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 capacity for parts from 1/16" to 2 5/8”
CNC Turning – CNC multi-axis machining centers for superior speed & flexibility
Custom Machining - expert machined components delivered on time
Multi Spindle Machining- Davenport, Euro turn, New Britain & Acme Gridley
Screw Machine Products – precision components from a broad variety of materials & Equipment
Swiss Machining – micro-parts to 1-1/4 round diameter providing speed, high capability including precision tolerances and specialized finishes
High Volume Machining – Specialized in machined parts exceeding 1,000 pieces up to millions of pieces for optimum efficiency
CNC Milling - Machining from bar stock, plate or block metal using up to 3 axis of motion
5 axis (11 axis) Machining – Multi Axis Multi spindle technology for completing complex parts efficiently in one operation. C=0 sampling plan & equipment versatility provide one stop shop capability for a variety of applications

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