Unable to print PLA

[wouldstain]

Continued from discussion in thread "Rotating Magnetic Sensor - Keeps Pausing Printer"

As previously mentioned... I cannot seem to print PLA regardless of slicer or slicer settings.

I've tested and changed many things in an effort to troubleshoot this issue. I have attempted to print old test and calibration gcode that were successful prior to the onset of this issue, I do not believe it's something I'm doing but I haven't ruled it out either.

The only remaining possible culprits are:

• Duet board
• Extruder
• Hotend
• Me (doing something stupid but again, I've tested files that previously printed
  without issue)

I do not understand how it can be any of those when PETG now prints with no issue since moving to 3.4-b5+1.

Additional info that raises suspicion re: Duet board:

• Randomly recurring issue where the BLTouch pin does not extend on command
  or during home function. Requires manually pulling pin and subsequently
  clearing the error in order to successfully home the bed. I have replaced
  BLTouch and wiring 3x now. Happens often enough I created a macro for this:
  M280 P0 S160 ; BLTouch clear alarm -- Issue occurs randomly .
• Home function randomly does not complete. May complete X, XY or even full
  XYZ but not consistently.
• Sometimes receive Error: G0/G1: insufficient axes homed even after complete
  homing. Have tested all end stops and they are working.

Prior to adding the MFM, while printing PLA I would often find the extruder grinding away at the filament to the point where it could no longer feed and would eventually end up with a clogged nozzle or worse. This occasionally occurred with PETG but far less frequently. This has not happened again with PETG since installing 3.4-b5+1.

MFM has prevented nozzle clogs by stopping prints when filament is no longer feeding.

Things to know:

• Printer used to print PLA without incident.
• When pause occurs, I can manually extrude via DWC ui with no issue
• Can also hit resume button on DWC and print will resume with no issue
  aside from possible hiccup in current layer.
• Tested temps from 190-245C with PLA. Issue Persists.
• Tension knob on extruder is backed out 3 full turns after fully tightening. Have
  tried tighter and looser to no avail.
• Issue occurs with files that had previously printed successfully (old gcode files,
  no re-slicing)
• Issue has persisted across updates. Started with 3.2 and continues.
• Built new config.g following upgrade to 3.3. Used @JohnOCFI's published file as
  foundation. Only mods are things like G31, M92, M579, M671 and lighting kit.
  Issue persists across config.g changes.
• This occurs with both Prusa slicer and Cura. The Prusa config is from
  @JohnOCFII with only changes reflecting minor differences in hardware build
  (I'm using a Railcore 300ZLT).
• I've wiped both Cura and Prusa Slicers and started from scratch more than once
  assuming I changed something I shouldn't have. Also, clean install on new
  workstation.
• Replaced Nozzle, throat and all PTFE tubing.
• Replaced Extruder motor
• Disassembled and cleaned extruder multiple times
• Tried multiple flavors of PLA, same issue
• Installed new PEI sheet on flexplate (no bubbles)
• Installed Garolite sheet (bed is now super flat!) issue persists.
• Worked with @3lemental to dial in M92 settings. Extruder delivers exactly
  100mm length segments when tested over 5 samples. Issue persists.
• Switched extruder from E0 to E1 to test driver. Issue persists.
• Submitted test gcode samples in previous thread. Others were able to print
  successfully where my printer fails on identical files.

Hotend: E3DV6
Extruder: Bondtech BMG
Duet2 WiFi w/ Duex
Magnetic Filament Monitor
RRF 3.4-B5+1
DWC 3.4-B5
Duet Wifi 1.26

111321_config.g

Any thoughts or insight would be very much appreciated! Been banging my head against this for months with no improvement.

