Thermal runaway...
For some reason I am suddenly getting failed prints with 'thermal runaway' errors...looks like after printing the first layer the front fan starts up and the extruder temperature drops from 210 to 190...and gives the error (which I am assuming means too cold rather than too hot!)
Not had this problem before, any ideas anyone? Almost looks like the heater cannot keep up, but if I preheat the printer stays at the correct temperature for an hour without problems??
I have not changed the cooling fan settings AFAIK and am now considering disabling it to see if I get any further...
Chris
RE: Thermal runaway...
Tried turning the fan off but it still ran after a while??
I switched to PETG and reprinted the same file and this was successful, even with the front cooling fan running! Temperature was 240 and 85 for the heated bed - which stayed stable throughout the print (7 hours+)
Not sure what is going on, might try the Prusa support...if the heater is giving up it would not reach 240 and maintain it for 7 hours surely??
Chris
RE: Thermal runaway...
Same problem on a new MK2.5s build. Part cooling fan comes on and temps went from 210 to 185 in seconds and had a hard time getting back over 200.
I think it is the fan duct blowing too much are at the hot end rather than the part.
RE: Thermal runaway...
cooling shroud moved so it's blowing more on the heater block?
RE: Thermal runaway...
Interesting! Over the weekend I refitted the silicon 'sock' that fell off a week ago with a new one and yes, the problem disappeared...so perhaps it is time to dismantle the extruder and have a good look at it - the cooling duct looks ok but perhaps once I have taken things to pieces and cleaned them up a bit things might be clearer?
Interestingly since getting a nice new powder coated steel sheet it is difficult getting things to stick so perhaps it is also time to 'recalibrate' the first layer again
Thanks for the reply!
Chris