In this thesis the influences of process parameters like holding pressure, melt temperature and mold temperature control on molding shrinkage and post-shrinkage of two different semi-crystalline polymers are examined. For this purpose two different injection molded parts are manufactured. The experimental results are compared with simulation results of Moldflow Plastics Insight 5.1 revision 2. The injection molded parts are a plate and a box. The semi-crystalline polymers used for all investigations are Ultraform N2320 (POM) and Stapron E EM605 (PC/PET). The simulations are performed using Midplane-, Fusion- and 3D-model meshes. The calculations are carried out with real processing parameters using default program settings and material data from the internal MPI database. The comparison between experiment and simulation are used to evaluate the results of MPI in a qualitative and quantitative aspect. Additionally to shrinkage results a comparison between experimental and simulated filling studies is carried out. All models show flow patterns close to reality. The measured molding shrinkage corresponds to the data of the manufacturer. Also simulation results of the packing and holding stage are compared with experimental cavity pressures. These results basically go along with reality.