Extruder Motor Skipping and Inconsistent Layers
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@engikeneer Yes last night I pulled the extruder gear and gave it a thorough cleaning. No missing teeth and I cleaned out all the plastic in it. After doing so, the same problem presented.
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@mendenmh I have resistors on hand, I will try this and see what happens.
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@mendenmh Alright, I made a 100K resistor jumper and a 1K, tested them both out and got temperature readings of 25.4C for the 100k and 163.6C for the 1K. So it seems like the ADC chip is fine. At this point, really seems like there's something up with the readings coming off of my thermistor, or my heater cartridge isnt working properly. But seeing as both of my V6 hotends are doing the exact same thing...this seems to me to speak to some form of software issue...just not sure what.
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What's you duet input voltage? If I'm correct, the heater outputs run at the input voltage.
The Prusa heater cartridge is expecting 24V, so if you are running your Duet board at 12V input, you're running you heater at half power. This would result in the symptoms you've been seeing.
So verify that the hot end heater is rated for the actual heater output voltage you are using.
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@mikeabuilder If I recall correctly, Prusa switched to 24v with their MK3 system. I'm running a MK2S, which is running 12v. I know this because the bed level probe I'm using is 12v which I direct soldered to one of the the PSU output cables.
Now your question does make me wonder about my PSU and whether or not I'm providing enough current to my duet board. The PSU I'm using has 2 12v output leads. For the previous board which the duet is replacing, Both of those output leads fed into the board directly and then all the peripherals were powered off of that.
For the duet board, I took one of the 12v leads, tied it into Vin and took the other and used it to power my Z probe. Could it be that I'm not giving enough current to my board?
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The very first step that you should have done is to actually verify your operating temperature on your nozzle as reported by the temperature graph on the Duet web interface. I don't recall if you have reported that as having been done but it would be silly to start any thread complaining about poor extrusion if you haven't even verified temperature as reported by the temperature graph. I therefore assume this was actually done..
If you are running a 24V heater with a 12V input voltage then you are actually running at (I believe) one quarter of the rated output power and not at one half. With such a low output power, you would never achieve a proper nozzle temperature and your Duet board would shut down with a temperature fault.
In other words, it is highly unlikely that you have a heater to input voltage mismatch.
Please confirm that the temperature graph reports the correct temperature that you have set for your nozzle and that it doesn't wildly dip as soon as the part cooling fab starts up or you start printing (I am pretty sure that any of these fault conditions would result in an immediate heater fault that shuts down everything). -
@jens55 Thank you for your input. I do not have a voltage mismatch, as my board is being powered by a 12v PSU which came standard for my model of Prusa printer. I am using with it a 12V 30W E3D heater cartridge. I initiated a print just now, closely monitoring the temperature graph as the print went, and it stayed stable the whole time despite the extruder skipping. Temperature is not dipping upon start of print or upon turning on the part cooling fan. We are staying stable. I have not received any heater faults throughout my use of this board/printer combo, and if I request a print, it initiates. The only problem I am having is my extruder skipping when feeding filament whether extruding through DWC or upon printing.
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Late to the game here.
A 30W heater is pretty weak. Do you have any higher rated ones?
I would focus on getting smooth, even extrusion in mid-air.
The things that can affect that are:
- the stepper
- the extruder
- the connection between the stepper and extruder
- the extruder heater
- the extruder fan
- the part fan
- the spool of filament
- the spool holder
Have you tried removing the stepper and feeding the filament by hand. If it is not feeding smoothly you will feel it.
Do you have any means to measure the temperature of the nozzle directly?
Frederick
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The suspense is killing me .... could we have an update please ?
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@jens55 Yes, sorry. No meaningful change has occurred yet. Here's what I've done since my last post.
- Took apart the hotend and checked for any sort of blockage. None could be found.
Swapped nozzles again to a fresh 0.4mm.
Double checked extruder motor wiring to make sure there was no loose connections. none found.
Swapped heater block from 12v 30W heater to 12v 40W heater.
Removed Filament feed gear from extruder and cleaned it thoroughly.
Changed to another roll of PLA.
Verified that my hotend fan was set to always on.
Fed filament by hand through the hotend, no rough feeding was felt.
Unfortunately none of this has yielded any meaningful change and my extruder motor is still skipping when extruding into air or if attempting a print. Unless I'm still missing something, it seems like there's no hardware left to test and that this issue must be originating from something in the software somewhere, but I don't understand where. That's where I'm at right now.
