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Prusa Mendel i3 z axis not moving correct distance

Posted by foul_owl 
Prusa Mendel i3 z axis not moving correct distance
May 11, 2014 03:08PM
Hi folks,

I am in the process of building my Prusa Mendel i3. I managed to get all three axis working well, being controlled manually with pronterface for testing. I went on vacation and left my build sit for a few weeks. Now that I'm back, it seems like the z axis is no longer working correctly. I try to move it 10mm with pronterface, but it appears to only move only about ~1mm or so. This is interesting to me as I know it was untouched for some time. I am unsure what has gone wrong, and what I can test.

What should I look at? (My guesses are: 1. Issue with pronterface 2. motors are somehow not set to the correct type in the firmware, if that's even an option. 3. voltage/power supply not providing enough power.)

Thanks!
Re: Prusa Mendel i3 z axis not moving correct distance
May 11, 2014 03:33PM
swap the stepper driver with other axes (power off) it maybe be damaged, if not, check your steps per mm
Re: Prusa Mendel i3 z axis not moving correct distance
May 22, 2014 12:14AM
My steps per mm are set to the default, which appears to be the default for the ultimaker. I'm assuming this is not correct.

I tried setting it to 4000, which I calculated here:
[calculator.josefprusa.cz]

It appears to travel the correct distance now, however, when homing via pronterface, the motors are very loud and turn quite fast. Using pronterface to move them manually up or down 10 mm, they appear to turn at the correct speed and are not loud.

Any thoughts?

Thanks!

Edited 1 time(s). Last edit at 05/22/2014 02:52AM by foul_owl.
Re: Prusa Mendel i3 z axis not moving correct distance
May 22, 2014 11:49AM
Quote
foul_owl
It appears to travel the correct distance now, however, when homing via pronterface, the motors are very loud and turn quite fast. Using pronterface to move them manually up or down 10 mm, they appear to turn at the correct speed and are not loud.

Any thoughts?

Thanks!

Set your max_acceleration on the x-axis lower eg. 2 or 3.
// default settings

#define DEFAULT_MAX_ACCELERATION {300,300,10,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.
Re: Prusa Mendel i3 z axis not moving correct distance
May 22, 2014 04:17PM
My line orginally looked like this:

#define DEFAULT_MAX_ACCELERATION {9000,9000,100,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.

I changed it to this:

#define DEFAULT_MAX_ACCELERATION {9000,9000,3,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.

Now when using the z axis at all, it makes a cool "jet engine starting up" type noise. Still quite noisy but only when homing. Going up and down as normal seems to work fine with no excess noise.
Re: Prusa Mendel i3 z axis not moving correct distance
May 24, 2014 02:52PM
thats mine

//// MOVEMENT SETTINGS
#define NUM_AXIS 4 // The axis order in all axis related arrays is X, Y, Z, E
#define HOMING_FEEDRATE {50*60, 50*60, 4*60, 0} // set the homing speeds (mm/min) ***********************************

// default settings

#define DEFAULT_AXIS_STEPS_PER_UNIT {71.11,71.11,4000.00,710*1.1}
#define DEFAULT_MAX_FEEDRATE {400, 400, 3, 25}
#define DEFAULT_MAX_ACCELERATION {6000,6000,100,10000}

changing your max accelerations for z is well low at 3 but my feedrate for z is 3

id look at the bit i have astrixed

Edited 1 time(s). Last edit at 05/24/2014 02:55PM by chris33.


Check my rubbish blog for my prusa i3

up and running
[3dimetech.blogspot.co.uk]
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