Thickness and waviness of surface coatings formed by overlap: modelling and experiment

Abstract

Several surface engineering techniques are known that form a hard facing coating on an inexpensive substrate by a successive overlap of individual cladding tracks. Typical examples include laser cladding and laser additive manufacturing. Realistic predicting the final thickness and waviness of the coating as a function of geometry of single cladding track and their overlap are lacking in literature. In this contribution a recursive model for the calculation of the coating profile is presented. A few basic shapes of single tracks are presumed and on the basis of physical assumptions a recursive formula is deduced to construct a shape of the whole coating profile. Calculations of such profiles for different shapes of tracks and different overlaps show a dependence of the coating thickness and its waviness on these parameters. The model is tested experimentally for a laser cladding process, in which the laser track is formed by a continuous deposition of small metallic particles into the meltpool formed by a high power laser beam continuously moving over the substrate.