A Method to Evaluate the Effects of Heat on a Spindle of a CNC Milling Machine

The article presents the results of modeling the heat transfer process of the vertical main spindle of a CNC milling machine for evaluating the temperature change inside of the spindle unit when it is working at high speed level such as 11,000 rpm. The model is used to simulate the heat transfer from ball bearings to other components inside of the spindle unit and then transfer to the housing and convective heat transfer with the atmosphere from the housing. From the results of the simulation, the authors have evaluated the heat transfer rule inside of the spindle. The findings suggested a suitable lubrication method and nozzle arrangement to cool the spindle bearings and the locations of the heat sensors to investigate the real temperature of the bearing outer ring before the experiment