PID tuning is the process of optimizing your printers temperature settings. Setting optimal P, I and D values can prevent temperature fluctuations.
PID stands for Proportional, Integral, Derivative - and is a control loop feedback mechanism used by marlin to keep your printer at a stable temperature.
M106 // start the fans at 100% M303 E-0 S230 C8 // run 8 test cycles for the first extruder at 230°C
This will take a while and the result of each test run is printed to the console. At the end you will see something like this:
bias: 91 d: 91 min: 206.48 max: 213.59 Ku: 32.59 Tu: 26.48 Classic PID Kp: 21.56 // P value Ki: 1.38 // I value Kd: 62.73 // D value
M301 P21.56 I1.38 D62.73 // Set the new values as seen above M500 // save to EEPROM
You can add them to configuration.h and compile your firmware with these default values:
#define DEFAULT_Kp 21.56 #define DEFAULT_Ki 1.38 #define DEFAULT_Kd 62.73