Interpolation error

Hello Guys, I'm working on a retroffiting with linuxcnc version 2.9 and 7i76E. Drives and servo motor (Chinese), the machine is making contours all perfect dimensions, but I'm pretty crazy because the interpolation is vibrating (leaving the axle just after reversing the axes) in the 4 corners, very symmetrical, only more on the Y axis (+ and -). I sent the images of the piece to see and understand better. The last image in calibration, where I changed the PID values ​​(without positive results), I changed the FF’s (I didn’t accept the change, as soon as it changed, there was an error on the machine), I changed all without good results. The step_scale was the first one that I adjusted the dimensional part and it was great. Ah, I also used the codes G’s, G61, G61.1. (the machine was shaking all over), I used the G64 P0.01, G64 Q0.01 (it didn't get better or worse ...). Guys I'm very lost if someone can show a light thank you very much.

Can you post your hal and ini files?

And what Kind of Servos do you use ? And your NC Programm is you circle written like this example or small Steps?
G2X0.000Y-40.000I-40.000J0.000
G2X-40.000Y0.000I0.000J40.000
G2X0.000Y40.000I40.000J0.000

Looks like backlash. They are worse at the reversal points.

Follow the hal and ini files

I am using Cimatron programming and I can only do it with G1 point to point. I tried to make a manual program in G2 and G3 as your example no longer ran.

Hi Scotth, do you know where to do this?

OK the hal/ini files look OK so I would expect the error is not in step generation

i guess pretty sure it's a tuning problem. But without to know which hardware did you use its hard to say, a useful answer. First step could be try to set the P value to 5 or 10 and see what happens. Another idea would be put a pencil in spindle and write the circle on paper. So you can see wath do machine without load.

this is example for 100mm circle and center is zero
G0X0.000Y50.000
G0Z5.000
G1Z0.000
G2X0.000Y50.000I0.000J-50.000
G0...

Look at this it wioo show you how he was testing.

forum.linuxcnc.org/49-basic-configuratio...etup?start=40#126232