Note: Descriptions are shown in the official language in which they were submitted.
FIXED CUTTER DRILL BIT HAVING SPHERICAL CUTTER ORIENTING SYSTEM
BACKGROUND OF THE DISCLOSURE
Field of the Disclosure
[0ool] The present disclosure generally relates to a fixed cutter drill bit
having a
spherical cutter orienting system.
Description of the Related Art
[0002] US 4,654,947 discloses a method and apparatus by which the cutting
face of
a drill bit is renewed. The drill bit has a cutting face including a plurality
of radially
spaced apart stud assemblies, each received within a socket. A polycrystalline
diamond
disc forms one end of the stud assembly. The socket is in the form of a
counterbore
extending angularly into the bit body so that when a marginal end of the stud
assembly
is forced into a socket, a portion of the face of the diamond disc extends
below the
bottom of the bit body for engagement with the bottom of a borehole. A
passageway
communicates with the rear of the counterbore and extends back to a surface of
the bit.
Fluid pressure is effected within the passageway, thereby developing
sufficient pressure
differential across the stud assembly to cause the stud assembly to move
respective to
the socket. This action forces a marginal end of the stud assembly to move
sufficiently
respective to the socket so that the free marginal end of the stud assembly
can be
grasped by a tool and manipulated in a manner to bring an unused cutting edge
of the
diamond disc into operative cutting relationship respective to the bottom of
the bit. The
reoriented stud assembly is forced back onto seated relationship respective to
the
socket. The stud assembly includes a circumferentially extending seal means
which
cooperates with the socket interior with a piston-like action.
[0003] US 5,285,859 discloses a drill bit cutter structure and means of
mounting said
cutter structure relative to a drill bit for drilling earth formations in
which the cutter
structure provides diverse rotational orientation of the cutting element about
at least one
axis relative to the drill bit. The cutter structure generally includes a
bearing surface
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associated with the drill bit, a supporting member articulable with the
bearing surface to
provide diverse orientation thereof, and a cutting element secured to said
supporting
member.
[0004] US 7,070,011 discloses a steel body rotary drag bit for drilling a
subterranean
formation including a plurality of support elements affixed to the bit body,
each forming
at least a portion of a cutting element pocket. Each of a plurality of cutting
elements has
a substantially cylindrical body and is at least partially disposed within a
cutter pocket.
At least a portion of the substantially cylindrical body of each cutting
element is directly
secured to at least a portion of a substantially arcuate surface of the bit
body. At least a
portion of a substantially planar surface of each cutting element matingly
engages at
least a portion of a substantially planar surface of a support element.
[0005] US 8,011,456 discloses a cutting element for use with a drill bit
including a
substrate having a longitudinal axis, a lateral surface substantially
symmetric about the
longitudinal axis and one or more key elements coupled to the lateral surface.
The
lateral surface lies between an insertion end and a cutting end of the
substrate. The one
or more key elements are substantially axially aligned with the longitudinal
axis and
configured to selectively rotationally locate the substrate in a pocket. A
drill bit
configured for retaining a cutting element having one or more key elements is
also
disclosed.
[0006] US 8,132,633 discloses a self positioning cutter element and cutter
pocket for
use in a downhole tool having one or more cutting elements. The self
positioning cutter
element includes a substrate and a wear resistant layer coupled to the
substrate. The
cutter element includes a cutting surface, a coupling surface, and a
longitudinal side
surface forming the circumferential perimeter of the cutter element and
extending from
the cutting surface to the coupling surface. The cutter element has one or
more indexes
formed on at least a portion of the coupling surface. In some embodiments, the
index
also is formed on at least a portion of the longitudinal side surface. Hence,
the coupling
surface is not substantially planar. Additionally, at least a portion of the
longitudinal side
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surface does not form a substantially uniform perimeter. The cutter pocket
also is
indexed to correspond and couple with the indexing of the cutter element.
[0007] US 9,481,033 discloses an earth-boring tool including a body having
at least
one blade, and at least one cutting element recess may be formed in a surface
of the at
least one blade. At least one cutting element may be affixed within the at
least one
cutting element recess. The at least one cutting element may comprise a
substantially
cylindrical lateral side surface configured to allow the at least one cutting
element to
rotate about a longitudinal axis within the at least one cutting element
recess when the
at least one cutting element is partially inserted into the at least one
cutting element
recess. The at least one cutting element includes a back face comprising
alignment
features configured to abut complementary alignment features disposed on a
back
surface of the at least one cutting element recess.
[0008] US 2017/0058615 discloses a convex ridge type non-planar cutting
tooth and
a diamond drill bit, the convex ridge type non-planar cutting tooth including
a cylindrical
body, the surface of the end portion of the cylindrical body is provided with
a main
cutting convex ridge and two non-cutting convex ridges, the inner end of the
main
cutting convex ridge and the inner ends of the two non-cutting convex ridges
converge
at the surface of the end portion of the cylindrical body, the outer end of
the main cutting
convex ridge and the outer ends of the two non-cutting convex ridges extend to
the
outer edge of the surface of the end portion of the cylindrical body, the
surfaces of the
end portion of the cylindrical body on both sides of the main cutting convex
ridge are
cutting bevels. The convex ridge type non-planar cutting tooth and the diamond
drill bit
have great ability of impact resistance and balling resistance. According to
the features
of drilled formation, convex ridge type non-planar cutting teeth are arranged
on the drill
bit with different mode, which can improve the mechanical speed and footage of
the drill
bit.
