Turning, milling, planing, grinding, drilling, boring, the highest precision of these machine tools and the tolerance levels that various processing methods can achieve are all here.

Workpiece rotates, and turning tool moves in a straight line or a curve in plane. Turning is generally carried out on a lathe to process inner and outer cylindrical surfaces, end surfaces, conical surfaces, forming surfaces and threads of workpiece.

 

Turning accuracy is generally IT8-IT7, and surface roughness is 1.6-0.8μm.
1) Rough turning strives to use a large depth of cut and large feed to improve turning efficiency without reducing cutting speed, but machining accuracy can only reach IT11, and surface roughness is Rα20-10μm.
2) Semi-finishing and finishing should use high-speed, small feed and cutting depth as much as possible, the machining accuracy can reach IT10-IT7, and surface roughness is Rα10-0.16μm.
3) High-speed precision turning of non-ferrous metal parts with finely researched diamond turning tools on a high-precision lathe can make machining accuracy reach IT7-IT5, and surface roughness is Rα0.04-0.01μm. This turning is called "mirror turning". ".

Milling is a highly efficient machining method in which a rotating multi-blade tool is used to cut a workpiece. It is suitable for processing planes, grooves, various forming surfaces (such as splines, gears and threads) and special shapes of molds. According to same or opposite direction of main movement speed and workpiece feed direction during milling, it is divided into down milling and up milling.
Machining accuracy of milling can generally reach IT8-IT7, and surface roughness is 6.3-1.6μm.
1) Machining accuracy during rough milling is IT11-IT13, and surface roughness is 5-20μm.
2) Machining accuracy of semi-finish milling is IT8-IT11, and surface roughness is 2.5-10μm.
3) Machining accuracy of fine milling is IT16-IT8, and surface roughness is 0.63-5μm.

Planing is a cutting method in which a planer is used to make a horizontal relative linear reciprocating motion on workpiece, which is mainly used for shape processing of parts.
Planing processing accuracy can generally reach IT9-IT7, and surface roughness is Ra6.3-1.6μm.
1) Rough planing accuracy can reach IT12-IT11, and surface roughness is 25-12.5μm.
2) Semi-finishing machining accuracy can reach IT10-IT9, and surface roughness is 6.2-3.2μm.
3) Finishing precision can reach IT8-IT7, and surface roughness is 3.2-1.6μm.

Grinding refers to processing method of using abrasives and abrasive tools to remove excess material on workpiece. It belongs to finishing and is widely used in machinery manufacturing industry.
Grinding is usually used for semi-finishing and finishing, accuracy can reach IT8-IT5 or even higher, and surface roughness is generally 1.25-0.16μm.
1) Surface roughness of precision grinding is 0.16-0.04μm.
2) Surface roughness of ultra-precision grinding is 0.04-0.01μm.
3) Surface roughness of mirror grinding can reach below 0.01μm.

 

Drilling is a basic method of hole making. Drilling is often carried out on drilling machines and lathes, and can also be carried out on boring machines or milling machines.
Machining accuracy of drilling is low, generally only reaching IT10, and surface roughness is generally 12.5-6.3 μm. After drilling, reaming and reaming are often used for semi-finishing and finishing.

Boring is an inner diameter cutting process in which a tool is used to enlarge a hole or other circular profile, and its applications generally range from semi-roughing to finishing. Tool used is usually a single-edged boring tool (called a boring bar).
1) Boring accuracy of steel materials can generally reach IT9-IT7, and surface roughness is 2.5-0.16μm.
2) Machining accuracy of precision boring can reach IT7-IT6, and surface roughness is 0.63-0.08μm.
Note:
Machining accuracy is mainly used to characterize fineness of produced products, and is a term for evaluating geometric parameters of machined surfaces. Standard for measuring machining accuracy is tolerance level. There are 20 from IT01, IT0, IT1, IT2, IT3 to IT18. Among them, IT01 indicates the highest machining accuracy of part, and IT18 indicates that machining accuracy of part is the lowest. Machinery belongs to IT7 level, and general agricultural machinery belongs to IT8 level. According to different functions of product parts, processing accuracy that needs to be achieved is different, processing form and processing technology selected are also different.