Tell me about the accuracy of CNC machining
by：QY Precision 2020-03-16
Recently, I received some comments from netizens asking me that the outer diameter accuracy of CNC machining can be 0. 001mm? What I want to say is that your accuracy is calculated according to your knife. The general machine tool can be controlled to 0. 01mm, better may be controlled to 0. 005mm. Therefore, it is impossible for CNC machining outer diameter to reach 0. 001 this precision is generally 0. 02mm ~ 0. 005mm so. Xiaobian has seen the highest CNC outer diameter processing can only do 0. 004mm. Friends who know the CNC machining center know that high precision is a major feature of the machining center. Machining accuracy refers to the degree of fineness of the produced product, which is used to evaluate the mechanical terminology of the machined surface. Machining accuracy is generally expressed by IT, which refers to the grade of determining the accuracy of dimensions, referred to as tolerance. The smaller the Tolerance grade, the higher the precision of the workpiece representing the product, and the greater the processing difficulty. Generally speaking, according to the Division of International precision Tolerance grades, IT6 is widely used in the important matching index of machining. IT6 indicates that the mating surface has high uniformity requirements, which can ensure a fairly high mating property and is stable and reliable in use, the machining center can complete drilling, milling, boring, expanding, hinge, rigid tapping and other processes. So let's talk about the accuracy of these processing procedures. 1. Drilling is another important machining process in the machining center. Drilling is a basic method of hole machining. Drilling is often performed on drilling machines and lathes, some high precision requirements can also be done in a machining center. The drilling precision is low, the tolerance grade can only reach IT10, and the surface roughness of the workpiece is generally 12. 5-6. 3 mu M, but after drilling is completed, reaming and reaming are often used for subsequent semi-finishing and finishing. 2. Milling and milling is the most important machining process in the machining center. It can be said that all machining processes in the machining center are carried out through milling. Milling is divided into reverse milling and forward milling according to the direction of spindle movement and workpiece feed. It is a high-efficiency and common machining method in the machining center by using a rotating multi-edge tool to cut the workpiece. It is suitable for processing special surfaces such as planes, grooves, various complex different surfaces and curved molds. The tolerance grade of precision milling in milling can generally reach IT16- IT8, under this tolerance precision machining standard, the surface roughness of the workpiece is 0. 63-5 muM. 3. Boring and boring is generally used for machining the inner diameter. It is a machining process that uses a tool to expand holes or cut the inner diameter of a circular outline, and is generally used from semi-coarse machining to finish machining. The tolerance grade for boring precision of steel workpieces can reach IT9-IT7, surface roughness 2. 5-0. 16 muM. In the current machining process, the grinding accuracy is the highest and the tolerance level is the lowest. However, the tolerance level of stamping and die casting is high, and only by understanding the accuracy tolerance of each process can we let the numerical control machining center play a high-precision role.