The processing time of CNC machining parts is the main part of the machining cost, and there are many factors to affect the time of machining: the machinability of materials, tool selection, machine performance, processing process and so on. We will introduce you here the factors affecting the machinability of materials in metal machining process.
1,The chemical composition of steel is very IMPORTANT:
The more the alloy composition of steel, the harder to produce;
when the steel own more carbon content, the metal cutting performance is lower.
2,The structure of steel is also very important:
Different structure includes: forged. casting, extrusion forming, rolled and material after previous machining.
The workpiece surface of forged and casting parts are hard to process.
3,Hardness is also a factor to influence metal cutting performances.
General rules is it is more difficult to process the material with harder surface.
High-speed Steel(HSs) cutting tools is available to process material with hardness maximum 330-400 HB ;
High-Speed Steel+Rubberized Coating(TiN), is available to process material with hardness maximum 45 HRC ;
To the material with hardness 65-70HRC, cemented carbide, ceramic, metal ceramic and CBN cutting tools must be used.
4,Adulteration of nonmetallic material
For example, Al2O3, it is purified ceramic with higher abradability. It will decrease the lifetime of cutting tools and make material difficult to process.
5,The last factor is residual stress.
The workpiece may have performance problem after processing if residual stress exists. Normally after rough machining process, stress release process is required to eliminate residual stress.