Appeal No. 1999-2010
Application No. 08/684,635
The invention is directed to a new manufacturing
technique for making the bodies of drag bits for drilling rock
formations.
Most of these bits comprise steel or cemented tungsten carbide
bodies in which are molten natural diamond or cutter inserts
having a layer of polycrystalline diamond. Even the smallest
of these bits have price tags which may exceed $100,000 each.
Any improvement in the cost of such bits is highly desirable.
The invention concerns a manufacturing technique by which the
cost of the bodies in which the diamonds or diamond inserts
are mounted can be reduced. Typically, the manufacture of
these bits involves a lot of cutting and machining. It is not
unusual in some bit designs to remove more metal from the
original bar than is left in the final bit body. Such
extensive machining is costly. According to this invention,
instead of controlling an NC (numerical control) milling
machine, a CAD file is used to control a rapid prototyping
apparatus. This is used to build, layer by layer, a plastic
body having the shape of a desired steel drill bit body. A
minimal amount of hand finishing may be required in some
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Last modified: November 3, 2007