Owing to the increase in laser-based metal additive manufacturing technologies, it becomes necessary to understand the main process parameters leading to flaw formation, so that proper strategies can be adopted in order to tackle them. Laser powder interaction at the melt pool level is one of the most critical aspects to deal with, since the characteristics of the molten region, such as its size and shape, directly impact micro- and macro-structural properties of the built part. Hence, achieving precise focus control, in presence of mechanical and thermal effects causing unintended shifts during operation, is essential to ensure process stability and consistent product quality.