In this diploma thesis we discuss the phenomenon of the amplitude variation of the magnetic field density along the circumference of the magnetic ring. This occurred due to the presence of a gap between the ring and the magnetization attachment, which is caused by deformations of the ring flange and laser engraving. We demonstrated the influence of laser engraving and flange deformations on appearance of the amplitude variation, by measuring the axial runout of test samples that exhibited only one of the two identified causes. We hypothesized that due to a tool manufacturing error, flange deformations occur during the vulcanization. We confirmed the success of solving the problem on the samples produced in new vulcanization tool, marked with adjusted engraving.