Three reasons and seven solutions for radial runou

Three reasons and seven solutions of milling machine tool radial runout

in the cutting process of NC milling machine, there are many reasons for machining errors, and the error caused by tool radial runout is an important factor, which directly affects the minimum shape error that the machine tool can achieve under ideal machining conditions and the geometric accuracy of the machined surface. In actual cutting, the radial runout of the tool affects the machining accuracy, surface roughness, tool wear non-uniformity and the cutting process characteristics of multi tooth tools. The larger the radial runout of the tool, the more unstable the machining state of the tool, and the more influence the machining effect. 2. Brief electric pull

I. causes of radial runout

the manufacturing error and clamping error of the tool and spindle components cause the drift and eccentricity between the tool axis and the ideal rotation axis of the spindle, as well as the specific processing technology and tooling, etc., may produce the radial runout of the NC Milling machine tool in processing

it depends on what materials it tests. 1 The main reasons for the radial runout error of the spindle are the coaxiality error of each journal of the spindle, various errors of the bearing itself, coaxiality error between bearings, spindle deflection, etc. their impact on the radial rotation accuracy of the spindle varies with the processing method. These factors are formed in the process of machine tool manufacturing and assembly. As the operator of machine tools, different models of electronic universal experimental machines are widely used in various industries of society, and it is difficult to avoid their impact

2. The influence caused by the inconsistency between the tool center and the spindle rotation center

during the installation of the tool to the spindle, if the center of the tool and the rotation center of the spindle are inconsistent, it will inevitably lead to the radial runout of the tool. The specific influencing factors are: the cooperation between the tool and the collet, whether the cutting method is correct, and the quality of the tool itself

3. The impact of specific processing technology

the radial runout produced by the tool during processing is mainly because the radial cutting force intensifies the radial runout. Radial cutting force is the radial component of the total cutting force. It will bend and deform the workpiece and produce vibration during machining, which is the main component affecting the machining quality of the workpiece. It is mainly affected by cutting parameters, tool and workpiece materials, tool geometric angle, lubrication method and machining method

second, the method of reducing radial runout

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

1 Use a sharp tool

select a larger tool rake angle to make the tool sharper to reduce cutting force and vibration. Choose a larger tool back angle to reduce the friction between the elastic recovery layer of the main back face of the tool and the transition surface of the workpiece, so as to reduce the vibration. However, the front and back corners of the tool should not be too large, otherwise the strength and heat dissipation area of the tool will be insufficient. Therefore, we should choose different front and back corners of the tool according to the specific situation. During rough machining, it can be taken smaller, but during finishing, for the consideration of reducing the radial runout of the tool, it should be larger to make the tool sharper

2. There are two main ways to increase the strength of the tool when using a tool with high strength

. First, the diameter of the tool bar can be increased. Under the same radial cutting force, the diameter of the tool bar can be increased by 20%, and the radial runout of the tool can be reduced by 50%. Second, it can reduce the extension length of the tool. The larger the extension length of the tool, the greater the deformation of the tool during processing. During processing, the radial runout of the tool will continue to change, resulting in the uneven machining surface of the workpiece. Similarly, the extension length of the tool will be reduced by 20%, and the radial runout of the tool will also be reduced by 50%

3. The rake face of the tool should be smooth

during machining, a smooth rake face can reduce the friction of chips on the tool and the cutting force on the tool, so as to reduce the radial runout of the tool

4. Spindle taper hole and collet cleaning

spindle taper hole and collet shall be clean and free of dust and debris generated during workpiece processing. When selecting machining tools, try to use tools with short extension length. When loading, the force should be reasonable and uniform, not too large or too small

4 number of steel back or steel shoe holes

5. The selection of cutting capacity should be reasonable

if the cutting capacity is too small, there will be processing slip, which will lead to the continuous change of the radial jump of the tool during processing, making the machined surface not smooth. If the cutting capacity is too large, the cutting force will increase, resulting in large deformation of the tool. Increasing the radial jump of the tool during processing will also make the machined surface not smooth

6. When using reverse milling in finish machining

due to the change of the clearance position between the lead screw and the nut during forward milling, the feed of the workbench will be uneven, resulting in impact and vibration, which will affect the service life of the machine tool and the tool and the machined surface roughness of the workpiece. When using reverse milling, the cutting thickness will change from small to large, the load of the tool will also change from small to large, and the tool will be more stable during machining. Note that this is only used in finish machining, and forward milling is still used in rough machining, because the productivity of forward milling is high, and the service life of tools can be guaranteed

7. Rational use of cutting fluid

rational use of cutting fluid the aqueous solution with the main cooling effect has little effect on the cutting force. Cutting oil with lubrication can significantly reduce the cutting force. Because of its lubrication, it can reduce the friction between the tool rake face and chip, and between the tool rake face and the workpiece transition surface, so as to reduce the radial runout of the tool