Problem with home built machine?

My new home build with ruida control is cutting rectangles fine, as well as circles, but on fill is drifting left the further it goes.

Any suggestions?

Belts and pulleys are tight on the X and Y axes.

If the burn area is shifting as the engraving progresses, the most likely issue is that your stepper motors are skipping steps. The underlying causes for skipping steps range from speed and acceleration on the axis being set too high, to excessive resistance for movement along the axis. The first place I would check is the ease of movement along the x-axis. Belts and pulleys can easily be too tight.

Turns out it was a PWM setting in the ruida control, switched that and now it works perfectly