how to adjust extruder

Hi Nick,

Can you explain me how to adjust the extruder ? With the factory setting I obtain 180mm when I command the printer to extrude 100mm ?
I tried to change this value on lcd panel: Control -> Motion -> Esteps/mm (900) with this formula (100/180) * 900 but it's worst
what can I do, I'm not able to print something ?

best

Reprapguru prusa i3 with PLA

Your math is right, but when the extruder acts worse, it's time to take a step back and calculate e-steps from ground up. ( where did the 900 steps come from ?)
You need to check your microstepping jumpers and the type of driver chip. RAPS128,TMC2100, DRV8825 have different jumper settings than A4988...

There is a very good guide to calculate your e-steps, but keep in mind, that your drivers are probably different.
Also your stepper motor can be different. ( 200 vs. 400 steps/rev )

Hi o_lamp,

thanks for your answer
I try to understand this formula :
e_steps_per_mm = (motor_steps_per_rev * driver_microstep) * (big_gear_teeth / small_gear_teeth) / (hob_effective_diameter * pi)

motor_steps_per_rev : I don't know it's a chip motor so I think 200
driver_microstep : I use A4988, tension is ok 0.55 v and three jumpers. On wiki I saw this config is 1/16
big _gear_teeth : ? the gear extruder has 40 teeth
small_gear_teeth: ? I have only one gear in the extruder
hob_effective_diameter: I think it's the bold between the extruder and the hot end. External diameter is 5.90mm

Best
Pierre

The formula is meant for geared extruders. Yours is direct drive and the hob_diameter is the diameter of the 40teeth gear, not the radius.

(200*16) / (11*pi ) ~93 steps/mm.
That explains why it didn't work with 900 steps

What do you advise as good quality extruder and hot end ?

I'm pretty happy with the all metal MK8 extruder most Prusa i3 have. Nothing wrong with it.