Unstable extruder temperature reading

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Anubis
Posts: 21
Joined: Thu Dec 15, 2016 12:58 am

Unstable extruder temperature reading

Postby Anubis » Fri Dec 29, 2017 10:40 pm

I have two N2 printers, and one of them has an issue with the extruder temperature reading that I can't figure out. I'm looking for suggestions to help track down and fix the issue.

The temp reading on both of the extruders will jump around by up to +-8 degrees. And it's not just a display error, as the heater LEDs show that the heaters are responding to the displayed temperature. Here's a video (Google Drive):
https://drive.google.com/file/d/1GgET7q ... sp=sharing

At first I thought it might be an EMI issue in the thermocouple signal lines, but that both readings jump simultaneously and in the same direction seems to indicate... something else.

Here's a list of things that I have tried:
  • Replace thermocouple
  • Replace extruder connection board
  • Replace hotend
  • Insulate hotend
  • Add a capacitor across the thermocouple terminals
  • Swapped left and right extruders (nothing changed; they both do it)
  • Updated firmware (currently 1.1.6rev1)
  • Updated touchscreen software (currently 0.9.2.1026)
  • Stared vapidly at the control board for an hour

I'm out of ideas. The only thing I haven't played with yet is the control board. It may be worth noting that this particular printer came with the controller board's blower fan plugged into the HE2 (heater 3?) port, causing some overheating issues early in its life.
Last edited by Anubis on Fri Dec 29, 2017 11:26 pm, edited 1 time in total.

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Michael.P@Raise3D
Posts: 225
Joined: Wed Jul 20, 2016 4:51 pm
Location: Costa Mesa
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Re: Unstable extruder temperature reading

Postby Michael.P@Raise3D » Fri Dec 29, 2017 11:02 pm

Hi Anubis,

if you would like to send us a support ticket so we can generate a ticket and run through the options im sure we can come up with something to help you. If you already have a ticket let us know the number and we can reopen it and look into the problem at hand.

It is normal for the temp to fluctuate a bit when printing but this is something else.
Michael Petitclerc, Technician
Tel: +888 963 9028
Web: http://www.raise3d.com

Anubis
Posts: 21
Joined: Thu Dec 15, 2016 12:58 am

Re: Unstable extruder temperature reading

Postby Anubis » Fri Dec 29, 2017 11:30 pm

Ticket submitted, thanks.

Hangry Jason
Posts: 12
Joined: Sat Jan 06, 2018 1:25 am

Re: Unstable extruder temperature reading

Postby Hangry Jason » Tue Jan 23, 2018 6:45 pm

I was wondering if there was a solution found for this? I'm trying to track down some very minor inconsistent layer issues on my prints and noticed my temperature fluctuates 8-9 degrees according to the display. I've performed the pid auto tuning which didn't make a difference, and insulated the hot ends, then re-ran the paid auto-tune, still no change. If I set my temp for 210c for the length of any print my temperature will dip to 205ish, and raise to 213-214ish. I haven't had much time from work lately to keep troubleshooting though, so I've been browsing google and the forums on my phone. From what I can tell after pid tuning the variance in temp should only be 2-3 degrees. Right?

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Vicky@Raise3D
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Joined: Fri Mar 25, 2016 3:54 am

Re: Unstable extruder temperature reading

Postby Vicky@Raise3D » Wed Jan 24, 2018 3:10 am

Hangry Jason wrote:I was wondering if there was a solution found for this? I'm trying to track down some very minor inconsistent layer issues on my prints and noticed my temperature fluctuates 8-9 degrees according to the display. I've performed the pid auto tuning which didn't make a difference, and insulated the hot ends, then re-ran the paid auto-tune, still no change. If I set my temp for 210c for the length of any print my temperature will dip to 205ish, and raise to 213-214ish. I haven't had much time from work lately to keep troubleshooting though, so I've been browsing google and the forums on my phone. From what I can tell after pid tuning the variance in temp should only be 2-3 degrees. Right?


What temperature did you tune the PID at? 250C or 215C or other?

Hangry Jason
Posts: 12
Joined: Sat Jan 06, 2018 1:25 am

Re: Unstable extruder temperature reading

Postby Hangry Jason » Wed Jan 24, 2018 3:36 am

I tried tuning at 215, and at 210. I have been printing mostly pla. I did do one petg print the other day and I tuned for 240 before the print, but at the time I hadn't noticed the temperature stability yet, so I don't know well it performed. I re-tuned for pla since then. Is it advised to reboot the printer after auto-tuning, or does that not make any difference. I'm not the most knowledgeable guy out there when it comes to the software/ firmware side of printers, but it feels like the pid tuning isn't being applied

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Vicky@Raise3D
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Re: Unstable extruder temperature reading

Postby Vicky@Raise3D » Wed Jan 24, 2018 7:31 am

Hangry Jason wrote:I tried tuning at 215, and at 210. I have been printing mostly pla. I did do one petg print the other day and I tuned for 240 before the print, but at the time I hadn't noticed the temperature stability yet, so I don't know well it performed. I re-tuned for pla since then. Is it advised to reboot the printer after auto-tuning, or does that not make any difference. I'm not the most knowledgeable guy out there when it comes to the software/ firmware side of printers, but it feels like the pid tuning isn't being applied


Which nozzle you are tuning for?
Please do the following steps for us:
1. Reboot.
2. Check the current PID values under Manual tune and take a picture.
3. Share the picture with us.

