Performance of laser surface textured cemented carbide tools during abrasive machining : Coating effects, surface integrity assessment and wear characterization

Abstract

Laser surface texturing (LST) and coating deposition are implemented on cemented carbide (WC-CoNi) tools to extent their application in abrasive-like machining processes. The topographic features of a conventional cubic boron nitride based honing stone are achieved by LST, whereas wear resistance is enhanced by deposition of a ceramic layer. Three tool types are considered here: uncoated and coated LST WC-CoNi tools, besides a honing stone used as reference. They are tested under abrasive-like cutting conditions using an in-house workbench and a workpiece made of 20MnCr5 steel. Wear resistance and mechanisms as well as surface integrity of the tools after cutting tests are evaluated. It is found that LST cemented carbide tools achieve similar material removal effectiveness to the honing stone. Furthermore, coated LST tool exhibits a better cutting capacity, in terms of machined workpieces with smoother surfaces and enhanced wear resistance. However, the cutting process using cemented carbide tools is not as stable as the one developed employing the honing stone. The different response is related to the tribological conditions of the cutting edges of the laser-shaped pyramids. Damage within constitutive microstructural phases is clearly reduced for the coated condition, although it is still directly related to geometrical complexity of the pyramids.