Understand CNC machining center friends know that high precision is a major feature of the machining center.CNC machining precision refers to the degree of fineness of the products produced, which is a mechanical term used to evaluate the machining surface.CNC machining accuracy is generally expressed by IT, which refers to the grade to determine the accuracy degree of dimension, or tolerance for short.The smaller the tolerance level, the higher the precision of the workpiece representing the product, and the greater the difficulty of processing.
Generally speaking, IT6 is widely used in machining important fit index according to international accuracy tolerance grade.IT6 indicates that the matching surface has high uniformity requirements, can ensure a fairly high matching property, stable and reliable use,CNC machining center can complete drilling, milling, boring, expanding, hinge, rigid tapping and other processes.So how to classify and define the precision of these CNC machining processes?
Milling is the most important machining process of CNC machining center. It can be said that all the processing process of CNC machining center is carried out through milling.Milling can be divided into reverse milling and forward milling according to the movement direction of the spindle and the feed of the workpiece.It is an efficient and common machining method for machining center to use rotating multi-edge cutter to cut workpiece.Suitable for processing plane, groove, various complex different surface and curved surface mold and other special surface.
Precision tolerance grades in fine milling can generally be up to IT16 — IT8, and the surface roughness of the workpiece under this tolerance standard is 0.63 — 5 microns.
Drilling is another important machining process of CNC machining center. Drilling is a basic method of hole processing. Drilling is often carried out on drilling machines and lathes.
The machining accuracy of drilling is low, the tolerance grade can only reach IT10 generally, the surface roughness of workpiece is 12.5 — 6.3m generally, but after drilling is completed, reaming and reaming are often used for subsequent semi-finishing and finishing.
Boring is generally used for machining inner diameter parts.It is a machining process that USES a cutter to enlarge the bore or cut the inner diameter of a circular contour.The tolerance grade of boring accuracy of steel workpiece can be up to IT9 — IT7 and the surface roughness is 2.5 — 0.16 micron.
In the current machining process, the grinding accuracy is the highest and the tolerance level is the lowest.And stamping and die casting tolerance level teaching high, understanding the accuracy of each process tolerance we can make the CNC machining center play a high precision characteristics.