Laser micromachining of TiN coatings with variable pulse durations and shapes in ns regime

The micro-structuring of thin surface coatings has become increasingly popular following the discovery of improved performance, especially in terms of the resulting tribological properties. The direct writing of microstructures via laser ablation offers flexibility, extending the applicability of micro-structuring to various materials and machined geometries. However, the laser ablation of coatings requires better comprehension to provide sufficient machining quality with improved productivity to render such processes more viable for industrial applications. This paper presents the processing conditions for the ablation of approximately 4-μm-thick coatings of TiN in the ns pulse regime, which is generally characterised by higher productivity with low machining quality. A range of pulse durations between 12 ns and 200 ns was employed. The effect of pulse duration on ablation threshold fluence and irradiance was investigated. The pulse shape was decomposed into peak and tail regions to investigate their respective effects on the ablation process. The opportune regulation of pulse properties allowed for the maintenance of high productivity and high-quality laser micromachining under delicate processing conditions, in the case of ceramic TiN surface coatings with limited thickness.