Mysterious Z axis errors

[Neale]

Was the cut supposed to be uniform in Z (i.e. no Z movement along the cut) or was there some Z movement?

[Clive S]

Was the cut supposed to be uniform in Z (i.e. no Z movement along the cut) or was there some Z movement?

Are you sure that the cutter is not being pulled out of the collet?

[dachopper]

So, the cutter is firmly in the collet. The part is uniform z from end to end, but across the part ( side to side ) there is z movement up in the middle, and down at each side. The CNN pass is parallel going across the part, move along by .5 mm, then across ... hundreds of times.

[Neale]

If there is a lot of Z movement, and you are sure that the mechanical side of things is spot on, have you seen this thread?

[dachopper]

Thanks for pointing out that thread Neale -

I found something funny happening to the Y axis in my UCCNC software, where my slaved axis was re-copying settings from another axis, including the wrong step and Dir information when I changed a specific value on one of the pages ( I'm not talking about the value of boxing slave, it's something else like if I make a change to the acceleration value, then the slave dumps all info and re-imports all info including the wrong pin and direction assignment ) . I still haven't figured out which value it is because I don't change the settings enough, but the randomly see my Y axis trying to go opposite directions as a result sometimes of me changing a few parameters.

When I went back in to fix the issue ( not knowing why it had changed, or how ) in the confusion of trying to get my Y axis motors to spin in the right direction ( together ) - I Clicked on active low, so I had some dir / pin steps on active low, and some on active High for my X and for my Z axis.

Guess where the errors were in my cut - in my z axis was the biggest, but X also had a left / right 1-2mm error by the end. So hopefully in a couple hours I can restart the beast up, and get my first workpiece cut out !

[dachopper]

May have an issue

G540 manual
the pulse polarity for the step and direction signals are ACTIVE HIGH.


UCCNC manual
Dir port & pin: Which is the physical output pin on the UC100 device for the step signal. The
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signal can be configured active low or active high selecting or unselecting a checkbox next to the
field. Changing the active polarity of the signal reverses the axis running direction.

Can this be the cause? How do I reverse the polarity while keeping the active high set?

[A_Camera]

May have an issue

G540 manual
the pulse polarity for the step and direction signals are ACTIVE HIGH.


UCCNC manual
Dir port & pin: Which is the physical output pin on the UC100 device for the step signal. The
15/76
signal can be configured active low or active high selecting or unselecting a checkbox next to the
field. Changing the active polarity of the signal reverses the axis running direction.

Can this be the cause? How do I reverse the polarity while keeping the active high set?

I don't understand the question. In UCCNC you can select active high or active low for each outputs. Set active high for both the step and the direction pins in UCCNC ( i.e. uncheck the box )and you should be fine. Once set up right UCCNC will send step pulses as active high pulses. DIR pin does not actually matter since what is happening depends on how your motors are installed, so if the axis would rotate in the wrong direction if all the DIR pins are set to active high you just change that to active low. This is actually happening with my Y axis because the motor is placed where it is placed, so my X and Z are set to active high and the the Y to active low. UCCNC takes care of that.