; Configuration file for My Printer -  based on config from @JohnOCFII
; Communication and general




; Debugging
M111 S0                             				; Debug (S0 = off, S1 = on)
M929 P"eventlog.txt" S0								; set logfile to eventlog.txt
M915 X Y S10 F0 R1									; log motor stalls

; General Preferences
G21													; work in mm
G90													; Send absolute coordinates...
M83													; ...but absolute extruder moves

M555 P2												; Set output to look like Marlin
M669 K1												; Select CoreXY kinematics (RRF 2.03 and later)

; Network and network services
M550 P"RailCore"									; Machine / Netbios name
M552 S1												; Enable WiFi
M586 P0 S1											; Enable HTTP
M586 P1 S0											; Disable FTP
M586 P2 S1											; Enable Telnet

; Motor Drivers
M584 X0 Y1 Z5:6:7 E3        						; Map Z to drivers 5, 6, 7. Define unused drivers 4,8 and 9 as extruders along with (actual) 3 TESTING E4 - returned to E3 10.26.21
M569 P0 S0                          				; Drive 0 goes forwards  	X/Y stepper (front?)
M569 P1 S1                          				; Drive 1 goes backwards	X/Y Stepper (rear?)
M569 P2 S1                         					; Drive 2 goes forwards		(unused)
M569 P3 S0                          				; Drive 3 goes forwards		Extruder (forward for LDO motor)
M569 P4 S0                          				; Drive 4 goes forwards		(unused) E1 Port
M569 P5 S0											; Drive 5 goes backwards	Front Left Z
M569 P6 S0											; Drive 6 goes backwards	Rear Left Z
M569 P7 S0											; Drive 7 goes backwards	Right Z

; Panel Due Display config
M575 P1 B57600 S1									; Comms parameters for PanelDue

;Leadscrew locations
;M671 X-10:-10:333  Y22.5:277.5:150 S7.5 			;Front left, Rear Left, Right  S7.5 is the max correction - measure your own offsets, to the bolt for the yoke of each leadscrew
M671 X-6.5:-10.24:341.54 Y6:260.81:131 S7.5 		; Test 

; Axis and motor configurations
M350 X16 Y16 Z16 E16 I1	    						; set 16x microstepping for axes& extruder, with interpolation
M906 X1400 Y1400 Z1000 E800 I60	    				; Set motor currents (mA)
M92 X200 Y200 Z1600 E814	    					; steps/mm -> 092021: droped E from 837 to 830. tested at 814
M566 X1000 Y1000 Z100 E1500            				; Maximum jerk speeds mm/minute
M201 X3000 Y3000 Z100 E1500          				; Accelerations (mm/s^2)
M203 X24000 Y24000 Z900 E3600      					; Maximum speeds (mm/min)
M84 S60												; Set motor idle timeout
M579 Z.99255 										; Scale Z Axis.  Old values: X1.0033 Y1.0046						

; Axis Limits
M208 X305 Y280 Z570	                 				; set axis maxima and high homing switch positions (adjust to suit your machine)
M208 X0 Y0 Z-0.5 S1                 				; set axis minima and low homing switch positions (adjust to make X=0 and Y=0 the edges of the bed)

; Endstops
M574 X1 S1 P"xstop"									; Set X endstop to xstop port active high
M574 Y1 S1 P"ystop"									; Set Y endstop to ystop port active high
M574 Z0 S585										; Set Z endstop to BLTouch Probe

; Z-Probe - BLTouch "Smart v3"
M950 S0 C"duex.pwm1"								; Define BLTouch Service (S0) on pwm1
M558 P9 C"^zprobe.in" H5 F150 T6000 A5 S0.02		; BLTouch connected to Z-Probe in pin
M208 S1 Z-0.2										; set minimum Z-0
;G31 X-1.8 Y31.12 Z2.311 H5 P25						; Offsets adj Y fr 42 to 31.12 102121 X fr -4 to -1.8 HS.04 Noz Btak Sheet: 101521 - 2.514 semi-working
;G31 X-1.8 Y31.12 Z2.349 H5 P25						; Offsets adj Y fr 42 to 31.12 102121 X fr -4 to -1.8 HS.04 Noz Garolite Sheet
G31 X-1.8 Y31.12 Z2.313 H5 P25						; combined flexpalte - garolite / PEI

; Duet3d Rotating Magnetic Filament Sensor
M591 P3 C"e0_stop" S1 D0 L26.5 R1:200				; filament monitor connected to E0_stop. 25mm/rotation Range 70-130%


; Mesh Bed Level info
M557 X10:295 Y10:290 S57:57							; From Tim Elmore / Filastruder  --  https://railcore.org/build_and_troubleshoot/bed_level.html
;M557 X103.9:228.9 Y77.32:192.32 P2:2				; calculated from Max_Plastic spreadsheet using actual offsets - 4 pt levelling


