The Finite Element Analysis (FEA) is a suitable tool for the process design and the determination of technical failure. Within this paper, the FEA is used for simulating and analyzing the thread milling process and the tapping process for reinforced lightweight extrusion profiles. Two different finite element models are developed to simulate both processes. An elastic material behavior is implemented in the simulation. For the tapping process, the computed stresses during the process as well as the geometrical displacements are considerably higher than the stresses computed for the thread milling operation. This is caused by the lower mechanical loads occurring in the thread milling process. The results can be used to identify areas of high stresses which may cause material failure. Moreover, both processes can be analyzed with respect to their influence on the workpiece. The simulation results are compared to experiments.