This powerful software feature – standard on Haas machine tools – uses a proprietary algorithm to compensate for the expansion and contraction (due to heating and cooling) of each linear axis.
The ETC algorithm utilizes a model of the lead screw, and estimates heating of the screw based on the distance travelled and the torque applied to the motor. Heat is represented by a thermal coefficient of expansion, and the axis distance is multiplied by the coefficient to get the amount of correction needed.
A real-time clock allows monitoring of in-motion time as well as non-motion time (e.g., lunch, breaks) and compensates accordingly.
Our testing shows about a 4 to 1 reduction in the error associated with average lead screw growth. A series of parameters allows this feature to be implemented on each axis of various models, with some room for fine-tuning.
Keep in mind that ETC does not correct for: thermal growth due to changes in ambient temperature; growth due to part expansion; or growth due to spindle expansion/retraction.