; Heaters
M308 S0 P"bedtemp" Y"thermistor" A"bed_heat" T100000 B3950 R4700 H0 L0 				; configure sensor 0 as thermistor on pin bedtemp
M950 H0 C"bed_heat" T0								; create bed heater output on bedheat and map it to sensor 0
M140 H0												; Inform firmware that bed heater 0 uses heater 0
M143 H0 S120										; Set temperature limit for heater 0 to 120C
M308 S1 P"e0temp" Y"thermistor" A"hotend_heat" T100000 B4725 R4700 C7.06e-8 H0 L0	; configure sensor 1 as thermistor on pin e0temp (Hotend)
M950 H1 C"e0heat" T1								; create nozzle heater output on e0heat and map it to sensor 1
M143 H1 S288										; Set temp limit for heater 1 to 288C
M308 S2 P"duex.e4temp" Y"thermistor" A"keenovo" T100000 B3950 R4700 C7.06e-8 H0 L0	; Secondary bed thermistor
M140 S0 R0											; Standby and initial Temp for bed set to 0 (-273 = "off")
M308 S10 Y"mcu-temp" A"mcu-temp"                    ; Display Duet2 CPU temp 

; Tools
M563 P0 D0 H1                       				; Define tool 0
G10 P0 X0 Y0 Z0                                   	; Set tool 0 axis offsets
G10 P0 S0 R0 F1                         			; Set tool 0 operating and standby temperatures(-273 = "off")

;M307 H0 R0.340 C1011.7 D27.77 S1.00 V24.1 			; Heater 0 - MIC bed
M307 H0 B0 R0.344 C393.5 D30.24 S1.00 V24.1
; M307 H1 R2.319 C204.6 D5.59 S1.00 V24.1 			; Heater 1 - Hot End
M307 H1 B0 R2.293 C190.7 D5.81 S1.00 V24.1			; Heater 1 - PID Tuned Values

; Fans
M950 F0 C"fan0" ;Q500								; create fan 0 on pin fan0 and set frequency
M106 P0 H-1 C"Parts_Fan"							; disable thermostatic mode for fan 0
M950 F1 C"fan1" ;Q500								; create fan 1 on pin fan1 and set frequency
M106 P1 S1 H1 T40 B0.1 C"Hotend" 					; enable thermostatic mode for fan 1

; LED Lights
M950 P8 C"duex.e3heat" Q500 						; Assign Pin X to expansion board h3 port
M42 P8 S1 											; send 24v to Pin X for LED lights _use S0.5 for 12V

; MCU Temp Calibration
m912 P0 S-13										; S = ((HE Temp + Bed Temp)/2) - MCU Temp)

;M570 S360											; Hot end may be a little slow to heat up so allow it 180 seconds

T0													; select first hot end

[deckingman]

@wouldstain The fact that you can print PETG coupled with the fact that you say the extruder grinds away at the filament leads me to think of one thing only. You are getting blockages in the heat break area, most likely because you have too much retraction which is pulling hot filament up into the heat break. Other causes of such blockages could be inefficient cooling of the heat break, or holding filament at print temperature for extended periods of time without printing. The reason you have the problem with PLA but less so with PETG, is that PLA has a lower glass transition temperature, so it will soften and deform more easily.

[PetrKroupa]

@wouldstain - Are you using Bontech BMG with gear 3:1? What kind of stepper do you use? 1.8 ° or 0.9 °? I use Bontech and my setings are mutch diferent.

M350 X16 Y16 Z8 E16 I1      		                            ; configure microstepping with interpolation
M92 X142.22 Y142.22 Z400.00 E420.00                      ; set steps per mm
M566 X600.00 Y600.00 Z60.00 E150.00                      ; set maximum instantaneous speed changes (mm/min)
M203 X18000.00 Y18000.00 Z1500.00 E7500.00               ; set maximum speeds (mm/min)
M201 X5000.00 Y5000.00 Z250.00 E5000.00                   ; set accelerations (mm/s^2)
M906 X1200 Y2500 Z2000 E450 I40         		                   ; set motor currents (mA) and motor idle factor in per cent

M591 D0 P3 C"121.io1.in" S1 R75:125 L24.8 E5.0

Have you tried measuring 100mm filament and extruding 100mm?

Can you tried to print with 0 retractions?

