Smith International, Inc.

Gary R Chunn

Anthony Griffo

Thomas W Oldham

Robert M Denton

Kumar T Kembaiyan

Brian A White

Saul N Izaguirre

Michael George Azar

Carl W Keith

Tommy Gene Ray

Mark A Johnson

Jonathan Craig Thiele

A bit body formed of a mixture of matrix material and superabrasive powder and including pockets lined with superabrasive-free matrix material, and a method for forming the same, are provided. The pockets are shaped to receive cutting elements therein. The superabrasive-free matrix material enhances braze strength when a cutting element is brazed to surfaces of the pocket. The method for forming the drill bit body includes providing a mold and displacements. The displacements are coated with a mixture of superabrasive free matrix-material and an organic binder. The mold is packed with a mixture of matrix material and superabrasive powder and the arrangement heated to form a solid drill bit body. When the solid bit body is removed from the mold, pockets are formed by the displacements in the bit body and are lined with the layer of superabrasive-free matrix material. The superabrasive material may be diamond, polycrystalline cubic boron nitride, SiC or TiBin exemplary embodiments.

Bonding of cutters in diamond drill bits

Bonding of cutters in drill bits

An insert for a drill bit which includes a diamond impregnated body, and a shearing portion disposed on said body is shown. In addition, a method for forming a drill bit that includes (a) forming a shearing portion on a diamond-impregnated insert body to form a cutting insert, (b) forming a bit body having a plurality of sockets sized to receive a plurality of the cutting inserts, and (c) mounting the plurality of cutting inserts in the bit body and affixing the plurality of cutting inserts to the bit body; wherein steps (a)&#x2013;(c) are carried out such that a total exposure of the diamond-impregnated insert to temperatures above 1000&#xb0; F. is greater than a total exposure of the shearing portion to temperatures above 1000&#xb0; F.

Bits and cutting structures

Thin walled metal alloy receptacles are filled with a filler material. If granular, the filler material is solidified in the receptacles. The receptacles are inserted in a bit mold with their open ends abutting against preformed cutter locations in the bit mold. The mold is filled with a steel or tungsten carbide powder and a binder and exposed to temperatures sufficient to cause the binder to infiltrate the steel or tungsten carbide as well as infiltrate the receptacle outer surfaces, metallurgically bonding the receptacles to the binder. The mold is then removed, revealing a bit body with the bonded filled receptacles. The filler material is removed from the receptacles PCD cutters are inserted in the receptacles and are brazed using conventional brazing techniques.

Brazing receptacle for improved PCD cutter retention

Growing community of inventors

Conroe, TX, United States of America

Gary R Chunn