The accuracy problem has been solved by enabling AICC and adjusting the parameters related to turning, acceleration and deceleration.
The following video is provided for your reference, G112 (G12.1) milling 160✕ 160 square, within 0.02mm accuracy.

https://youtu.be/elYbW5NjTFE

Hi everyone
we've had this problem for a long time...
machining a square with G112(G12.1) of accuracy question
using test indicator to measure squareness and straightness and concentricity of surface
the test results are as follows

https://youtu.be/FjUvMglQSBg

when the C axis is 180°, the square eccentricity of 0.24mm
how adjustment the accuracy of G112(G12.1)?

※ the live tool is on center of the machine
※ it's a Taichung Vturn A20Y machine with a Fanuc Oi-TF control.