[o_lampe]

@wouldstain
This line in your config.g is invalid. See here

M574 Z0 S585										; Set Z endstop to BLTouch Probe

Why do you use a Duex pin to deploy the probe-pin? AFAIK there is only a AWG26 ribboncable to feed 5V to the Duex. Might be too much voltage drop for the BLTouch?

; Z-Probe - BLTouch "Smart v3"
M950 S0 C"duex.pwm1"								; Define BLTouch Service (S0) on pwm1

[rjenkinsgb]

With the multiple erratic problems, I'd suspect a power supply or power wiring problem as well..

[wouldstain]

@petrkroupa Yes i have. it delivers 100mm reliably.

[wouldstain]

@deckingman The issue only occurs when printing PLA. PETG prints reliably.
The grinding has become a non-issue since the addition of the MFM.

What is vexing about this is that there is no actual blockage. I am able to immediately issue a manual extrude command following a stop with no issue. To ensure there was no small / partial blockage, I replaced the nozzle, throat and PTFE tube between the extruder and hotend.

I am not holding filament at print temp for extended periods. This occurs randomly during any prints with PLA, and again, I can manually extrude immediately after the MFM triggers a pause due to lack of filament movement.

Additionally, I have attempted to print gcode that I had sliced and printed prior to the onset of this issue. These models will no longer print but the retraction settings are baked into the gcode.

I do not disagree about the difference in material properties being a factor, but I am baffled as to what else I can do to isolate the issue, although I have not yet tried replacing the heat break fan.

I will order a replacement heat break fan and give that a try, but otherwise, I am not sure what else is left.

Thank you!

[wouldstain]

@petrkroupa I'm using a 0.9 ° LDO motor. I'm looking at the packaging for the extruder and it does not indicate the gear ratio but looking at the website I believe it is 3:1.

As far as the settings go, what I'm using closely follows a widely used starter Railcore config.g. Additionally, the person who generated that original config has a very similar hardware setup (same extruder and extruder motor) so I would hesitate to start making changes there as I know his is working with these same settings.

I have tried printing with 0 retraction distance and 0 pressure advance as well as many combinations of both.

Thank you for responding! I really appreciate the input!

[wouldstain]

@o_lampe

Thank you! Corrected S value for M574!

As far as it connecting to PWM1, the connections are correct per
the Railcore build guide here.

[achrn]

This doesn't really fit all your symptoms, but what is the ambient temperature - that is, temperature of the air around the extruder?

I have a printer with direct drive extruder inside a fairly insulated enclosure, and PLA doesn't like it when the air in the enclosure gets too hot. The extruder is hobbed drive direct on the stepper shaft. If the air in the enclosure gets too warm, and the extruder gets hot, the stepper skips steps as if filamnet is jammed.

I fixed mine by gluing (with conductive epoxy) heat-sinks on the sides of the extruder stepper and arranging a fan and shroud to blow through the heatsink pins, plus opening the doors of the enclosure if it gets too hot.

I felt possibly the surface of the filament was softening enough to not feed nicely. I admit, it doesn't sound likely, but one hot summer I had all these filament feed problems, and cooling the stepper resolved them, so...

I'm not at all convinced this fits your case, because in a BMG the filament drive won't be getting heat conducted from the stepper, but it's another variable to explore...

[wouldstain]

@rjenkinsgb

I do not think there are any wiring problems but I was planning on doing a rewire to switch to a drag chain configuration in the near future, so I will be re-seating / reconnecting everything.

I had not considered the power supply as a possible source of trouble as PETG prints consistently. I do not have another 24V power supply to to test with, however I would expect that if there was any dip in voltage output I would see a dimming in the lighting kit.

I do have a fluke meter with data logging capabilities if you happen to have some suggestions on what to look for.

Thank you for your input! I would love to get this put to rest!

[deckingman]

@wouldstain said in Unable to print PLA:

................. What is vexing about this is that there is no actual blockage.

Well that depends on how you define blockage. The fact that you've had the extruder grinding away at the filament indicates that there must be some sort of restriction. As I tried to explain, PLA has a very low glass transition temperature of about 60 deg C. So, if you get heat creep up through the filament, or if you pull pull too much filament out when you retract, then you can end up with filament that is above the glass transition temperature, inside the heat break. When you then "unretract" the filament, the pressure from the extruder will the cause this softened filament to swell and bulge out sideways rather than travel forward, and so it (partially) blocks the heat break - or more precisely, it causes a restriction. I'm even more convinced that this is what is happening because you say that you can then manually extrude. Which indicates that the swollen filament inside the heat break has either cooled and hardened, or it has softened further and thus become less viscous.

