Calibrate extruder stepper motor



  • Hi,

    I have read, and follow the guide to calibrate de steps in extruder motor… but i am no convinced.

    the method i have follow is this: https://reprappro.com/documentation/commissioning-introduction/calibration-duet/#X_Y_and_Z_axis_calibration

    This idea… what mistakes have....

    1 - My printer, a TLM, uses a Nema17 Stepper motor in extruder, with a Step of 1,8º
    2 - Think, i am not sure, i have to check, the extruder have a gear to drag de filament of external diam. 12mm
    3 - If external diam=12 mm, the perimeter is Per=2xPIXr, in this case Per=2 x Pi x 6 mm = 37.69 mm
    4 - If 1 step is 1,8º --> 360º / 1,8 = 200 steps for revolution
    5 - 1 revolution -->360º --> 200 steps --> 37.69 mm: 1 step advance --> (37.69/200) = 0,1884 extruded filament

    In gcode, E92, you adjusts the steps .... but ,

    A)- What are you adjusting? The steps in M92... what represent, 1 mm (notes in config.g, say that)? in teory, no. Why think this, i have this E92, in my config.g

    [[language]]
    M92 X160 Y160 Z160 E837 ; Set steps per mm
    
    

    If the theory show up its true, I suspect that no. When stepper motor, runs 837 steps, it would have to extrude: 837 x 0,1884 = 157,6908…. and NO. The theory its WRONG.

    What are the correct maths?
    I could light up someone?

    Thanks



  • Check out this guide - http://reprap.org/wiki/Triffid_Hunter%27s_Calibration_Guide#Measure

    Basically I'd disconnect your hot end, cut the filament flush with the extruder and extrude 100mm of filament not faster than 5mm/s and then measure what you get, You can then adjust the steps with this equation.

    G91 ;relative movement
    G1 E100 F300 ; extrude 100mm at 5mm/s

    new_e_steps = old_e_steps * (100 / distance_actually_moved)



  • What you've linked to seems to be a way to load the filament so I can see why you are confused. There are better guides such as this one http://reprap.org/wiki/Triffid_Hunter%27s_Calibration_Guide. Or simply put "Calibrating a 3D printer extruder" orr some such into your favourite search engine.

    Edit. Typing at the same time as DADIY (funny how we both chose the same guide).


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