Detection of Machine Lead in Ground Sealing Surfaces

During the finishing of contact surfaces of rotary shaft lip type seals, unwanted lead patterns may appear. Depending on the direction of rotation, these spiral marks may lead to early leakage or dry run, which may affect directly the longevity of the parts. New methods for satisfying the high requirements of the automotive industry are presented to determine the lead angle, the period length, and the number of starts. In contrast to earlier approaches, with a new fusion strategy, a robust extraction of the parameters of interest is attained even in the case of slightly pronounced lead structures. Moreover, by enhancing the measurement set-up with additional optical components, an in-line inspection becomes possible.