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SUMMARY OF THE DISCLOSURE
[0009] The present disclosure generally relates to a fixed cutter drill bit
having a
spherical cutter orienting system. In one embodiment, a bit for drilling a
wellbore
includes: a shank having a coupling formed at an upper end thereof; a body
mounted to
a lower end of the shank; and a cutting face forming a lower end of the bit.
The cutting
face includes: a blade protruding from the body; a cutter including: a
substrate mounted
in a pocket formed in the blade; and a cutting table made from a superhard
material,
mounted to the substrate, and having a non-planar working face with a cutting
feature;
and a cutter orienting system (COS). The COS includes a knob mounted to or
formed
on a back face of the substrate; and a dimple formed in a back wall of the
pocket and
engaged with the knob. The dimple and the knob are positioned relative to the
cutting
feature to orient the cutting feature to an operative position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] So that the manner in which the above recited features of the
present
disclosure can be understood in detail, a more particular description of the
disclosure,
briefly summarized above, may be had by reference to embodiments, some of
which
are illustrated in the appended drawings. It is to be noted, however, that the
appended
drawings illustrate only typical embodiments of this disclosure and are
therefore not to
be considered limiting of its scope, for the disclosure may admit to other
equally
effective embodiments.
[00] Figures 1A-1D illustrate manufacture of an alloy body of a fixed
cutter drill bit
having a spherical cutter orienting system (SCOS), according to one embodiment
of the
present disclosure.
[0012] Figure 2A illustrates a typical leading cutter pocket of the drill
bit with a dimple
of the SCOS. Figures 2B-2D illustrate a shaped cutter having knobs of the
SCOS.
[0013] Figures 3A-3D illustrate brazing of the shaped cutter into the
pocket and
engagement of the knobs with the dimples.
[0014] Figure 4 illustrates the completed drill bit.
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[0015] Figures 5A-50 illustrate a mold of a casting assembly for
manufacture of a
matrix body fixed cutter drill bit having the SCOS, according to another
embodiment of
the present disclosure.
[0016] Figures 6A and 6B illustrate a typical leading cutter displacement
of the
casting assembly. Figure 6C illustrates installation of the cutter
displacement into a
displacement pocket of the mold.
[0017] Figure 7A illustrates the casting assembly. Figure 7B illustrates
the casting
assembly placed in a furnace for melting binder thereof.
[0018] Figures 8A illustrates a typical leading cutter pocket of the matrix
drill bit.
Figure 8B illustrates the infiltrated body of the matrix drill bit.
[0019] Figures 9A-9C illustrate brazing of the shaped cutter into the
pocket and
engagement of the knobs with the dimples.
[0020] Figures 10A and 10B illustrate a second shaped cutter for use with
the
SCOS, according to another embodiment of the present disclosure. Figures 100
and
10D illustrate a third shaped cutter for use with the SCOS, according to
another
embodiment of the present disclosure.
[0021] Figures 11A and 11B illustrate a fourth shaped cutter and knobs of a
second
SCOS, according to another embodiment of the present disclosure. Figure 110
illustrates a knob of a third SCOS, according to another embodiment of the
present
disclosure. Figure 11D illustrates a sixth shaped cutter for use with the
SCOS,
according to another embodiment of the present disclosure.
DETAILED DESCRIPTION
[0022] Figures 1A-1D illustrate manufacture of an alloy body 2 of a fixed
cutter drill
bit 1 (Figure 4) having a spherical cutter orienting system (SCOS) 3 (Figure
3D),
according to one embodiment of the present disclosure. Figure 2A illustrates a
typical
leading cutter pocket 4 of the drill bit 1 with a dimple 3d of the SCOS 3.
Referring
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specifically to Figure 1A, a piece of round stock 5 may be received from a
metalworking
plant. The round stock 5 may be made from an alloy, such as steel. The round
stock 5
may be mounted in a computer numerical control (CNC) machine tool 6.
[0023] Referring specifically to Figure 1B, the round stock 5 may be turned
in the tool
6 to form a lap coupling adjacent to a mounting end thereof. The round stock 5
may be
further turned in the tool 6 to form a bore (not shown) therein extending from
the
mounting end and a plenum (not shown) therein extending from the bore. The
round
stock 5 may be further turned in the tool 6 to form a taper 7 in an outer
surface thereof
adjacent to the lap coupling. The round stock 2 may be further turned in the
tool 6 to
form an inner cone 8c (numbered in Figure 4) in a cutting face thereof, an
outer
shoulder 8s in the cutting face, and an intermediate nose 8n between the cone
and the
shoulder. The cutting face may be located at an end of the round stock 5
opposite to
the mounting end. The round stock with the turned features will now be
referred to as a
blank.
[0024] The tool 6 may then be operated to mill fluid courses in the cutting
face of the
blank, thereby forming a plurality of blades 9 between adjacent fluid courses.
The tool 6
may be further operated to drill a plurality of ports 23 (Figure 3A) into the
blank. The
ports 23 may extend from the fluid courses and to the plenum of the blank. The
tool 6
may also be operated to mill junk slots in an outer surface of the blank,
thereby forming
a plurality of gage pads 10 between adjacent junk slots. Each gage pad 10 may
extend
from a respective blade 9 to a respective taper 7 and each junk slot may
extent from a
respective fluid course to the lap coupling. The gage pads 10 may extend along
the
body 2 generally longitudinally with a slight helical curvature. The gage pads
10 and
junk slots may form a gage section and may define an outer portion of the
drill bit 1.
