temperature drops after a few minutes

[maybites 0]

Hi

Since the exchange of my temperature sensor I observe a strange temp. drop after a few minutes. When freshly switched on, the temp. regulation works fine, but after a few minutes of printing the temp slowly starts to drop (from 230 to 210 - see attachment).

There are NO GCode commands. This happens when using the controller and preheat to a specified temp aswell. The sensor senses correct - as far as I could measure with another device - so I guess the heater has a problem.

any ideas?

[billdempsey 0]

It could be that your fan shroud is allowing the fan to blow directly onto your hot end, rather than downward onto the hot plastic. The fan isn't on at the start (default settings), so the temp probably drops when the fan kicks on. You might consider printing out a replacement fan mount, like the one Daid designed on Thingiverse. It works much better than the origami thing they ship.

 

[maybites 0]

You were spot on. My fan shroud did exactly this, since it was designed for the old hot end. My new fan shroud is now ajusted to the new hot end and this phenomenon has disapeared.

thank you.