볼 엔드밀 가공에서 고경도 강재의 절삭특성에 관한 연구

A Study on the Machinability of High Hardness Steel in Ball End Milling

The STD11 and KP4 are important steels and applied to the manufacturing of the die and mold. The purpose of this study is to investigate the machinability of tool steels of STD11(HRC60) and KP4(HRC32) when machining them by using ball end milling tools coated with TiAlN. Cutting forces by using a Kistler piezo-cell type tool dynamometer, surface roughness and tool wear by using tool microscope are used in the tests. The results from the cutting tests of KP4 specimens show that 85m/min. of cutting speed and 0.32mm/rev. of feed per revolution are optimum conditions for the higher productivity and 0.26mm/rev. with the same cutting speed are optimum conditions for better surface finishing. The results from machining STD11 workpiece at 30m/min. of cutting speed and 0.17m/rev. of feed per revolution show recommended for the higher productivity. The KP4 shows relatively smaller cutting forces than STD11 and STD11 shows the better surface finish than KP4.