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In this paper a numerical procedure is presented to calculate a laser ablation process for ceramic thick film coatings. The code is required to cover temperature dependent material data, projected beam intensities and inhomogeneous coating-substrate combinations to calculate the hole shape geometry, the temperature distribution under the surface and the ablation rate per pulse. Therefore, the ablation speed was calculated by an Arrhenius equation while the temperature distribution was simulated by means of the heat conduction equation, which is solvable by a finite differences scheme. Hence, an adaptive mesh is used and the expansion of the code to three spatial dimensions enables the simulation of more complex ablation geometries. The simulation time was held low by introducing actualization frequencies, where critical and time consuming steps were only run if necessary. A validation of the numerical simulation was done by comparing the calculated temperature depth distribution and hole geometry with micrographs of experimental ablations.

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Abstract. To improve the surface behavior of metal structures, like wear-and heat resistance or hardness, often thermally sprayed ceramic coatings are applied. A modern technology to realize dense layers is the High Velocity Oxygen Fuel (HVOF) technique. The deposition process and necessary pretreatments can cause high residual stresses within the coating and the substrate. While tensile stresses in the brittle coating may cause cracks, compressive stress states can even improve the materials behavior. To guarantee high product quality, it is necessary to know exactly the occurring residual stresses in the metal-ceramic hybrid system. A very common measurement technique is the incremental hole drilling (IHD) method. To determine the residual stresses out of IHD measurements the differential method (DM) or integral method (IM) can be used. To investigate the influence of interfacial layers, nonlinear stresses, cracking, anisotropy, variation of coating thickness and calculation formalisms several FEM models have been build, while case sensitive calibration was used for the coated systems.

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