Heater Decoupled since updating to latest firmware

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NikolaiD
Posts: 16
Joined: Wed Sep 03, 2014 6:38 pm

Re: Heater Decoupled since updating to latest firmware

Post by NikolaiD »

Ok, so I did about 18 hours of printing now and so far so good (kinda... the peek insulator melted on me, but I just took the one from the second extruder and kept going).
After about 11 hours of printing, I got some better, copper heat sinks. I replaced the one on the ATmega and added a little one on the MOSFET that drives extruder 1.
Image

And now... Oh, my god... I set the temp to 220C, and it sits at 220.00 for hours!!! Zero fluctuation. I've never had this thing work so well.

The next thing will be to draw up a new case for the circuit board with fan mounting and I'll pull the power supply out from under the electronics to completely overkill it since now I'm convinced that cooling helps.

A week ago I couldn't get the printer to go past the nozzle purge on most prints! :D
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DSC_0747.JPG

Lizzy Design
Posts: 17
Joined: Wed Nov 20, 2013 10:53 pm

Post by Lizzy Design »

Hi,
I seem to have a decoupling issue when I print ABS. The printer keeps going but the hotends and the bed stop heating. Lost already quite some prints because of this.
Is there anyone that can explain in layman's terms who has no idea what P, I and D values are, how to resolve or improve on the issue?
Many thanks for any kind help.
Regards,
Lizzy

Lizzy Design
Posts: 17
Joined: Wed Nov 20, 2013 10:53 pm

Post by Lizzy Design »

Ok, I think I found those PID values. Although I have no idea what they are for I changed them to what Marc suggested in his first message. So far, so good. My print finished for a change. The bed temp. fluctuates about 5 degrees and the hot end about 2 degrees. I’ll try Guillaume’s settings next.
Thanks for your guys debate on the issue. Although I didn’t really understand much of it, it may well have solved the issue. Fingers crossed.

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DDME-Marc
Posts: 71
Joined: Sun Nov 24, 2013 11:04 pm
Location: New Zealand

Post by DDME-Marc »

Hi Lizzy,

Please find attached an article which explains PID in a reasonably simple format, well within reason anyway.

In the persuit of fast yet stable response I find myself currently with a P value of 11.5, an I value of 0.125 and D value of 72. I observe less than half a degree of temperature oscillations when working at 250 degrees and response is reasonably fast.

Edit: And PID intergral drive max at 200, and drive min at 5.

Just be aware your setup my differ slighly so custom settings may be in order. Hopefully this is where the article will help make further changes.

Cheers,

Marc
Attachments
f-wescot.pdf
(292.14 KiB) Downloaded 59 times
Felix 3.0 Dual Head * E3D Titan V6 * Repetier-Host V2.1.3 * Repetier-Firmware 0.92.9 (01/08/17 - Modified) * KISSlicer Pro - 1.6.3 * Arduino 1.8.5 *

Lizzy Design
Posts: 17
Joined: Wed Nov 20, 2013 10:53 pm

Post by Lizzy Design »

Cheers Marc,
I'll have a read through. At first glance it seems manageable. Although I can put this printer toghether, software adaptations are not my strong side. Thanks for all the efforts. Lizzy

NikolaiD
Posts: 16
Joined: Wed Sep 03, 2014 6:38 pm

Post by NikolaiD »

I'm back at it again.. Decoupling again, but this time it's a different issue.
Since I cooled the board, I have about ~150 hours of perfect printing. Last weekend I printed some stuff from Arnitel 45D and when I went back to PLA it started decoupling in the beginning of the print between the nozzle purge and the actual print. If it gets past that, the temps are perfect and the print finishes.

What I see happening is when the printer retracts the filament to travel, the hot end temperature spikes and it decouples immediately.

If I start a print placed very close to 0mm x an 0mm y, no issues (not enough time to spike).

Seems to me like the hot end might just need a good cleaning, but I'm kind of scared to take it apart since I don't have any spare parts and if i break anything, the printer will be down. If it was ABS, I would clean it with acetone, but how do I clean the Arnitel 45D?

