Z Axis MATH & "E" Axis ?

Hi, I'm using Repetier as my host application & am so close to finally calibrating my Prusa i3... but for some reason the Z-axis is not stepping far enough each turn .. So I think I need to increase the z-axis steps. yes ?

I've looked over the Prusa calculator... but I'm not sure exactly how to add this to Marlin''s Configuration.h file

Here's the area within the file that I believe the math should be changed yes ??


#define DEFAULT_AXIS_STEPS_PER_UNIT {78.7402,78.7402,200.0*8/3,760*1.1} // default steps per unit for ultimaker


So my question is.... do I change the DEFAULT AXIS STEPS PER UNIT ??? & if so whaich number corresponds to the z-axis ? I think it could be 200.0*8/3 ...... if so, is it safe enough to simply double the "200.00" ?

p.s - what is the E-axis..... I'm guessing its the filament feed rate yes ?

Edited 2 time(s). Last edit at 07/24/2013 04:52AM by Mickman.

The order in these array is always x,y,z,extruder and yes, e-axis is extruder.

So it should be the 3rd value. To calulate it, you can also use the calculater in Repetier-Host 0.90 in the Tools menu. M8 with 1/16 Stepping need 2560.

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z = s * m / l

where;

    z = Z axis STEPS per MM
    s = STEPS per REVOLUTION
    m = microstepping: 1, 2, 4, 8, 16 or 32.
    l = LENGTH of travel (in mm) for one rotation

As repetier already wrote for a standard 1.8° stepper motor (s = 200),
1/16 stepping (m = 16) and M8 threaded bar (l = 1.25) this works out to:

z = 200 * 16 / 1.25 = 2560

Just plug in the proper values for your stepper motor, stepper motor driver microstepping and threaded bar.

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Bob Morrison
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"Luke, use the source!"
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so if this is the formula I have 200*16/0,8 = 4000

I am using M5 rod for z axis but 4000 is too fast for marlin :/

what should i do ?

4000 are steps per mm not speed! What makes the problem is the commanded feedrate. Your feedrate must be <10mm/s in z direction. You have to test, how far you can go. Also you need a very slow acceleration for z. A range of 1-10 should do in combination with low z-Jerk.

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The ReaRap Calculator3 may help:


[calculator.josefprusa.cz]