The injection molding process makes mass production of plastic components possible because of its good reproducibility and low cost. However, during the process variations occur, which have an influence on the component quality. In this work, quality influencing factors were examined on mass produced components. Thereby, quality was defined by dimensions, which were necessary for the functionality of the component. The investigated factors were reduced to the process parameters of the injection molding machine. The components were taken out of the mass production in three measurement series. The first measurement series gave clarity about the overall process variation. With the second and the third measurement series long-term variations in the process over a longer production time were investigated. The lengths of the components were determined using two different optical measurement systems. One system was the ATOS II SO (Advanced Topometric Sensor). With this method the whole surface of the component was digitized and evaluated using the Software Geomagic Studio and Geomagic Qualify. Since all the component dimensions were related to centers of circles, these were determined in each case using a Best-Fit-algorithm. It turned out that the scattering of the components to each other was below the accuracy of ATOS II SO measurement system. The second measuring method was a telecentric lens system. With this device the accuracy was improved by a factor of 10 compared to the ATOS II SO system. Then the component was simulated using Autodesk Moldflow Insight (AMI). In particular it was examined, whether the influence of the process parameters on the component lengths could be calculated with the simulation software. It was found, that the simulation software could predict the exact direction of the warpage but not the correct absolute value.