What is the difference between roughing and finishing of CNC lathes?

CNC lathe roughing is the process of removing more machining allowance from the workpiece. Rough machining generally uses low-speed large-scale cutting to quickly remove excess metal materials on the workpiece, and the product size achieved is the process size of the semi-finished product rather than the process size of the finished product. The accuracy that can be achieved is low, the processing surface is rough, and the production efficiency is high, which is usually the preparation process for finishing. The machining accuracy of rough machining can generally reach IT12-IT11 grade, and its surface roughness Ra value can reach 50-12.5 μm.

in rough machining, the general focus is on the processing speed, so the amount of knife and feed are relatively large, and the cutting speed is small, but this will cause a lot of vibration to the lathe, but also increased the wear of various parts of the lathe. If conditions permit, we can use different lathes for roughing and finishing to better protect the machinery and equipment.

CNC lathe finishing is also known as precision machining. There are two main ways to realize the finishing of workpieces. One is to use high-precision CNC lathes to process workpieces with high precision; the other is to use error compensation technology to improve The machining accuracy of the workpiece. The machining accuracy of finishing can reach IT8-IT6 grade, and the surface roughness Ra value can reach 1.6-0.8 μm, and even Ra0.4μm under better conditions.

The main function of finishing is to improve the size and surface accuracy of the workpiece, not the amount of cutting. Through the high precision and high rigidity of the lathe and fine grinding tool, with a very high cutting speed and a small amount of cutting and feed on the surface of the workpiece to remove a thin layer of metal material process, obviously, this process is able to significantly improve the machining accuracy of the workpiece.