The geometry of the interaction zone (surface and/or capillary shape and properties) is a fundamental factor in laser beam welding. The geometry determines the number of absorption and reflection processes taking place within the interaction zone, which in turn governs the total absorption of laser radiation. In heat conduction welding, the interaction zone is mostly flat, resulting in few interactions, while in deep penetration welding multiple interactions within the vapor capillary significantly increase total absorption. Different methods have been proposed to increase the total absorption by changing the interaction zone geometry, for example by roughing, texturing or application of particles. In this study, micro milled Solitary Geometrical Elements (SGE) in the form of capillary-like blind holes are investigated. Properties of those SGE are explored towards process initiation in heat conduction and deep penetration welding of aluminum using high speed videography. Results show that the relation between laser beam spot and SGE diameter serves as a criterion for process initiation in both regimes. For the heat conduction welding threshold (melt pool formation), the hypothesis was tested that such SGEs would primarily serve as catalysts for breaking up the aluminum oxide layer and that their internal blind hole shape would therefore be less relevant. For the deep penetration threshold (vapor capillary / keyhole formation), the results show a significant effect of the different cutting tools used in SGE micro milling. Analyses using scanning electron microscopy suggest that surface features within the SGE are the reason for the observed differences.