Printer calibration z-axis

[aeternum]

Hi everyone.
I bought a I3 Pro B and i'm trying to calibrate it. I visited some web site with tutorials and all say the same thing about the z-axis. At Triffid Hunter's Calibration wiki, for example, there is this formula about z-axis calibration:
steps_per_mm = (motor_steps_per_rev * driver_microstep) / thread_pitch

I have Nema 17 motors, 200 steps per revolution, 16 driver microstep, the threaded rods are 8mm diameter and 2mm pitch.
So the value of steps per mm would be 1600.
But the fabric default is 400 (80 for x and y axis). Am i making some mistake?

Also there is a pratical way to calibrate the printer and store values in the firmware?

I'm using PETG, 20 teeth pulley and 2mm pitched belts
both x and y axis

Thanks.

[William]

Hi，The calibration formula for the x/y axis is:

steps_per_mm = (motor_steps_per_rev * driver_microstep) / (belt_pitch * pulley_number_of_teeth)

So you can calculate it as
   Steps=(200*16)/(2*20)=80;

The lead for the z-axis is 8,
So the formula is: steps=(200*16)/8=400

I hope this can help you.

[aeternum]

Thank you. So is important the diameter and not the pitch? I'm not an expert in mechanics

[William]

Hi, referring to the lead.

[aeternum]

Thank you, i believed that lead and pitch were the same. Now, surfing in mehcanical sites, i find that isn't so. Single start, multiple starts... I'll study.

[William]