[0025] The blades 9 may include one or more primary blades 9p (numbered in
Figure 4) and one or more secondary blades 9s. The blades 9 may be spaced
around
the cutting face and may protrude from a bottom and side of the body 2. The
primary
blades 9p may each extend from a center of the cutting face to the shoulder
8s. The
primary blades 9p may extend generally radially along the cone 8c and nose 8n
with a
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slight spiral curvature and generally longitudinally along the shoulder 8s
with a slight
helical curvature. One or more of the ports 23 may be disposed adjacent to the
center
of the cutting face. The secondary blades 9s may each extend from a location
on the
cutting face adjacent to a respective inner port to the shoulder 8s. The
secondary
blades 9s may extend generally radially along the nose 8n with a slight spiral
curvature
and generally longitudinally along the shoulder 8s with a slight helical
curvature. Since
the blades 9 are formed integrally with the body 2, the blades are also made
from the
same material as the body.
[0026] Referring specifically to Figure 2A, the CNC machine tool 6 may be
further
operated to mill a row of leading cutter pockets 4 along a leading edge of
each blade 9.
For the primary blades 9p, each row of leading cutter pockets 4 may extend
from the
center of the cutting face to a shoulder end of the respective blade. For the
secondary
blades 9s, each row of leading cutter pockets 4 may extend from the location
adjacent
to the respective inner port to a shoulder end of the respective blade. Each
leading
cutter pocket 4 may be shaped to receive a substrate 17 (Figure 2B) of a
respective
shaped cutter 15. Each leading cutter pocket 4 may be defined by a curved
sidewall 4s
and a flat back wall 4b.
[0027] The CNC machine tool 6 may be further operated to mill a row of
backup
pockets along portions of the blades 9 in the shoulder section 8s. Each row of
backup
pockets may extend into portions of the blades 9 in the nose section 8n. Each
backup
pocket may be aligned with or slightly offset from a respective leading cutter
15. The
CNC machine tool 6 may be further operated to mill one or more stud pockets in
each
primary blade 9p at a bottom of a portion thereof in the cone section 8c. The
stud
pockets may each be in a backup position relative to a respective leading
cutter pocket
4 and may be aligned with or slightly offset from the respective leading
cutter 15.
[0028] Referring specifically to Figures 10 and 2A, the CNC machine tool 6
may be
further operated to mill a set of one or more, such as three, dimples 3d
extending from
each leading cutter pocket 4 into the respective blade 9. Each set of dimples
3d may be
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located along the back wall 4b of the respective cutter pocket 4. Each dimple
3d may
be hemi-spherical.
[0029] Referring specifically to Figure 1D, the body 2 may be removed from
the tool
6 and delivered to a welding station (not shown). A shank 12 having a lap
coupling may
be assembled with the lap coupling of the body 2 and the connection
therebetween
secured by a weld. The shank 12 may have a threaded coupling, such as a pin,
formed
at an end opposite to the lap coupling for assembly as part of a drill string
(not shown).
[0030] Alternatively, threaded couplings may be used to connect the body 2
and the
shank 12. Alternatively, the shank may also be formed from the round stock 5
using the
tool 6, thereby resulting in monoblock body 2 and shank 12.
[0031] The body 2 and shank 12 may be moved from the welding station and
mounted in a laser cladding machine 13. The laser cladding machine 13 may be
operated to deposit hardfacing 14 onto the blades 9 and gage pads 10 to
increase
resistance thereof to abrasion and/or erosion. The hardfacing 14 may be
ceramic or
cermet, such as a carbide or carbide cemented by metal or alloy. The
hardfacing 14
may be deposited on a portion of a leading face, a portion of a trailing face,
and a
bottom/outer surface of each blade 9. The hardfaced portions of the leading
and trailing
faces may extend from the leading and trailing edges of each blade 9 to or
past mid-
portions thereof. The pockets 4 may be masked from the hardfacing 14. The
hardfacing 14 may be deposited on a portion of a leading face, a portion of a
trailing
face, and an outer surface of each gage pad 10.
[0032] Figures 2B-2D illustrate a shaped cutter having knobs 3k of the SCOS
3. The
shaped cutter 15 may include a non-planar cutting table 16 mounted to a
cylindrical
substrate 17. The cutting table 16 may be made from a superhard material, such
as
polycrystalline diamond, and the substrate 17 may be made from a hard
material, such
as a cermet, thereby forming a compact, such as a polycrystalline diamond
compact.
The cermet may be a cemented carbide, such as a group VIIIB metal-tungsten
carbide.
The group VIIIB metal may be cobalt.
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[0033] The cutting table 16 may have an interface 18 with the substrate 17
at a rear
end thereof and a non-planar working face at a front end thereof. The
substrate 17 may
have the interface 18 at a front end thereof and a rear end for being received
in the
leading cutter pocket 4. The rear end of the substrate 17 may have an outer
chamfered
edge 17e formed in a periphery thereof and a back face 17b opposite from the
interface
18.
