What is the highest machining accuracy of the machine tool?


CNC Turning


The workpiece rotates, and the turning tool performs cutting processing of linear or curved movement in the plane. Turning is generally performed on a lathe to process the inner and outer cylindrical surfaces, end surfaces, conical surfaces, forming surfaces and threads of the workpiece.


The cnc turning precision is generally IT8-IT7, and the surface roughness is 1.6~0.8μm.


1) Rough turning strives to use large cutting depth and large feed to improve turning efficiency without reducing the cutting speed, but the machining accuracy can only reach IT11, and the surface roughness is Rα20~10μm.


2) For semi-finishing and finishing turning, try to use high speed and small feed and cutting depth, the machining accuracy can reach IT10~IT7, and the surface roughness is Rα10~0.16μm.


3) High-speed precision turning of non-ferrous metal parts with a finely-refined diamond turning tool on a high-precision lathe can make the machining accuracy reach IT7~IT5, and the surface roughness is Rα0.04~0.01μm. This kind of turning is called "mirror turning" ".

Cnc Milling


Cnc Milling refers to the use of rotating multi-edge tools to cut workpieces, and is a highly efficient processing method. It is suitable for processing planes, grooves, various forming surfaces (such as splines, gears and threads) and special shapes of molds. According to the same or opposite direction of the main movement speed and workpiece feed direction during milling, it is divided into down milling and up milling.


The processing accuracy of cnc milling is generally IT8~IT7, and the surface roughness is 6.3~1.6μm.


1) The machining accuracy during rough milling is IT11~IT13, and the surface roughness is 5~20μm.


2) The machining accuracy of semi-finishing milling is IT8~IT11, and the surface roughness is 2.5~10μm.


3) The machining accuracy of finishing milling is IT16~IT8, and the surface roughness is 0.63~5μm.




Planing processing is a cutting processing method in which a planer is used to make a horizontal relative linear reciprocating motion on the workpiece, and is mainly used for the shape processing of parts.


The machining accuracy of planing can generally reach IT9~IT7, and the surface roughness is Ra6.3~1.6μm.


1) The rough planing precision can reach IT12~IT11, and the surface roughness is 25~12.5μm.


2) The precision of semi-finish planing can reach IT10~IT9, and the surface roughness is 6.2~3.2μm.


3) The precision of finishing planing can reach IT8~IT7, and the surface roughness is 3.2~1.6μm.




Grinding refers to the processing method of using abrasives and abrasive tools to remove excess material on the workpiece. It is a finishing process and is widely used in the machinery manufacturing industry.


Grinding is usually used for semi-finishing and finishing, and the precision can reach IT8~IT5 or even higher. The surface roughness is generally 1.25~0.16μm.


1) The surface roughness of precision grinding is 0.16~0.04μm.


2) The surface roughness of ultra-precision grinding is 0.04~0.01μm.


3) Mirror grinding surface roughness can reach below 0.01μm.




Drilling is a basic method of hole processing. Drilling is often carried out on drilling machines and lathes, but also on boring machines or milling machines.


The machining accuracy of drilling is relatively low, generally only reaching IT10, and the surface roughness is generally 12.5~6.3μm. After drilling, reaming and reaming are often used for semi-finishing and finishing.




Boring is an inner diameter cutting process that uses tools to expand holes or other circular contours. Its application range generally ranges from semi-rough machining to finishing. The tools used are usually single-edged boring tools (called boring bars).


1) The boring accuracy of steel materials can generally reach IT9~IT7, and the surface roughness is 2.5~0.16μm.


2) The machining accuracy of precision boring can reach IT7~IT6, and the surface roughness is 0.63~0.08μm.

Shbury focus on precision machining, cnc turning products, if you want learn more, can contact vivi@shburycnc.com 

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