Author: Site Editor Publish Time: 12-01-2021 Origin: Site
We know that precision machining has high requirements for precision, precision machining has good rigidity, high manufacturing precision, and accurate tool setting, so it can process parts with high precision requirements. So what are the parts suitable for precision machining? The following are introduced by Xiaobian:
First of all, compared to ordinary lathes, CNC lathes have a constant line speed cutting function, regardless of the lathe end face or the outer diameter of different diameters can be processed at the same line speed, that is to ensure a uniform surface roughness value and relatively small . The ordinary lathe has a constant speed, and the cutting speed varies with the diameter. When the material of the workpiece and the tool, the finishing allowance and the tool angle are constant, the surface roughness depends on the cutting speed and feed speed.
When processing surfaces with different surface roughness, a small feed rate is used for a surface with a small roughness, and a higher feed rate is used for a surface with a large roughness, which has good variability, which is difficult to achieve on ordinary lathes. Complex contoured parts. Any plane curve can be approximated by a straight line or a circular arc. CNC precision machining has the function of circular interpolation, which can process various complex contour parts. The use of cnc precision machining requires the operator’s careful use.
CNC precision machining mainly includes fine turning, fine boring, fine milling, fine grinding and grinding processes:
(1) Fine turning and fine boring: Most precision light alloy (aluminum or magnesium alloy) parts of aircraft are processed by this method. Natural single crystal diamond tools are generally used, and the arc radius of the blade edge is less than 0.1 micron. Machining on a high-precision lathe can achieve 1 micron accuracy and surface unevenness with an average height difference of less than 0.2 micron, and coordinate accuracy can reach ± 2 micron.
(2) Fine milling: used for machining aluminum or beryllium alloy structural parts with complex shapes. Rely on the accuracy of the guide and spindle of the machine tool to obtain higher mutual position accuracy. High-speed milling with carefully ground diamond tips for precise mirror surfaces.
(3) Fine grinding: used for machining shaft or hole parts. Most of these parts are made of hardened steel and have high hardness. Most high-precision grinding machine spindles use hydrostatic or dynamic pressure liquid bearings to ensure high stability. In addition to the influence of the rigidity of the machine tool spindle and the bed, the ultimate accuracy of grinding is also related to the selection and balance of the grinding wheel and the machining accuracy of the center hole of the workpiece. Fine grinding can achieve dimensional accuracy of 1 micron and out-of-roundness of 0.5 micron.
(4) Grinding: Selecting and processing irregular raised parts on the surface to be processed using the principle of mutual research of matching parts. Abrasive particle diameter, cutting force and cutting heat can be precisely controlled, so it is the most accurate machining method in precision machining technology. The hydraulic or pneumatic mating parts of the precision servo parts of the aircraft and the bearing parts of the dynamic pressure gyro motor are all processed in this way to achieve an accuracy of 0.1 or 0.01 micron and a micro unevenness of 0.005 micron.