What precision tolerance levels can be achieved by turning, milling, planing, grinding, drilling, and boring?

Turning can usually achieve an accuracy of IT8~IT7, with a surface roughness of 0.8~1.6 μ m. The accuracy during rough driving is limited to IT11, and the surface roughness is relatively high. High precision turning, such as "mirror turning", can achieve an accuracy of IT7~IT5 and extremely low roughness.

The milling accuracy is generally between IT8~IT7, with a surface roughness of 6.3~1.6 μ m. The accuracy of rough milling, semi precision milling, and precision milling increases in sequence, while the roughness decreases accordingly.

The precision of planing can reach IT9~IT7, and the roughness is 1.6~6.3 μ m.

Grinding is a common method for precision machining, ranging from ordinary grinding IT8~IT5 to precision grinding and ultra precision grinding, with surface roughness reduced to below 0.01 μ m.

The drilling accuracy is usually IT10.

The precision of boring on steel materials can reach IT9~IT7, with a surface roughness of less than 0.16 μ m.

-Detailed explanation of the "tolerance level" of CNC machining accuracy

Tolerance grade is a level used to measure machining accuracy. The national standard specifies 20 grades, with higher grade values indicating lower machining difficulty and higher tolerance values. Product components are processed using different forms and techniques based on their functional requirements. The following will provide a detailed introduction to the machining accuracy that can be achieved by several common machining forms.
In turning, the turning tool moves in a straight or curved line within a plane to process inner and outer cylindrical surfaces, end faces, conical surfaces, forming surfaces, and threads. The general turning accuracy is IT8~IT7, and the surface roughness is 1.6~0.8 μ m. When rough machining, with the premise of not reducing the cutting speed, using a large cutting depth and feed rate, the machining accuracy can reach IT11, and the surface roughness is R α 20~10 μ m; During semi precision and precision machining, high-speed and small feed rates are used, with machining accuracy of IT10~IT7 and surface roughness of R α 10~0.16 μ m; Using finely polished diamond turning tools on high-precision lathes for high-speed precision turning can achieve machining accuracy of IT7~IT5, with a surface roughness of R α 0.04~0.01 μ m, known as mirror turning.
Milling is the use of rotating multi blade cutting tools for cutting, suitable for machining flat surfaces, grooves, various forming surfaces, and special shaped surfaces of molds. The milling accuracy is generally IT8~IT7, and the surface roughness is 6.3~1.6 μ m. The rough milling accuracy is IT11~IT13, and the surface roughness is 5-20 μ m; The semi precision milling accuracy is IT8~IT11, and the surface roughness is 2.5~10 μ m; The precision milling accuracy is IT16~IT8, and the surface roughness is 0.63~5 μ m.
Planing is a cutting process that uses a planer to perform horizontal relative linear reciprocating motion, mainly used for machining the shape of parts. The machining accuracy is IT9~IT7, and the surface roughness is Ra6.3~1.6 μ m. The rough planing accuracy is IT12~IT11, and the surface roughness is 25~12.5 μ m; The semi precision planing accuracy is IT10~IT9, and the surface roughness is 6.2~3.2 μ m; The precision of fine planing is IT8~IT7, and the surface roughness is 3.2~1.6 μ m.
Grinding is a machining method that uses abrasives and grinding tools to remove excess material from workpieces, with an accuracy of IT8~IT5 or even higher, and a surface roughness of generally 1.25~0.16 μ m. The surface roughness of precision grinding is 0.16~0.04 μ m; The surface roughness of ultra precision grinding is 0.04~0.01 μ m; The surface roughness of mirror grinding can reach below 0.01 μ m.
Drilling is the basic method of hole machining, with low accuracy, generally only reaching IT10, and surface roughness of 12.5-6.3 μ m. After drilling, semi precision machining and precision machining are often carried out by enlarging and reaming holes.
Boring is a cutting process that enlarges the inner diameter of a hole or other circular contour, generally ranging from semi rough machining to precision machining, with an accuracy of IT9~IT7 and a surface roughness of 2.5~0.16 μ m. The precision boring machining accuracy can reach IT7~IT6, and the surface roughness is 0.63~0.08 μ m.

-What precision standards can lathe machining achieve?

The accuracy standards for turning machining are usually divided according to international tolerance (IT) levels, ranging from IT8 to IT7. Correspondingly, the surface roughness standard is 1.6 to 0.8 micrometers.
In the rough cutting stage, in order to improve efficiency, larger cutting depths and feed rates are often adopted. In this case, although the efficiency is improved, the machining accuracy can usually only reach the IT11 level, with a surface roughness of R α 20 to 10 microns.
During the semi finishing and finishing stages, it is more inclined to use high speed, small feed rate, and small cutting depth. This operation can achieve higher machining accuracy, reaching IT10 to IT7 levels, with a surface roughness of R α 10 to 0.16 microns.
3. By using high-precision lathes and finely polished diamond cutting tools, high-speed precision machining of non-ferrous metal parts can be achieved, with IT7 to IT5 levels and surface roughness of R α 0.04 to 0.01 microns. This level of turning is also known as mirror turning.
Processing accuracy is an important indicator for measuring product quality, and both it and processing error are terms that characterize the geometric parameters of the processed surface. The machining accuracy is measured by the tolerance level, and the lower the level value, the higher the accuracy; The processing error is represented by specific numerical values, and the larger the value, the greater the error. Generally speaking, the higher the machining accuracy, the smaller the machining error.
There are 20 tolerance levels ranging from IT01, IT0, IT1 to IT18. Among them, IT01 indicates the highest machining accuracy, while IT18 indicates the lowest machining accuracy. In general, IT7 and IT8 are widely used machining accuracy grades.