Horizontal lines

Phaedrux

The pictures are a little hard to see but I get the idea.

It's tough to find accurate information on the creality motors. 700ma seems to be the default from Marlin, but I'm not really sure what the rated max for those motors actually is. You could test using higher motor current to see if it improves, just keep an eye on the temperature of the motors.

Switching motors may help, but that's only if they are the problem. If you move the Z axis up and down several times does it remove back to the same point you started at?

Are both motors in sync? Do you have a means of leveling them to the bed surface before the print? Are you driving them from the Z axis A and B plugs, or are you using a spare driver to drive each motor independently?

dc42

I found the Z motor specification at https://ecksteinimg.de/Datasheet/Schrittmotor/JK42HS34-0844A/JK42HS34-0844YA-01.pdf. Those are low current motors, probably chosen so that 2 of them can be connected in parallel and driven from whatever driver Creality uses. Driving them in series from the ZA and ZB motor connectors on the Duet is not optimal if your VIN voltage is only 12V. It would be better to connect them in parallel, wired to just ZA, or wire one to ZA and the other to the E1 output if it is spare (either way, put the jumpers back in ZB).

Harley3D

@dc42 I did upgrade to dual axis and that came with like a "2 in 1" cable connection. So using that might solve the issue?

Harley3D

@phaedrux The lines are there just hard to focus at macro level and the poor light. They are random and some evenly spaced which made me think it could me the lead screw or connectors not plum.
They're in sync. I have traveled the Z axis to max and back to min and then used a 3" x 1" calibrated metal block to check if the X axis is level with the bed, which it is.

Veti

@harley3d

wiring them up to z and e1 has another benefit.
you can use
https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors#main

Ringo1508

@Harley3D did you solve the issue? I'm curious what you did to fix it if you did. I'm experiencing some pretty bad lines. I'm about ready to pop my Z motors and X axis off and run a square on my Z axis again to make sure that the Duet enclosure I bolted on didn't somehow torque the frame out of alignment.

I also need to figure out how to determine the correct belt tightness (I used Prusa's way of using pliers to hold the motor shaft and putting some pressure on the axis and seeing if it deformed the belt at all.) It doesn't deform when pressing, but it doesn't really make an audible noise when plucking lol.

Lastly, I tightened the hell out of the grub screws because my LDO motors did not come with a flat spot on the shaft. I'm assuming I should grab my file and create a notch lol

My Z motors are LDO-42STH34-1004L420EZRB. This is a Cartesian printer (set up like a Prusa i3 but with Bear frame) and I have motors plugged into ZA and ZB (so series.)

I'm playing with the acceleration, jerk, and speed settings now, but the Z axis lines are driving me nuts.

Config.g
; Configuration file for Duet Maestro (firmware version 1.21)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v2 on Wed May 22 2019 18:14:39 GMT-0500 (Central Daylight Time)

; General preferences
G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves

; Network
M550 P"DuetMaestro" ; Set machine name
M552 P192.168.10.173 S1 ; Enable network and set IP address
M553 P255.255.255.0 ; Set netmask
M554 P192.168.10.1 ; Set gateway
M586 P0 S1 ; Enable HTTP
M586 P1 S0 ; Disable FTP
M586 P2 S0 ; Disable Telnet

; Drives
M569 P0 S1 ; Physical drive 0 goes forwards
M569 P1 S0 ; Physical drive 1 goes backwards
M569 P2 S0 V0 ; Physical drive 2 goes backwards
M569 P3 S1 ; Physical drive 3 goes forwards
M350 X16 Y16 Z16 E32 I1 ; Configure microstepping with interpolation
M92 X200 Y200 Z400 E1011 ; Set steps per mm
;M201 X1000 Y1000 Z200 E2000 ; Set accelerations (mm/s^2)
M201 X9000 Y9000 Z500 E10000 ; Set accelerations (mm/s^2)
M203 X15000 Y15000 Z300 E15000 ; Set maximum speeds (mm/min)
;M204 P1250 T1250 ; Set default accelerations for max printing and travel moves
M204 P1250 T3000 ; Set default accelerations for max printing and travel moves
;M566 X500 Y500 Z12 E500 ; Set maximum instantaneous speed changes (mm/min)
M566 X900 Y900 Z30 E3000 ; Set maximum instantaneous speed changes (mm/min)
M906 X1000 Y1000 Z450 E450 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Axis Limits
M208 X0 Y-4 Z0 S1 ; Set axis minima
M208 X250 Y210 Z320 S0 ; Set axis maxima

