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Method to Eliminate Bullet Cutter Usage in the Cone Region of Steel Body Fixed Cutter Drill Bits

IP.com Disclosure Number: IPCOM000241817D
Publication Date: 2015-Jun-02
Document File: 3 page(s) / 141K

Publishing Venue

The IP.com Prior Art Database

Abstract

Fixed cutter PDC bits are typically available in two body types, metal matrix composite or steel. The metal matrix composite is manufactured through an infiltration process where a mold is machined and cutter pockets displaced to produce the final bit. Steel bits however are manufactured using more traditional machining processes such as turning and milling of bar stock or a casting. Due to the geometry in the cone or center of a fixed cutter PDC bit, it is extremely difficult to machine cutter pockets without interference from neighboring blades. Because of this constraint, bullet cutters (PDC cutters with spherical ends rather than flat cylindrical ends) are placed in the cone or center of fixed cutter steel bits. This new method of manufacture allows standard spherical milling tools to be utilized when cutting the pocket but the pocket will be able to accept a standard cylinder cutter through use of a welded in hemispherical cutter pocket support.

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Method to Eliminate Bullet Cutter Usage in the Cone Region of Steel Body Fixed Cutter Drill Bits

ABSTRACT:

Fixed cutter PDC bits are typically available in two body types, metal matrix composite or steel. The metal matrix composite is manufactured through an infiltration process where a mold is machined and cutter pockets displaced to produce the final bit. Steel bits however are manufactured using more traditional machining processes such as turning and milling of bar stock or a casting. Due to the geometry in the cone or center of a fixed cutter PDC bit, it is extremely difficult to machine cutter pockets without interference from neighboring blades. Because of this constraint, bullet cutters (PDC cutters with spherical ends rather than flat cylindrical ends) are placed in the cone or center of fixed cutter steel bits. This new method of manufacture allows standard spherical milling tools to be utilized when cutting the pocket but the pocket will be able to accept a standard cylinder cutter through use of a welded in hemispherical cutter pocket support.

BODY:

A new manufacturing method has been developed to successfully allow for standard cylinder PDC cutters, Figure 1, to be utilized in the center of a fixed cutter steel body drill bit. This new method allows for traditional spherical milling tools to be used during the manufacturing process and is compatible with standard repair and maintenance processes. The underlying component that makes this possible is a prefabricated hemispherical pocket support that is welded to the bit prior to bit brazing.

Current processes mandate that special “bullet” shaped cutters must be utilized in the center of a steel bit that are cylinder shaped with one end including a polycrystalline diamond cutting face and the other end a hemispherical carbide backin...