Is It Necessary to Warm Up when Turning on the CNC Machine?
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Is It Necessary to Warm Up when Turning on the CNC Machine?
The factory uses precision CNC machine tools (machining centers, EDM, slow wire and other machine tools) for high-precision machining. Do you have such an experience? When you turn on the machine every morning for processing, the accuracy of the first part is often not good enough; The accuracy of the first batch of parts is often very unstable, and the probability of failure in high-precision machining is extremely high, especially the position accuracy.
Factories without precision machining experience often attribute this unstable accuracy to equipment quality problems. And factories with precision machining experience will pay great attention to the environmental temperature and the heat balance of the machine tool. They are very clear that even high-precision machine tools can only obtain stable machining accuracy under a stable temperature environment and thermal equilibrium. In the case of high-precision machining and production after starting up, preheating the machine tool is the most basic common sense of precision machining.
Why do we need to warm up the machine?
The thermal characteristics of CNC machines have an important impact on machining accuracy, accounting for almost half of the machining accuracy.
The main shaft of the machine tool, the guide rails used by the XYZ motion axis, the lead screw and other components will be heated and deformed due to load and friction during the movement, but the final impact on the machining accuracy in the thermal deformation error chain is the relative difference between the main shaft and the XYZ motion axis. Displacement of the worktable.
The machining accuracy of the machine tool in a long-term shutdown state and in a thermal equilibrium state is quite different. The reason is that the temperature of the spindle and each motion axis of the CNC machine is relatively maintained at a certain fixed level after running for a period of time, and with the change of processing time, the thermal accuracy of CNC machine tends to be stable, which shows that it is very necessary to preheat the spindle and moving parts before processing.
However, the preparatory part of the “warm-up exercise” of machine tools is ignored or unknown by many factories.
How to warm up the machine?
If the machine is left for more than several days, it is recommended to preheat for more than 30 minutes before high-precision machining; if the machine is left for only a few hours, it is recommended to preheat for 5-10 minutes before high-precision machining.
The preheating process is to allow the machine tool to participate in the repeated movement of the machining axis. It is best to perform multi-axis linkage, such as moving the XYZ axis from the lower left corner of the coordinate system to the upper right corner, and repeating diagonal lines.
When executing, you can write a macro program on the machine tool to make the machine tool repeatedly perform the preheating action. For example, when the CNC machine tool is stopped for a long time or before high-precision parts processing, according to the mathematical 3D elliptic parameter curve and the preheated machine tool space range, t is the independent variable, and the three motion axis coordinates of XYZ are used as the parameter. With a certain incremental step, the maximum range of the specified XYZ motion axis is used as the boundary condition of the parameter curve, and the spindle speed and the feed speed of the XYZ motion axis are associated with the independent variable t, so that it can continuously change within the specified range, generating The recognizable numerical control program of the numerical control machine tool is used to drive each movement axis of the machine tool to produce synchronous no-load movement, and is accompanied by the control transformation of the spindle speed and the feed speed during the movement.
After the machine is fully warmed up, the energetic machine tool can be put into high-precision processing and production, and you will get stable and consistent processing accuracy.
Why do we know so much? Because we have been a professional supplier of CNC cutting tools for many years.
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