Unable to print PLA

[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.

[fcwilt]

@wouldstain

What kind of PLA are you trying to print?

Certain types of PLA require little or nor retraction.

Frederick

[wouldstain]

@fcwilt Ive tried several brands of PLA, all with the same result.

[wouldstain]

@t3p3tony PETG printed as well as you would expect with no retraction or pressure advance... ugly corners and some stringing across axis markers on XYZ calibration cube.

PLA wont even finish the starting nozzle wipe at the moment. Tried three times.

Only differences in setup:

PETG:
Layer 1 Print temp: 235C
Layers > 1 Print temp: 230C
Z offset: -.15

PLA:
Print Temp: 220C
Z offset: 0

This is a new error:
M120 M83 G1 E100 F300 M121
Error: G0/G1: insufficient axes homed

Also found this in the console from earlier:
M290 R1 Z-0.05
Error: M290: insufficient axes homed
Error: M290: insufficient axes homed

Again, all axis are homed and machine starts up PETG jobs normally.
Not sure if this is related or not but I don't imagine I should be seeing these errors.

Both gcode files attached.

no_retract_PLA_220_xyzCalibration_cube.gcode

no_retract_PETG_230_xyzCalibration_cube.gcode

[wouldstain]

@T3P3Tony One other thing I just remembered, not that it should make a difference... When I replaced the heatbreak, I used Boron Nitride paste rather than white thermal grease (had some handy at the time!) but I don't think this is the issue as the problem started prior to replacement.

To eliminate this as a variable, I have ordered some white thermal grease of the same composition as that provided by E3D in their hotend kits. It should be here tomorrow so I will pull apart the hotend, clean it and put in another heatbreak with white thermal grease. That should return it to as absolutely close to its original configuration as I can get it.

@deckingman's responses re: glass transition point have me going over everything in my head that could impact temperature at the heatbreak.

[T3P3Tony]

@wouldstain said in Unable to print PLA:

M122.txt
Supply voltage: min 23.9, current 24.1, max 24.3, under voltage events: 0, over voltage events: 0, power good: yes

That shows that between the last M122 and that M122 (or power up) you have not had any power issues with VIN.

@wouldstain said in Unable to print PLA:

M120 M83 G1 E100 F300 M121
Error: G0/G1: insufficient axes homed
Also found this in the console from earlier:
M290 R1 Z-0.05
Error: M290: insufficient axes homed
Error: M290: insufficient axes homed

that looks like you tried to babystep without the axis homed.

When you say it wont print past the pruge line, do you mean the filament monitor errors at that point?

[wouldstain]

@t3p3tony

that looks like you tried to babystep without the axis homed.

I did indeed! one less thing to worry about!

When you say it wont print past the pruge line, do you mean the filament monitor errors at that point?

Correct. In fact, I just took a look at the bed and the purge line looked to be about half of normal length when it paused.

Extruder 0 reported 'tooLittleMovement'

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 131 agc >>75, measured sensitivity 1079.51mm/rev, min -31% max 133% over 16.9mm

Even though I've never set a firmware retraction value or used G10/G11, I did take a look at M207 just to see if there was anything and found this:

Tool 0 retract/reprime: length 2.00/2.00mm, speed 16.7/16.7mm/sec, Z hop 0.00mm

dont know if that matters w/o G10/G11 calls but it is there.

[o_lampe]

@wouldstain said in Unable to print PLA:

Duex has it's own positive lug on 24V power supply

That's not related. Duex boards only have a 12V buck converter, but no 5V.
There's a 5V_AUX_IN connector and a 5V_AUX_Select jumper for servo power.

[deckingman]

@wouldstain As bizarre as this sounds, try printing PLA at a lower temperature. If you can't even get beyond purging/priming, that indicates the flow restriction (lets call it that rather than blockage) happens very early on. So maybe you are seeing heat creep up through the filament during the warm up phase, such that the PLA inside the heat break is already above it's glass transition temperature by the time you try the first extrusion. Looking through your gcode file, I note that you are setting the temperature to 220 deg C which is at the top of the range for PLA. So if you set the temperature to the low end at say 190, that 30 degrees lower might be enough to prevent the filament inside the heat break from reaching it's glass transition temperature.