[0034] The working face may have a plurality of recessed bases, a plurality
of
protruding ribs, and an outer chamfered edge 16e. The bases may be located
between
adjacent ribs and may each extend inward from a side 16s of the cutting table
16. Each
rib may extend radially outward from a center 16c of the cutting table 16 to
the side 16s.
Each rib may be spaced circumferentially around the working face at regular
intervals,
such as at one-hundred twenty degree intervals. Each rib may have a ridge 19a-
c and
a pair of bevels each extending from the ridge to an adjacent base.
[0035] The substrate 17 may have a knob 3k mounted to the back face 17b for
each
ridge 19a-c. Each knob 3k may be formed separately from the rest of the cutter
15 and
then mounted to the substrate 17 thereof, such as by brazing. Each knob 3k may
be
angularly offset from the associated ridge 19a-c, such as being located
opposite
therefrom. Each knob 3k may be hemi-spherical and have a diameter ranging
between
twenty-five and forty-five percent of a diameter of the back face 17b. The
knobs 3k may
be spaced about the back face 17b at regular intervals, such as at one-hundred
twenty
degree intervals. The dimples 3d may be sized and arranged about the back wall
4b of
the pocket 4 to mate with the knobs 3k. The knobs 3k and dimples 3d may be
arranged
to mate in any of three different orientations of the cutter 15. Peripheries
of the knobs
3k and dimples 3d may be slightly spaced apart and centers of the knobs and
dimples
may be located on corners of an equilateral triangle (not shown). Each knob 3k
may be
made from the same material as the substrate or a different material than the
substrate,
such as a metal or alloy, such as steel.
[0036] Alternatively, each knob 3k may be formed integrally with the
substrate 17
during formation of the substrate 17 or during high pressure high temperature
sintering
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of the cutter 15. Alternatively, each knob 3k may be formed integrally with
the substrate
17 after formation of the rest of the cutter 15 by machining the knobs into
the back face
17b.
[0037] Figures 3A-3D illustrate brazing of the shaped cutter 15 into the
pocket 4 and
engagement of the knobs 3k with the dimples 3d. The body 2 and shank 12 may be
moved from the laser cladding machine 13 to a cutter station. The cutter
station may be
manual or automated. The shaped cutters 15 may be mounted in the leading
cutter
pockets 4 of the blades 9. Each cutter 15 may be delivered to the respective
pocket 4
by an articulator 21. The articulator 21 may retain the shaped cutter 15 only
partially in
the pocket 4 such that the knobs 3k and the dimples 3d do not engage.
[0038] Once delivered, a second braze material 20 may be applied to an
interface
formed between the respective pocket 4 and the cutter 15 using an applicator
22. As the
second braze material 20 is being applied to the interface, the articulator 21
may rotate
the shaped cutter 15 relative to the pocket 4 to distribute the second braze
material 20
throughout the interface. The articulator 21 may then be operated to align the
knobs 3k
with the dimples 3d and engage the aligned members, thereby ensuring that the
shaped
cutter 15 is properly oriented within the respective pocket 4 to an operative
position. The
operative position may be that the operative ridge 19a is perpendicular to a
projection
24 of the leading edge of the respective blade 9 through the leading cutter
pocket 4.
[0039] A heater (not shown) may then be operated to melt the second braze
material
20. Cooling and solidification of the braze material 20 may mount the cutter
15 to the
respective blade 9. The brazing operation may then be repeated until all of
the shaped
cutters 15 have been mounted to the respective blades 9. The brazing operation
may
also be repeated for mounting the backup cutters and studs into the backup
pockets
and stud pockets. Once the cutters 15 have been mounted to the respective
blades 9,
a nozzle (not shown) may be inserted into each port 23 and mounted to the body
2,
such as by screwing the nozzle therein.
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[0040] Alternatively, the second braze material 20 may be heated by a torch
while
the cutter is being articulated.
[0041] A first braze material 11 used to mount the knobs 3k to the
substrate 17 may
have a greater liquidus temperature than the second braze material 20 used to
mount
the cutters 15 to the blades 9 so that the knobs 2k are not de-brazed from the
substrates 17 while the cutters 15 are being mounted to the blades. The first
liquidus
temperature may be ten percent, twenty percent, thirty percent forty percent,
or fifty
percent greater than the second liquidus temperature. Each braze material 11,
20 may
be a metal or alloy.
[0042] Each backup cutter may include a cutting table mounted to a
cylindrical
substrate. The cutting table may be made from a superhard material, such as
polycrystalline diamond, and the substrate may be made from a hard material,
such as
a cermet, thereby forming a compact, such as a polycrystalline diamond
compact. The
cermet may be a cemented carbide, such as a group VIIIB metal-tungsten
carbide. The
group VIIIB metal may be cobalt. Each stud may be made from a cermet.
[0043] Figure 4 illustrates the completed drill bit 1. In use (not shown),
the drill bit 1
may be assembled with one or more drill collars, such as by threaded
couplings,
thereby forming a bottomhole assembly (BHA). The BHA may be connected to a
bottom of a pipe string, such as drill pipe or coiled tubing, thereby forming
a drill string.
The BHA may further include a steering tool, such as a bent sub or rotary
steering tool,
for drilling a deviated portion of the wellbore. The pipe string may be used
to deploy the
BHA into the wellbore. The drill bit 1 may be rotated, such as by rotation of
the drill
string from a rig (not shown) and/or by a drilling motor (not shown) of the
BHA, while
drilling fluid, such as mud, may be pumped down the drill string. A portion of
the weight
of the drill string may be set on the drill bit 1. The drilling fluid may be
discharged by the
nozzles and carry cuttings up an annulus formed between the drill string and
the
wellbore and/or between the drill string and a casing string and/or liner
string.
