.
    It also seems to be speed dependent.

    Cura print speed 60mm/sec
    X surge spacing .94mm (ripple distance peak to peak over a 10 peak count)
    Y surge spacing 1.48mm

    Cura print speed 20mm/sec
    X surge spacing 0.34mm
    Y surge spacing 0.53mm

    Yea and different spacing between X and Y.
    There is no loss of position, I only see this when my acceleration is stupid high
    or my jerk is around 100 or more, no surprise.
    My acceleration and max speed tested out much higher than set but I saw no reason to run that hard.
    Shakes everything in the room(old house).
    Also not Cura, MDI'ed G1 X100 F500....still there.
    Seems to be more prominent in one direction over the other but still there.

    I'm lost anybody out there with the clue I need??
    Starting to suspect a bad set of drivers(?! more than 1?) or the Duet/firmware.

    The filament definition also has Monitor, pressure advance and hardware retract parameters.
    TestBlocks1.jpg

    Config:
    ; Configuration file for Duet WiFi (firmware version 1.21)
    ; generated by RepRapFirmware Configuration Tool v2 on Thu Apr 25 2019 22:03:51 GMT-0400 (Eastern Daylight Time)
    ; General preferences
    G90                                          
    M83                                          
    ; Network
    M550 P"Spiffy"          
    M552 S1                                     
    M586 P0 S1                                   
    M586 P1 S0                                   
    M586 P2 S0                                   
    ; Drives
    M569 P0 S1                                   
    M569 P1 S1                                   
    M569 P2 S1                                   
    M569 P3 S1 
    ****                                 
    M350 X16 Y16 Z16 E16 I1                      
    M92 X100.00 Y100.00 Z900.00 E89.73          
    M566 X600.00 Y600.00 Z600.00 E600.00          
    M203 X30000.00 Y30000.00 Z10000.00 E12000.00      
    M201 X400.00 Y400.00 Z800.00 E400.00          
    M906 X1800.00 Y1800.00 Z1800.00 E1800.00 I30 
    M84 S30                                      
    M350 X256 Y256 Z256 E256
    ****		     
    M208 X-52.1 Y0 Z0 S1                         
    M208 X312 Y400 Z300 S0                       
    ;M564 S0 H0									 
    M574 X1 Y1 S0                                
    ; Z-Probe
    M574 Z1 S2                                   
    ;M558 P5 R0.4 H5 F1200 T6000                  
    M558 P5 I1 R0.4  F800 X0 Y0 Z0
    G31 P100 X0 Y0 Z-0.12                          
    M557 X15:280 Y25:290 S20                    
    ; Heaters
    ;M307 H0 B0 S1.00                             
    M305 P0 T100000 B3950 R4700                  
    M143 H0 S120                                 
    M305 P1 X200 R400                           
    M143 H1 S280                                 
    M307 H0 A90.0 C700.0 D10.0 S1.00 V0.0 B0	
    ; Fans
    M106 P0 S0 I0 F500 H-1                   
    M106 P1 S255 I0 F500 H1 T45              
    ; General
    M404 N1.75 D0.4				     
    M375 		     			     
    ;M207 S0.5 R0.07 F2700			    
    ; Tools
    M563 P0 S"Std Head" D0 H1 F0                 
    G10 P0 X0 Y0 Z0                              
    G10 P0 R0 S180                                 
    M572 D0 S0.05					
    M591 D0 P5 C3 R40:200 E3.0 S1  
    

    Printer1dodged.jpg



  • Great looking printer!

    I have somewhat similar problems, vibration/rattling at certain speed (CoreXY, 3030 frame). Initially I thought it comes from the linear bearings but figured out recently that it comes from the motors themselves and was able to reproduce it with belts removed.

    I got this from amazon https://www.amazon.com/gp/product/B07GWN6V89 , did a quick experiment and it seems to do miracles so designing now a proper mount with the hope that the problem will go away, at last.

    Can you reproduce the vibrations (frame resonance?) with belt removed and running one motor at a time at varying speed (a simple macro gcode file can do that for you)? If so, it will eliminate many suspects.



  • @tcoleman978 said in Drive chatter:

    M350 X256 Y256 Z256 E256

    I suspect you've overwhelming the step rate. Can you provide the results of M122 after a print? I suspect you'll see a high number of hiccups.

    Stick to x16 microstepping interpolated to 256 by the drivers. Best of both worlds and was really the design intent of the Duet. The only axis that may benefit from higher natural microstepping is the extruder if it's ungeared, as it appears to be in your case. Even there x128 is more than enough to regain some extruder resolution.



  • Started at 16x/no micro went to micro256 to help smooth...or not.
    256x hiccups=big number (m350 x256)
    16x hiccups=0 (no M350)
    print and vibration same.
    === Move ===
    Hiccups: 0, FreeDm: 157, MinFreeDm: 149, MaxWait: 0ms
    Bed compensation in use: mesh, comp offset -0.272
    === DDARing ===
    Scheduled moves: 1434, completed moves: 1425, StepErrors: 0, LaErrors: 0, Underruns: 0, 0
    This is with no M350.

    Oh and Zapta The motors have plenty of dampening No lost steps, this is not ringing its still there even if I go stupid slow.



  • Looks like you have a steel core belt on your x-axis with normal size idlers and pulleys...That can cause big issues and they should be changed out to standard type Gates belts.



  • Dang already have, had to the steel was coming out.
    Just ran a test at a Cura print speed of 160mm/s.
    Better than I expected but still had the surging just a wider spacing.



  • @tcoleman978 said in Drive chatter:

    M375

    Best not to load the heightmap at startup before the Z axis has been homed. Load it in the slicer start gcode after homing.

    What are the motor specs?

    What firmware version?



  • Just updated to:
    Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
    Firmware Electronics: Duet WiFi 1.02 or later
    Firmware Version: 2.05 (2019-12-13b1)
    WiFi Server Version: 1.23
    Web Interface Version: 1.22.5

    Saw no change.

    Motors:17HS19-2004S1
    1.8deg
    83.6ozin
    2A/phase
    1.4ohm/phase
    2.8V
    3mH



  • @tcoleman978 said in Drive chatter:

    Oh and Zapta The motors have plenty of dampening No lost steps,

    Can you post a picture of the X stepper damper? I am designing for my own printer and am looking for ideas.

    (BTW, in my case is vibration and frame resonance, no missing steps)



  • Zapta:
    No specific dampers. I did buy a set just like you had. didn't need them.
    The belts, mass of the carriage and the friction of the bushings provide plenty of dampening. Especially with the microstepping. That head has some reasonable mass, 4" square 1/4"thick Al plate, Al bearing housings 2" x 2-1/2" x 1/4" Head Flexplate for the piezo and 2-1/2" Al angle 2" long for the head mount. plus nuts,bolts and screwballs and sensors to boot. The steppers have PLENTY of torque. I got my knuckle in the way. Oh man....plenty of torque!


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