The high temperature of the guide bearing of the CNC vertical lathe may be caused by the following reasons:

1. Poor lubrication: The lubrication condition of the guide bearing will directly affect the temperature. If the lubricating oil is insufficient or the quality is not up to standard, or there is a malfunction in the lubrication system, resulting in poor lubrication, the heat generated by the friction of the bearing cannot be effectively dissipated, resulting in an increase in the temperature of the bearing.
2. Overload use: If the load of the CNC vertical lathe is too large or exceeds the rated load of the bearing, the bearing will generate too much friction and heat, exceeding the heat resistance of the bearing, which will cause the temperature of the bearing to rise.
3. Bearing damage or wear: Bearing damage, wear or loose internal parts will lead to increased friction, and the heat generated by friction cannot be dissipated in time, which will increase the temperature of the bearing.
4. Bearing grease aging: Bearing grease that has been used for a long time or has a long service life will lose its lubricating performance due to aging, resulting in increased friction and temperature.
5. Ambient temperature and humidity: If the ambient temperature is too high or the humidity is too high, the temperature of the guide bearing may rise. High temperature and high humidity environments both increase bearing friction and heat generation.
6. Design and selection of the guide bearing: the design of the guide bearing is unreasonable or mismatched, and the size of the selected bearing is too large or too small, and the thermal load of the bearing cannot be reasonably distributed, which may cause the temperature of the bearing to rise.

If the temperature of the guide bearing is too high, measures should be taken immediately to deal with it, such as checking and replacing lubricating oil, repairing the lubrication system, reducing load or adjusting process parameters, etc. In addition, regular maintenance and inspection of guide bearings to ensure proper operation, proper lubrication and load range can also help reduce problems with excessive bearing temperatures. If the problem persists, a professional technician should be consulted for diagnosis and resolution.