SEAL RING AND METHOD OF FORMING MICRO-TOPOGRAPHY RING SURFACES WITH A LASER

摘要

A seal ring of a shaft seal has micro-topography depth features, such as wavy faces or radial grooves, formed in the seal face which define a hydrodynamic seal region between opposing seal faces. The micro-topography depth features are formed by an excimer laser shaped such that the beam shape at least has non-linear side edges which define convergent side areas of the beam. The convergent side areas are defined by side edge sections which converge toward each other and preferably are non-linear. For example, the beam shape may be circular or elliptical. The laser beam first cuts repeatedly along the same beam path to define a cut with an increasing depth, whereby the laser beam is shifted incrementally sidewardly to define multiple adjacent beam cuts that form the micro-topography feature such as a valley of a wavy face, a radial groove or the like. As the laser beam cuts adjacent parallel grooves, sidewardly adjacent beam passes overlap one with each other and blend the edges of the sidewardly adjacent grooves together. The method of the invention provides micro-topography depth features that are precisely and accurately defined to improve performance of the seal ring.