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[0044] Upon retrieval of the drill bit 1 from the wellbore, the drill bit
may be inspected
for wear. Should a wear flat be observed on any of the leading cutters 15, the
worn
cutter may be de-brazed from the respective leading cutter pocket 4 and
rotated, such
as by one-hundred twenty degrees, so that one of the unused ridges 19b,c is
moved to
the operative position and then the knobs 3k and dimples 3d reengaged during
re-
brazing thereof, thereby extending the service life of the cutters 15.
[0045] Figures 5A-5C illustrate a mold 25 of a casting assembly 26 (Figure
7A) for
manufacture of a matrix body fixed cutter drill bit (not completely shown)
having the
SCOS 3, according to another embodiment of the present disclosure. Figures 6A
and
6B illustrate a typical leading cutter displacement 28 of the casting assembly
26. Figure
6C illustrates installation of the cutter displacement 28 into a displacement
pocket 29 of
the mold 25. Figure 7A illustrates the casting assembly 26.
[0046] The casting assembly 26 may include the thick-walled mold 25, one or
more
displacements, such as the leading cutter displacements 28, a stalk 30 and one
or more
port displacements 31, a funnel 32, and a binder pot 33. Each of the mold 25,
the
displacements 28, 30, 31, the funnel 32, and the binder pot 33 may be made
from a
refractory material, such as graphite. The mold 25 may be fabricated with a
precise
inner surface forming a mold chamber using a CAD design model (not shown). The
precise inner surface may have a shape that is a negative of what will become
the facial
features of the matrix drill bit.
[0047] The mold 25 may be fabricated with a displacement pocket 29 for each
leading cutter pocket 34 (Figure 8A) of the matrix drill bit. Each
displacement pocket 29
may be shaped to receive a rear portion of the respective leading cutter
displacement
28. Each displacement pocket 29 may be defined by a flat back wall 29b, an
access
groove 29g, a curved ledge 29d, and a keyway 29w. The keyway 29 may be formed
in
the back wall 29b adjacent to an edge thereof. The ledge 29d may extend from
the
back wall 29b and the groove 29g may be formed in the ledge adjacent to the
edge of
the back wall 29b. Each keyway 29w may include a semi-cylindrical mid-section
and a
pair of quarter-spherical end-sections.
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[0048]
Each leading cutter displacement 28 may be cylindrical having a rear face 28r
for insertion into the displacement pocket 29, a front face 28f for extension
into the mold
chamber, and a side 28s extending between the faces.
Each leading cutter
displacement 28 may also have a key 28k protruding from the rear face 28r
adjacent to
an edge of the rear face. The key 28k may be formed as an integral part of the
displacement 28 and may include a semi-cylindrical mid-section and a pair of
quarter-
spherical end-sections for mating engagement with the keyway 29w.
[0049]
Each leading cutter displacement 28 may also have a set of dimple-formers
28m formed therein. The dimple-formers 28m may be located at an edge of the
front
face 28f and may extend therefrom along a portion of the side 28s. Each dimple-
former
28m may be hem i-spherical and have a diameter corresponding to that of the
respective
knob 3k, such as equal to or slightly greater than. The dimple-formers 28m may
be
spaced about the front face 28f at regular intervals, such as at one-hundred
twenty
degree intervals. Peripheries of the dimple-formers 28m may be slightly spaced
apart
and centers of the dimple-formers may be located on corners of an equilateral
triangle
(not shown). A first one of the dimple-formers 28m may be angularly offset
from the key
28k, such as being located opposite therefrom.
[0050]
Each leading cutter displacement 28 may be aligned and inserted into the
respective displacement pocket 29 such that the key 28k mates with the keyway
29w
and mounted therein, such as by adhesive. The leading cutter displacements may
be
removed after infiltration to form the leading cutter pockets 34 in blades 36
(Figure 8B)
of the matrix drill bit for receiving respective shaped cutters 15. The port
displacements
31 may be positioned adjacent to a bottom of the mold chamber and mounted to
the
mold. The stalk 30 may be positioned and mounted within the center of the mold
chamber adjacent to a top of the port displacements 31. The stalk 30 may be
removed
after infiltration to form a bore 35b and plenum 35p (Figure 8B) of the matrix
drill bit. The
port displacements 31 may be removed after infiltration to form respective
ports 35n
(Figure 8B) of the matrix drill bit.
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[0051] The casting assembly 26 may further include a plurality of backup
cutter
displacements (not shown) disposed adjacent to the bottom of the mold chamber
and
the backup cutter displacements may be removed after infiltration to form
backup
pockets in the blades 36 of the matrix drill bit for receiving respective
backup cutters
(Figure 9A). The casting assembly 26 may further include a plurality of stud
displacements (not shown) disposed adjacent to the bottom of the mold chamber
and
the stud displacements may be removed after infiltration to form pockets in
the blades of
the matrix drill bit for receiving respective studs (not shown).
