[neurotoxin312]

Hey guys, so I recently put together my X2 cnc machine and I got it working mechanically. Im currently in the fine tuning stage and for some reason when I try to mill circular holes they come out off (see picture).

1. I adjusted the gibs and checked for binding,
2. greased up the ways and cleaned them off.
3.Check,tuned, and verified the motor tuning options in Mach3 against my installed iGaging DRO's,
4. accounted for backlash, and
5. made sure the Gcode file was good.

What do you guys think could be the problem? Something I did notice was that while Mach3 was excuting the code there were small pauses between lines of code. I'm not sure if this is normal. This could also be relevant: I'm currently only microsteping @ 1/2 as opposed to others who are doing 1/8 so im not sure if this effects accuracy to that extent. Thanks for your time guys and any help would be much appreciated!

[macpod]

This could be a software, hardware, OR mechanical issue. You're going to have fun..

-First thing I would do is disable accounting for backlash. It's just one more variable in this mix
-Next I would try checking to see if you are loosing steps by running g-code that in the end SHOULD end up where you started. You should be listening for missed steps too
-I would also experiment by reducing your speed and acceleration which could cause results like this

Pausing sounds strange.. what computer are you running this on? It's best to dedicate these machines to the task vs trying to use them as a combo cad/cam setup.


Edit:
Have you measured the width/height of the circles? Are they both off compared to what you expected or is only one axis off? It's just a gut feeling, but I feel like this is being caused by your x-axis coupler set screw(s) being loose.

[Fastest1]

Check the CV setting within Mach 3 config/general config then look under motion mode. This will make motion much less hesitant during machining. Also set the "look ahead" farther out, maybe 100 lines.

Macpod could be right in regards to the coupler or you have a bad case of backlash, though generally if backlash comp is enabled but the wrong value is there. It leaves a little tit right at the transition.

[spoocke]

i think your couplers slip.
had the same problem.
removed the little allenkey screw.
screwed in a modified stainless steel screw in my lovejoy couplers.
problem solved.
for me that is.
my lead screws dont have a flat side on them ( for now )
and the 425Oz stepper motors i use build up a lot of force on the 1605 lead screws.
so when i pushed my lil X2
the couplers slipped.
and compensating backlash wont resolve the problem.

so like macpod said.

[Fastest1]

If you read what I said about backlash comp. I wasnt recommending to use it (though I do recommend its use). I was pointing out the evidence of using it. He was not complaining of that problem.

[spoocke]

he should use it.
but with a variable slip its kinda useless to start to use backlash compensation on that point.
still i find your info very clear and usefull.
i should have been that clear.
so i excuse my self on my part for that
have a nice day