At this moment, industrial robot arms are increasingly used to automate manufacturing processes in the aerospace industry. However, these robot arms lack position accuracy to effectively mill parts or assemble products. In this work, this gap is investigated following two approaches; on one hand existing calibration methods of robot arms are evaluated. On the other hand, two methods to define the impact of the robot arm inaccuracy on final dimensional variance of assembly products are compared. It is concluded that at least three extensions to current calibration models improve the accuracy of industrial robot arms. Moreover, multiple advantages and drawbacks of two tolerance analysis methods are given.