Cutting Characteristics of CBN Ball Endmills for STD-11 of Various Hardnesses

STB-11 경도변화에 따른 CBN볼 엔드밀의 절삭특성

The use of CBN tool material has been greatil increased because of the superior metal cutting performance for the machining of hardened steels. This paper presents some experimental results on the ball endmilling of hardened steels. Three different hardnesses of STB-11 workpieces were machined using CBN ball endmills, and the machining charteristics including cutting forces, tool wear, and surface roughness of machined surface were compared. It has been found that the CBN ball endmill works better in the machining of harder workpieces. The microscopic examination explains that this unusual phenomenon is cause by the difference of microstructure of each workpieces.