Prusa i3 Mk2.5s hot end thermal runaway issues
I have been getting a consistent issue on my printer. I had the Prusa mk2s, which I got the upgrade kit for to make it a 2.5s. Working well for years, however the past few weeks I have been getting hot end thermal runaways always at the exact same layer, around 15 mins into a print.I have attached an image of my Octopi temperature viewer that shows how the printer drops temperature in the exact same pattern every print.
On the slicer, I use default settings for Prusament PLA, which I noticed turns the fans to 100% power at the 4th layer. This is the layer where the temperature drops. I tried turning down the max power to 60%, even down to 30%, but still get the thermal runaway issue. There is a also a setting called "Enable auto-cooling" which I don't understand it's function.
I replaced my thermistor, my heating element, and heat-block with original Prusa parts.. My fans are all 12V fans for the mk2.5s 12v system. I know this is some sort of software slicer issue because my first layers are all really good. If anyone knows anything, would really appreciate it. Thanks!
RE: Prusa i3 Mk2.5s hot end thermal runaway issues
I've had this problem too, it seem the new configuration of the part cooler directs too much cool air to the heat block. There are 2 solutions that I found, one is to adjust the part cooling fan to run at a lower speed. The other is to put a silicon sock over the heat block.
Cheers
-Bob
Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit