Improvements in or relating to elements with superhard material

摘要

A preform element, which may be used as a cutter in a rotary drill bit, includes a facing table (42) of polycrystalline diamond bonded to a tungsten carbide substrate (41).The facing table (42) is of non-uniform thickness and comprises a region of greater thickness adjacent the cutting edge and extending towards the interior of the element. In one embodiment the region of greater thickness comprises a ridge of superhard material which extends into the substrate (41), or from the front face of the element, and is of substantially constant width as it extends away from the cutting edge. The provision of the ridge causes the cutting edge to wear in a pointed configuration in use.