1. About
  2. Features
  3. Explore

I have got a problem that after upgrading my printer to an aluminum frame my extruder went from around 400 steps per mm at 16 micro steps (which did match the manufacturer's recommendation perfectly) to a bit over 1000 steps per mm at 16 micro steps.

This is a problem for me, since the limited amount of steps per second lower my maximum retraction speed.

What I tried since the rebuild:

  1. Replace and adjust the current of the stepper driver - no change, even with another type of driver on different micro steps, of course with other values, but also about 2.5 times too high;

  2. Connecting another motor with another cable - the other motor with nothing attached to it drove the same angle as my extruder stepper.

Could it be that the ATmega2560 on my MKS gen 1.4 board got damaged? Or did I change something in the firmware, which does have this effect?

I am using Marlin 1.8.5 and a E3D Titan 1:3 geared extruder and I am using the same setup as before! E3D claims to have 437 steps per mm on a 200 steps/revolution Nema 17 stepper and 16 micro steps. This value was working perfectly fine before.

Update:

With an Arduino Nano I measured the amount of steps my board sends at 418.5 steps/mm (programmed in EEPROM and in firmware) on a specific amount of extrusion length

G92 E0 -> G1 F100 E30 

and I got

5220 steps for 30mm extrusion (reproducible). 

It should be

418.5 steps/mm*30mm = 12555 steps. 

Where,

(12555/5220) * 418.5 steps/mm = 1007 steps/mm 

to have the effect of 418.5 steps/mm

...which is, oddly, the exact number that I got by marking filament, extruding, measuring and calculating.

1 Answer 1

After a rebuild, and certainly after changing to another extruder (e.g. replacing it by a geared extruder like you supposedly did as taken from the comments above before the edit, which now clearly is not the case) or setup e.g. other stepper drivers, you should always calibrate the extruder.

To calibrate you e.g. disconnect the hot end nozzle and command to extrude 100 mm. Be sure to make marks and measure the extruded distance. Divide the latter value by 100 to divide this result by the steps per mm value in the configuration file. So, if you measured 102 mm and commanded 100 for 400 steps, the new would be 400/(102/100) = 392. There is a lot to find on this matter on the internet. All can be done with G-codes that can be entered through a terminal connected over the USB port. E.g. applications as Pronterface, Repetier-Host, OctoPrint, etc. all have a terminal interface to the printer if connected over USB.

You could find more detailed instructions e.g. here, or this video.