PTJ Manufacturing Shop

PTJ Manufacturing Shop

What are the machining accuracy grades of cnc machining centers?

Machining accuracy grades

PTJ Shop is a professional manufacturer specializing in high-precision cnc machining. It has more than 50 sets of imported CNC automatic lathe machine, cutting machine, turning and milling machining center and cnc CNC machining center. Many friends who know cnc processing industry. We all know that the precision of CNC machining has a graded division. Next, PTJ Shop will take you to understand the classification of CNC machining.

machining accuracy gradesIn general, according to the international precision tolerance class, IT6 is widely used in machining important coordination index. IT6 indicates that the surface has a high uniformity requirement, can ensure a relatively high mating property, and is stable and reliable. The machining center can complete various processes such as drilling, milling, boring, expanding, reaming, and rigid tapping.


Drilling is another important machining process in the machining center. Drilling is a basic method of hole machining. Drilling is often carried out on drilling machines and lathes. Some precision requirements can also be achieved in machining centers.
The machining accuracy of drilling is low, the tolerance grade can only reach IT10, and the surface roughness of the workpiece is generally 12.5-6.3μm. However, after drilling, reaming and reaming are often used for subsequent semi-finishing and finishing.


Milling is the most important machining process in the machining center. It can be said that all machining processes in the machining center are developed by milling. Milling is divided into up-cut milling and down-cut milling depending on the direction of spindle motion and workpiece feed. Cutting the workpiece by using a rotating multi-blade tool is a highly efficient and common machining method in the machining center. It is suitable for processing special surfaces such as planes, grooves, various complex surfaces and curved molds.
The precision tolerance of milling in milling is generally up to IT16-IT8. The surface roughness of the workpiece is 0.63-5μm under the machining standard of tolerance accuracy.


Boring is generally used for the machining of the inner diameter portion. It is a machining process that uses a tool to enlarge a hole or cut the inner diameter of a circular profile, and is generally used from semi-roughing to finishing. The tolerance of the precision of the steel workpiece is up to IT9-IT7 and the surface roughness is 2.5-0.16μm.

In the current machining process, the grinding accuracy is the highest and the tolerance level is the lowest. The tolerance level of stamping and die-casting is high, and we can understand the precision tolerance of each process so that the CNC machining center can achieve high-precision characteristics. Different industries have different precision grades for different products. As practitioners and manufacturers, it is necessary to understand and pay attention to the actual needs of user products. For example, medical and automotive parts require relatively high precision. The accuracy requirements are relatively low. PTJ SHOP serves customers with a set of rigorous and perfect product solutions. With 18 years of industry accumulation, we offer high quality and professional processing services. Welcome to call us.

PTJ Machining Capabilities

Automatic Bar Machining Multi-spindle cam automatic screw machines
CNC Turning – CNC delivers peak cost efficiency in shorter volumes, as well as high capacity production of mechanically simple components
Custom Machining - with up to 12 axes of control
Multi Spindle Machining- ISO 9001:2015 certified
Screw Machine Products – The number of customized production parts per hour can reach 10000pcs
Swiss Machining – with up to 9 axes of CNC control, to produce precision components with complex geometries in one operation
High Volume Machining – 100 Advanced Production Turning Bar Automatics On-line and Ready
CNC Milling - Machining Fully compliant with the exacting requirements of our customers
5 axis (11 axis) Machining – Tolerance | 0.1mm alignment

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