The usefulness of the laser surface modifications is considerably reduced by the fact that the pre-evaluation and reproduction of these processes are not sufficent. To reach advance in these fields, we have to clarify the physical processes taking place during the treatment. To do this a dynamical penetration model will be presented in this paper taking into account some new parameters on penetration is not clearly understood. In the first part the penetration conditions will be mathematically defined with some restrictions and estimations (for example, the impact of the particle is evaluated by a modified Stokes-model, which is to describe the sinking of a slow particle originally). In the second part, the effect of the Marangoni-convection and the particle solubility will be discussed.