Anyone else had this happen?

Dreide
Posts: 176
Joined: Sun Sep 29, 2013 12:32 am
Location: Lausanne, Switzerland

Post by Dreide »

NikolaiD wrote:I'm back at it again.. Decoupling again, but this time it's a different issue.
Since I cooled the board, I have about ~150 hours of perfect printing. Last weekend I printed some stuff from Arnitel 45D and when I went back to PLA it started decoupling in the beginning of the print between the nozzle purge and the actual print. If it gets past that, the temps are perfect and the print finishes.
Hard to believe that the cooling really helps with the decoupling, unless something is wrong with the electronics. And now decoupling just because of retraction!? What happens if you switch the part cooling fan on and off. That should have much more of an impact on the extruder temperature.
Is the print started automatically after the temperature is okay? If so, the PID control might not be in a fully settled state by then (even though the temp seems to look fine) and therefore is more sensitive to small disturbances like even a retraction. But I hardly can believe this, unless your PID values are off or something is not quite right with the electronics.
Could you post a temp plot, so we can see how it looks like (a) during the print, (b) when the part cooling is turned on and off, and (c) when it decouples?
Felix 2.0->3.0dual * Repetier (host+firmware) * KISSlicer Pro, Simplify3D * Cubify Design

NikolaiD
Posts: 16
Joined: Wed Sep 03, 2014 6:38 pm

Post by NikolaiD »

Dreide wrote: Hard to believe that the cooling really helps with the decoupling, unless something is wrong with the electronics. And now decoupling just because of retraction!? What happens if you switch the part cooling fan on and off. That should have much more of an impact on the extruder temperature.
Is the print started automatically after the temperature is okay? If so, the PID control might not be in a fully settled state by then (even though the temp seems to look fine) and therefore is more sensitive to small disturbances like even a retraction. But I hardly can believe this, unless your PID values are off or something is not quite right with the electronics.
Could you post a temp plot, so we can see how it looks like (a) during the print, (b) when the part cooling is turned on and off, and (c) when it decouples?
I'll try it with the part cooling fan off, but for now no more decoupling, so I can't get a screen shot. I heated the hot end to 260C and pushed a lot of ABS through using the fast ►► button and it looks like it cleaned up the Arnitel.
What used to happen is the plot looks normal, no spikes displayed, but on retract and long travel, printing at 220C, it would say the temperature detected is 245C-250C. Since purging the nozzle, it's "almost" back to where it was before.

For PID values, I ran the auto tune and just plugged those values in. P=5.97, I=0.3, D=29.58. Been using those for a long time now. Thoughts?

Now as far as cooling the electronics, I think the difference maker was cooling the MOSFET more than cooling the processor.
When I first got a fan going, I was able to print again. When I added a heatsink on the MOSFET, the extruder output graph flattened out.

On my pic from the previous page, the printer works and I was happy, but take a look at the "Output extruder" graph, it's on/off/on/off and it keeps going that way.
Image

Now here's one that's printing right now. Not a perfect example because it's a lot of retractions and travel and I'm printing at 24mm/s, but even now, the output hovers around ~45% and then goes up/down slightly to adjust the temperature instead of going full on and full off. Same PID values.
Image
When I print a solid part, that line is almost completely flat.

Do you think my electronics are damaged? (bad MOSFET maybe?)
Attachments
Temperatures.jpg

guidoforrier
Posts: 11
Joined: Sat Aug 03, 2013 10:16 pm

Post by guidoforrier »

what happened with the latest firmwares ?
i print pla at 205°with a Felix 2
temperature is not stable and always decoupling !
-i blowed cool air over the board
- as the room temperature is low i lowered the fan speed
- i used a spare thermistor
- i used the latest firmware 6.04.01
nothing helps
see my screenshots .
i hope to find a solution as a will start to design table ware . i already could print some objects but that was with older firmware .
Attachments
guido.png

guidoforrier
Posts: 11
Joined: Sat Aug 03, 2013 10:16 pm

Post by guidoforrier »

here another screenshot
thanks for helping !
guido
Attachments
guido2.png

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