Why is the precision of 5-axis CNC machining unstable?

CNC machining factories use precision CNC machine tools (machining centers, EDM, slow wire-traveling machine tools, etc.) for high-precision machining. Do you have this experience: when the machine is turned on every morning for processing, the machining accuracy of the first piece is often not good enough; when the machine is turned on 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 processing, especially position accuracy.

5-axis CNC machining factories that have no experience in precision machining often attribute this unstable accuracy to equipment quality issues. Factories with precision machining experience will attach great importance to the thermal balance between ambient temperature and machine tools. They know very well that even high-precision machine tools can only obtain stable processing accuracy in a stable temperature environment and thermal equilibrium state. When a five-axis CNC machining factory starts up, it will be put into high-precision machining production. Preheating the machine tool is the most basic precision machining common sense.

1. Why does a 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 more than half of the machining accuracy. The main spindle of the five-axis CNC machining factory machine tool, the guide rails, screws and other components used in the X, Y, Z motion axes will heat up and deform due to load and friction during movement, but the thermal deformation error chain will ultimately affect the processing accuracy. It is the displacement of the spindle and XYZ motion axis components relative to the worktable. 2F Prototypes is a machining factory with more than ten years of CNC processing experience. It has complete equipment, CNC turning/milling/grinding/drilling/processing. Partners with parts processing needs are welcome to call us for quotations.

The machining accuracy of the machine tool is significantly different between the long-term stop operation state and the thermal equilibrium state. The reason is that the temperature of the spindle and each motion axis of the CNC machine tool is relatively maintained at a certain fixed level after running for a period of time, and As the processing time changes, 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, many factories ignore or are unaware of the “warm-up exercise” of five-axis CNC machining factory machine tools.

2. How does a CNC machining factory preheat machine tools?

If the machine tool is idle for more than several days, it is recommended to preheat for more than 30 minutes before high-precision machining; if the machine tool is idle for only a few hours, it is recommended to preheat for 5-10 minutes before high-precision machining.

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

During execution, you can write a macro program on the machine tool to let the machine tool repeatedly perform the preheating action.

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