Which parts are suitable for precision machining?

Which parts are suitable for precision machining?

We know that precision machining requires high precision. Precision machining has good rigidity, high manufacturing precision and accurate tool setting, so it can process parts with high precision. Which parts are suitable for precision machining? Here’s the introduction:

First of all, compared with the general lathe, CNC lathe has the function of constant linear speed cutting. No matter for the end face or the outer circle with different diameters, it can be processed with the same linear speed, which guarantees the surface roughness value and is relatively small. The general lathe is a constant speed, different diameter cutting speed is different. In the case of workpiece and tool material, finishing allowance and tool angle, surface roughness depends on cutting speed and feed speed.

When machining surfaces with different surface roughness, small feed speed is selected for surfaces with small roughness, and larger feed speed is selected for surfaces with large roughness, which has good variability, which is difficult to achieve in general lathe. Parts with complex contour. Any plane curve can be approximated by a straight line or an arc. CNC precision machining has the function of arc interpolation, which can process various parts with complex contour. The use of CNC precision machining needs the careful use of the operator.

CNC precision machining mainly includes finishing turning, boring, milling, grinding and other processes:

(1) Fine turning and fine boring: most of the precision light alloy (aluminum or magnesium alloy, etc.) parts of the aircraft are processed in this way. Generally, natural single crystal diamond cutting tools are used, and the arc radius of the cutting edge is less than 0.1 μ M. The surface roughness of 1 μ m and average height difference less than 0.2 μ M can be obtained by machining on high-precision lathe, and the coordinate accuracy can reach ± 2 μ M.

(2) Finish milling: used for machining aluminum or beryllium alloy structural parts with complex shape. Depending on the precision of machine tool’s guide rail and spindle, we can get high precision of mutual position. The precise mirror surface can be obtained by high-speed milling with a carefully ground diamond cutter head.

(3) Fine grinding: used for machining shaft or hole parts. Most of these parts are made of hardened steel with high hardness. Most high-precision grinding machine spindles adopt hydrostatic or hydrodynamic liquid bearings to ensure high stability. The grinding accuracy is not only affected by the rigidity of machine tool spindle and bed, but also related to the selection and balance of grinding wheel, the machining accuracy of workpiece center hole and other factors. The size accuracy of 1 μ m and the out of roundness of 0.5 μ M can be obtained by fine grinding.

(4) Grinding: select and process the irregular convex parts on the surface to be processed by the principle of mutual grinding of mating parts. Abrasive diameter, cutting force and cutting heat can be precisely controlled, so it is a high-precision machining method in precision machining technology. The hydraulic or pneumatic mating parts of the precise servo components of the aircraft and the bearing parts of the dynamic pressure gyro motor are processed by this method to achieve the accuracy of 0.1 or even 0.01 μ m and the micro unevenness of 0.005 μ M.