; Endstops
M574 X1 Y1 S1 ; Set active high and disabled endstops

; Z-Probe
M574 Z1 S2 ; Set endstops controlled by probe
M558 P5 H5 F600 T3000 A3 ; Set Z probe type to switch and the dive height + speeds
G31 P500 X23 Y5 Z0.9 ; Set Z probe trigger value, offset and trigger height
M557 X33:228 Y10:210 P7:7 ; Define mesh grid

; Heaters
M305 P0 T100000 B4138 R2200 ; Set thermistor + ADC parameters for heater 0
M143 H0 S120 ; Set temperature limit for heater 0 to 120C
M307 H1 A261.5 C118.0 D4.1 V24.2 B0 S1 ; PID Heater
M305 P1 T100000 B4725 C7.060000e-8 R2200 ; Set thermistor + ADC parameters for heater 1
M143 H1 S290 ; Set temperature limit for heater 1 to 290C

; Fans
M106 P0 S0 I0 F250 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 S1 I0 F250 H1 T45 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on

; 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

; Automatic saving after power loss is not enabled

; Custom settings are not configured

Veti

@ringo1508

these artefacts can be due to binding of the lead screws. unscrew the coupler from the lead screws and move the gantry up and down. there should be no noticeable resistance to the movement.

dc42

@ringo1508 said in Horizontal lines:

My Z motors are LDO-42STH34-1004L420EZRB

I didn't find an exact match, but as far as I can tell they are rated at 1A and have 8 ohm phase resistance. So 8V per phase at rated current. They should definitely not be connected in series if the VIN voltage is only 12V.

Ringo1508

@dc42, I'm running 24V PSU. Should I still connect one to E1 and put the jumpers back on ZB? I have attached the motor spec. Jason Bao over at LDO also gave me the inductance: 9.5mH. These are the "Zaribo 320" motors. I know Prusa uses LDO motors for their machines and my i3 MK2S Z motors never got hot. I reduced my Z motors to 45% on the Duet because they were getting quite hot (I could hold them for about 10-15 secs and then had to pull my fingers off.) If I wire them up in parallel, will this reduce the heat? 0_1559225538307_LDO-42STH34-1004L420EZRB-Z2-RevC.pdf

@Veti, the lead screws came already installed in the motors. Do I need to pull the motor apart? I will also double check the dust protector (a piece that screws down to nearly the motor so it protects dust from getting into the motor around the lead screw.) Someone provided me with a macro that mimics what Prusa machines do: it homes the axis, then centers the X axis and goes up to 5mm before the top of the printer, lowers the current to 30% and then goes up 20mm in order to make sure that the X gantry is level, and finally brings it back down.

I upped my currents and printed a second xyz calibration cube. The right one in the pictures was X1000 Y1000 Z450. The left one was X1200 Y1200 Z700; this puts 70% current to them.

!

Ringo1508

I have a suspicion that maybe I tightened the X rod end screws too much (that help make sure the ends are in-line in case rods are too long/short.) I cannot test it yet as I seem to have screwed up ... lol. My motors have round shafts and I cranked the pulley grub screw pretty good because I didn't want it to slip. Well I tried to remove the pulley so I could file a flat and I got the pulley stuck on the shaft. I have to wait till I get my dremel in order to carefully cut it off. Thankfully I have spare Gates 2GT 16T pulleys.

I did verify that the lead screws spin freely and that the dust "nut" is not causing any drag as I moved it about 1mm above the motor. Z frame is as close to square to the Y frame as possible (maybe about 0.2mm of gap 406mm up -- 16" square with ruler.) X axis confirmed to be square to Y axis (as far as I could tell with a ruler up against the Z frame laying across the heatbed lining up the dotted horizontal lines on it with the ruler.)

So now I wait for Printed Solid's shipment of a new motor to test if it was the end screws (or anything mechanical at all.)

@dc42, let me know if you think I should run ZA and E1 for my motors (24V PSU.) Will I lose the mesh bed leveling with the P7:7 command that figures out my points automatically if I switch to this?

Thanks in advance!

Ringo1508

Pulled the motor apart and stuck the shaft into my drill ...it wobbles. This is the X axis motor.

Ringo1508

So while I wait for my new motor, I hope I'm not going to beat a dead horse with this parallel vs series. I know (after reading a bunch of other posts) that in series both motors get full current but half the voltage whereas in parallel it's inverse. If I'm running 24V then both these 8V motors would be fine. My question now is, if ramps board (Prusa i3 MK2S) is running Z motors in parallel due to 12V PSU, and the Marlin firmware settings are compiled with 830ma, then each Z motor is only getting 415ma?

Assuming the above is correct, then to simplify life for me on 24V PSU, I can keep them in series and then just set Z current to 450ma like I had before and be good?

