CNC accuracy problems

[ynneb]

LOL, I meant post it in a txt file and upload that.
You might want to edit your post.

[kdoney]

I've run the code in a couple of simulators I have and it looks straight and valid. I would say you should re-check the motor tuning to make sure the pulses per unit are correct. Are you using steppers or servos? A mechanical problem can cause loss steps in x or y fairly consistently.

[jtriggs]

I'm using servos with gecko 320 drivers.

[kdoney]

Sorry, I see you said that before. Do you use double screws on one axis? Can you run a simple square the same size?

[jtriggs]

No,
Both the X and Y axis use a single ball screw.
I'll try running a square and rectangle without the ears and see
what the cut comes out like.

[jtriggs]

Okay, I just ran a plain square (2"x2") and rectangle (1.5"x3"). Nothing
fancy here but I still get a skewed cut. bottom left slants slightly in,
bottom right slightly out. In addition I used a zig-zag cut pattern and about
every third cut it jumped over one row (leaving a rough island). Also, the
cuts in one direction were slightly deeper than the cuts coming back the
opposite way.
I ran a straight line down a piece of scrap wood approx. 30" long and then
ran the cutter next to the line in the direction of the skews (the line on the
scrap was aligned with the line cut in my waste top that is square with
the gantry's travel).

The cut was square to the line I had drawn on the wood when using the jog
to transverse left to right.

[ger21]

Have you tried increasing the pulse width?

[jtriggs]

Okay... first I've found the problem with the rough cuts on my square and
rectangle. I programed the cuts using a 1/2" bit but, since all my other
stuff has used a 1/4" bit, I forgot to switch bits. Duh.
Anyway, I checked the pulse width. It was set at 1. I reset it to 4. The cuts are
far cleaner but I don't really know if the pulse width change had anything to do with
that. I assume using the proper bit is what accounts for that.
There is still a slight skewing to the cuts but now it is the opposite of what it
was before.

[Malkaelan]

Hoping someone can help, not sure this is even the right place to post this...

I have a problem with gaining steps, I have marked on the work crosshairs and this is my start point. Using Mach3, a short program (2 minutes) goes out, engraves its thing and then when it comes back to what Mach3 says is X,Y =0 it is out by just under 1 mm in both axis in the positive direction.

It is not a sudden thing, this occurs over the course of the program. My guess is that noise is being generated from somewhere, affecting both the X and the Y but sheilding all the wires seems to have no effect.

Hoping someone can please help, out of ideas and hair