CNC milling machine cutting is a more commonly used processing technology, but we should often appear in the process of processing, due to the cutting tool, there are processing errors. For these errors, what are the reasons? Can we How to reduce the occurrence of these phenomena? Let’s take a look at the causes and solutions of cutting errors in CNC turning and milling.

From the actual operation in China, I learned that the radial deviation of the tool in the machining process is mainly due to the radial deviation aggravated by the radial cutting force. Therefore, reducing the radial cutting force is an important principle to reduce the radial deviation. There are several ways to reduce radial deviation:

 

1. Use Sharp tools

Use a larger tool rake angle to make the tool sharper to reduce cutting force and vibration. The larger relief angle of the tool is used to reduce the friction between the main surface of the tool side and the elastic recovery layer of the transition surface of the workpiece, which reduces vibration. However, the front and rear corners of the tool cannot be too large, otherwise the resistance and heat dissipation area of ​​the tool will be insufficient. Therefore, it is necessary to select different tool inclination and clearance angles according to specific conditions, which can be smaller during grinding, but in the case of finishing, in order to reduce the radial deviation of the tool, a larger tool should be made. Avant-garde.

 

2. Use high-strength tools

There are two main ways to increase the strength of the tool. First, the shaft diameter can be increased. Under the same radial cutting force, the diameter of the tool holder can be increased by 20%, and the radial deflection of the tool can be reduced by 50%. Second, the length of the tool extension can be reduced. The greater the extension of the tool, the greater the deformation of the tool during processing. The machining is constantly changing, and the radial deviation of the tool is constantly changing, thereby forming a workpiece. Because the machined surface is not smooth, the extension length of the tool is reduced by 20%, and the radial deviation of the tool is reduced by 50%.

 

3. The rake face of the tool should be smooth

During processing, the soft rake surface reduces the friction of the tool in the tool, reduces the cutting force of the tool, and thereby reduces the radial deviation of the tool.

 

4. Clean the spindle cone and collar

The cone and the spindle collar are clean, and dust and debris must not be generated during the processing of the parts. When selecting processing tools, when using short extension tools, the force must be reasonable and uniform, not too large or too small.

 

5. The number of blades used is reasonable

When the number of blades is too small, sliding will occur during the machining process, which will cause the blades to constantly change the radial deviation of the tool during machining. When the machined surface is not smooth, the cutting force will increase, which will cause large deformation of the tool, increase the radial deviation of the tool during the machining process, and make the machined surface not smooth.

 

6. Use up-cut milling in the finishing process

Since the gap position between the feed screw and the nut changes during the following milling process, the feed table is unbalanced. Therefore, there are shocks and vibrations that affect the service life of the machine tool, the tool, and the surface roughness of the workpiece. When using up-milling, the cutting thickness increases from small to large, and the tool load increases from small to large, and the tool is more stable during the machining process. Please note that this is only used during finishing and is still used for roughing, because milling productivity is high and tool life can be guaranteed.

 

7. Reasonable use of cutting fluid

The cooling-based aqueous solution has almost no effect on the cutting force. The cutting oil based on lubrication can significantly reduce the cutting force. Due to its lubrication, the friction between the inclined surface of the tool and the chips and between the surface of the side and the transition surface of the part can be reduced, which reduces the deflection of the tool.