The method to reduce the tool radial runout in CNC milling

The radial runout of the tool during machining is mainly because the radial cutting force aggravates the radial runout. Therefore, reducing the radial cutting force is an important principle to reduce the radial runout. The following methods can be used to reduce radial runout:

1. Use sharp knives

Choose a larger rake angle to make the tool sharper to reduce cutting force and vibration. Choose a larger tool relief angle to reduce the friction between the tool's main relief surface and the elastic recovery layer of the transition surface of the workpiece, thereby reducing vibration. However, the rake angle and back angle of the tool cannot be selected too large, otherwise the strength and heat dissipation area of the tool will be insufficient. Therefore, it is necessary to select different tool rake angles and back angles according to the specific conditions. The rough machining can be smaller, but in the finishing machining, for the consideration of reducing the radial runout of the tool, it should be larger to make the tool Sharper.

2. Use strong tools

There are two main ways to increase the strength of the tool. One is to increase the diameter of the tool bar. Under the same radial cutting force, the tool bar diameter increases by 20%, and the radial runout of the tool can be reduced by 50%. The second is to reduce the protruding length of the tool. The greater the protruding length of the tool, the greater the deformation of the tool during machining. When machining is in constant change, the radial runout of the tool will continue to change, resulting in a workpiece The machining surface is not smooth, too, if the extension length of the tool is reduced by 20%, the radial runout of the tool will also be reduced by 50%.

3. The rake face of the tool should be smooth

During processing, the smooth rake face can reduce the friction of the chips on the tool, and can also reduce the cutting force on the tool, thereby reducing the radial runout of the tool.

4. Spindle taper hole and chuck cleaning

The spindle taper hole and the chuck are clean and free of dust and debris generated during workpiece processing. When selecting a machining tool, try to use a tool with a shorter extension length to load the knife, and the force should be reasonable and even, not too large or too small.

5. Choose a reasonable amount of knife

If the amount of cutting tool is too small, the phenomenon of machining slippage will occur, which will result in the continuous change of the radial runout of the tool during machining. When the machining surface is not smooth, the cutting force will increase accordingly. It will cause large deformation of the tool, increase the radial runout of the tool during machining, and also make the machined surface not smooth.

6. Use up milling in finishing

As the position of the gap between the lead screw and the nut changes during down milling, it will cause uneven feed of the worktable, resulting in shock and vibration, affecting the life of the machine tool and tool, and the surface roughness of the workpiece. When up-milling, the cutting thickness changes from small to large, the load of the tool also changes from small to large, and the tool is more stable during processing. Note that this is only used for finishing, and down milling should be used for roughing. This is because down milling has high productivity and the tool life can be guaranteed.

7. Reasonable use of cutting fluid

Reasonable use of cutting fluid, mainly cooling water solution, has little effect on cutting force. The cutting oil whose main function is lubrication can significantly reduce the cutting force. Due to its lubricating effect, it can reduce the friction between the tool rake face and the chip and between the flank face and the transition surface of the workpiece, thereby reducing the tool radial runout.