Different materials coated on milling tools (tungsten carbide) such as TiCN, TiAlN, TiN
and DLC are integrated in this study for the analysis of cutting performance such as tool wear,
surface roughness and noise induced in high-speed machining of mold steels such as NAK80 and
SKD61 under different combinations of cutting conditions. The study attempts to find out the
advantages and adaptabilities in various coating materials being suitable for which cutting
circumferences with specific performance request.
High-speed milling experiments of NAK80 and SKD61 mold steels with four materials coating
tools were carried out in the laboratory. The tool wear was measured through the toolmaker’s
microscope and the roughness of the machined surface was measured by the roughness measuring
instruments after each surface layer was removed from the workpiece in the experiment. Besides,
the noise-mediator was used to detect cutting noise during each surface layer workpiece removing
of high-speed milling process, and the curl chips removed from the workpiece were also collected
for the result verifications.
Good surface quality and small amount of tool wear can be achieved under the cutting conditions
of high-speed revolutions, small feed rate and small depth of cut for four materials coating tools.
From the observations of the annealing temperature from the removed chips and the analysis of the
cutting noise levels, TiAlN material coating tool has the better tool life and it is suitable for rougher
high-speed machining, while DLC material coating tool only has a good surface roughness in
shallow cut and hence it is not suitable for high-speed machining of mold steel with excellent
cutting performance request.