Prusa upgraded to duet, weird extrusion

Veti · 9 Dec 2019, 20:51

@Murloc992 said in Prusa upgraded to duet, weird extrusion:

Did you swap just X and Y steppers or all of them?

i only swapped x and y
https://e3d-online.com/high-torque-motor
(be aware i only found out they have no cut shaft, but they work nonetheless.)

Murloc992 · 9 Dec 2019, 20:57

@Veti said in Prusa upgraded to duet, weird extrusion:

(be aware i only found out they have no cut shaft, but they work nonetheless.)

You mean no flat spot?

Veti · 9 Dec 2019, 21:09

yes. i mainly got them because those were the only ones with swappable cable.

a good alternative are the steppers suggested here
https://www.thingiverse.com/thing:3382718

Murloc992 · 10 Dec 2019, 08:17

@Veti

Maybe you have pics of print results with E3D motors? I have some motors with same specs to buy locally, but E3D are.. cheaper?

Veti · 10 Dec 2019, 18:46

those where posted here
https://forum.duet3d.com/topic/9438/artefacts-on-walls

Murloc992 · 12 Nov 2019, 05:10

@Veti

Thank you. Now I just need to wait till my steppers arrive and update this post. Going to change X/Y and E.

Murloc992 · 17 Dec 2019, 22:55

So I've upgraded my motors to E3D ones:

X/Y: https://e3d-online.com/high-torque-motor
E: https://e3d-online.com/compact-but-powerful-motor

Now I have a WEIRD pattern that comes from the extruder motor:

(I know, my first layer is too high, I just wanted to test ASAP)

I can hear the extruder motor making such "patterned noise"..

I have started at 1000mA current(both driver and motor cool), then tried to make it 1400mA(driver a bit hotter than lukewarm, motor cool/warm) with no change in behavior. What is this artifact?

Veti · 18 Dec 2019, 06:29

@Murloc992 said in Prusa upgraded to duet, weird extrusion:

Now I have a WEIRD pattern that comes from the extruder motor:

are you sure its from the extruder? how does it look if you switch back to the old motor on the extruder?

Murloc992 · 18 Dec 2019, 07:22

@Veti

I am sure, it's making pulsing noise even when spinning alone, without any plastic or idler engaged.. The old one doesn't pulse.. I have tried increasing microsctepping and disabling interpolation (nothing), reducing current(nothing), increasing current to maximum(heat increased only)..

This is the best I got:

The pattern is uniform on all sides.

Last time I had it was when I had too thin wires for my motor on an old printer and wires were heating up. But these are E3D cables, I haven't even changed the pins, tried different cables too and they are not heating up at all even at maximum current..

The one I had on my old printer was extreme.. and fixed after changing the extruder cabling.

Murloc992 · 18 Dec 2019, 09:52

Maybe this could be related to low voltage? I use 12V. Also I got an advice to attempt to reduce microstepping of the extruder motor to 8 microsteps. I will lose the interpolation though.. Will this matter?

Need an expert here.

droftarts · 18 Dec 2019, 10:58

I'd say that somewhere in your extruder drive, a gear is running eccentrically, or there's some other mechanical factor that's causing the the filament to speed up and slow down as it passes through the extruder. Is the stepper motor geared to the hobbed drive, or directly connected? I'd look if the gear on the motor shaft is running eccentrically, due to the hole being off centre, particularly if it's a geared extruder drive, as this would give the short frequency of over/under extrusion you're seeing. If you're using Chinese cloned gears (I think the Bear uses Bondtech BMG parts), this is quite likely!

Edit: Could also be caused by using very coarse hobbed drive.

Ian

Murloc992 · 18 Dec 2019, 11:22

@droftarts

This might be a possibility. I use a genuine Prusa MK2.5S that was torn apart and resurrected into a Full Bear + Bear Extruder + Duet + New motors(now).

The gears are genuine Bondtech, extruder is as direct as it gets (Bear Extruder), but I wonder how can it be eccentric.. With old motor I didn't have this.. Maybe a difference in flatspots? Or could it have happened if I tightened onto the flatspot a bit angled? Maybe a bent motor shaft (I hope not..)?

droftarts · 18 Dec 2019, 11:38

@Murloc992 Quite possibly one of those! As it's so consistent, I'd think it has to be mechanical. If you can't spot anything obvious, maybe refit the old motor and revert extruder settings in config.g?

Ian

Murloc992 · 18 Dec 2019, 11:39

@droftarts

Every time I have to take the extruder of a prusa apart(including the wiring loom) I die a little inside, but I guess I will have to if I can't center the main gear..

Will need to upgrade the extruder wiring loom someday to use a PCB at the back, so the wiring loom will be independent..

Phaedrux · 18 Dec 2019, 18:16

The fact that you can hear it pulsing makes me think it's the motor itself. Does it still sound like that if you run it free of any connection to the extruder gearing?

Murloc992 · 18 Dec 2019, 20:39

The motor shaft is straight, the gear is straight. Motor switch didn't help. All of them pulse. I will try reducing my microsteps to 8.. Maybe somebody knows about a TMC parameter called "Velocity"? I remember there's some register adjustments but I can't find it at the moment..

Murloc992 · 18 Dec 2019, 20:41

@Phaedrux It does, in fact, all the 0.9 degree motors I bought sound like that. Even without load.. I suspect that I need to adjust something in the drivers themselves. I used 1.8 degree steppers, now I got 0.9 degree ones.

Phaedrux · 18 Dec 2019, 20:44

What is the power supply?

Murloc992 · 18 Dec 2019, 20:58

@Phaedrux Whatever came with Prusa MK2S originally.. 12V and I guess 20A? Maybe 15A, not sure.

Phaedrux · 18 Dec 2019, 21:01

Can you post the results of an M122 command after doing a print?