Sudden Temp drop mid print. Help!  

Re: Sudden Temp drop mid print. Help!

Is heatbed temp. sensor in place? It might have dropped off.

Re: Sudden Temp drop mid print. Help!

Is heatbed temp. sensor in place? It might have dropped off.

Well at the Start oft every Print the temp is at 95 and if i dont Print anything the temp. Holds at 95. Just after the first layers it drops. It could be that it starts when the filament fan gets turned on. But I don't see how this could be possible.....

Re: Sudden Temp drop mid print. Help!

What is "filament fan"?
There is HE fan, which starts when HE reaches 50°C. Not this case.
Then there is cooling fan, which should not start at all since you're printing from ABS according to temperatures shown in graph.

Re: Sudden Temp drop mid print. Help!

Hi,

Suddenly i get temperature drops mid print from the heat bed. This started like 3 or 4 printe before, did not change anything in slicer.

What could cause this ?

Could it be the temperature probe connection at the motherboard? Maybe the connector is a little loose, and when the printer starts to move, it loses connection.

John

Re: Sudden Temp drop mid print. Help!

Hi

@david

Well as i see it there is the hotend cooling fan and there is the filament [cooling] fan. And sorry i did forget to mention i print PETG so the cooling fan is indeed running after layer 3.

@John,

Hmm i checked the connection on the board and it seems pretty tight.

I just confirmed. The temp is dropping as soon as the cooling fan starts. Before it holds the temp nicely and after layer 3 temps starts to fall.
If i stop the cooling fan (with my hand) the temp climbs very fast again. How can an active cooling fan trough the heated bed so much of course ?

Why could that be ?

Re: Sudden Temp drop mid print. Help!

OK then it looks like the heatbed cannot cope with intense cooling from cooling fan. You can try to decrease cooling in slicing software or let it turn on at higher layers.
BTW does it ever cause any problem?

Re: Sudden Temp drop mid print. Help!

Hello David,

Well it does not cause problems for now but it suddenly appeared and i think it it not normal. After all the cooling fan does not put out so much cool air to the bed so it gets cooler. (Was NEVER the case before)

So i want to understand why it does happen and prevent it, as it is something that the machine is doing without being instructed to do so. Thats never a good thing. Also yesterday the HB was really hot i would assume it was hotter than the 90 degrees but i have no good thermometer so i can not check it...

Re: Sudden Temp drop mid print. Help!

Are you running in an enclosure? If not I wonder if on those occasions there was a breeze or draft. The fan can cause slight temp drops but not anything like you have.

However if it is able to maintain a temp then it shows it is model/gcode related.

Alternatively go try turning the fan off for the first 3 layers and see how you get on.

Re: Sudden Temp drop mid print. Help!

Did you resolve your issue?