What is precision machining

What is precision machining

Precision machining refers to a machining technology with a machining accuracy of 1 to 01 μm and a surface roughness of Ra01 to 001 μm.

The problems to be solved by precision machining are: one is machining accuracy, including geometric tolerance, dimensional accuracy and surface condition; the other is machining efficiency. Some machining can achieve better machining accuracy, but it is difficult to achieve high machining efficiency. Precision machining includes processing technologies such as micromachining, ultra-fine machining, and finishing. Traditional precision machining methods include abrasive belt grinding, precision cutting, honing, precision grinding and polishing.

(1) Abrasive belt grinding is to use a blended cloth with abrasives to process the workpiece. It belongs to the category of coated abrasives grinding and has the characteristics of high productivity, good surface quality and wide application range.

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

(3) Honing, the honing head composed of whetstone sand bars reciprocates along the surface of the workpiece under a certain pressure, and the surface roughness after processing can reach Ra0.4~0.1µm, preferably Ra0.025µm, mainly used for For processing cast iron and steel, it is not suitable for processing non-ferrous metals with low hardness and good toughness.

(4) Precision grinding and polishing is a machining method that makes the workpiece achieve the required size and precision through the mechanical friction between the workpiece and the tool, the abrasive and the processing fluid, and the workpiece and the grinding tool. Precision grinding and polishing can achieve precision and surface roughness that cannot be achieved by other processing methods for metal and non-metal workpieces. The roughness of the ground surface is Ra≤0.025µm. The processing deterioration layer is small, the surface quality is high, and the precision grinding equipment Simple, mainly used for the processing of plane, cylindrical surface, gear tooth surface and mating parts with sealing requirements. It can also be used for the finishing of gauges, gauge blocks, fuel injectors, valve bodies and valve cores.

(5) Polishing is a kind of micro-processing on the surface of the workpiece by mechanical, chemical and electrochemical methods. It is mainly used to reduce the surface roughness of the workpiece. The commonly used methods are: manual or mechanical polishing, ultrasonic polishing, chemical polishing, electrochemical polishing and Electrochemical mechanical composite processing, etc. Surface roughness of workpiece after manual or mechanical polishing.