Processing method of radial runout of CNC machine tools
Method of reducing radial runout
The radial runout of the tool during machining is mainly due to the radial cutting force exacerbating the radial runout. Therefore, reducing the radial cutting force is an important principle to reduce the radial runout. There are several ways to reduce radial runout:
1. Use sharp tools
Use a larger tool rake angle to make the tool sharper to reduce cutting forces and vibration. The larger tool back angle is used to reduce the friction between the main flank face of the tool and the elastic recovery layer of the workpiece transition surface, thereby reducing vibration. However, the front and back corners 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, which can be smaller when roughing, but in the case of finishing, in order to reduce the radial runout of the tool, it should be made larger to make the tool More sharp.
2. Use high strength tools
There are two main ways to increase the strength of the tool. First, the diameter of the arbor can be increased. Under the same radial cutting force, the shank diameter can be increased by 20%, and the radial runout of the tool can be reduced by 50%. Secondly, the extension length of the tool can be reduced. The larger the tool extension length, the larger the tool deformation during machining. The machining is constantly changing, and the radial runout of the tool changes continuously, resulting in the workpiece. As the machined surface is not smooth, the tool extension length is reduced by 20% and the tool's radial runout is reduced by 50%.
3. The rake face of the tool should be smooth
During machining, the smooth rake face reduces the friction of the chip on the tool and reduces the cutting force on the tool, thus reducing the radial runout of the tool.
4. Spindle taper and collet cleaning
The spindle taper and the collet are clean and must be free of dust and debris from the machining of the workpiece. When selecting a machining tool, try to use a tool with a short extension length to make the force uniform and not too large or too small.
5. It is reasonable to use the amount of knife
When the amount of knife is too small, there will be a phenomenon of processing slippage, which will lead to the continuous change of the radial runout of the tool during processing, so that when the processed surface is not smooth, the cutting force will increase, so that the cutting force will increase. As a result, the tool is deformed greatly, and the amount of radial runout of the tool during machining is increased, and the machined surface is not smooth.
6. Use up-cut milling during finishing
Due to the change of the position of the gap between the lead screw and the nut during the milling process, the feed of the table is uneven, which has impact and vibration, which affects the life of the machine tool, the tool and the surface roughness of the workpiece. In the case of up-cut milling, the cutting thickness is increased from small to large, the load of the tool is also increased from small to large, and the tool is more stable during processing. Note that this is only used during finishing and is still used for roughing because of the high productivity of the milling and the long service life of the tool.
7. Reasonable use of cutting fluid
The rational use of the cutting fluid in the cooling-based aqueous solution has little effect on the cutting force. Cutting oils based on lubrication can significantly reduce cutting forces. Due to its lubrication, the friction between the rake face of the tool and the chip and between the flank face and the transition surface of the workpiece can be reduced, thereby reducing the tool runout.
Practice has proved that as long as the accuracy of manufacturing and assembly of various parts of the machine tool is ensured, and a reasonable process and tooling are selected, the influence of the radial runout of the tool on the machining accuracy of the workpiece can be minimized.
