How to deal with chatter marks during CNC lathe processing?

Causes of chatter marks

Chatter marks are usually a surface defect caused by vibration during the machining process. Its causes can be summarized as follows:

1. Equipment factors: Insufficient rigidity of CNC lathes, guide rail wear, low spindle precision and other factors can all lead to chatter marks.

2. Process parameters: Inappropriate cutting speed, feed speed, tool geometry and cutting depth may all be the cause of chatter marks.

3. Tool status: Tool wear, improper tool material selection or poor contact between tool and workpiece can cause vibration and lead to chatter marks.

4. Workpiece material: The physical properties, hardness and internal stress distribution of the workpiece material will affect the vibration behavior during the cutting process.

5. External environment: The instability of the machining environment, such as workbench vibration and uneven ground, may also cause chatter marks.

Identification and detection of chatter marks

After understanding the causes of chatter marks, timely discovery and identification of chatter marks is the key to solving the problem. Common chatter mark characteristics are:

1. The surface has obvious wavy marks, which can be seen with the naked eye.

2. When you stroke it with your fingernails or other tools, you feel unevenness.

3. The surface roughness measured by measuring tools (such as microscopes, roughness meters) exceeds the standard.

Solutions to chatter marks

For the chatter marks that have occurred, the following solutions can be adopted:

1. Adjust the status of equipment and tools

Check the maintenance and care of the CNC lathe to ensure that the equipment is in good working condition, replace the tools regularly, and prevent chatter marks caused by excessive tool wear. At the same time, check the clamping degree of the spindle to ensure that it is stable and not loose.

2. Modify process parameters

Optimizing cutting parameters is an effective way to solve chatter marks. Generally, appropriately reducing the cutting speed, adjusting the feed rate and cutting depth can effectively reduce the vibration generated during the processing. In addition, by selecting the appropriate tool geometry design, the stability of the processing can be significantly improved.

3. Strengthen workpiece fixation

Use appropriate fixtures and tools to ensure the stability of the workpiece during the processing. The design of the fixture needs to be tailored to the characteristics of the workpiece to avoid displacement due to the weight of the workpiece or the force generated during the processing.

4. Improve the processing environment

Ensure the stability of the processing environment, regularly check and maintain the processing table, and avoid vibration interference caused by the movement of other mechanical equipment. You can consider adding shock-absorbing materials under the processing equipment to further reduce the impact of the environment on the processing accuracy.

Preventive measures for vibration marks

The key to preventing the occurrence of vibration marks lies in the early preparation and later monitoring. The following are some effective preventive measures:

1. Regular equipment maintenance

Regularly conduct a comprehensive inspection and maintenance of the CNC lathe to ensure the rigidity and accuracy of the equipment to reduce the possibility of vibration during processing.

2. Reasonable selection of tools

Select tools that are suitable for the workpiece material, and prepare the tools before processing, including sharpening and checking the integrity of the tools.

3. Routine testing and monitoring

For important processing processes, if necessary, you can connect monitoring equipment to monitor the status of the cutting process in real time, and adjust the process parameters immediately if abnormalities are found.