Simple piece for step / mm calibration, before printing check the belt tension and the bed setting well, take the steps of your printer as originally, then proceed to print and measure, the calibration formula is always the same: theoretical value of the piece (in this case 145 mm for all the axes) divided by the measured value multiplied by the steps of the axis, for example if X originally has 100 as the value of the steps and measured measured on X 145.7 the calculation will be 145: 145.7x100 = 99.51