CNC Machining: What are the Processing Techniques of Precision CNC Machining?

We know that precision CNC machining requires high precision. Precision CNC machining has good rigidity, high manufacturing precision, and accurate tool setting. Therefore, CNC parts with high precision requirements can be machined. So What are the processing techniques of precision CNC machining? The following is an introduction by our chief engineer of VMT:

First of all, compared with ordinary lathes, CNC machining lathes have a constant line speed cutting function. The same linear speed can be used to process the end face of the car or the outer circle of different diameters, which ensures that the surface roughness value is consistent and relatively small. The ordinary lathe has a constant speed, and the cutting speed is different with different diameters. When the material, finishing allowance and tool angle of the precision CNC machined parts and tools are constant, the surface roughness depends on the cutting speed and feed speed.

When CNC machining surfaces with different surface roughness, the surface with small roughness should use a small feed rate, and the surface with large roughness should use a larger feed rate, and the variability is very good, which is difficult to do on ordinary lathes. To; precision CNC machining parts with complex contour shapes, any plane curve can be approximated by straight lines or arcs, precision CNC machining has the function of arc interpolation, and can process parts with various complex contours, the use of precision CNC machining is good or bad Requires careful use by the operator.

Precision CNC machining mainly includes fine turning, fine boring, fine milling, fine grinding and grinding processes:

(1) Fine turning and fine boring: Most of the precision CNC machining (aluminum or magnesium alloy, etc.) parts in the aircraft are processed by this method. Generally, natural single crystal diamond tools are used, and the radius of the blade arc is less than 0.1 microns. Machining on a lathe can obtain an accuracy of 1 micron and a surface unevenness with an average height difference of less than 0.2 microns, and the coordinate accuracy can reach ±2 microns.

(2) Fine milling: It is used for CNC machining of aluminum or beryllium alloy precision CNC machining parts with complex shapes. It relies on the precision of the guide rail and spindle of the machine tool to obtain high mutual position accuracy, and uses a carefully ground diamond cutter head for high-speed milling. Cut to get an accurate mirror finish.

(3) Fine grinding: It is used for CNC machining shafts or precision CNC machining parts of holes. Most of these parts are made of hardened steel with high hardness, and most high-precision grinder spindles use hydrostatic or dynamic hydraulic bearings to ensure high stability. The ultimate precision of grinding is not only affected by the stiffness of the machine tool spindle and bed, but also related to the selection and balance of the grinding wheel, the CNC machining accuracy of the center hole of the workpiece and other factors. roundness.

(4) Grinding: Using the principle of mutual research of mating parts to select CNC machining of irregular raised parts on the machined surface, the diameter of abrasive particles, cutting force and cutting heat can be precisely controlled, so it is the highest in precision CNC machining technology. Precision machining method. The hydraulic or pneumatic fittings in the precision servo parts of the aircraft and the bearing parts of the dynamic pressure gyro motor are all processed by this method to achieve an accuracy of 0.1 or even 0.01 microns and a microscopic unevenness of 0.005 microns.