Skipping stepper

Chriss

Hi *,

I hope that somebody can help me here.
I have a Voron v0 (CoreXY) with LDO 14HS20-1504S for X and Y. I drive them with:

M906 X1000 Y1000 Z1000 E900 I30

One of the steppers starts skipping since some days and I'm unable to find the reason. I reduced the "M566" and "M201" a lot to reduce it. And the skipping is not from the very beginning. It starts sometimes after 2 0 of 30 layers. Sometimes very bad, so the head stops moving, sometimes a tiny layer shift of 2 mm. Very unpredictable....

So I removed the steppers from the printer now to have on my bench to play a bit with them. What I did so far:
I shortened the pins in the mainboard connector to make sure that the wiring is OK. (Steppers are harder to turn.
I measured the resistance, all wires pairs are around 3Ohm.
I moved the axis and tried to hold the stepper with my fingers: I was easily ale to hold the stepper when there is a pully on the stepper. I'm unable to hold them id there is no pully. Sounds good, right?
I reduced to current to 500 and below, that makes it very easy to hold the stepper. So that should be fine than and my test setup seems to be right though.

I saw some messages on the console telling me:
Error: over temperature shutdown reported by driver(s) 1
Warning: high temperature reported by driver(s) 1

That is gone since a while.

I changed the drivers (one is still free) with the same result. Honestly? I have no idea any more. Should I recrimp the connectors? Should I go to more than the 1A? The stepper is made for 1.5A, the 70% rule brought me to the 1A.

(foll config below, you will see there far more aggressive setting in the config.g, they worked till some days.)

Edit told me that I should mention that I gave the stepper some time to cool down back than when I did some testprints while the steppers where still in the printer.) They where not overheated from my point of view. The V0 has no backpannel, so the steppers can radiate there heat into the open room.

Cheers, Chriss

; Default config.g template for DuetPi
; Replace this with a proper configuration file (e.g from https://configtool.reprapfirmware.org)

; M302 S1 ; allow cold extrusion
; M302 S0 ; Deny cold extrusion
; M564 S0 to disable axis limits
; M564 S0 H0

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Hardware:
; Duet mini 5+
; XY Stepper LDO 14HS20-1504S
; Z: Current: LDO-35STH42-0504AH(VRN) Future: 17LS13-0404E-200G

; Enable network
if {network.interfaces[0].type = "ethernet"}
    M552 P0.0.0.0 S1
else
    M552 S1

; Network
M586 P0 S1                                         ; enable HTTP
M586 P1 S1                                         ; enable FTP
M586 P2 S1                                         ; enable Telnet

G90                                         ; send absolute coordinates...
M83                                         ; ...but relative extruder moves
M550 P"v0"                                  ; set printer name
M669 K1										; 1=select CoreXY mode   0=Cadasian


;; Drives

;; XY
; - Rechts
M569 P2 S1									; physical drive 2
M584 Y2
; - LINKS
M569 P3 S1									; physical drive 4
M584 X3

; Z
M569 P4 S1									; physical drive 3
M584 Z4

; Extruder
M569 P1 S1									; physical drive 1
M584 E1



;M671 X-31.5:437.4:198.5 Y63:63:440 S30.0		; Z-Level leadscrews at left (connected to E6(9)) and right (connected to E2) of X axis (S=MaxCorrection)
;M671 X-30:437.4:198.5 Y63:63:440 S30.0			; Z-Level leadscrews at left (connected to E6(9)) and right (connected to E2) of X axis (S=MaxCorrection)

M350 X16 Y16 Z16 E16 I1							; configure microstepping with interpolation
M92 X80.00 Y80.00 Z400.00 E400  			    ; set steps per mm   M92 X80.00 Y80.00 Z400.00 E420.00
M566 X400.00 Y400.00 Z12.00 E120.00				; set maximum instantaneous speed changes (mm/min)
;M566 X4000.00 Y4000.00 Z12.00 E120.00			; set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z480.00 E1200.00			; set maximum speeds (mm/min) Z180
;M203 X100000.00 Y100000.00 Z900.00 E1200.00	; set maximum speeds (mm/min) Z180
M201 X400.00 Y400.00 Z20.00 E250.00				; set accelerations (mm/s^2)
;M201 X75000.00 Y75000.00 Z20.00 E250.00		; set accelerations (mm/s^2)
M906 X1000 Y1000 Z1000 E900 I30					; set motor currents (mA) and motor idle factor in per cent
M84 S30                                         ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1                                ; set axis minima
M208 X115 Y115 Z120 S0                          ; set axis maxima
;; Endstops -- Display status with: M119
M574 X2 S1 P"io2.in"		; X
M574 Y2 S1 P"io3.in"		; Y
M574 Z1 S1 P"!io4.in"		; Z


