We know that precision machining has a very high requirement for precision. Precision machining has good rigidity, high manufacturing precision, and precise tool, so we can process parts with high precision. So what parts are suitable for precision machining?
First of all, compared with the ordinary lathe, CNC CNC lathe has a constant linear speed cutting function, no matter for the end face or different diameters of the cylindrical can be used for the same linear speed processing, that is, to ensure that the surface roughness value is consistent and relatively small. The ordinary lathe is a constant speed, the diameter of different cutting speed is different. The surface roughness depends on the cutting speed and feed speed when the workpiece and tool material, finishing allowance, and tool Angle are fixed.
In the processing of different surface roughness, the small roughness of the surface with a small feed rate, the large roughness of the surface with a larger feed rate, the variability is very good, this is difficult to achieve in the ordinary lathe. Parts with complex Outlines. 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 all kinds of complex contour parts. The use of CNC precision machining needs the careful use of the operator.
CNC precision machining mainly includes fine turning, fine boring, fine milling, fine grinding, and grinding.
(1) Finishing and boring: Most precision light alloy (aluminum or magnesium alloy, etc.) parts of aircraft are processed in this way. Generally used natural single crystal diamond tool, the edge arc radius is less than 0.1 micron. The precision and average height difference of 1 micron is less than 0.2 micron, and the coordinate precision can be up to ±2 microns.
(2) Precision milling: used for machining complex aluminum or beryllium alloy structural parts.Depending on the precision of the guide and spindle of the machine tool to obtain higher mutual position accuracy. High-speed milling using a carefully ground diamond tool tip yields an accurate mirror surface.
(3) Fine grinding: used for machining shaft or hole parts. Most of these parts are hardened steel with high hardness. Most high-precision grinding spindles use static or dynamic pressure liquid bearings to ensure high stability. The ultimate grinding precision is not only affected by the rigidity of machine spindle and bed but also related to the selection and balance of grinding wheel and machining precision of the workpiece center hole. The precision of the 1-micron dimension and 0.5-micron roundness can be obtained by fine grinding.
(4) Grinding: The irregular convex parts on the processed surface are selected for processing by using the principle of mutual grinding of mating parts. Abrasive diameter, cutting force, and cutting heat can be precisely controlled, so it is the highest precision machining method in precision machining technology. Hydraulic or pneumatic mating parts of precision servo parts of aircraft and bearing parts of dynamic pressure gyro motor are processed in this way to achieve the precision of 0.1 or even 0.01 micron and micro-roughness of 0.005 microns.