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Weird motions, link on desc

Posted by matheustorres 
Weird motions, link on desc
January 23, 2018 04:03PM
So let me explain what is happening: Right on the start of the video I press home X and for some reason the Z axis turned and it seems like it got stuck, then X goes home normally;

Next problem is the Y axis, I gave the command to move 10mm and it went like 100mm and when I press 1mm, it moves probably like 10mm, and, with the 1mm command, the Y bed moves catching a lot with a really jerky motion, when I press Y home it hits the Y endstop, moves a bit forward and comes back really quickly, unlike the home X did.

Both Y and X have 160 steps/mm and they are giving completely different results, even though they have the same mechanical parts.

GT2 pulley 2mm pitch, 20 pulley teeth, drv8825 with 3 jumpers (32 microsteps?), 200 steps per revolution stepper motor.

Can someone please help?


Edited 1 time(s). Last edit at 01/24/2018 09:53AM by matheustorres.
Re: 3 problems in one video, link on desc
January 24, 2018 02:56AM
Which tool did you use to home the axes individually? If it was pronterface, you must know, that it's travel speed is set way to high for Z axis with leadscrew. Also it has it's own macros. So it's possible that the z-axis lifts a bit before homing X.
The Y-axis is another story. Factor 10 between sent data and reality could be a typo in the firmware. ( 1600steps/mm instead of 160 ). Find out by sending "M92" from your command line. The controller will answer with the current settings.

Just for fun you could send M92 Y160 before homing Y. It might make a difference.

There's also a chance your microstepping jumpers are bad or the pins have cold solder joints. You could swap X & Y steppers and endstops too and see if the error is on the X-axis now.

Edited 2 time(s). Last edit at 01/24/2018 03:01AM by o_lampe.
Re: 3 problems in one video, link on desc
January 24, 2018 05:05AM
Yes I was using pronterface, actually this homing problem is caused not only when I home X, but when I first open the program, the first time I press home, either X or Y, it lifts the Z, and after that the home works fine. Pronterface has a macro to do that? Which software do you recommend?
Re: Weird motions, link on desc
January 24, 2018 12:17PM
Update: It was really a typo error, for some reason I can't turn the Z axis down, only up, why is that? How am I going to position my endstop on Z axis without the program letting me move it down?
Re: Weird motions, link on desc
January 25, 2018 02:08PM
Only the home function (G28) will move the Z axis down in that situation, normal travel moves will not.

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