Machine tool selected point temperature rise identification based on operational thermal modal analysis

Abstract

A new method to fast identify machine tool selected point temperature rise is presented. Based on operational thermal modal analysis, a temperature rise curve of each machine tool selected point can be obtained, and thermal equilibrium time and steady-state temperature can be calculated based on the measured temperature data during a short time of a warm-up run. The major advantage of this approach is to predict selected point temperature rise of the machine tool in the short test period of time like half an hour instead of 3 to 6-h running test in practice. A spindle system model is analyzed in ANSYS software, and the simulation temperature data of several selected points are treated as the measured temperature. By dealing with the assuming measurement temperature based on the new method, the effectiveness of the method is verified and how to get the minimal time for identification is also illustrated. At last, the temperature rise test in the vertical machining center has been done. The temperature rise of the selected point has been identified in 26.35 min while the time of obtaining the temperature rise curve from the start-up of machine tool to the temperature steady-state machine tool reaching in practice is 320 min. The root mean squared error (RMSE) between the estimated and measured temperature is 0.107 °C, and the error between the estimated and measured steady-state temperature is 0.155 °C. So this method is proven to be effective and quick for identifying the machine tool selected point temperature rise. Furthermore, it has universal applicability due to the validation in the different spindles.