;; Heaters :: Tune with: M303 H0 S115
; Bed
M308 S0 P"temp0" Y"thermistor" T100000 B4138     ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out0" T0                               ; create bed heater output on out0 and map it to sensor 0
M307 H0 B0 S1.00                                 ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0                                          ; map heated bed to heater 0
M143 H0 S120                                     ; set temperature limit for heater 0 to 120C

; Head 1 (Hotend)
; Tune in with:  M303 H1 S270
M308 S1 P"temp1" Y"thermistor" T500000 B4702 C1.171057e-7   ; configure sensor 1 as thermistor on pin temp1    400°
;M308 S1 P"temp1" Y"thermistor"  T100000 B4676 C6.340805e-8 ; 300° version
M950 H1 C"out1" T1                 				            ; create nozzle heater output on out1 and map it to sensor 1
M307 H1 B0 S1.00                                		    ; disable bang-bang mode for heater  and set PWM limit
M143 H1 S310                                       			; set temperature limit for heater 1 to 280C


;; Fans
; Fan for the printed part
M950 F0 C"out5" Q500			; create fan 0 on pin out1 and set its frequency
M106 P0 S0 H-1 C"Part"			; set fan 0 value. Thermostatic control is turned off

; Fan for the hotend
M950 F1 C"out6" L0:1000 Q50			; create fan 1 on pin out6 and set its frequency
M106 P1 S1 H1 T45 C"Hotend"			; set fan 1 value. Thermostatic control is turned on


;; Tool
M563 P0 S"Tool" D0 H1 F0            		; 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


; Filament sensor : Status  M591 D0
;M591 D0 P7 C"io6.in" L7 R55:150 E22 S0 ;Bigtree smart filament moniter v2 set to moniter between 55%-150% of 7 counts over a distance of 22mm
;M591 D0 P5 C"121.io1.in" R230:360 E3.0 S0          ; S1 = Enabled S0 = Disabled

;;;;;;;;;;;; Setup Only
;M564 S0 H0 			; Allow movement over the endstops
;M302 P1 ; allow cold extrusion
;M302 S1 ; deny cold extrusion
;M91
;;;;;;;;;;;; Setup Only END

; Miscellaneous
;M593 PDAA F30										; Anti ghosting
M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000"	; set voltage thresholds and actions to run on power loss
M501						; Load config-override.g

; Serial interface
M575 P1 B115200 S1
; Mini 12864
M918 P2
;M918 P2 E4 R3 C100
;M150 X2 R255 U255 B255 S3		; set all 3 LEDs to white
M150 X2 R0 U255 B0 S3			; set all 3 LEDs to red

T0						; Select the tool 0 as default

mrehorstdmd

@chriss Your instantaneous speed changes seem to be a little high for someone who is experiencing `````````````````````````````````````````````````````skipped steps.

Sorry, my cat is helping me write posts this morning.

As I was saying, your jerk speed seem a little high. I'd turn that down to 20-30 mm/sec and try again.

Chriss

@mrehorstdmd

Sorry, I'm a bit lost... What do you mean with "jerk speed"?

Cheers, Chriss

chrishamm

@chriss It's the value set by M566 (instantenous maximum speed change aka "jerk"). Your motor settings look really conservative to me and TBH I drive my cartesian printer at much higher values than those in your current config.g.

I guess you already checked but is there perhaps excessive friction anywhere on the XY plane?

Chriss

@chrishamm M566, thanks a lot...

I guess you notice the other settings which are commented out. That where the old settings I had before I the step skipping nightmare began.

To the printer was far more aggressive in the past and was working.

Yes, the mechanical thing is something I was looking at the very beginning. Let me explain why I do not think that I have a mechanical issue:
I print a plat part. lets say a sqare cube, 40x40x20mm. With two or three holes, 5 wall lines and 40% infill.

