What is the surface roughness of CNC machining?

The CNC machining center has a strong comprehensive processing capability. After the workpiece is clamped oCNCe, it can complete more processing contents and has higher processing accuracy. For medium and difficult to process batch workpieces, its efficieCNCy can reach 5~10 times of that of ordinary equipment. In particular, it can complete processing that many ordinary equipment cannot complete. It is more suitable for single processing or small batch and multi variety production with complex shape and high accuracy requirements. What is the surface roughness of CNC machining?

Lathe processing parts
The surface roughness is generally formed by the processing method adopted and other factors, such as the friction between the tool and the part surface during CNC processing, the plastic deformation of the surface layer metal during chip separation, and the high-frequeCNCy vibration in the process system. Due to different CNC machining methods and workpiece materials, the depth, density, shape and texture of the traces left on the machined surface are different.
Generally, ordinary machine tools are about 3.2, and high-speed machines can achieve a finish of 1.6; Note that the tool and cutting

parameters used in the processing shall be considered. The details are as follows:
1、 Roughness of CNC turning:
CNC turning is a computer CNC processing process in which the turning tool moves in a straight line or curve in the plane through the rotation of the workpiece to process the internal and external cylindrical surfaces, end faces, conical surfaces, forming surfaces and threads.
(1) Generally, the surface roughness of CNC turning is 1.6-0.8 μ M。
(2) Rough turning: use large cutting depth and large feed to improve efficieCNCy without reducing cutting speed. The surface roughness is required to be 20-10 μ m。
(3) Semi finish turning and finish turning: small cutting speed and high speed feed are adopted, and the surface roughness is required to be 10-0.16 μ M。
(4) For high-precision CNC lathe: precision grinding diamond turning tool can be used for high-speed precision turning of non-ferrous metal workpieces, with surface roughness of 0.04-0.01 μ m. Also called "mirror turning".
2、 CNC boring processing roughness:
Boring is an internal cutting technology that uses a boring cutter to enlarge a hole or other existing circular contour. The tool used is usually a single edged boring tool (boring bar). Suitable for semi rough machining to finish machining.
(1) The boring accuracy of steel can reach 2.5-0.16 μ M。
(2) The precision of fine boring can reach 0.63-0.08 μ M。
3、 Roughness of CNC milling:
CNC milling refers to the process of machining static workpieces with rotating multi-point cutters on computer controlled machine tools, which is suitable for machining grooves, planes, gears and special features.
(1) The general surface roughness of milling is 6.3-1.6 μ M。
(2) Rough milling accuracy: 20-5 μ M。
(3) Semi finish milling: 10-2.5 μ M。
(4) Finish milling: 6-0.63 μ M。

3、 CNC machining roughness of grinding machine:
Grinding is an abrasive processing technology that uses the grinding wheel to cut off the redundant materials on the workpiece. It is widely used in the mechanical manufacturing industry, usually used for semi finishing and finishing, and can achieve finishing and precision cutting. The grinding can be controlled to move around the fixed workpiece.
(1) The ground surface roughness is generally 1.25-0.16 μ M。
(2) The surface roughness of precision grinding is 0.16-0.04 μ M。
(3) The surface roughness of ultra precision grinding is 0.04-0.01 μ M。
(4) The surface roughness of mirror grinding is less than 0.01 μ M。
The surface roughness of CNC machining is closely related to the matching property, wear resistaCNCe, fatigue strength, contact stiffness, vibration and noise of mechanical parts, and has an important impact on the service life and reliability of mechanical products. Ra is used for general marking.
The sampling length shall be selected according to the formation and texture characteristics of the actual surface of the part. The sampling length shall be measured according to the general trend of the actual surface profile. The sampling length is specified and selected to limit and weaken the influeCNCe of surface waviness and shape error on the measurement results of surface roughness.
CNC parts processing
Surface roughness has a great influeCNCe on the use of parts. Generally speaking, small surface roughness will improve the fitting quality, reduce wear and prolong the service life of parts, but the processing cost of parts will iCNCrease. Therefore, the surface roughness value should be selected correctly and reasonably. When designing a part, the selection of surface roughness value is determined by the role of the part in the machine.

Milling parts
Although CNC machining can produce parts with strict toleraCNCe and fine parts from various metal or plastic materials, due to the reduction of the machining process, the part surface will have small tool marks after machining. However, we can use a variety of methods to improve the surface roughness, visual performaCNCe and wear resistaCNCe of CNC machined parts. What is the classification of CNC machining accuracy?
The existing CNC machining process requires the highest and minimum toleraCNCe for grinding accuracy. PuCNChing machine, die-casting and other stations can be taught high. Mastering the accuracy toleraCNCe of each process can make CNC machining center play a good role. For different industries, the accuracy levels for different products are different. Let's have a look at the details!
In general, IT6 is an important fit index widely used in CNC machining, which is classified according to international precision toleraCNCe. IT6 indicates that the mating face has high uniformity requirements, can ensure a fairly high mating performaCNCe, and is stable and reliable in use. The machining center can complete multiple processes such as drilling, milling, boring, expanding, reaming, and tapping.
Drilling is an important process of the machining center, and drilling is the basic method of machining holes. Generally, drilling is performed on the drilling machine and lathe, and some of them require high precision, which can also be completed by using the CNC machining center. The drilling accuracy is not high, generally only 12.5~6.3 μ m. Generally, the surface roughness of workpiece is only 12.5~6.3 μ m. However, the subsequent semi finishing and finishing are generally completed through reaming and reaming.
Milling is the most important processing procedure of CNC machining center. It can be said that all machining of CNC machining center is performed with milling cutter. Milling can be divided into up milling and down milling according to different feed rates. It is an efficient and common machining method to cut workpiece with rotary multi blade cutter. It is used to process surfaces of various complex shapes, such as plane, groove, etc., such as surface molds. The workpiece machined with this toleraCNCe accuracy has a surface roughness of 0.63~5 μ m, and the precision toleraCNCe of precision milling can generally reach IT16-IT8.
The inner diameter is usually machined by boring. A CNC machining method that uses tools to enlarge the hole diameter or trim the circumfereCNCe profile, usually used to convert semi rough machining to finish machining. For steel structures, the boring accuracy error grade can reach IT9-IT7, and the surface roughness is 2.5~0.16 μ m.
CNC processing factory
The above is the classification of rough surface and CNC machining accuracy using CNC.