Abstract: Methods are disclosed for determining mounting locations of ingots on a wire saw machine. The methods include measuring a test surface of a test wafer previously sliced by the wire saw machine from a test ingot to calibrate the system. A magnitude and a direction of an irregularity of the measured test surface of the test wafer is then determined. The mounting location is then determined for another ingot to be mounted on the ingot holder based on at least one of the magnitude and direction of the irregularity of the measured test surface of the test wafer.