Precision machining refers to various machining processes that achieve higher machining accuracy and surface finish than corresponding finishing methods. Precision machining includes precision cutting (such as diamond boring, precision turning, and wide-blade planing) and high-precision grinding. The machining accuracy of precision machining is generally between 0.1 and 10 μm, with a tolerance grade of IT5 or higher, and a surface roughness Ra below 0.1 μm.
Precision cutting is a process that uses high-precision, rigid machine tools and finely ground cutting tools to remove an extremely thin layer of metal from the workpiece surface at very high or very low cutting speeds, very small depths of cut, and small feed rates. Obviously, this process significantly improves the machining accuracy of parts. Because the residual area after cutting is small, and the adverse effects of cutting forces, cutting heat, and vibration are minimized, the surface alteration layer left by the previous process can be effectively removed. The machined surface has virtually no residual tensile stress, and the roughness is greatly reduced, significantly improving the quality of the machined surface.