Hangry Jason
Posts: 12
Joined: Sat Jan 06, 2018 1:25 am

Re: Unstable extruder temperature reading

Postby Hangry Jason » Wed Jan 24, 2018 5:41 pm

I'll get to it tonight, I'm tuning for the left nozzle. I have a n2+ dual but lifted the right nozzle out of the way. I've only had the printer a few weeks but I have already installed the bondtech extruder and 0.6mm nozzles that I bought from you guys. I'm pretty happy with the printer so far, I'm just trying to nail down this last "very minor" issue of layers not visually being lined up perfectly (minor enough that it's only noticeable when the light hits it right) and it wasn't until i used some old stubborn third party pla that had poor layer bonding below 205 but occasionally bubbles/boils at 215 that I started paying closer attention to the temperature stability. But I'm also just a hobbyist and haven't had the chance to spend as much time with it as I'd like the last week (I didn't even get to turn on any printers yesterday) Also, I hope I'm not hijacking the thread btw.

Hangry Jason
Posts: 12
Joined: Sat Jan 06, 2018 1:25 am

Re: Unstable extruder temperature reading

Postby Hangry Jason » Thu Jan 25, 2018 3:50 am

Heres my Pid Tuning process. I discovered today that my right hot end is a lot more stable than my left. The variance in my left hot end is +/- 4 degrees and the variance in my right hot end is +/- 2 degrees.

The insulation tubing is the same that zemlin used in his post http://forum.raise3d.com/viewtopic.php?f=4&t=930&hilit=insulation&start=20 but the temperature sway was the same before and after installing it.

Apologies for the sideways pictures, they were the correct orientation on my PC before uploading them

Manual Screen before running auto tune
20180124_184133.jpg
Manual Screen before running auto tune


Auto Tune Setup Screen
20180124_184204.jpg
Auto Tune Setup Screen


AutoTune complete
20180124_184846.jpg
AutoTune complete


Manual Screen after auto tune
20180124_184936.jpg
Manual Screen after auto tune


Verified Manual Screen after reboot
20180124_185229.jpg
Verified Manual Screen after reboot


Youtube Video (unlisted) of temperature variance on left extruder after this PID Tuning
https://youtu.be/zgjCQOWb6-Y

Youtube Video (unlisted) of temperature variance on right extruder after this PID Tuning
https://youtu.be/x_qwqucNbRQ

Hangry Jason
Posts: 12
Joined: Sat Jan 06, 2018 1:25 am

Re: Unstable extruder temperature reading

Postby Hangry Jason » Thu Jan 25, 2018 4:18 am

P.s. if this is within the realm of normal tolerance, please let me know too. Sometimes I can get lost chasing little things that might not even be a problem :)

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Vicky@Raise3D
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Re: Unstable extruder temperature reading

Postby Vicky@Raise3D » Thu Jan 25, 2018 5:19 am

Have you tried with higher temperature to tune PID to compare whether there has any difference between the result with 215C, such as 230C, 250C?

Hangry Jason
Posts: 12
Joined: Sat Jan 06, 2018 1:25 am

Re: Unstable extruder temperature reading

Postby Hangry Jason » Thu Jan 25, 2018 6:30 am

I have good news, I might have found my fix. After noticing the difference between the left and right temperatures, I decided to remove and reconnect the wires from the heater cartridges and the Thermistors to the circuit board attached to the extruder and now after re-accomplishing the Pid Tuning, my left extruder now only fluctuates +/- 2 degrees!! :D (if that hadnt worked my next step was going to be swapping the heater cores between blocks and connectors, or the thermistors and see if the issue followed any particular piece of hardware.)

I still need to re-ziptie the cables and verify its still good, but I think a re-seating of the wires might have been all I needed. I'll let you know tomorrow. I have to go to bed unfortunately. I also want to do some Petg prints soon, so I will probably PID tune to 240ish in the next day or two

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Vicky@Raise3D
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Re: Unstable extruder temperature reading

Postby Vicky@Raise3D » Thu Jan 25, 2018 7:25 am

If possible, would you also like to help test only switching one of the heater nor temperature sensor to check which one is the main factor.

Hangry Jason
Posts: 12
Joined: Sat Jan 06, 2018 1:25 am

Re: Unstable extruder temperature reading

Postby Hangry Jason » Fri Jan 26, 2018 6:09 am

So, long story short, when I got home from work today and turned the N2+ back on, the temperature sway was back, roughly 4 degrees above and below, this time on both extruders. I swapped the thermocouplers and the heater cores one at a time in every combination, and every one exhibited the drift and Pid Autotuning never helped. I finally just put everything back to their original places, and decided to do a factory reset under the advanced options on the touch screen and now my temperatures are super stable!! when I set the hot end for 240, it is now only dropping 1 degree then popping back up to 240. I've cooled the printer back down power it off and then back on and the temperature is still stable. Maybe the Autotuning wasnt working propery, or I needed to perform a factory reset after the last firmware update? But it seems to be working properly now, 100% (I sure hope I dont jinx it by saying that) Now I'm back to my test prints to see if this might have had something to do with the original issue I was chasing of the layer lines that just didnt look smooth (but not z-banding)


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