Three Stages of Machining

Machining is divided into three stages: general machining, precision machining, and ultra-precision machining. 

At present, precision machining refers to processing technology with processing accuracy of 1 ~ 0.1 ? and surface roughness of Ra0.1 ~ 0.01 ?, but this limit is constantly changing with the progress of processing technology. Today's precision processing It may be the general processing tomorrow. The problems to be solved by precision machining are machining accuracy, including geometric tolerance, dimensional accuracy and surface condition.

The second is processing efficiency. Some processing can achieve better processing accuracy, but it is difficult to achieve high processing efficiency. Precision machining includes micro-machining, ultra-micro machining, finishing and other processing technologies. Traditional precision machining methods include abrasive belt grinding, precision cutting, honing, precision grinding and polishing. 

a.Abrasive belt grinding is to process the workpiece with a blended cloth with abrasives as an abrasive tool. It belongs to the category of coated abrasive tool grinding. It has the characteristics of high productivity, good surface quality and wide range of use. 

b.Precision cutting, also known as diamond tool cutting (SPDT), is performed with high-precision machine tools and single crystal diamond tools. It is mainly used for precision processing of soft metals such as copper and aluminum that are not suitable for grinding, such as computer Magnetic drums, magnetic disks, and metal mirrors for high-power lasers are 1 to 2 levels higher than the general cutting accuracy. 

c.Honing, honing head composed of whetstone strips, reciprocating along the surface of the workpiece under a certain pressure, the surface roughness after processing can reach Ra0.4 ~ 0.1 ?, can reach Ra0.025 ?,mainly Used for processing cast iron and steel, not suitable for processing non-ferrous metals with low hardness and good toughness.