On the geometry of coating layers formed by overlap

Abstract

A recursive model is presented for the prediction of the profile of a coating layer formed by single track overlap. A known shape of single track is assumed and on the base of simple physical assumptions the recursive sequence is deduced to construct an entire profile of such coatings. Calculations of these profiles for different basic shapes and overlaps of tracks show the dependence of coating thickness, waviness and cladding angle on these parameters. A generalized formulation of the model based on purely geometric considerations allows for an application towards different types of cladding processes, including multilayer cladding and 3D depositions. The model is tested experimentally for the laser cladding process in two different set-ups. The cladding track is formed by a continuous deposition of metallic particles into the melt-pool formed by a high power laser beam that continuously moves over a substrate. Good agreement with the parabolic shape of a single track and experimental observations of height and waviness was concluded for a wide range of overlap ratios.