First print: tiny layer shift at layer 6
2nd print: 10seconds permanent skipping at 10x30 at layer 18mm
3rd print: Layer shift of 3mm at layer 3 starting somewhere at 30x25.
X moves almost free, lets say as much as you can tell with the belt installed without the steppers.
The belts are not over tight. The start to slip if I loose them more. The pully are tight.

What was confusing to me what the force of the hotend. Let me give you an example:

I can force the hotend to stop with my index finger when I see the layer shift issue. I need at least 3-4 finger to stop the hotend when I do not see the issue. The printer starts to move on my desk than. I have the feeling that I loose force somewhere or current.

I recriped the wires in the meantime. I will start a print now. (I need a part for my Voron 2.4 build. The toolboard needs a holder)

Well, I will start the print now, lets see how far I will come now with:
M566 X200.00 Y200.00 Z12.00 E120.00

Cheers, Chriss

chrishamm

@chriss Since you have DAA commented out, I reckon you are using 3.4-bX. Do you have b3 installed? If not, perhaps try to upgrade. When the layer shifts occur, do you hear the motors skipping? Are the steppers hot at the time the shifts occur? When I faced similar problems in the past, I just cranked up the motor currents temporarily to check if it made a difference - I didn't have any problems doing so with the TMCs.

Chriss

@chrishamm
DAA?

No, my v0 is still "3.2.2". I had no time to update that.... That is/was my only working printer, so I needed at least one ABS capable printer for my v2.4 build.

Yes, you can hear the stepper skipping. As I said, it could be so bad that the head stops a a position for 10+ seconds while the stepper still try to move. It gave it a gentle push and the hotend continued it's journey. I know that this sounds like a mechanical problem but this happens from time to time at various locations on the XY axes. It could be that the nozzle got stuck at a blob of extruded filament, I don't know....
Anyway, I to not think that it makes sense that a hotend get stoped by a tiny filament blob. There should be enough bower to overcome that, don't you think so?

Did you see the message from the console I posted in the initial post? I have never seen that before. Again: That are tiny steppers, driven with 1A. How can that overhead the driver?
And last but not least: The printer was working with the old parameters very okish. No the nicest prints etc but the printer was printing with 80mm/s and a travel of 280mm/s and up. With the same firmware version etc. I came back from a to short vacation and I print with 40mm/s and a very slow acceleration.

That is a bit strange to be honest. There where nearly no change, I had to unscrew the hotend to reroute the thermistor wire and I gave both belts a very little more pretensioning. But do not overrate that, the belts are still var to loose. And I unfastened the belts in the meantime for testing etc... :? I do not think that this is a firmware thingy.. maybe a strange race condition?

Cheers,

Chriss

chrishamm

@chriss Ahh, in any case try to upgrade to v3.3 then. I was assuming you were on the latest beta because you had this in your config.g:

;M593 PDAA F30

This line uncommented would output an error on v3.4-bX because DAA is no longer supported due to newer IS types.

I'd indeed think the momentum of the hotend should suffice to travel across little blobs, they just happen from time to time. I run my bed at 1600mA and the extruder (without gearing) at 1800mA, although the latter requires some extra cooling.

If there were overheating stepper drivers, you should be able to see them on DWC as well. If they become too hot, they shut down temporarily, but I still don't see how that could happen at 1000mA.

Chriss

@chrishamm

The config is handcrafted and I'm sure I used one of my other printers as a template. Maybe my Ratrif Vcast which is already at 3.3. Keeping 5 printers always at the very latest version is a challenge.

Be careful regarding the current. The LDO 14HS20-1504S are Nema 14 witch 1.5A max: https://www.omc-stepperonline.com/download/14HS20-1504S.pdf

Yes, the overheating message showed up in the DWC. My first reflex what a hardware issue in the direction of the crimping. The fact that the error message followed the driver No. after I changed the stepper to a other driver pointed me into this direction. That so I replaced all of them and had a close look than.

Anyway, the print went trough, finally. Without any layer change at a very slow speed. I will upgrade the firmware and redo some test. I will crank up the speed than. I'm happy enough that I have at least one working setup for now. Better slow printing than none printing at all.

Cheers, Chriss