I would like to calculate the amount of steps to turn the motor to have 1 mm of the filament.

I did the following (using approximate values):

The gear on the outside of the teeth as a diameter of 11mm. Therefore the circumference is 34.56mm. Divided into one degree i get 0.096mm / degree. The stepper does 1.8 degree per step which results in 0.1728mm per step.

To get 1mm of filament pushed into the extruder I will have to do 5.787 steps.

The same extruder is in a Geeetech i3. The firmware there is configured to do 93 steps per millimeter.

I don't have any experience in working with stepper motors but in theory, this would be my approach with a huge difference to an existing firmware.

Where is my mistake?


1 Answer 1


Microstepping. Your board likely has 16x microstepping, so that each step is divided up into 16 parts. Your 5.787 figure, when multiplied by 16, comes out to 92.6 steps/mm - matching the value in your firmware.

  • $\begingroup$ Ouhhhh yeah, i read about this months ago when assembling... Omg didn't remember thanks for the info ;-) $\endgroup$
    – Silberling
    Jan 8, 2017 at 0:53

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