Modelling and studying of thermal behaviour of thin layer using finite element method – application to coated tools

The continuous evolution of thin-layer technologies is essential in modern dry machining, where effective thermal control of coated cutting tools is critical for limiting heat-induced wear and extending tool life. The purpose of this article was to investigate and model the thermal response of coated cutting tools and to evaluate the influence of single-layer and multilayer thin coatings on heat transfer during orthogonal dry cutting. To achieve this objective, a transient thermal model based on the finite element method was developed using a Galerkin formulation combined with an implicit Crank-Nicolson time integration scheme. The numerical framework was applied to three tool configurations: an uncoated WC-Co insert, a TiN-coated insert, and a TiN/Al₂O₃ double-coated insert. Experimental dry turning tests were conducted to validate the numerical predictions. The results showed that the numerical model accurately reproduced the temporal evolution of temperature at the tool–chip interface and within the insert. The uncoated tool exhibited rapid heat penetration and pronounced internal thermal gradients. The TiN coating slightly increased the surface temperature but offered limited resistance to heat diffusion. In contrast, the TiN/Al₂O₃ multilayer configuration significantly restricted heat transfer towards the substrate, leading to lower internal temperatures and reduced thermal gradients. The Al₂O₃ layer acted as an effective thermal barrier, confining heat near the cutting edge and protecting the tool core from excessive thermal loading. These findings demonstrated that multilayer ceramic coatings provided superior thermal protection compared with single-layer coatings. The proposed finite element method approach could be effectively applied to coating design, tool optimisation, and thermal management in dry machining applications