[0052] Once the displacements 28, 30, 31 have been placed into the mold 25,
a
blank 37 may be placed within the casting assembly 25. The blank 37 may be
tubular
and may be made from an alloy, such as steel. The blank 37 may be centrally
suspended within the mold 25 around the stalk 30 so that a bottom of the blank
is
adjacent to a bottom of the stalk. Once the displacements 28, 30, 31 and the
blank 37
have been positioned within the mold 25, body powder 38b may be loaded into
the mold
to fill most of the mold chamber. The loading may include pouring of the body
powder
38b into the mold 25 while compacting thereof, such as by vibrating the mold.
The body
powder 38b may be a ceramic, a cermet, or a mixture of a ceramic and a cermet.
The
ceramic may be a carbide, such as tungsten carbide, and may be cast and/or
macrocrystalline. The cermet may include a carbide, such as tungsten carbide,
cemented by a metal or alloy, such as cobalt.
[0053] Once loading of the body powder 38b has finished, shoulder powder
38s may
be loaded into the mold 25 onto a top of the body powder to fill the remaining
mold
chamber. The shoulder powder 38s may be a metal or alloy, such as the metal
component of the ceramic of the body powder 38b. For example, if the body
powder is
tungsten carbide ceramic and/or tungsten carbide-cobalt cermet, then the
shoulder
powder 38s would be tungsten.
[0054] Once loading of the shoulder powder 38s has finished, the binder pot
33 may
be rested atop the funnel 32 and may be connected thereto, such as by a lap
joint. The
binder pot 33 may have a cavity formed therein and a sprue formed through a
bottom
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thereof providing communication between the cavity and the funnel chamber.
Binder 39
may then be placed into the cavity and through the sprue of the binder pot 33.
The
binder 39 may be in the form of pellets or chunks. The binder 39 may be an
alloy, such
as a copper based alloy. Once the binder 39 has been placed into the binder
pot 33,
flux (not shown) may be applied to the binder for protection of the binder
from oxidation
during infiltration.
[0055] Figure 7B illustrates the casting assembly 26 placed in a furnace 40
for
melting binder 39 thereof. The furnace 40 may include a housing 40h, a heating
element 40e, a controller, such as programmable logic controller (PLC) 40c, a
temperature sensor 40t, and a power supply (not shown). The furnace 40 may be
preheated to an infiltration temperature. The casting assembly 26 may be
inserted into
the furnace 40 and kept therein for an infiltration time 40m. As the casting
assembly 26
is heated by the furnace 40, the binder 39 may melt and flow into the powders
38b,s
through the sprue of the binder pot 33. The molten binder may infiltrate
powders 38b,s
to fill interparticle spaces therein. A sufficient excess amount of binder 39
may have
been loaded into the binder pot 33 such that the molten binder fills a
substantial portion
of the funnel volume, thereby creating pressure to drive the molten binder
into the
powders 38b,s.
[0056] Figures 8A illustrates a typical leading cutter pocket 34 of the
matrix drill bit.
Figure 8B illustrates the infiltrated body 41 of the matrix drill bit. Once
the binder 39 has
infiltrated the powders 38b,s, the casting assembly 26 may be controllably
cooled, such
as by remaining in the furnace 40 with the heating element 40e shut off. Upon
cooling,
the binder 39 may solidify and cement the particles of the powders 38b,s
together into a
coherent matrix body 41. The binder 39 may also bond the body 41 to the blank
37.
Once cooled, the casting assembly 26 may be removed from the furnace 40. The
mold
25, funnel 32, and binder pot 33 may then be broken away from the body 41. A
thread
may be formed in an inner surface of the upper portion of the blank 37 and a
threaded
tubular extension screwed therein, thereby forming the shank 42. The threaded
connection between the extension and the blank 37 may be secured by a weld.
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[0057] Each leading cutter pocket 34 may be shaped to receive the substrate
17 of
the respective shaped cutter 15. Each leading cutter pocket 34 may be defined
by a
curved sidewall 34s and a flat back wall 34b and have the set of dimples 3d
formed in
the back wall by the dimple-former 28m.
[0058] Figures 9A-9C illustrate brazing of the shaped cutter 15 into the
pocket 34
and engagement of the knobs 3k with the dimples 3d. The matrix body 41 and
shank
42 may be moved to the cutter station. The shaped cutters 15 may be mounted in
the
leading cutter pockets 34 of the blades 36. Each cutter 15 may be delivered to
the
respective pocket 34 by the articulator 21. The articulator 21 may retain the
shaped
cutter 15 only partially in the pocket 34 such that the knobs 3k and dimples
3d do not
engage.
[0059] Once delivered, the second braze material 20 may be applied to an
interface
formed between the respective pocket 34 and the cutter 15 using the applicator
22. As
the second braze material 20 is being applied to the interface, the
articulator 21 may
rotate the shaped cutter 15 relative to the pocket 34 to distribute the second
braze
material throughout the interface. The articulator 21 may then be operated to
align the
knobs 3k with the dimples 3d and engage the aligned members, thereby ensuring
that
the shaped cutter 15 is properly oriented within the respective pocket 4 to
the operative
position.
[0060] A heater (not shown) may then be operated to melt the second braze
material
20. Cooling and solidification of the second braze material 20 may mount the
cutter 15
to the respective blade 36. The brazing operation may then be repeated until
all of the
shaped cutters 15 have been mounted to the respective blades 36. The brazing
operation may also be repeated for mounting the backup cutters and studs into
the
backup pockets and stud pockets. Once the cutters 15 have been mounted to the
respective blades 36, a nozzle (not shown) may be inserted into each port 35n
and
mounted to the matrix body 41, such as by screwing the nozzle therein.
