Burning Rubber

[AndyPost]

This has happened several times in the last few months. I'm printing away on version X of a new design and I start smelling burning filament. Smoke is pouring out of the nozzle. Printing ABS, extrusion is 265 degrees I shut it all down, restart and watch the temp as I heat up the hot end. It steadily climbs to somewhere in the high 210 teens then jogs back and forth a degree, like it can't heat up any more. But it's actually burning up and starts to smoke. So....bad thermistor?

I've seen posts about loose thermistor wires. I can of course see where it plugs into the machine. Should I also check the board connection? If so, how would I identify it.

I have extra thermistors as this is a recurring problem. But that is what makes me think its not the thermistor but a dodgey connection somewhere.

Share your thoughts.

[airscapes]

Sure I would check the connection at the rambo board..
What ABS are you using.. I have never needed to print any hotter than 235..

[Gwhite]

There are two facets to the thermistor connections: electrical & thermal. Even if the wiring is good, the thermistor may have come loose in the hot end. The actual thermistor is in a small metal tube. I think the tube is held in place with a setscrew, and that may have loosened up. I doubt that would drop the thermistor reading enough to smoke your filament, but it's worth checking.