Laser stripping of TiAlN coating to facilitate reuse of cutting tools

Abstract

The potential of using the laser ablation process to perform controlled stripping of titanium aluminium nitrite (TiAlN) coating from tungsten carbide (WC) substrate is explored in this paper. TiAlN coatings are extensively used in cutting tools to improve machining capability, and to extend the life of the tools. However, if any error is detected on the coated tools, or when the tooling needs to be reused, it is mandatory to remove the existing coating to facilitate reshaping/recoating. The existing coating removal process uses chemical stripping methods, which are not environmentally friendly and not suitable for selective coating removal. In the present work, excimer laser removal of TiAlN from coated WC flat plates has been studied and demonstrated as a viable alternative to existing chemical stripping methods. The ablation thresholds of the TiAlN coating and WC substrate were identified as 1.85 J/cm2 and 2.3 J/cm2 respectively. The paper also presents experimental and theoretical evidence of the process mechanism responsible for laser stripping of TiAlN coatings