In the process of CNC machine tool spindle running, the spindle bearing temperature will increase due to insufficient spindle lubrication, too thick lubricant, spindle machining, and installation. Spindle bearing temperature is too high, can cause the material to expand, cause the mechanical gap to become smaller to appear the noise and the mechanical damage.
Keywords: CNC machine tool spindle bearing; detection
0 Preface
CNC machine tools can use the measurement method to monitor the spindle bearing temperature. By measuring the temperature rise in the operation of the spindle bearings, to understand whether the spindle bearings are normal. The bearing temperature is generally limited to a temperature increase of no more than 45°C. If the temperature of the bearing exceeds 70-80°C during the monitoring, it should be stopped immediately.
1 Installation and wiring
CNC machine tools can use the combination of thermal resistance, multi-channel digital instruments and PLC control system to realize the spindle bearing temperature detection.
Mount four thermal resistors on the front, center, and rear bearing of the spindle. The PLC control system collects the temperature of four measurement points to monitor the bearing temperature rise at different locations.
2 control requirements and principles
The temperature control system uses a thermal resistor to measure the temperature at the measurement point and uses a multi-channel digital instrument to display the temperature of the spindle bearing. PLC realizes parameter setting, remote monitoring, data storage and alarm processing functions. In the actual programming process, there is no need to write a program that reads or writes PLC registers. After the I/O variables are defined through the method of data definition, the variable names can be directly used for system control, operation display, data recording, and alarm.
The system sets a start button to start the control program and sets two red and green indicators to show the temperature status. The temperature of the 4 measuring points is within the required range. The green light is on, indicating that the spindle can operate normally. When the temperature of a measured point reaches the upper limit, the red light will be on even if the spindle speed has not reached the required level. The corresponding bearing alarm. The operator will stop the spindle immediately and check the corresponding position of the spindle bearing according to the corresponding alarm number, so as to avoid grinding of the spindle bearing.
3 Conclusion
Modern PLC has the prominent features of strong functions, high integration, strong anti-interference ability, flexible configuration and stable operation, and is widely used in the automatic control of modern industry. PLC can expand some intelligent control modules to form different control systems. The detection of spindle bearing temperature mentioned in this article is an intelligent temperature control system with PLC as the core, which is easy to operate and has good reliability. It has important practical significance.
