Hot end temperature problems after putting MK3S+ in enclosure
 
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JPMakesStuff
(@jpmakesstuff)
Eminent Member
Hot end temperature problems after putting MK3S+ in enclosure

 

I have already re-seated the hot end temperature sensor cable on the board, and was REALLY careful moving all the cables when building the enclosure.  What could have gone wrong?

Posted : 10/10/2022 7:29 pm
cwbullet
(@cwbullet)
Member
RE:

You could have a partial break in the thermistor cable.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 10/10/2022 7:41 pm
JPMakesStuff
(@jpmakesstuff)
Eminent Member
Topic starter answered:
RE: Hot end temperature problems after putting MK3S+ in enclosure

Seems I can't edit my own post anymore...

Problem persists with second attempt at printing in the enclosure...  Updated OctoPi to latest version, reset printer to defaults by running Welcome/calibration procedure.  First layer calibration went OK.  Now second print I'm still getting wild problems...

Posted : 10/10/2022 7:44 pm
cwbullet
(@cwbullet)
Member
RE: Hot end temperature problems after putting MK3S+ in enclosure

I would try to print without Octoprint and see if you still have the issue.  It is just removing one possibility from the equation.    

--------------------
Chuck H
3D Printer Review Blog

Posted : 10/10/2022 7:50 pm
JPMakesStuff
(@jpmakesstuff)
Eminent Member
Topic starter answered:
RE: Hot end temperature problems after putting MK3S+ in enclosure

Ok, so here's how I solved it...

Printing from OctoPrint vs. the printer's SD card made no difference - so I went down the rabbit hole of there being a short or break in a wire.

When measuring resistance through the hot end heater, and flexing the cable, I noticed the resistance changed wildly.  So, I cut the hot end wires off, about 4 cm from where they exit the hot end, and soldered on some new high flex silicon wire, covered with heat shrink, and ran them back to the control board.

I did the same test with the hot end temperature wires but the resistance didn't change much at all, so I assume these wires were OK.

Did all the calibration and tests again (still passed) and now prints look good and temperate doesn't swing wildly.

 

...interestingly, this was a relatively new hot-end that I purchased from Prusa (I replaced the old only because cause it started leaking from the top of the heat block) I did notice the wires on this new hot end were stiffer, and the entire length of the wires (both heater power and temperature sensor) seemed to be coated in the sticky heat resistant insulation all the way to the PCB connector.  Obviously not sure if this problem is because of the new hot ends, or just a random defect - but I'm glad I was able to fix it and up and running.

This is what my temperature graph looks like now - does it seem normal?  I guess I never payed that close attention before, is the little ripple normal (likely due the the heater cycling on and off?)  The print I started does look great at least!

Posted : 11/10/2022 4:42 am
Thejiral
(@thejiral)
Noble Member
RE: Hot end temperature problems after putting MK3S+ in enclosure

Have you tried doing a PID calibration?
Putting your Prusa into an enclosure changes the environment so a PID calibration under those new conditions could help. Unless of course the problem lies elsewhere but no harm in doing that calibration:

https://help.prusa3d.com/article/pid-tuning_2265

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 11/10/2022 6:22 am
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