What Is The Highest Machining Accuracy of A Machine Tool?

The highest precision and tolerance levels that can be achieved by various machining methods for turning, milling, planing, grinding, drilling, and boring are all here.

Turning

Workpiece rotation is a cutting process in which the turning tool moves in a straight or curved line within a plane. Turning is generally carried out on a lathe to process the inner and outer cylindrical surfaces, end faces, conical surfaces, forming surfaces, and threads of workpieces.

The machining accuracy of turning is generally IT8-IT7, and the surface roughness is 1.6-0.8 μ M.

1) Rough turning aims to improve turning efficiency by using large cutting depth and feed rate without reducing cutting speed, but the machining accuracy can only reach IT11 and the surface roughness is R α 20-10 μ M.

2) Semi precision and precision turning should use high-speed and smaller feed rates and cutting depths as much as possible, with machining accuracy of IT10~IT7 and surface roughness of R α 10~0.16 μ M.

3) Using finely polished diamond turning tools on high-precision lathes for high-speed precision turning of non-ferrous metal parts can achieve machining accuracy of IT7~IT5, with a surface roughness of R α 0.04~0.01 μ m. This type of turning is called "mirror turning".

Milling

Milling refers to the use of rotating multi blade cutting tools to cut workpieces, which is an efficient machining method. Suitable for processing flat surfaces, grooves, various formed surfaces (such as splines, gears, and threads), and special shaped surfaces of molds. According to whether the main motion speed direction during milling is the same or opposite to the workpiece feed direction, it is further divided into forward milling and reverse milling.

The machining accuracy of milling can generally reach IT8~IT7, and the surface roughness is 6.3~1.6 μ M.

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

2) The machining accuracy during semi precision milling is IT8~IT11, and the surface roughness is 2.5~10 μ M.

3) The machining accuracy during precision milling is IT16~IT8, and the surface roughness is 0.63~5 μ M.

Planing

Planer machining is a cutting method that uses a planer to perform horizontal relative linear reciprocating motion on a workpiece, mainly used for machining the shape of parts.

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

1) The rough planing accuracy can reach IT12~IT11, and the surface roughness is 25~12.5 μ M.

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

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

Grinding

Grinding refers to the processing method of using abrasives and grinding tools to remove excess material from workpieces, which belongs to precision machining and is widely used in the mechanical manufacturing industry.

Grinding is usually used for semi precision and precision machining, with an accuracy of up to IT8~IT5 or even higher, and a surface roughness of generally 1.25~0.16 for grinding μ M.

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

2) The surface roughness of ultra precision grinding is 0.04~0.01 μ M.

3) Mirror grinding surface roughness can reach 0.01 μ Below m.

Drilling

Drilling is a basic method of hole machining, and drilling is often done on drilling machines and lathes, as well as on boring or milling machines.

The machining accuracy of drilling is relatively low, usually only reaching IT10, and the surface roughness is generally 12.5~6.3 μ m. Expanding and reaming are often used for semi precision machining and precision machining after drilling.

Boring

Boring is an inner diameter cutting process that uses a tool to enlarge a hole or other circular contour. Its application range generally ranges from semi rough machining to precision machining, and the tool used is usually a single edge boring cutter (called a boring bar).

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

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

Note: Processing accuracy is mainly used to characterize the level of precision in producing products, and is a term used to evaluate the geometric parameters of the processed surface. The standard for measuring machining accuracy is tolerance level. There are a total of 20 parts from IT01, IT0, IT1, IT2, IT3 to IT18. Among them, IT01 represents the highest machining accuracy of the part, IT18 represents the lowest machining accuracy of the part. Generally, industrial and mining machinery belongs to IT7 level, and general agricultural machinery belongs to IT8 level. The processing accuracy required for product components varies according to their functions, and the selected processing forms and processes also vary.