How To Classify The Machining Accuracy of CNC Machining Center
Machining accuracy refers to the fineness of the produced product and is a mechanical term used to evaluate the surface of a machined part. Machining accuracy is generally expressed by IT, which refers to the level that determines the degree of dimensional accuracy, referred to as tolerance. The smaller the tolerance level, the higher the precision of the workpiece of the product, and the more difficult it is to process.
According to the classification of international precision tolerance differences, IT6 is an important coordination index widely used in machining. IT6 indicates that the mating surface has a higher uniformity requirement, which can ensure a fairly high mating property, and is stable and reliable. The machining center can complete drilling, milling, boring, expanding, reaming, rigid tapping and other processes.
So how is the accuracy of these processing procedures divided and defined? Milling Milling is the most important processing procedure of a machining center. It can be said that all the machining processes of a machining center are carried out by milling. Milling is divided into up and down milling according to the direction of spindle movement and workpiece feed. The use of rotary multi-blade tools to cut workpieces is an efficient machining method for machining centers, and is suitable for machining special profiles such as planes, grooves, various complex different surfaces and curved molds.
The precision tolerance level of precision milling in milling can generally reach IT6—IT8. Under this tolerance accuracy processing standard, the surface roughness of the workpiece is 0.63-5 μm.
Drilling Drilling is a basic method of hole processing. Drilling is generally performed on a drilling machine and a lathe. Some high precision requirements can also be completed by a machining center. The drilling accuracy is low, the tolerance level can only reach IT10, and the surface roughness of the workpiece is generally 12.5-6.3 μm. However, after drilling, the method of reaming and reaming is often used for subsequent semi-finishing and finishing.
Boring Boring is a machining process that uses a tool to enlarge a hole or cut the inner diameter of a circular contour. It is generally used for machining inner diameter parts. The tolerance grade of boring accuracy for steel workpieces can reach IT9-IT7, and the surface roughness is 2.5-0.16 μm. In the current machining process, the precision of grinding is the highest, and the tolerance level is the lowest; the tolerance level of stamping and die-casting is relatively high.
As long as we understand the precision tolerances of each process, we can let the CNC machining center play high precision.