I do not disagree about the difference in material properties being a factor, but I am baffled as to what else I can do to isolate the issue, although I have not yet tried replacing the heat break fan.

I will order a replacement heat break fan and give that a try, but otherwise, I am not sure what else is left.

Before you do that, reduce or disable retraction and see what happens. The print might have blobs and be stringy but it will prove a point one way or another. Ideally, look at using firmware retraction (G10/G11). This is much better because it enables you to tune it "on the fly" - both distance and speed.

EDIT. By they way, I've spent the last two years designing and building prototype hot ends, and before that spent a few years "taming" multi-input mixing hot ends. I've seen exactly the sort of thing you describe many times.

[wouldstain]

@deckingman Just tried multiple test prints with zero retraction

First one:

MFM stopped the job with the following error:
"Extruder 0 reported 'tooLittleMovement'"

Output from M591 D0:

Duet3D rotating magnet filament monitor v3 on pin e0stop, enabled, sensitivity 26.50mm/rev, allow 1% to 200%, check every 3.0mm, version 3, mag 130 agc 74, measured sensitivity 26.48mm/rev, min 0% max 105% over 606.9mm

If not for the MFM, this is where it would the extruder would start grinding away at the filament.

Repeated test with similiar results with temperatures ranging from 190C to 230C.

Also:
m572
Extruder pressure advance: 0.000

[PetrKroupa]

@wouldstain - Firts your AGC value is too low.

In my opinion, a 0.9 stepper on a geared extruder doesn't make sense. 0.9 always has less torque and less speed at the same voltage. Maybe it's one of the problems you have. PLA is relatively dense and is more difficult for the extruder to extrude.

[o_lampe]

@wouldstain said in Unable to print PLA:

As far as it connecting to PWM1, the connections are correct per
the Railcore build guide here.

Do you use an external 5V supply for the Duex? Otherwise the BLTouch servo connection is shady

[deckingman]

@wouldstain said in Unable to print PLA:

@deckingman Just tried multiple test prints with zero retraction ..................

If not for the MFM, this is where it would the extruder would start grinding away at the filament.

Repeated test with similiar results with temperatures ranging from 190C to 230C.

But you can reliably print PET-G yes? Have you tried recently? It would be important to know for sure if this is related only to PLA or if some other factor has crept in between you trying PET-G and then switching to PLA.

[T3P3Tony]

@wouldstain said in Unable to print PLA:

any dip in voltage output

You can check this by sending M122 - Vin voltage is monitored by the Duet.

@petrkroupa said in Unable to print PLA:

@wouldstain - Firts your AGC value is too low.

AGC can be too high (over 110 or so) but not really too low in our MFM design. A lower value indicates the magnetic field is being sensed more strongly, so better. (it is presumably possible to have a huge magnet and have a different problem but that does not apply here.

@wouldstain
can you try the following test:

1. Slice a file for PETG, that previously did not work for PLA, preferably with no retractions.
2. Confirm it prints correctly with PETG
3. manually edit just the temperature setting at the beginning of the file to be appropriate for PLA.
4. reprint it with PLA.

[wouldstain]

@t3p3tony

After @deckingman's replies, I took a closer look at the heat break fan and realized it could be seated a bit lower
on the heat sink and moved it. Sadly it did not change the results.

Tried another PLA job @200 and 215 with same result. M122 Voltage looks normal.

M122.txt

I will follow up with a PETG and PLA with manually adjusted temp and post results.

[wouldstain]

@o_lampe Duex has it's own positive lug on 24V power supply. Negative is chained with main board per build instructions here+Wiring+the+Electronics/16?lang=en).

[wouldstain]

@petrkroupa The extruder and motor combination is common configuration for Railcore.
AFAIK I'm the only one having this issue so it's something specific to my components, physical installation, or slicing. However, the slicing has been tested by others already in previous thread and as I've mentioned, this has not always been a problem.

Aside from cleaning the hotend, extruder and swapping out the nozzle, throat and bowden tubes, the rest of the configuration is relatively unchanged from initial build when it was working.