Hotend not reach setted temperature

#1

I’ll try describe my issue if I set the tempurature with pronterface to 200º the temperature never reaches that value for instance it almost target that tempeurate 196/197ª and then start to drop to 184/85º end then start to raise again to the 196/97º. And remains in this loop forever, I’m not able to start any print because tempurate never stabilize.

I’ve try to configure the PID (M303 E0 S200 C8) with 8, 12, 15 intervals not help the issue continue.

I’ve try to change heatblock and termistor not help

Its important to refer this behaviour occur in any tempurate if I fix 150º it never reaches 150º it go to 146/147º and then drops again 10/15º and restart the loop. Same thing if I fix the tempurature to 210º.

Also I’ve tested this in multiple versions of marlin 1.1.8 and 1.1.9.The version of marlin 1.1.8 have worked in the same print in the past.

I’m have not clue about what can cause this issue, maybe its a board malfunctions (mosfet) or a powersupply malfunction.

Somebody can help me on this?

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#2

Hi,
this can happen when you do the pid tuning for example for pla without the part cooling fan on.

I personally do it with the fan on 66%, then you have a little drop when the fan starts @100% but then the temp should be a little lower then targeted one within the temp runaway protection range.

Or when available -> put a slicone sock on the heater block.

For ABS -> no fan :wink:

I have the standard pid (for me i print mostly pla) in the firmware.
but i have the corresponding gcode line to set (not get) in the gcode start script.

---- edit ----

or check the resistance of the heater if it is damaged
or the temperature sensor

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#3

Thanks for your help I’ve try yo setup pid with blow fan at maximum speed. I forgot to mentions that I’ve update my heat cartrige to 50w I didnt know If that could leave to that issue.

I’ve tested with multiple termistor, but not have change the heat cartrige.

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#4

for your 50w heater it should be 2,88 ohm @12V
and
11,5 ohm @24V

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