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 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 such that depth of the main depression decreases in a radial direction towards the edge of the cutting element. An ultra hard material layer is bonded to the end face of the cutting element body such that the cutting layer is the thickest over the main depression. Consequently, the cutting layer edge making contact with the earth formations during drilling has an increased thickness.