Methods for pre-sharpening impregnated cutting structures for bits, resulting cutting structures and drill bits so equipped

摘要

Processes for pre-sharpening cutting structures comprising particles of superabrasive material such as diamond grit, dispersed in a metal matrix material such as cemented tungsten carbide. Matrix material may be removed from a surface of a cutting structure to a desired depth to expose superabrasive particles within the matrix material adjacent the surface, and to increase exposure of partially exposed superabrasive particles at the surface. Electrodischarge machining (EDM), laser machining, electrolytic etching and chemical etching may also be employed. Pre-sharpened cutting structures are also disclosed.

主权项

1. A method of pre-sharpening an impregnated cutting structure for a bit for subterranean use, the impregnated cutting structure comprising superabrasive material particles dispersed in and mutually separated by a metal matrix material, the method comprising, prior to placing the impregnated cutting structure in a wellbore on the bit:
selecting at least one formation engaging surface of the impregnated cutting structure; and removing a depth of the metal matrix material by machining the metal matrix material of the at least one selected formation engaging surface adjacent, between and separating superabrasive particles dispersed therein to at least one of enhance exposure of already exposed superabrasive particles to an increased height above the metal matrix material or expose portions of unexposed superabrasive particles adjacent the metal matrix material.