Characterization of structural / tribological properties of tungsten carbide cutting tools coated with TiAlN/TiSiN and AlCrSiN and their milling performances on plastic injection die steel

In this thesis, double-layer TiAlN/TiSiN and single-layer AlCrSiN coatings were grown on the base material by cathodic arc physical vapor deposition (CAPVD) technic to enhance the wear performance of carbide cutting tool material produced for machining plastic injection die steel in machining. Coating processes were applied both on carbide end mills and on cylindrical test specimens. Characterization of coatings was applied on cylindrical test specimens. The tribological, mechanical and structural characteristics of the produced coatings were determined via X-ray diffraction meter, microhardness device, tribometer, scanning electron microscope (SEM) and optical profilometer. So as to specify the real working effect of the coatings, the workpiece made of plastic injection die steel (Impax steel) with untreated and coated end mills was machined with CNC vertical machining center. G codes and toolpaths were created with both classical cutting and modern cutting strategies. After the machining, the wear performance of the cutting tools was investigated by SEM and mass loss method. Also the surface grade of the steel work piece was determined after the machining processes. The adhesion and hardness results of the double-layered TiAlN/TiSiN thin film coated specimen were higher than the single-layer AlCrSiN coated specimen. Consequently the value of wear rate of the double-layered TiAlN/TiSiN thin film coated specimen was less then AlCrSiN coated and uncoated samples. Although better surface quality and less mass loss are observed in milling operations performed using the 2,5-axis module, the iMachining module was more advantageous as regards machining time.