- Took apart the hotend and checked for any sort of blockage. None could be found.
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@secretasianman7 said in Extruder Motor Skipping and Inconsistent Layers:
@jens55 Yes, sorry. No meaningful change has occurred yet. Here's what I've done since my last post.
- Took apart the hotend and checked for any sort of blockage. None could be found.
Swapped nozzles again to a fresh 0.4mm.
Double checked extruder motor wiring to make sure there was no loose connections. none found.
Swapped heater block from 12v 30W heater to 12v 40W heater.
Removed Filament feed gear from extruder and cleaned it thoroughly.
Changed to another roll of PLA.
Verified that my hotend fan was set to always on.
Fed filament by hand through the hotend, no rough feeding was felt.
Unfortunately none of this has yielded any meaningful change and my extruder motor is still skipping when extruding into air or if attempting a print. Unless I'm still missing something, it seems like there's no hardware left to test and that this issue must be originating from something in the software somewhere, but I don't understand where. That's where I'm at right now.
Well you can always step back to 3.3.0 firmware - which is what I use. Doing so would allow you to rule out 3.4.x as the problem.
What is the part number of the stepper motors you have tried. There is much more info that controls how a stepper performs than just the current rating.
How long is the wiring to the stepper? What gauge wire is it?
Based on my past experience it seems like the stepper is not up to the task.
Frederick
- Took apart the hotend and checked for any sort of blockage. None could be found.
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@fcwilt The stepper motor I started with was a Prusa LDO 018 stepper This model. The one I'm running currently is a creality 4240
Wiring on each is about 20-24 inches and it looks to be 24 gauge wire.
Here's why I dont believe it to be a stepper motor issue though. The machine I'm tweaking started its life as a Prusa Mk2S. The only hardware changes I've made to it thus far since installing a duet 2 wifi board have been the extruder stepper and an EZABL bed probe, instead of the PINDA the machine came with.
The machine functioned just fine before the board swap, and only developed these problems upon installing the duet 2 wifi. So with that in mind, how can it be a hardware problem when the same hardware functioned fine on a different board, right?
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@secretasianman7 said in Extruder Motor Skipping and Inconsistent Layers:
@fcwilt The stepper motor I started with was a Prusa LDO 018 stepper This model. The one I'm running currently is a creality 4240
Wiring on each is about 20-24 inches and it looks to be 24 gauge wire.
Thanks for that.
Here's why I dont believe it to be a stepper motor issue though. The machine I'm tweaking started its life as a Prusa Mk2S. The only hardware changes I've made to it thus far since installing a duet 2 wifi board have been the extruder stepper and an EZABL bed probe, instead of the PINDA the machine came with.
The machine functioned just fine before the board swap, and only developed these problems upon installing the duet 2 wifi. So with that in mind, how can it be a hardware problem when the same hardware functioned fine on a different board, right?
All of my printers have been kits I have modified to suit my desires or designs of my own. Two of them use the Duet 2 WiFi board, the other three use the Duet 3 Mini.
I have no problems extruding but there are three significant differences:
- I use the 3.3.0 firmware - I have never tried 3.4.x
- I use 24 volt power
- I use Zesty Nimble remote drive extruders. The steppers I use have a rated torque appx 50% more than the CR unit you listed.
These are the settings for the Nimble:
M92 E2750 ; steps per mm (suggested 2750) M203 E3600 ; max speed (mm/min) (suggested 3600) M566 E40 ; max instant speed change (jerk) (mm/min) (suggested 40) M201 E120 ; acceleration (mm/s^2) (suggested 120) M906 E500 ; motor current (mA) (suggested 500)Perhaps the drivers on the previous controller are better suited to your stepper motors.
If there was some sort of terrible flaw in the Duet 2 WiFi it would be well known by now. Is your board a genuine E3D board?
At this point I would suggest first stepping back to 3.3.0 firmware and see if that makes a difference.
If that didn't change anything I would think about using a 24 volt power supply. At a minimum that would involve changing fans. The voltage rating of the CR stepper is reported as 4.8. The steppers I use are 2.8. I seem to recall that the voltage rating of a stepper can play a role in how well it works on 12 volts.
Maybe @dc42 will jump in here and have an idea.
I'll keep thinking on it.
Frederick
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@fcwilt Thank you for all your thoughts and suggestions. To my knowledge, I am running a genuine duet board. It came from Matterhackers.
