Matters needing attention when using CNC machining center tools

It is very important to observe and judge the working state of the tool during CNC machining. The tool can only achieve good machining accuracy and finish in the best state. So where should we observe? Let me tell you about it.

1. The new tool of the CNC machining center is stuck during machining, and the machining is very difficult. What parameters need to be adjusted at this time?

The reason for the difficult machining is that the power and torque of the spindle cannot bear the current cutting amount. The reasonable approach is: re-path, reduce the cutting depth, slotting depth, and trimming amount. If the overall machining time is less than 30 minutes, the cutting state can also be improved by adjusting the tool speed.

2. What is the role of the cutting fluid in the CNC machining center?

Pay attention to adding cooling oil during metal processing. The role of the cooling system is to take away the cutting heat and flying chips, and play a lubricating role in the machining. The coolant takes away the cutting heat, reduces the heat transferred to the tool and motor, and increases their service life. Take away the flying chips to avoid secondary cutting. Lubrication can reduce cutting force and make the machining more stable. In copper machining, the use of oily cutting fluid can improve the surface quality.

3. What stages does the wear of CNC machining center tools include?

Tool wear is divided into three stages: initial wear, normal wear, and rapid wear. In the initial wear stage, the main reason for tool wear is that the tool temperature is low and has not reached the optimal cutting temperature. At this time, the wear of the tool is mainly abrasive wear. Such wear has a greater impact on the tool. For more CNC programming knowledge, pay attention to the WeChat public account (CNC programming teaching) to receive tutorials. This stage is a very dangerous stage. If it is not handled properly, it may directly lead to tool failure. When the tool passes the initial wear period, the cutting temperature of the tool reaches a certain value. This is the main wear and tear is diffusion wear, and its main function is to cause local peeling. Therefore, the wear is relatively small and slow. When the wear reaches a certain degree, the tool fails and enters the rapid wear period.

4. Why do CNC machining center tools need to be run-in, and how to run-in?

As we said above, the tool is very easy to break in the initial wear stage. In order to avoid the phenomenon of breaking, we must run-in the tool. Make the cutting temperature of the tool gradually rise to a reasonable temperature. It has been verified by experiments that the comparison is made using the same processing parameters. It can be seen that after running-in, the tool life has increased by more than 2 times.

The method of running-in is to reduce the feed speed by half while maintaining a reasonable spindle speed, and the processing time is about 5 to 10 minutes. Take a small value when processing soft materials and a large value when processing hard metals.

5. How to judge whether the CNC machining center tool is seriously worn?

The method to judge whether the tool is seriously worn is:

1) Listen to the processing sound, and there is a harsh sound;

2) Listen to the spindle sound, and the spindle has obvious stalling phenomenon;

3) Feel the vibration increase during processing, and the machine tool spindle has obvious vibration;

4) Look at the processing effect, the processed bottom surface knife pattern is good and bad (if it is like this at the beginning, it means that the cutting depth is too deep).

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6. When should the tool be changed?

We should change the tool at about 2/3 of the tool life limit. For example, if the tool is severely worn after 60 minutes, the tool should be changed after 40 minutes during the next processing, and the habit of changing the tool regularly should be developed.

7. Can the severely worn CNC machining center tool continue to be processed?

After the tool is severely worn, the cutting force can increase to 3 times the normal value. The cutting force has a great influence on the service life of the spindle electrode. The life of the spindle motor is inversely proportional to the force to the cube. For example, when the cutting force increases by 3 times, processing for 10 minutes is equivalent to the spindle being used for 10*33=270 minutes under normal circumstances.

8. How to determine the extension length of the CNC machining center tool during rough processing?

The shorter the extension length of the tool, the better. However, in actual processing, if it is too short, the length of the tool must be adjusted frequently, which will greatly affect the processing efficiency. So how should the extension length of the tool be controlled in actual processing? The principle is this: the tool bar with a diameter of φ3 can be processed normally if it extends 5mm. The tool bar with a diameter of φ4 can be processed normally if it extends 7mm. The tool bar with a diameter of φ6 can be processed normally if it extends 10mm. Try to go below these values when cutting. If the length of the cutting is greater than the above value, try to control the depth of processing when the tool is worn. This is a bit difficult to grasp and requires more practice.

9. How to deal with a sudden broken tool during processing?

1) Stop processing and check the current processing sequence number.

2) Check the broken tool to see if there is a broken tool body. If there is, remove it.

3) Analyze the cause of the broken tool. This is the most important thing. Why did the tool break? We need to analyze it from the various factors that affect the processing mentioned above. But the reason for the broken tool is that the force on the tool suddenly increased. Or it may be a path problem, or the tool vibrates too much, or there are hard lumps in the material, or the spindle motor speed is incorrect.

4) After analysis, change the tool for processing. If the path is not changed, the processing should be advanced by one sequence number on the original sequence number. At this time, you must pay attention to reducing the feed speed. One is because the broken tool is severely hardened, and the other is to run-in the tool.