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[0061] Alternatively, the second braze material 20 may be heated by a torch
while
the cutter is being articulated.
[0062] Figures 10A and 10B illustrate a second shaped cutter 43 for use
with the
SCOS 3, according to another embodiment of the present disclosure. The second
shaped cutter 43 may include a non-planar cutting table 44 mounted to a
cylindrical
substrate 45. The cutting table 44 may be made from a superhard material, such
as
polycrystalline diamond, and the substrate 45 may be made from a hard
material, such
as a cermet, thereby forming a compact, such as a polycrystalline diamond
compact.
The cermet may be a cemented carbide, such as a group VIIIB metal-tungsten
carbide.
The group VIIIB metal may be cobalt.
[0063] The cutting table 44 may have an interface 46 with the substrate 45
at a rear
end thereof and the working face at a front end thereof. The working face may
have a
plurality of recessed bases 47a-c, a protruding center section 48, a plurality
of
protruding ribs 49a-c, and an outer edge. Each base 47a-c may be planar and
perpendicular to a longitudinal axis of the second shaped cutter 43. The bases
47a-c
may be located between adjacent ribs 49a-c and may each extend inward from a
side of
the cutting table 44. The outer edge may extend around the working face and
may
have constant geometry. The outer edge may include a chamfer located adjacent
to the
side and a round located adjacent to the bases 47a-c and ribs 49a-c.
[0064] Each rib 49a-c may extend radially outward from the center section
48 to the
side. Each rib 49a-c may be spaced circumferentially around the working face
at
regular intervals, such as at one-hundred twenty degree intervals. Each rib
49a-c may
have a triangular profile formed by a pair of curved transition surfaces, a
pair of linearly
inclined side surfaces, and a round ridge. Each transition surface may extend
from a
respective base 47a-c to a respective side surface. Each ridge may connect
opposing
ends of the respective side surfaces. An elevation of each ridge may be
constant
(shown), declining toward the center section, or inclining toward the center
section.
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[0065] An elevation of each ridge may range between twenty percent and
seventy-
five percent of a thickness of the cutting table 44. A width of each rib 49a-c
may range
between twenty and sixty percent of a diameter of the cutting table 44. A
radial length
of each rib 49a-c from the side to the center section 48 may range between
fifteen and
forty-five percent of the diameter of the cutting table 44. An inclination of
each side
surface relative to the respective base 47a-c may range between fifteen and
fifty
degrees. A radius of curvature of each ridge may range between one-eighth and
five
millimeters or may range between one-quarter and one millimeter.
[0066] The center section 48 may have a plurality of curved transition
surfaces, a
plurality of linearly inclined side surfaces, and a plurality of round edges.
Each set of
the features may connect respective features of one rib 49a-c to respective
features of
an adjacent rib along an arcuate path. The elevation of the edges may be equal
to the
elevation of the ridges. The center section 48 may further have a plateau
formed
between the edges. The plateau may have a slight dip formed therein.
[0067] The substrate 45 may have the interface 46 at a front end thereof
and a rear
end for being received in either leading cutter pocket 4, 34. The substrate
front end
may have a planar outer rim, an inner mound for each rib 49a-c, and a shoulder
connecting the outer rim and each inner mound. A shape and location of the
mounds
may correspond to a shape and location of the ribs 49a-c and a shape and
location of
the outer rim may correspond to a shape and location of the bases 47a-c except
that
the mounds may not extend to a side of the substrate 45. Ridges of the mounds
may
be slightly above the bases 47a-c (see dashed line in Figure 10B). A height of
the
mounds may be greater than an elevation of the ribs 49a-c. Similar to that
discussed
above for the substrate 17, the substrate 45 may have one of the knobs 3k
mounted to
a back face thereof for each ridge of the respective rib 49a-c.
[0068] Alternatively, a ridge of each mound may be level with or slightly
below the
bases 47a-c.
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[0069] Figures 100 and 10D illustrate a third shaped cutter 50 for use with
the SCOS
3, according to another embodiment of the present disclosure. The third shaped
cutter
50 may include a concave cutting table 51 mounted to a cylindrical substrate
52. The
cutting table 51 may be made from a superhard material, such as
polycrystalline
diamond, and the substrate may be made from a hard material, such as a cermet,
thereby forming a compact, such as a polycrystalline diamond compact. The
cermet
may be a cemented carbide, such as a group VIIIB metal-tungsten carbide. The
group
VIIIB metal may be cobalt.
[0070] The cutting table 51 may have an interface 53 with the substrate 52
and a
working face opposite to the interface. The working face may have an outer
chamfered
edge, a planar rim adjacent to the chamfered edge, a conical surface adjacent
to the
rim, and a central crater adjacent to the conical surface. The interface 53
may have a
planar outer rim and an inner parabolic surface. The thickness of the cutting
table 51
may be a minimum at the crater and increase outwardly therefrom until reaching
a
maximum at the rim. A depth of the concavity may range between four percent
and
eighteen percent of a diameter of the third shaped cutter 50. Similar to that
discussed
above for the substrate 17, the substrate 52 may have the knobs 3k mounted to
a back
face thereof. Since the third shaped cutter 50 is symmetric, the SCOS 3 may be
used
as an indexing system (should the cutter develop a wear flat) instead of an
orienting
system.
