The circle is distorted, the horizontal and vertical output ratios are different.

jeongbyungheon

What is the cause? Please help me.~~

The x-axis is a belt

The motor's step angle is also 1.8 degrees, the step is 1/16, the belt pitch is 2mm, and the number of gear teeth is 8

The y-axis is a screw

The motor's step angle is also 1.8 degrees, the step is 1/16, the screw pitch is M8 P1.25mm, and the gear ratio is 1

Dimensions based on the X-axis are 60, and the actual output is 63.66

Dimensions based on the Y-axis are 60, and the actual output is 61.84

Repetier

If belt tension is too low you get more motion then you think from theory. Same if tension is too high, so check this.
For the screw it is harder to say. You should also print a smaller test object to see if you have a fixed error distance in which case you might have some reversion play. Also screws are more demanding with higher friction, but normally you loose steps so it would be less travel then in theory. So no real idea what is causing this.