Prusa upgraded to duet, weird extrusion

[Veti]

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]

@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]

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

[Murloc992]

@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]

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]

@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]

@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]

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]

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]

@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]

@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]

@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]

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]

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]

@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]

What is the power supply?

[Murloc992]

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

[Phaedrux]

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

[Phaedrux]

Using 8x microstepping probably won't do much other than make the motor noisier.

I use the same E3D motor for my Titan aero without such a pattern.

[Murloc992]

@Phaedrux

M122
=== Diagnostics ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 2.04 running on Duet WiFi 1.02 or later
Board ID: 08DGM-9T6BU-FG3S4-6JKDD-3S06R-KBQ3D
Used output buffers: 3 of 24 (7 max)
=== RTOS ===
Static ram: 25680
Dynamic ram: 92824 of which 0 recycled
Exception stack ram used: 436
Never used ram: 12132
Tasks: NETWORK(ready,628) HEAT(blocked,1232) MAIN(running,1664) IDLE(ready,200)
Owned mutexes:
=== Platform ===
Last reset 00:06:26 ago, cause: software
Last software reset time unknown, reason: User, spinning module GCodes, available RAM 12132 bytes (slot 0)
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0441f000 BFAR 0xe000ed38 SP 0xffffffff Task 0x4e49414d
Error status: 0
Free file entries: 9
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 10.7ms, max retries 0
MCU temperature: min 41.3, current 41.7, max 42.4
Supply voltage: min 12.1, current 13.0, max 13.5, under voltage events: 0, over voltage events: 0, power good: yes
Driver 0: ok, SG min/max 0/384
Driver 1: standstill, SG min/max 0/400
Driver 2: ok, SG min/max not available
Driver 3: ok, SG min/max 0/463
Driver 4: ok, SG min/max not available
Date/time: 2019-12-18 23:02:44
Cache data hit count 1365610563
Slowest loop: 117.87ms; fastest: 0.06ms
I2C nak errors 0, send timeouts 0, receive timeouts 0, finishTimeouts 0, resets 0
=== Move ===
Hiccups: 0, FreeDm: 157, MinFreeDm: 146, MaxWait: 135474ms
Bed compensation in use: mesh, comp offset 0.007
=== DDARing ===
Scheduled moves: 357, completed moves: 353, StepErrors: 0, LaErrors: 0, Underruns: 0, 0
=== Heat ===
Bed heaters = 0 -1 -1 -1, chamberHeaters = -1 -1
Heater 0 is on, I-accum = 0.7
Heater 1 is on, I-accum = 0.6
=== GCodes ===
Segments left: 1
Stack records: 2 allocated, 0 in use
Movement lock held by null
http is idle in state(s) 0
telnet is idle in state(s) 0
file is doing "G1 Z2.198 X134.775 Y95.225 E0.63527" in state(s) 0
serial is idle in state(s) 0
aux is idle in state(s) 0
daemon is idle in state(s) 0
queue is idle in state(s) 0
autopause is idle in state(s) 0
Code queue is empty.
=== Network ===
Slowest loop: 83.15ms; fastest: 0.00ms
Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0) Telnet(0)
HTTP sessions: 1 of 8
- WiFi -
Network state is running
WiFi module is connected to access point 
Failed messages: pending 0, notready 0, noresp 0
WiFi firmware version 1.23
WiFi MAC address 80:7d:3a:15:2c:b0
WiFi Vcc 3.39, reset reason Turned on by main processor
WiFi flash size 4194304, free heap 25696
WiFi IP address 192.168.1.253
WiFi signal strength -44dBm, reconnections 0, sleep mode modem
Socket states: 0 0 0 0 0 0 0 0
=== Filament sensors ===
Extruder 0 sensor: ok

I am doing a print right now, so here you go.

FYI the PSU IS overvolted to 12.5V.

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

Using 8x microstepping probably won't do much other than make the motor noisier.

Yup, didn't do anything.