It is very important to prevent the CNC milling machine from breaking the tool. The following measures can be taken:

1. Reasonable selection of tools: CNC milling machines select appropriate tool types, sizes and materials according to the processing materials, processing technology and processing requirements. Ensure the quality and durability of the tool, and avoid using severely worn or inappropriate tools.

2. Control cutting parameters: CNC milling machines reasonably set cutting speed, feed speed and cutting depth to avoid excessive cutting parameters that cause excessive force on the tool and increase the risk of tool breakage. During the initial processing, the cutting parameters can be gradually increased to ensure the appropriate load between the tool and the workpiece.

3. Regularly check the tool: CNC milling machines regularly check the wear and tip condition of the tool, and replace severely worn or damaged tools in time. CNC milling machines ensure that the tool maintains a good cutting state and reduces the possibility of tool breakage.

4. Check tool fixation: CNC milling machines ensure the stability and reliability of the tool clamping system, check the tightness of the tool clamping components, and prevent tool breakage caused by loose tools.

5. Strengthen machine tool maintenance: Regularly maintain and maintain CNC milling machines to maintain the accuracy and performance of all parts of the machine tool. In particular, the maintenance of the lubrication system and cooling system ensures that the tool is well lubricated and cooled during the processing process to reduce the risk of tool breakage.

6. Use appropriate workpiece clamping: The CNC milling machine uses appropriate workpiece clamping methods and fixtures to ensure that the workpiece is firmly fixed during the processing process to avoid tool collision or breakage due to loose workpieces.

7. Monitor the processing process: The CNC milling machine uses the monitoring function of the CNC system to monitor the tool status and processing conditions during the processing in real time, detect abnormal conditions in time and take corresponding measures to avoid tool breakage.

In summary, by reasonably selecting tools, controlling cutting parameters, regularly checking tool and machine tool maintenance, strengthening workpiece clamping, and monitoring the processing process, the problem of tool breakage in CNC milling machines can be effectively prevented, and processing efficiency and safety can be improved.