Is this a genuine E3D V6 by the way, or is it a clone? Is the heat sink cooling fan working properly? Try a high flow fan if you can.

[wouldstain]

@deckingman I've tried it at 190 but I'll give it another try with this same file w/ manual adjustment.

I bought all of the parts from Filastruder so I have to believe it's not a clone.

The fan is the one that came with hot end. If you have any recommendation for a 24v high flow fan and mount, at this point I'd certainly give it a shot.

[wouldstain]

@o_lampe

After re-reading your posts and looking at the duex drawings, I now understand what you're saying a bit better. You think there might be too much of a voltage drop at the PWM headers to drive the BLTouch as the 5V power source is the WiFi board...

That's probably a discussion for @T3P3Tony here and the other smart folks who design the railcore stuff on the railcore discord.

I'm hesitant to make any connection changes without very clear instructions on how to test and what changes to make.

Thank you though! I havent been playing with this long enough to feel confident in doing that sort of thing without guidance from someone with more knowledge and experience than me.

[fcwilt]

@wouldstain

I drive a BLTouch from a Duex5 without any problems.

This is the M950:

M950 S0 C"duex.pwm5"                      ; create servo pin 0 for BLTouch

Frederick

[wouldstain]

@deckingman Ran it at 190. got as far as the skirt loop then stopped.

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 132 agc 75, measured sensitivity 30.15mm/rev, min 0% max 121% over 24.8mm

[Phaedrux]

Are you saying that the filament sensor is stopping the print after the skirt? If you disable the filament monitor does it complete?

[wouldstain]

@phaedrux No. By stopping the print, the filament sensor is preventing the extruder from grinding the filament.

[deckingman]

@wouldstain About the only other thing I can think of which would cause the print to fail so quickly due to lack of filament movement, is if the nozzle is so close to the bed that it is preventing the filament from exiting. But if that is the problem, then it should be the same for both PLA and PETG.

Suggest you try increasing the Z offset by at least a layer height or even more. It might be that the print will fail because it won't adhere to the bed, but even if it's an "air print", if the extruder continues to run, it will prove a point.

[wouldstain]

@deckingman Agree.. that was one of the first things I looked at. Sadly, if I raise the head any higher (+.05), filament does not stick to the bed and just gets dragged around. This was true on PEI and is now true on garolite w/ elmers glue stick. I havent tried it on garolite w/ bed weld but that may be next.

In the mean time, I'm going to tear down hotend again, clean out the boron nitride paste and apply white thermal grease. Seems like it shouldnt make a difference but I think restoring it to as close to the condition it was in the last time I was able to successfully print PLA is the way to go.

[wouldstain]

@deckingman replaced heat-damaged heatsink fan and added higher cfm fan. no improvement.
I'm thinking of moving to a mosquito hotend and ditching the E3D V6 at this point but if that doesnt work that leaves only the extruder and the Duet board as possible problems.

[theruttmeister]

@wouldstain Have you tried a different thermistor? Even good quality thermistors can be highly variable...I've seen them vary by +/- 20C from device to device. What you think is 190C might actually be 210C...

The other thing I'd check is if the idler force on the extruder drive is actually too high. People often think that gripping the filament more tightly is a solution, but that rapidly loads up the drive bearings and can often deform the filament to the point it cannot feed through rest of the filament path.

[wouldstain]

@theruttmeister

Thank you for responding!
I actually had to replace the thermistor at one point, and this problem was already present when I replaced it and still persists.

One thing I did find today was that I was using the wrong beta value for it. My base config came with 4750. The E3D documentation specifies 4267. I do not know how significant that change is, but I did make it hoping it would resolve the issue.

To set the idler tension I screwed it all the way in (w/o filament) and then backed it out 3 full turns. I was advised that this is the right tension setting for the Bondtech BMG. It seems to work quite well for PETG and TPU. I have not had anyone tell me that idler tension should be set differently for PLA but I am always open to suggestions!