We know that precision machining
requirements for precision is very high, precision machining of good rigidity, high manufacturing accuracy, accurate tool setting, so it can process parts with high precision requirements. So which parts are suitable for precision machining?
First of all, compared with ordinary lathe, CNC lathe has constant linear speed cutting function, no matter for turning end face or different diameter outer circle can be processed with the same linear speed, that is to ensure the surface roughness value is consistent and relatively small. While ordinary lathe is constant speed, the cutting speed is different for different diameters. Under the condition that the material of workpiece and tool, finishing allowance and tool angle are certain, the surface roughness depends on the cutting speed and feed speed.
When processing the surface with different surface roughness, a small feed speed is chosen for the surface with small roughness, and a larger feed speed is chosen for the surface with large roughness, with good variability, which is difficult to be achieved in ordinary lathes. Parts with complex contour shapes. Any plane curve can be approximated by a straight line or arc, cnc precision machining with arc interpolation function, can process a variety of complex contours of the parts. cnc precision machining needs the careful use of the operator's good or bad.
CNC precision machining
mainly has fine turning, fine boring, fine milling, fine grinding and grinding processes
Fine turning and fine boring: most of the precision light alloy (aluminum or magnesium alloy, etc.) parts of the aircraft are mostly processed by this method. Generally with natural single crystal diamond tools, the radius of the cutting edge circle is less than 0.1 micron. In the high precision lathe processing can obtain 1 micron accuracy and average height difference of less than 0.2 micron surface unevenness, coordinate accuracy can reach ± 2 micron
Used to machine structural parts of aluminum or beryllium alloy with complex shapes. Rely on the accuracy of the machine's guide and spindle to obtain high mutual position accuracy. High-speed milling with a carefully ground diamond tip can achieve an accurate mirror surface.
Used for machining shaft or hole type parts. Most of these parts are made of hardened steel, which has high hardness. Most high-precision grinding machine spindles use hydrostatic or dynamic pressure liquid bearings to ensure high stability. The ultimate accuracy of grinding is influenced by the machine tool spindle and bed stiffness, but also by factors such as the selection and balance of the grinding wheel and the machining accuracy of the center hole of the workpiece. Fine grinding can obtain a dimensional accuracy of 1 micron and an out-of-roundness of 0.5 micron.
The principle of mutual grinding of mating parts is used to selectively process the irregular raised parts on the machined surface. The grinding grain 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 in precision servo parts of aircraft and bearing parts of dynamic gyro motors are machined by this method to achieve 0.1 or even 0.01 micron accuracy and 0.005 micron micro-unevenness.