The factory uses precision CNC machine tools (machining centers, EDM, slow wire and other machine tools) for high-precision processing. Do you have such experience: every morning boot processing, the first piece of processing accuracy is often not good enough; The first parts of the boot processing after the long holiday are often very unstable accuracy, high probability of failure in high precision processing, especially position accuracy.
Factories without experience in precision processing often attribute such accuracy instability to equipment quality problems. And factories with precision processing experience will attach great importance to the thermal balance between the ambient temperature and the machine tool. They know that even high-precision machine tools can only achieve stable machining accuracy in a stable temperature environment and thermal equilibrium. In the case of high-precision machining production after boot, preheating the machine tool is the most basic common sense of precision machining.
Why do we need to preheat machine tools?
The thermal characteristics of CNC machine tools have an important influence on machining accuracy, which accounts for more than half of the machining accuracy. The spindle of the machine tool, the guide rail used by the XYZ moving shaft, the lead screw and other parts will heat up and deform due to the load and friction in the movement, but the final impact of the thermal deformation error chain is the displacement of the spindle and the XYZ moving shaft parts relative to the table.
The machining accuracy of the machine tool is different in the state of long-time stop operation and the state of thermal balance. The reason is that the temperature of the spindle and the moving axis of the CNC machine tool is relatively maintained at a fixed level after running for a period of time. And with the change in the processing time, the thermal accuracy of the CNC machine tool tends to be stable. This shows that it is necessary to preheat the spindle and moving parts before machining.
However, the “warm-up exercise” of machine tool preparation is ignored or not known by many factories.
02 How to preheat the machine tool?
If the machine is in a state of suspension for more than a few days, it is recommended to preheat for more than 30 minutes before high precision machining; If the shelving state is only for a few hours, it is recommended to warm up for 5-10 minutes before high precision machining.
The process of preheating is to allow the machine tool to participate in the repeated movement of the processing axis. It is best to carry out multi-axis linkage, such as moving the XYZ axis from the lower left corner of the coordinate system to the upper right corner and repeatedly walking the diagonal.
When the execution can be written on the machine tool a macro program so that the machine tool repeatedly performs the preheating action.
After the machine is fully warmed up, the dynamic machine can be put into high precision machining production, you will obtain a stable and consistent machining accuracy.
