Temp swings 8 deg.

I am having an issue where the nozzle temp swings 8-10 degrees (4 up, 4 down). It does this over and over again. The printer is seemingly unable to reach a steady state. It doesn’t do this all the time, but it is frequent. Is this normal?

I’ve uploaded a short video:


Thank you for your thoughts!

Turn your filament cooling fan down some if you are using it. If you aren’t using it it could be the thermistor.

It could be signs of a failing power supply. Not setting extrusion fan to 100% helped, but I think the PSU will ultimately fail.

You might start by making sure your PID settings are correct. I have found https://www.lulzbot.com/support/fine-tune-your-marlin-pid-settings to be extremely useful at smoothing out the temperature swings when I swap hotends/extruders.

The PID tuning made a huge difference.

For the print I am doing in PLA I wanted the fan at 100%. I’ve alwyas found that with the fan set that high, the hotend barely has the power to hold temps. You know what? I did the PID tune while the fan was cranked to 100% and then put the values in the start script just for that temp/fan/print speed(volume of filament through the hot end can also affect temps) combo. It gets to steady state pretty quickly now, and stays dead-on except in circumstances when the extrusion volume changes dramatically etc… Then, it regains steady state pretty quickly. I highly reccommend PID tuning.

Thank You!