Unplanar non-axisymmetric inserts

摘要

Cutting elements for incorporation in a drill bit are provided having a body having an end face interfacing with an ultra hard material cutting layer. A main depression having a nonplanar surface is formed on the substrate and extending to the peripheral edge of the substrate subjected to the highest impact loads during drilling. This edge is immediately below the edge of the cutting layer which makes direct contact with the earth formations during drilling. The main depression is formed by forming a plurality of secondary depressions or steps. A second main depression is formed by forming a plurality of secondary depressions or steps. The second main depression also extends to the peripheral edge of the substrate. An ultra hard material layer is bonded to the end face of the cutting element body over the main depressions.