Horrible print quality since upgrading

totalitarian

@totalitarian:

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dc42 is the duet capable of 1/8 stepping?

The gcode Wiki is always a good resource for these sorts of question - see here https://duet3d.com/wiki/G-code#M350:_Set_microstepping_mode

Ah so that's why even though I set 1/8 my steps didn't need to change. Thanks. Running a new test at 1/8….

totalitarian

@Shen:

I'm also had a similar issue. I think it's caused by the non-linearity of micro steps. From my calculation, the pattern is repeating every full step of the stepper motor. I also tried a 0.9 degree stepper motor instead of the 1.8 degree motor I was using, the length of the pattern halved. Stepper motor current does affect micro stepping linearity, you need to find the optimal value. You may also try replacing the extruder motor which worked for me.

So are you saying it was the motor in the end that was causing the issue? Was it a failing motor?

totalitarian

Just noticed this in the wiki

If using a highly-geared extruder (for example, an extruder that uses a flexible drive cable to transmit the torque from the motor to a worm reduction gear), use a short low-inductance 1.8deg/step motor to drive it.

I'm not too electrically minded, but this is my motor, is it suitable?

https://www.amazon.co.uk/gp/product/B01J3IKKHW/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Size: 42*40mm
Weight: 279g
Voltage: 3.3V
Current: 1.5A
Power: 35W
Step Angle: 1.8°
Phases: 2
Resistance: 5.2Ω±10%
Inductance: 9.0mH±20%
Holding Torque: 4.0Kg ·cm
Detent Torque: 150g·cm
Insulation resistance: 500VDC 100MΩ
Insulation class: B
Rotor inertia: 57g ·cm²

dc42

No. That motor is long and it has high inductance.

Shen

@totalitarian:

@Shen:

I'm also had a similar issue. I think it's caused by the non-linearity of micro steps. From my calculation, the pattern is repeating every full step of the stepper motor. I also tried a 0.9 degree stepper motor instead of the 1.8 degree motor I was using, the length of the pattern halved. Stepper motor current does affect micro stepping linearity, you need to find the optimal value. You may also try replacing the extruder motor which worked for me.

So are you saying it was the motor in the end that was causing the issue? Was it a failing motor?

It's not failing, but it might not be the best option for your extruder.

totalitarian

@dc42:

No. That motor is long and it has high inductance.

Could you suggest a specific stepper?

totalitarian

BTW, I reduced the steps to 1/8 but it made no difference. The diagonal lines had the same frequency

bot

Is there any way to revert to the original extruder setup, so that you can isolate the variables?

totalitarian

Sure, i'll refit my old titan this evening and do some more test prints

DjDemonD

This type of motor works for me for both flex3drive/nimble and titan:
https://www.omc-stepperonline.com/hybrid-stepper-motor/nema-17-bipolar-18deg-13ncm-184ozin-1a-35v-42x42x20mm-4-wires-17hs08-1004s.html

Its lightweight, and has enough torque to drive a geared extruder.

Long/large motors are needed when you need to achieve high holding torque, or to move a large heavy load such as a large 3 leadscrew bed etc.. for turning an extruder with gearing like 40:1 or 30:1 requires almost no torque at all. What more important is can you spin it up quickly and reverse it quickly.

The image with the cube above, does show what appears to be pulsing of the extruder, maybe this is the effect of the drive cable tightening and loosening as it turns. Grease it up and look at the path it takes to see if you can keep it from having to go around a tight radius.

totalitarian

Yeah i'm not convinced I have the optimal route for the cable worked out yet. I've also noticed that the cable doesn't spin concentrically at the motor end. Not sure if this makes a difference or not or how I would fix this

https://photos.app.goo.gl/lTdTj8taKpn6q29Z2

The only other stepper I have kicking around is the one recommend for the titan

https://e3d-online.com/nema17-slimline-stepper-motor

but this is 0.9deg.

T3P3Tony

I agree with bot, if its possible to split the issue to isolate the issue(s). I know people on this forum have had good success with flexible drives but minimising the number of variables changing at once can help to find the problem quicker.

totalitarian

OK I switched back to my E3D titian extruder. Not good news. Constantly skipping and then my x axis started stuttering too!

https://photos.app.goo.gl/MGCq8oO2NUPvVVIT2

Here is my config for the titian

[[language]]
; Drives
M569 P0 S0 ; Drive 0 goes backwards
M569 P1 S0 ; Drive 1 goes backwards
M569 P2 S1 ; Drive 2 goes forwards
M569 P3 S1 ; Drive 3 goes forwards
M92 X80 Y80 Z400 E800 ; Set steps per mm
M350 E16 I1 ; Configure microstepping with interpolation
M350 X16 Y16 Z16 I1 ; Configure microstepping with interpolation
M566 X300 Y300 Z24 E300 ; Set maximum instantaneous speed changes (mm/min)
M203 X30000 Y30000 Z600 E300 ; Set maximum speeds (mm/min)
M201 X500 Y500 Z100 E250 ; Set accelerations (mm/s^2)
M906 X800 Y800 Z800 E1100 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

