The decreasing of the dimensions of injection-molded parts lead to a higher sensitivity to changes in the processing parameters. Caused by high cooling and shearing rates, the interaction between the process, the evolving morphology and the resulting properties is strong - particularly for semi-crystalline thermoplastics. The correlations between the process parameters, the morphology and the machine response were compared experimentally and by using simulation. For a cylindrical micro-tensile specimen, with a shot weight of around 0.04 g, good correlations were found for the skin layer formation and the injection pressure with the help of an experimental design (DoE). When the skin layer formation dominates, the effect on the mechanical properties is evident. Measurements of the rheological material data provided the basis for an improved process simulation.