The wear performance of carbide tools coated with TiAlSiN, AlCrN and TiAlN ceramic films in intelligent machining process

Abstract

Nitride-based coatings are applied by cathodic arc physical vapor deposition (CAPVD) to improve the tribological properties of cutting tools. The present study examines the tool life of carbide tools coated with TiAlSiN, AlCrN and TiAlN films in intelligent machining process. Coating process was applied on both prismatic carbide test specimens and solid carbide end mills. Coating characterization was carried out on the test specimens. The structural, mechanical and tribological properties of different nitride-based coatings were investigated by means of field emission scanning electron microscope (FEG-SEM), X-ray diffractometer (XRD), scratch tester, reciprocating tribometer, calotester, microhardness device and optical profilometer. Impax steel was machined in CNC vertical machining center with uncoated and coated carbide end mills in order to determine the actual operating performance of the coatings. The g codes and toolpaths were created in the SolidCAM iMachining software. The cutting speed, feeds and overlap values are selected automatically and variably depending on geometry, tool and workpiece materials. The flank wear widths of tools were determined by SEM. In addition, the surface roughness values of the impax steel were measured from the finish surfaces. According to the scratch test results, the best adhesion results were obtained for TiAlN coating and the Lc1 critical load value was determined as about 30 N. The reciprocating sliding test results showed that the highest wear rate was obtained for the TiAlSiN coated specimen and the lowest wear rate was obtained for the uncoated specimen. Flank wear was observed on the tools after the milling process and the highest wear resistance was obtained TiAlN coated end mill. The lowest surface roughness value was obtained from the surface of impax steel workpiece which was milled with carbide end mill coated with TiAlN ceramic film.