A Study on Machining Characteristics of KP4 Steel Using Alumina Coated Insert
In this study examine KP4 steel (HRC 32), a non-thermal treated material among plastic mold steels, a material widely used in the mold industry. The sample will be machined upwards and downwards at different angles (15°, 30°, 45°). To this end, it uses a multicoated carbide tool (1 to 4 layers of AlTiN using physical vapor deposition (PVD) and ion plating). This study presents basic processing data of the multi-coated ball end-mill and discuss the characteristics of high-speed machining. For measuring the roughness of the coated tool surface, this study uses Atomic Force Microscope (AFM) manufactured by PSIA, which can measure specimen surface in nm range. In this experiment, the specimen was scanned by 20×20 μm units, to observe and measure the surface roughness of the tools according to the layers of coating. Mechanical properties of the specimen are found to be the best when the carbide ball end-mill is coated in three layers, with the hardness of the coating layer being 29.7GPa and surface roughness 0.042 μm. The cutting component forces are better in the upwards direction than in downwards, and become smaller as the effective diameter of the tool increases as the angle of inclination of the material got bigger.