The study presented started with a significance study of process parameters on resulting fiber orientation distributions of an injection-molded housing. The part is injection-molded from hydrolysis stabilized short glass fiber reinforced Polybutylene Terephthalate. It can be shown which parameter has most significant influence on fiber orientation, determined by X-ray micro computer tomography. Finally the fiber orientation is not the important data to measure, but mechanical properties for a part undergoing temperature changes as one of the operational loads. Another issue which is directly affected by the fiber orientation is warpage. So the study will show how accurate the fiber orientation distribution must be predicted to get data for thermo-mechanical loading as well as warpage which will be used for a pre-correction of the part before an initial sampling takes place. In order to show this behavior a decent analysis of material data as well as material models is required. Therefore, issues like solidification criteria, applied deformation laws for anisotropic shrinkage will be critically evaluated.