1. Use sharp tools
Use a larger tool rake angle to make the tool sharper to reduce cutting force and vibration. Use a larger tool back angle to reduce the friction between the main back face of the tool 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 too large, otherwise it will lead to insufficient strength and heat dissipation area of the tool. Therefore, different tool rake angles and back angles should be selected according to specific conditions. Smaller ones can be used for rough machining, but larger ones should be used for fine machining to reduce the radial runout of the tool, so that the tool is sharper.
2. Use strong tools
The strength of the tool can be increased in two main ways. One is to increase the diameter of the tool bar. Under the same radial cutting force, the radial runout of the tool can be reduced by 50% if the tool bar diameter increases by 20%. Secondly, it can reduce the tool extension length. The longer the tool extension length is, the greater the tool deformation will be during processing. During processing, the tool is in a constant change, and the radial runout of the tool will change accordingly, resulting in an uneven workpiece surface. Similarly, if the tool extension length is reduced by 20%, the radial runout of the tool will also be reduced by 50%.
3. The front cutting edge of the tool should be smooth
During processing, a smooth front cutting edge 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. Clean the spindle taper and chuck
The spindle taper and chuck should be clean, and there should be no dust or debris generated during workpiece processing. When selecting a processing tool, try to use a tool with a shorter extension length. The force when cutting should be reasonable and uniform, not too large or too small.
5. The amount of cutting should be selected reasonably. If the cutting amount is too small, the machining will slip, which will cause the radial runout of the tool to change continuously during machining, making the machined surface rough. When the cutting amount is too large, the cutting force will increase accordingly, resulting in large deformation of the tool. Increasing the radial runout of the tool during machining will also make the machined surface rough.
6. Use reverse milling during finishing. Because the gap position between the lead screw and the nut changes during forward milling, it will cause uneven feeding of the worktable, resulting in impact and vibration, affecting the life of the machine tool and the tool and the roughness of the machining surface of the workpiece. When using reverse 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 machining. Note that this is only used during finishing. For rough machining, forward milling should still be used because forward milling has high productivity and the service life of the tool can be guaranteed.
7. Use cutting fluid reasonably.
Reasonable use of cutting fluid. Aqueous solution with cooling as the main function has little effect on cutting force. Cutting oil, which mainly acts as a lubricant, can significantly reduce cutting forces. Due to its lubrication effect, it can reduce the friction between the rake face of the tool and the chips, and between the flank face and the transition surface of the workpiece, thereby reducing the radial runout of the tool.
Practice has proved that as long as the manufacturing and assembly accuracy of each part of the machine tool is guaranteed and reasonable processes and tooling are selected, the impact of the radial runout of the tool on the machining accuracy of the workpiece can be minimized.