I don't mean to imply that there is something wrong with the duet boards, I wouldn't buy that myself. I simply feel that whatever problem I am experiencing with my setup originates with some sort of software misconfiguration or perhaps a mismatch of how my hardware was originally configured to run, vs how it is being run now. I am also very open to the idea that I have some sort of either firmware misconfiguration or poorly setup config file, as this is my first time doing anything with a 3d printer that isn't factory stock. I could have easily messed something up, or just have a lack of knowledge or understanding somewhere that is leading me to have this issue.
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@secretasianman7 said in Extruder Motor Skipping and Inconsistent Layers:
@fcwilt Thank you for all your thoughts and suggestions. To my knowledge, I am running a genuine duet board. It came from Matterhackers.
I don't mean to imply that there is something wrong with the duet boards, I wouldn't buy that myself. I simply feel that whatever problem I am experiencing with my setup originates with some sort of software misconfiguration or perhaps a mismatch of how my hardware was originally configured to run, vs how it is being run now. I am also very open to the idea that I have some sort of either firmware misconfiguration or poorly setup config file, as this is my first time doing anything with a 3d printer that isn't factory stock. I could have easily messed something up, or just have a lack of knowledge or understanding somewhere that is leading me to have this issue.
Well reverting to 3.3.0 should be a piece of cake.
You should only have to download Duet2and3Firmware-3.3.zip and upload that to the Duet via the DWC.
Have you made any changes to config.g recently? Do you have a config-override.g file?
I don't recall seeing any problems with the config.g file I looked at but it was a while back.
Frederick
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@fcwilt Alright, I just reverted to 3.3, heated to 215 and tried extruding into the air again, and its the same result. Skipping motor. I do notice that when I put my fingers on the filament and exert some downward pressure, I can get it to extrude with no skipping. I haven't made any changes to the config file since the last one I posted.
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@secretasianman7 said in Extruder Motor Skipping and Inconsistent Layers:
@fcwilt Alright, I just reverted to 3.3, heated to 215 and tried extruding into the air again, and its the same result. Skipping motor. I do notice that when I put my fingers on the filament and exert some downward pressure, I can get it to extrude with no skipping. I haven't made any changes to the config file since the last one I posted.
Well good - so now we know that the firmware is not the problem.
The fact that adding external force using your hand makes the symptoms go away reinforces my belief that the stepper, for some reason, is not able to do the job.
Which takes me back to thinking that using a 12 volt power supply with a 4.8 volt stepper may be the problem.
Not too long ago I updated all of my 12 volt printers to 24 volts because of performance issues related to running steppers on 12 volts. BUT I don't recall exactly what the issue was. The problem was described to dc42 and his suggestion was to move to 24 volts - and it solved the problem.
Frederick
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@fcwilt Sounds like my next test will be to swap to 24V and see what happens then. Thank you for all your input.
EDIT: Upon second thought, I'd really like to avoid swapping to 24v if at all possible, because then I'm going to have to replace a lot of parts like my heater cartridge, bed heater and fans. Secondly, I've got a friend with a duet board printer he built thats 500x500, running 2amp steppers for his machine and he's on 12v running his machine without an issue. Also to add to that, once more, this machine worked perfectly in its original configuration on 12v before swapping to the duet board, so how could the origin on my problem be a voltage issue?
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@secretasianman7 Interesting update: Just put a temperature probe from my meter under the silicone sock on the hotend and saw a consistent 20C temperature difference between what the duet reported vs what was on my meter. Throughout all temperature ranges tested, the meter reported 20C lower temperature than what was posted on the duet. This leads me to think I've got a thermistor issue of some sort. Any thoughts anyone? Where might I go from here?
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@secretasianman7 It's really hard to get good enough thermal contact to get closer than 20 degrees, unless the probe is really clamped in a well, the way the thermistor is. This is close enough that it probably means your hot end is fine.
I had a thought about the extruder motor. Try the following: with no filament in it, send it a command that makes it run for a good long time (5-10 minutes). It doesn't need filament, since with a current-regulated drive, the heating of a stepper is pretty much independent of its load; it is just I^2 R. Multiple short runs, back to back, are fine, too. Now, put your hand on the motor. My criterion for how hard I like to push a stepper (if necessary) is that at this point it is fairly hot. Not so hot that it burns, but hot enough that it is very uncomfortable to hold your hand on for an extended period. This puts the outside of the motor in the 50C-60C range, which is way inside the safe range. If your motor is much cooler than this, you can certainly raise the drive current without any risk.
