A polycrystalline diamond cutting element has a non-planar, non-linear interface between a substrate and a table. The substrate has one or more protrusions mounted on the surface of the substrate and in spaced relationship. Each protrusion has a generally curved shape such as a delta or triangular shape...http://www.google.de/patents/US5928071?utm_source=gb-gplus-sharePatent US5928071 - Abrasive cutting element with increased performance
