Causes and solutions for the radial runout of the tool during CNC milling machine processing - News - Global IC Trade Starts Here.

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I. INTRODUCTION During the machining process of CNC milling machines, there are many reasons for machining errors. The error caused by the radial runout of the tool is one of the important factors, which directly affects the minimum shape error that the machine can achieve under ideal machining conditions. The geometric accuracy of the surface being machined. In actual cutting, the radial runout of the tool affects the machining accuracy, surface roughness, tool wear unevenness and cutting process characteristics of the multi-tooth tool. The greater the radial runout of the tool, the more unstable the machining state of the tool, and the more the machining effect is affected.

Second, the radial runout causes the manufacturing error of the tool and the spindle component, the clamping error causes the drift and eccentricity between the tool axis and the ideal axis of the spindle, and the specific machining process, tooling, etc. may produce the diameter of the CNC milling tool in the processing. Jumping.

1. The main cause of the spindle runout error caused by the radial runout of the spindle itself is the coaxiality error of each spindle of the spindle, various errors of the bearing itself, coaxiality error between bearings, and spindle deflection. The influence on the radial rotation accuracy of the spindle varies with the machining method. These factors are formed during the manufacture and assembly of the machine tool, and it is difficult for the operator of the machine tool to avoid the effects.

2. The influence of the inconsistency between the tool center and the spindle rotation center During the process of mounting the tool to the spindle, if the center of the tool and the center of rotation of the spindle are inconsistent, the radial runout of the tool will inevitably occur. The specific influencing factors are: the fit of the cutter and the chuck, the correct method of the upper knife and the quality of the cutter itself.

3. The impact of the specific machining process The radial runout of the tool during machining is mainly due to the radial cutting force exacerbating the radial runout. The radial cutting force is the component of the total cutting force in the radial direction. It will cause the workpiece to bend and deform and generate vibration during processing, which is the main component that affects the processing quality of the workpiece. It is mainly affected by factors such as the amount of cutting, the tool and the material of the tool, the geometry of the tool, the lubrication method and the processing method.

Third, the method of reducing the radial runout The tool produces radial runout during machining mainly because the radial cutting force exacerbates 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 a sharp tool to select 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. The use of high-strength tools can increase the strength of the tool in two ways. 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. When machining, the smooth rake face can reduce the friction of the chip on the tool, and can also reduce the cutting force of the tool, thus reducing the radial runout of the tool.

4. Spindle taper and collet cleaning The spindle taper and 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. If the amount of knife to be used is reasonable, the amount of knife will be too small, and 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 be too large. As a result, the tool is greatly deformed, and the amount of radial runout of the tool during machining is increased, and the machined surface is not smooth.