You don't know about precision machining knowledge!

　The concept of precision machining


Precision machining is the process of changing the size or performance of a workpiece through a machine. According to the temperature state of the workpiece, it is divided into cold processing and Hot working. Cold machining is usually performed at room temperature without causing chemical changes to the workpiece. Generally speaking, the machining that will cause chemical changes in the workpiece during the process above or below the normal temperature is called Hot working. Cold processing can be divided according to different mechanical processing methods. It is used for cutting and pressure machining. Hot working is commonly used in heat treatment, calcination, casting and welding.


The production process of precision machining


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


From a hardware perspective, the processing of mechanical components is carried out through various mechanical equipment, such as automobiles, milling machines, planers, grinders, broaches, and machining centers. The inherent processing accuracy of each equipment is different, so in order to achieve a certain level of accuracy, it is necessary to select appropriate mechanical processing techniques and equipment when adding work hours.


From a software perspective, it is an operator's skill that involves the operational skills of various equipment operators. These skills include a thorough understanding of equipment, understanding of mechanical processing, and understanding of parts and materials, which can be gradually accumulated in daily work.



Processing methods for precision machining


In order to ensure the machining accuracy, rough machining and precision machining should be carried out separately. During rough machining, a large number of workpieces are subject to large cutting forces, clamping forces, and heat generation, and Case-hardening is simply formed. There is a large internal stress in the workpieces. If the finish machining and rough machining are continuous, the precision of precision parts after finish machining will be redistributed with the stress, and will soon be lost. For certain parts with high machining accuracy. After rough machining and before finishing, low-temperature annealing or aging treatment should be carried out to eliminate internal stress.



2. Reasonably select mechanical processing equipment. The main process of rough machining is to cut off most of the machining allowance, without requiring higher machining accuracy. Therefore, rough machining machines only require high power and low precision machining. Precision machining requires more precise machine tools. Rough and fine machining on different machine tools can not only fully utilize the performance of the equipment, but also extend the service life of precision machine tools.


3. Heat treatment is often required during mechanical processing. The arrangement of the heat treatment process is as follows: in order to improve the cutting performance of the metal, such as annealing, normalizing, tempering, etc., it is usually carried out before mechanical processing. In order to eliminate internal stress, such as aging treatment and quenching and tempering treatment, it is generally carried out after rough machining and before precision machining. In order to improve the mechanical properties of parts, carburization, quenching, tempering, etc. are generally carried out after mechanical processing. If there is deformation after heat treatment, the final processing process must be arranged.