Steps permm of filament settings

Rchilso

The EEPROM of my p802e Tronxy says extr .1 is 90 steps per mm. the motor moves 1.8 deg per step so 90 steps equals 162+ deg which translates to 7.9 mm when measuring the diameter of the drive gear. I'm up grading from remote extruder to a geared direct extruder and a reprap smart display. how do i figure the steps i need for the new extruder.

Repetier

1.8° is for a full step. You need to multiply with microsteps set in firmware for stepper driver. Often 16. With gear you also need to incormporate gear ratio which reduces the step size.
So 7.9mm in full step with 16 substeps and gear ratio 1:3 make sit 7.9/16*1/3=0.1646mm/step just for example. But also the radius of the filament driving part needs to be considered.

You normally just get close so always do a step calibration by slowly moving 100mm filament inside and measure real moved distance. Multiply steps per mm by the ratio and set that in eeprom and try again.

It is crucial to use slow extusion here or you might get slip etc. making measurement invalid.