Abstract: The thermal error of a machine tool is inevitable, and it holds a great proportion in the total error of the CNC. Modeling an accurate thermal error which could be used to forecast and compensate the unexpected error is of great importance. During the last thirty years, many researchers focused on the research of the modeling of the thermal error. And there are two general schools, namely the empirical-based and the principle-based. The empirical-based models are mainly used in the compensation of thermal error, and the models are established based on the statistical analysis. The principle-based models are used for the avoidance of thermal error, and the model is built according the equations of heat transfer, force and displacement constraint. The equations are solved by numerical methods. Based on the two directions, the research status in this area is discussed. The advantages and disadvantages are summarized and future research prospects are concluded.

Key words: machine tool, temperature prediction, thermal drift, thermal error