Dalian precision machining mainly includes fine turning, fine boring, fine milling, fine grinding and grinding.

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

② Finish milling: used to process aluminum or beryllium alloy structural parts with complex shapes. High mutual position accuracy is obtained by relying on the accuracy of guide rail and spindle of machine tool. Accurate mirror surface can be obtained by high-speed milling with carefully ground diamond cutter head.

③ Finish 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 use hydrostatic or hydrodynamic liquid bearings to ensure high stability. The limit accuracy of grinding is not only affected by the stiffness of machine tool spindle and bed, but also related to the selection and balance of grinding wheel and the machining accuracy of workpiece center hole. The dimensional accuracy of 1 micron and out of roundness of 0.5 micron can be obtained by fine grinding.

④ Grinding: select and process the irregular convex parts on the machined surface by using the principle of mutual grinding of mating parts. Abrasive diameter, cutting force and cutting heat can be accurately controlled, so it is the machining method to obtain the highest precision in precision machining technology. The hydraulic or pneumatic mating parts in the precision servo components of aircraft and the bearing parts of dynamic pressure gyro motor are processed by this method to achieve the accuracy of 0.1 or even 0.01 micron and the micro unevenness of 0.005 micron.

The production process of precision machining refers to the whole process of manufacturing products from raw materials (or semi-finished products). It is used for processing and production, including transportation and preservation of raw materials, production preparation, rough processing, part processing and heat treatment, product assembly and commissioning, painting and packaging.

1. From the perspective of hardware, the precision machining of mechanical parts is carried out through a variety of mechanical equipment such as automobile, milling machine, planer, grinder, zipper, machining center and so on.

2. From the perspective of software, it is the technology of operators, including the operation technology of various equipment operators. These technologies include the understanding of equipment, machining, parts and materials. These technologies can be gradually accumulated in daily work.

Processing method of precision machining

1. In order to ensure the machining accuracy, we must do a good job in preliminary machining and deep machining. During the initial processing, the cutting amount, pressing force and heat of a large number of castings are large, which is easy to cause the hardness of the surface layer. There is too much internal stress in the castings. If the deep processing and initial processing are continuous, the accuracy of high-precision parts after deep processing will be evenly distributed according to the internal stress and quickly lost. Relative to some parts with high machining accuracy. After the initial machining and before the deep machining of precision machining, lower temperature annealing process or solid solution treatment shall be done to remove the internal stress.

2. Production and processing equipment shall be selected reasonably for precision machining. The specific process technology of initial machining is to cut off most of the cutting parameters, which does not require more machining accuracy. Therefore, the initial machining lathe tool only needs the initial machining with high power and low accuracy. Special equipment with higher precision for deep processing. Rough and deep machining on different special equipment can not only make full use of the performance of special equipment, but also prolong the service life of precision machine tools.

3. Heat treatment and quenching are often required in precision machining process. The arrangement of heat treatment process is as follows: it is usually carried out before machining to improve the cutting performance of metal, such as annealing, standardization, quenching and tempering. In order to eliminate internal stress (such as aging treatment and adjustment treatment), it is usually carried out after rough machining and before finishing machining. In order to improve the mechanical properties of parts, carburizing, quenching and tempering are usually carried out after processing. If there is deformation after heat treatment, the processing technology shall be placed.