Duet 0.6 Extruder issues.

Hey all,

I'm having issues I suspect with the extruder driver on my duet 0.6 (from replikeo). Everything has been working perfectly, then a couple days ago it stopped extruding while printing. But only while printing. When I pause the print, or just using the web ui I can extrude just fine, but when printing the extruder motor just vibrates and doesn't move. It does move when it hits a retraction (currently set to 2mm). I can reproduce the problem by repeatedly sending a line of gcode pulled from the file i'm printing (G1 X-26.214 Y3.542 E0.05192), interestingly if I remove the X & Y and send G1 E0.05192 everything works fine. I can replicate the issue with multiple different steppers, with and without even connecting them to my extruder, so it doesn't seem to be the stepper, or a jamming issue.

Thoughts?

I did recently add some new steppers, which are 2A because that's what they had at the US warehouse. I'm having to run at a much higher mA rating in config.g (M906 X1800 Y1800 Z1800 E800). But I had quite a few successful prints this way before things went haywire...

Not sure what other info to add. I'm running 12v, an atx PSU @400w, steppers mentioned above

I have a duet wifi preordered, but it's batch 3(?) and I'd like to have something working in the meantime...

edit: I've checked that my wiring is all snug, 12v supply seems fine (it heats the bed & hot end & drives the 3 movement steppers just fine). Tried both relative and absolute extrusion.

Thanks!

Edited 1 time(s). Last edit at 07/21/2016 12:12AM by wrangellboy.

1.8A is very high for the A4982 drivers on the Duet. I recommend 1.5A maximum, which is the highest current for which the A4982 has guaranteed specifications. To run at 1.8A you will need to cool the board very well with a fan, especially the underside. If the drivers get too hot then they go into thermal shutdown, which I suspect is what is happening when extrusion fails. When the printer is paused or idle, the motor currents are reduced after 30 seconds, which is probably why you can extrude then.

Try improving the cooling of the board and/or reduce the motor currents to 1.5A.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I knew 1.8A was pretty high. I do have a cooling fan across the top of the board, not the bottom. I'll try to get some better cooling and drop the mA back down to 1500 and see if that resolves things for now. I believe the drivers on the Duet Wifi can accomodate more amps, is that correct? In either case it seems the 17HM19-2004S steppers I have are not really suitable for current Duet boards, they miss steps at 1.5A on my machine and it's pretty smooth mechanically with little extra weight on the head.

Thanks for the input!

I'm surprised that your 2A motors miss steps at 1.5A. I use 1.68A motors on my delta and I run them at just 1A. In fact they work OK at 0.8A except for high speed high acceleration travel moves.

What sort of printer is yours? If it is a Cartesian with a bed moving in the Y direction, then it is likely that the X motor doesn't need as much current as the Y motor. Also, what are your acceleration and jerk settings? Reducing them may allow you to reduce the motor currents.

HOWEVER, I just re-read your message and I see you are using just 800mA for the extruder. So I doubt that the problem is caused by extruder driver overheating. My best guess is that you have either an intermittent connection in the E motor wiring loom, or a bad soldered joint on one of the pins of the stepper driver chip that drives the E motor, or a bad soldered joint where the E motor connector is soldered to the Duet..

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

The printer is a folgertech kossel. Or was, really only the frame & linear rails remain stock. I was a bit surprised by how hard I had to drive the steppers as well. I've tried backing the xyz steppers down to 1500mA, and it doesn't solve the problem.
The strangest part to me is that sending just E steps works (G1 E0.05192), but sending xy moves along with E steps fails (G1 X-26.214 Y3.542 E0.05192), even in the case when that command results in no movement (ie sending it repeatedly). Is there some limit to the amount of total mA you can simultaneously supply across all drivers? I would think I have plenty of amperage available via the PSU.

I'll take a closer look at the wiring for loose connections tonight. But wouldn't a loose connection manifest consistently whether it was printing or just extruding? That's the thing that has me scratching my head. If I pause the print at any point and just extrude via the web ui, it extrudes just fine. Restart the print and the stepper just starts twitching again.

Maybe I'll revert back to my old steppers and see if things start working...

When you send a G1 command that includes XY movement, the feed rate is assumed to refer to the XYZ movement speed. The extrusion speed will be whatever is needed to keep up. So specifying significant amounts of extrusion with only small XY movement will demand very high extrusion rates, and the extruder motor will skip.

Are you sure that you have the correct extruder steps/mm set in config.g, and the correct filament diameter and nozzle diameter configured in your slicer?

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I think it's the 17HM19-2004S steppers generating some kind of noise. As soon as any motion from the towers begins my extruder starts buzzing. So I tried an experiment, paused a print part way, unplugged the xyz steppers and unpaused the print. Extrusion works just fine...

I'd already ordered the lower amperage 17HM19-1684S steppers you recommended on your blog anyway, so I'll give those a shot when they get in. Odd thing is the new steppers worked just fine for a dozen or so prints before this issue cropped up, but they definitely seem to be causing the issue one way or another.

Not to dredge up a dead topic, but I received my 17HM19-1684S steppers and hooked them up. That didn't solve the problem. At this point I have parts on order to switch to 24v & a duet wifi so I figured I might as well have some fun. It looks like the culprit was M203 E3600. I switched it to E15000 and things are humming along nicely now.

For posterity, my config now looks like this:
M906 X1300 Y1300 Z1300 E700 ; Set motor currents (mA)
M201 X1200 Y1200 Z1200 E600 ; Accelerations (mm/s^2)
M203 X10000 Y10000 Z10000 E15000 ; Maximum speeds (mm/min)
M566 X600 Y600 Z600 E600 ; Maximum instant speed changes

Quote
wrangellboy
I think it's the 17HM19-2004S steppers generating some kind of noise. As soon as any motion from the towers begins my extruder starts buzzing. So I tried an experiment, paused a print part way, unplugged the xyz steppers and unpaused the print.

You are lucky that you didn't damage the stepper drivers. Never plug in or unplug stepper motors with the electronics powered up.

Edited 1 time(s). Last edit at 08/01/2016 03:11AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42

Quote
wrangellboy
I think it's the 17HM19-2004S steppers generating some kind of noise. As soon as any motion from the towers begins my extruder starts buzzing. So I tried an experiment, paused a print part way, unplugged the xyz steppers and unpaused the print.

You are lucky that you didn't damage the stepper drivers. Never plug in or unplug stepper motors with the electronics powered up.

I power my duet via different sources, 5v USB for the "low voltage" side and 12v via an atx psu. If I unplug the 12v before fiddling with steppers, is that safer? Either way, good to know.

It's certainly safer, but it might not be completely safe.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].