For precision parts, the processing is very strict, and the processing procedures include knife feeding, knife discharging, etc. Dalian precision parts processing has specific requirements for size and precision, such as 1mm plus or minus micrometers. If the size is too much wrong, it will become a waste product. At this time, it is equivalent to having to re process, time-consuming and laborious. Sometimes, the entire processing material will be scrapped, which leads to increased costs. At the same time, the parts are definitely useless.
In the past, China's precision machining production enterprises were relatively backward in technology compared with foreign countries. They generally lacked independent innovation ability and support of key and core technologies. The products they machined were mainly low-end products, lacking competitiveness in the world. There was a significant gap between China's precision machining machine tools and foreign advanced products in terms of quality stability, reliability and durability.
Cold working refers to working at room temperature without causing chemical and physical changes to the workpiece. The processing above or below the normal temperature will cause the chemical or physical changes of the workpiece, which is called hot processing. Cold processing can be divided into cutting processing and pressure processing according to the difference of processing methods. This type of processing requires high equipment for processing, even auxiliary oil. This type of processing mainly produces some small workpieces.
For precision parts with high precision requirements, their rough and finish machining shall be separated to ensure the quality of parts. The processing of shaft parts can generally be divided into three stages: rough turning (rough turning of excircles, drilling of center holes, etc.), semi precision turning (semi precision turning of all excircles, steps, grinding of center holes and secondary surfaces, etc.), and rough and fine grinding (rough and fine grinding of all excircles). Each stage is roughly divided by heat treatment.