Four-axis CNC machining is a numerical control processing technology that, based on the traditional three-axis processing, adds an additional rotating axis to achieve more complex and precise machining operations. The following methods to avoid overload operations in four-axis CNC machining mainly include the following aspects:

1. Selecting Cutting Parameters Appropriately: Cutting parameters (including cutting depth, feed rate, and cutting speed) directly affect the quality of machine tools, cutting tools, and workpieces. Either excessive or insufficient cutting parameters can lead to overloaded operations. Therefore, it is essential to choose cutting parameters appropriately based on the power and rigidity of the machine tool, as well as the material of the workpiece and the required processing accuracy.

2. Maintain Sharp Cutting Tools: The sharpness of cutting tools directly affects the size of the cutting force. Sharp tools can reduce cutting force and lower the machine's load. Therefore, it is necessary to regularly inspect and replace cutting tools to maintain their sharpness.

3. Streamlined Machining Paths: By optimizing the machining paths, unnecessary travel and motion of the machine tools during the machining process can be reduced, thereby lowering the load on the machine tools.

4. Machine Tool Status Monitoring: Real-time monitoring of machine tool operation status, including spindle load and feed axis load. When excessive load is detected, it is essential to promptly adjust cutting parameters or take other measures to prevent overloading operations.

5. Overload Protection Setup: The machine tool is equipped with an overload protection device. In the event of the machine tool exceeding the set load value, the protection device will automatically shut down the machine or reduce the load, thereby preventing overload operations from causing damage to the machine tool and workpiece.