I use this calibration object for my printer. It gives you a descent reference about the X-Y calibration.
Print it and to avoid any deformation remove it until the platform is cold to the touch (or at room temperature) . The center hole fits a nickel.
- Distance from side to side: 40 mm.
- Each small block: 2 x 5 mm
-Total height: 5 mm
- Block height: 2 mm