Anycubic i3 Mega PID calibration is a crucial step to keep the hot end temperature at desired level.
You would get a thermal runaway error without it or your printed model would have artifacs from changing temperature while printing.
How does it work?
The hot end will be heated up to desired temperature, turned off and these actions will be repeated a few times until the PID values will be calculated.
You can see how an extruder PID calibration looks like in a temperature graph in OctoPrint.
Move the printing head to the bed.
You should do this, because you print on the bed, not in the air.
PID calibration using OctoPrint
If you use OctoPrint, let’s calibrate it via that.
Open OctoPrint interface and connect your printer.
Go to the Control tab and click on Fan On in the General settings.
Why? Because usually we print with the cooling fan on.
Cold air from the cooling fan blows on the hot end and affects the hot end temperature and PID values.
Open Terminal and send PID tuning command:
M303 E0 S230 C10
PIDtuning Extruder0 TargetTemperature230°C 10Repetitions
You can watch the PID calibration in the Temperature tab
When is the PID tuning/calibration complete, you must save new PID values.
Use this command with your PID values: M301 P16.52 I1.11 D61.73
Send the command and wait for confirmation.