What’s wrong with the unstable accuracy of 5-axis CNC machining

CNC machining factories use precision CNC machine tools (machining centers, electric sparks, slow wire, etc.) for high-precision machining. Do you have such experience: every morning when you start up for processing, the processing accuracy of the first piece is often not good enough; start up after a long holiday The accuracy of the first batch of parts processed is often very unstable, and the probability of failure is extremely high during high-precision machining, especially the position accuracy.

5-axis CNC machining factories without experience in precision machining often attribute the instability of precision to equipment quality problems. And factories with experience in precision machining will attach great importance to the thermal balance of ambient temperature and machine tools. They are very clear that even high-precision machine tools can only obtain stable machining accuracy in a stable temperature environment and thermal equilibrium state. The 5-axis CNC machining plant will be put into high-precision machining production after starting up. Preheating the machine tool is the most basic precision machining common sense.

1. Why does the CNC machining factory need to preheat the machine tool?
The thermal characteristics of CNC machine tools have an important impact on machining accuracy, accounting for almost half of the machining accuracy. The main shaft of the machine tool of the 5-axis CNC machining factory, the guide rails and lead screws used in the XYZ motion shaft parts will all be heated and deformed due to load and friction during motion, but the main shaft is the one that ultimately affects the machining accuracy in the thermal deformation error chain and the displacement of the XYZ motion axis components relative to the worktable. 2F Prototypes is a machining factory with more than ten years of CNC machining experience. It has complete equipment, CNC turning/milling/grinding/drilling/processing. Welcome partners who have parts processing needs to contact us for quotations.

The machining accuracy of the machine tool in the state of long-term stop operation and the state of thermal equilibrium is quite different. The reason is that the temperature of the spindle and each movement axis of the CNC machine tool is relatively maintained at a certain level after running for a period of time, and With the change of processing time, the thermal accuracy of CNC machine tools tends to be stable, which shows that it is very necessary to preheat the spindle and moving parts before processing.

However, the preparation link of the “warm-up exercise” of machine tools in 5-axis CNC machining factories is ignored or not known by many factories.

2. How does the CNC machining factory preheat the machine tool?
If the machine tool has been left on hold for more than a few days, it is recommended to preheat for more than 30 minutes before high-precision machining; if the machine is left on hold for only a few hours, it is recommended to preheat for 5-10 minutes before high-precision machining.

The process of warming up is to let the machine tool participate in the repeated movement of the machining axis. It is best to perform multi-axis linkage, such as moving the XYZ axes from the lower left corner of the coordinate system to the upper right corner, and repeatedly walking diagonally. 2F Prototypes is a machining factory with more than ten years of CNC machining experience. It has complete equipment, CNC turning/milling/grinding/drilling/processing. Welcome partners who have parts processing needs to contact us for quotations.

When executing, you can write a macro program on the machine tool to let the machine tool repeatedly perform the warm-up action.

After the machine tool is fully warmed up, the vigorous machine tool can be put into high-precision machining production, and you will get stable and consistent machining accuracy.