And here is my M112

M122

[[language]]
=== Diagnostics ===
Used output buffers: 3 of 32 (8 max)
=== Platform ===
RepRapFirmware for Duet WiFi version 1.19 running on Duet WiFi 1.0
Board ID: 08DGM-95BNL-MGPSJ-6J1F8-3SD6T-1KZ3W
Static ram used: 21176
Dynamic ram used: 95960
Recycled dynamic ram: 1648
Stack ram used: 1304 current, 4840 maximum
Never used ram: 7448
Last reset 00:02:17 ago, cause: software
Last software reset reason: User, spinning module GCodes, available RAM 3232 bytes (slot 2)
Software reset code 0x0003, HFSR 0x00000000, CFSR 0x00000000, ICSR 0x00400000, BFAR 0xe000ed38, SP 0xffffffff
Error status: 0
Free file entries: 10
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 0.0ms
MCU temperature: min 18.9, current 19.4, max 20.6
Supply voltage: min 11.5, current 11.5, max 11.7, under voltage events: 0, over voltage events: 0
Driver 0: stalled standstill
Driver 1: standstill
Driver 2: stalled standstill
Driver 3: stalled standstill
Driver 4: standstill
Date/time: 2017-11-10 23:38:33
Slowest main loop (seconds): 0.004425; fastest: 0.000034
=== Move ===
MaxReps: 0, StepErrors: 0, FreeDm: 240, MinFreeDm 240, MaxWait: 0ms, Underruns: 0, 0
Scheduled moves: 0, completed moves: 0
Bed compensation in use: none
Bed probe heights: 0.000 0.000 0.000 0.000 0.000
=== Heat ===
Bed heater = 0, chamber heater = -1
Heater 1 is on, I-accum = 0.0
=== GCodes ===
Segments left: 0
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 idle 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 state is running
WiFi module is connected to access point 
WiFi firmware version 1.19
WiFi MAC address 2c:3a:e8:0b:07:75
WiFi Vcc 3.02, reset reason Turned on by main processor
WiFi flash size 4194304, free heap 38904
WiFi IP address 192.168.1.56
WiFi signal strength -37dBm
HTTP sessions: 2 of 8
Socket states: 2 0 0 0 0 0 0 0
Responder states: HTTP(1) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0)

dc42

Was that M122 report produced after a print, or before? The power supply voltage is a little low, and if it drops further when the heaters are on then you could be getting motor driver dropout due to the voltage going too low. OTOH if that M122 report is the first one you did after a print, then the minimum voltage is OK and there are no under-voltage events reported.

totalitarian

It was after, i'll boost it up a little

Dougal1957

Have you got anywhere with solving the issues with the prints yet it would be interesting to know.

Doug

MrBlom

I had similar problems with my drive shaft extruder
it was like long waves
the solution for me was to make a more solid mount for the e3d/heatsink
i was using the normal e3d heatsink with a clamp at the top
but i guess the cable made it "swing a little" making this long waves
after changing to the aero heatsink (it has 2 screw holes , so it can be screwdown very tight)
this problem vent a way

may not be your problem but try to add some straps or something to test if that's your problem

totalitarian

@MrBlom:

I had similar problems with my drive shaft extruder
it was like long waves
the solution for me was to make a more solid mount for the e3d/heatsink
i was using the normal e3d heatsink with a clamp at the top
but i guess the cable made it "swing a little" making this long waves
after changing to the aero heatsink (it has 2 screw holes , so it can be screwdown very tight)
this problem vent a way

may not be your problem but try to add some straps or something to test if that's your problem

You know it may have been that. I was using a piezo probe / mount. I did return the drive in the end as i'm afraid I had projects that needed to be completed by Christmas, so reinstalled my old extruder. I must say, the flex3drive creator was very helpful in supporting me but unfortunately I never got to the solution. I know other users who run a similar setup to me without issues. I can only assume it was a combination of the drive cable and my mount.

Mutley

Just to update on this. I received the parts back to assess what might have been the cause given that this patterning was highly unusual from a Flex3Drive. Not seen before, anomaly!

Returned unit was fitted to a machine. Printed perfectly, Found deformation on plastics due to heavy over tightening of bolts. Was able to recreate the issue to confirm s thats good.. Steps taken to prevent recurrance.