Is there a benefit from wiring one to ZA and one to E1? Which would you do if it were your printer? lol (easiest way to ask)

Veti

see
https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors

Phaedrux

If I had a free motor driver I would give each Z motor it's own driver and use the link Veti provided to do a self leveling routine, much the same way that prusa rams the X axis into the top of the printer to ensure they are even.

I'm not really savvy on how serial versus parallel wiring would affect your particular motors given your PSU voltages. DC42 would have a better idea I'm sure.

dc42

@ringo1508 said in Horizontal lines:

@dc42, let me know if you think I should run ZA and E1 for my motors (24V PSU.) Will I lose the mesh bed leveling with the P7:7 command that figures out my points automatically if I switch to this?

Yes, I suggest you do that. It won't affect mesh bed compensation.

Ringo1508

Thank you @dc42, @Veti, and @Phaedrux. Once I get my new motor in I'll try a print before swapping the Z motors to the new set up and then swap the motors and post back for anyone that stumbles on this thread who might have the same issue.

Ringo1508

Just an update.

I received my new motors (same motors, just new ones) as the other seemed to have a bent shaft. I did the following tests:

printed cube on my Prusa i3 MK2.5 Bear with TMC2208 X and Y external drivers
printed cube using one of my other 1.8deg stepper motors as X motor (Z motors connected to ZA and ZB)
printed cube using new 0.9deg replacement X motor (Z motors connected to ZA and ZB)
printed cube using new 0.9deg replacement X motor using "faster" slicer profile (Z motors connected to ZA and E1)
printed cube using new 0.9deg replacement X motor using "slower" slicer profile (Z motors connected to ZA and E1)

Cubes in picture are 1 through 5 from left to right.

Interestingly enough, I do see the lines/differences on the Prusa and might be worse than the Duet printer! (hah!)

I don't see a huge difference between any of these. If you zoom in, you can definitely see the line differences. Maybe I just didn't pay as much attention to them before getting into "building my own printer" phase? Do these lines look normal/acceptable to others? Should I work on trying to get them smoother or more uniform?

I'm using Amazon PETG and I did put them in the food dehydrator on 140F for 8+ hours before printing with them in order to make sure moisture wasn't a variable.

Other things I did:

confirmed that X, Y, and Z axes are dang near perfectly square
made sure belts were not too tight or too loose
found the X carriage to have a weird tension when moving, then got easier to move, then harder, then easier ...loosened grub screws and moved the 16T pulley a little bit away from motor housing and tightened grub screws up ...this fixed that (I guess it was rubbing, which makes me think there's still a little wobble to the shaft)

I guess I just live with it I'll try printing that speed and acceleration print again and see if it looks like the original pictures I posted.

Veti

@ringo1508 said in Horizontal lines:

Amazon PETG

thats the worst petg i have tried so far.
unfortunately i ordered 3 rolls. used up 1 to figure out how to print it well.
the other 2 are still unused. ordered different petg and was much happier.

Ringo1508

@veti, I'll try the Atomic PETG I have then ...or see if I have some Hatchbox left over.

My next test will also to be to use S3D to slice it and see if that makes a difference. At least now I'm happy to know it's most likely not a mechanical issue. I do like having motors on different drivers now too.

@veti, do you have experience using multiple drivers for Z? I followed the link. I just want to make sure what I'm doing is good, or too much, or if there's something better:

bed.g

M561 ; clear any bed transform
G28  ; home all axes
G30 P0 X11 Y105 Z-99999 ; probe near a leadscrew, half way along Y axis
G30 P1 X220 Y105 Z-99999 S2 ; probe near a leadscrew and calibrate 2 motors
G30 P0 X11 Y105 Z-99999 ; probe near a leadscrew, half way along Y axis
G30 P1 X220 Y105 Z-99999 S2 ; probe near a leadscrew and calibrate 2 motors
G30 P0 X11 Y105 Z-99999 ; probe near a leadscrew, half way along Y axis
G30 P1 X220 Y105 Z-99999 S2 ; probe near a leadscrew and calibrate 2 motors
G29  ; probe the bed and enable compensation

I have 2 motors (i3 style printer) so I'm making sure that the bed gets leveled between the two motors before doing teh G29. My config.g has the following in it:

config.g snippet

; Z-Probe
M574 Z1 S2					; Set endstops controlled by probe
M558 P5 H5 F600 T3000 A3			; Set Z probe type to switch and the dive height + speeds
G31 P500 X0 Y0 Z0.9				; Set Z probe trigger value, offset and trigger height
M557 X11:220 Y5:196 P7:7			; Define mesh grid

Veti

whats your M671 line?