[0071] Alternatively, the cutting table 51 and substrate 52 may each be
elliptical
instead of circular. The SCOS 3 may then be used to orient the major or minor
axis of
the elliptical alternative cutter to the proper orientation. Alternatively,
the cutting table
51 may each be circular or elliptical and have asymmetric curvature along
different axes
thereof. The SCOS 3 may then be used to orient the different axes of the
asymmetrical
alternative cutter to the proper orientation.
[0072] Figures 11A and 11B illustrate a fourth shaped cutter 54 and knobs
59 of a
second SCOS, according to another embodiment of the present disclosure. The
fourth
shaped cutter 54 may include a non-planar cutting table 55 mounted to a
cylindrical
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substrate 56. The cutting table 55 may be made from a superhard material, such
as
polycrystalline diamond, and the substrate 56 may be made from a hard
material, such
as a cermet, thereby forming a compact, such as a polycrystalline diamond
compact.
The cermet may be a cemented carbide, such as a group VIIIB metal-tungsten
carbide.
The group VIIIB metal may be cobalt.
[0073] The cutting table 55 may have an interface 57 with the substrate 56
at a rear
end thereof and the working face at a front end thereof. The working face may
have an
outer edge and a ridge 58 protruding a height above the substrate and at least
one
recessed region extending laterally away from the ridge 58. The ridge 58 may
be
centrally located in the working face and extend across the working face. The
presence
of the ridge 58 may result in the outer edge undulating with peaks and
valleys. The
portion of the ridge 58 adjacent to the outer edge may be an operative
portion. Since
the ridge 58 extends across the working surface, the ridge may have two
operative
portions. The working face may further include a pair of recessed regions
continuously
decreasing in height in a direction away from the ridge 58 to the outer edge
that is the
valley of the undulation thereof. The ridge 58 and recessed regions may impart
a
parabolic cylinder shape to the working face. The outer edge of the cutting
table 55 may
be chamfered (not shown).
[0074] The substrate 56 may include a pair of knobs 59 mounted thereto, one
knob
for each operative portion of the ridge 58. Each knob 59 may be located on the
back
face of the substrate 56. Each knob 59 may be angularly offset from the
associated
operative portion, such as being located opposite therefrom. The knobs 59 may
be
similar to the knobs 3k except that the knobs 59 may be arranged in a co-axial
configuration instead of a triangular configuration and each knob 59 and have
a
diameter ranging between thirty and fifty percent of a diameter of the back
face of the
substrate 56. The second SCOS may include the knobs 59 and a pair of
complementary dimples (not shown) formed in either pocket 4, 34 for mating
therewith.
[0075] Alternatively, the second SCOS may be used with the third shaped
cutter 50
instead of the SCOS 3.
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[0076] Figure 11C illustrates a knob 61 of a third SCOS, according to
another
embodiment of the present disclosure. The third SCOS may used with a fifth
shaped
cutter 60 which is similar to the fourth shaped cutter 54. The fifth shaped
cutter 60 may
include the non-planar cutting table 55 mounted to a cylindrical substrate 62.
The
substrate 62 may include the single knob 61 mounted to the back face of the
substrate.
The knob 61 may be similar to the knobs 3k except for being singular and
having a
diameter ranging between thirty and seventy-five percent of a diameter of the
back face
of the substrate 62. The third SCOS may include the knob 61 and a
complementary
dimple (not shown) formed in either pocket 4, 34 for mating therewith.
[0077] Figure 11D illustrates a sixth shaped cutter 63 for use with the
SCOS 3,
according to another embodiment of the present disclosure. The sixth shaped
cutter 63
may be similar to the second shaped cutter 43 except for having six ribs and
six bases
instead of three. The sixth shaped cutter may have the knobs 3k mounted to a
back
face of a substrate thereof or may have six knobs formed on the substrate back
face. A
fourth SCOS (not shown) may include the six knobs and a complementary set of
six
dimples (not shown) formed in either pocket 4, 34 for mating therewith
[0078] Alternatively, the sixth shaped cutter may have any N number of ribs
and
bases and have N number of knobs mounted to the back face of a substrate
thereof,
where N is an integer ranging between three and six. The SCOS for use with the
alternative sixth shaped cutter may include the N knobs and a complementary
set of N
dimples formed in either pocket 4, 34 for mating therewith.
[0079] Advantageously, as compared to one or more of the prior art
references
discussed above, the SCOS 3 is self-guiding, whereas the prior art references
require
precise alignment to engage, thereby slowing down the brazing of the cutters
into the
pockets. Further, the SCOS 3 significantly increases bonding area for the
second braze
material, whereas the prior art references do not. Further, the dimples 3d are
simple
shapes to form in either of the pockets 4, 34 whereas the shapes of the prior
art
references can be cumbersome to form in the pockets. Further, the precision of
the
dimples 3d can be rough, whereas, the prior art references require precise
receptacles
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in the pockets. Further, the robustness of the knobs 3k resist damage due to
rough
handling of the cutters during brazing into the pockets 4, 34, whereas, the
shapes of the
prior art references can be quite fragile.
[0080]
While the foregoing is directed to embodiments of the present disclosure,
other and further embodiments of the disclosure may be devised without
departing from
the basic scope thereof, and the scope of the invention is determined by the
claims that
follow.
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