Note: Descriptions are shown in the official language in which they were submitted.
FIXED CUTTER DRILL BIT HAVING CUTTER ORIENTING SYSTEM
BACKGROUND OF THE DISCLOSURE
Field of the Disclosure
[0001] The present disclosure generally relates to a fixed cutter drill bit
having a 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 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.
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[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 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
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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.
SUMMARY OF THE DISCLOSURE
[0009] The present disclosure generally relates to a fixed cutter drill bit
having a 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
including: a keyway formed in the substrate and angularly located opposite
from the
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cutting feature; and a key formed in or mounted to the pocket and engaged with
the
keyway.
[0010] In another 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 by brazing material; and a cutting table made from a superhard
material and
mounted to the substrate; and a cutter orienting system including: a keyway
formed in an
edge of the substrate; and a key formed in or mounted to the pocket at an edge
of the
pocket and engaged with the keyway.
[0011] In another embodiment, a method of manufacturing a drill bit
includes:
machining a body and cutting face from alloy stock, the cutting face having a
blade
protruding from the body; forming a pocket in the blade; forming a socket in
the pocket;
mounting a pin in the socket; and brazing a cutter into the pocket while
engaging a keyway
of the cutter with the pin, thereby orienting the cutter.
[0012] In another embodiment, a method of manufacturing a drill bit
includes: forming
a mold having an inner surface formed into a negative shape of facial features
of the drill
bit, the mold having a cutter displacement pocket with a keyway formed
therein; mounting
a cutter displacement into the cutter displacement pocket while engaging a key
formed
on the cutter displacement with the keyway, thereby orienting a key-former of
the cutter
displacement; assembling the mold as part of a casting assembly; loading
powder into
the mold, the powder comprising at least one of: ceramic powder and cermet
powder;
placing a binder alloy into the casting assembly over the mold; inserting the
casting
assembly, powder, and binder alloy into a furnace; operating the furnace to
melt the
binder alloy, thereby infiltrating the powder with the binder alloy and
forming a body and
a blade protruding from the body and having a cutter pocket formed by the
cutter
displacement; and brazing a cutter into the pocket while engaging a keyway of
the cutter
with a key formed by the key-former, thereby orienting the cutter.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0013] 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.
[0014] Figures 1A-1D illustrate manufacture of an alloy body of a fixed
cutter drill bit
having a cutter orienting system (COS), according to one embodiment of the
present
disclosure.
[0015] Figures 2A and 2B illustrate a typical leading cutter pocket of the
drill bit.
Figures 2C and 2D illustrate installation of a key of the COS into the cutter
pocket.
[0016] Figures 3A-3C illustrate a shaped cutter having keyways of the COS.
[0017] Figures 4A-4D illustrate brazing of the shaped cutter into the
pocket and
engagement of the key with one of the keyways.
[0018] Figure 5 illustrates the completed drill bit.
[0019] Figures 6A-6C illustrate a mold of a casting assembly for
manufacture of a
matrix body fixed cutter drill bit having a second COS, according to another
embodiment
of the present disclosure.
[0020] Figure 7A illustrates a typical leading cutter displacement of the
casing
assembly. Figures 7B and 7C illustrate installation of the cutter displacement
into a
displacement pocket of the mold.
[0021] Figure 8A illustrates the casting assembly. Figure 8B illustrates
the casting
assembly placed in a furnace for melting binder thereof.
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[0022] Figures 9A and 96 illustrate a typical leading cutter pocket of the
matrix drill bit.
Figure 9C illustrates the infiltrated body of the matrix drill bit.
[0023] Figures 10A-10C illustrate brazing of the shaped cutter into the
pocket and
engagement of a key of the second COS with one of the keyways.
[0024] Figures 11A-11C illustrate a second shaped cutter for use with
either COS,
according to another embodiment of the present disclosure. Figures 11D and 11E
illustrate a third shaped cutter for use with either COS, according to another
embodiment
of the present disclosure. Figure 11F illustrates a fourth shaped cutter for
use with either
COS, according to another embodiment of the present disclosure.
DETAILED DESCRIPTION
[0025] Figures 1A-1D illustrate manufacture of an alloy body 2 of a fixed
cutter drill bit
1 (Figure 5) having a cutter orienting system (COS) 3, according to one
embodiment of
the present disclosure. Figures 2A and 2B illustrate a typical leading cutter
pocket 4 of
the drill bit 1. Referring 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.
[0026] 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 5) 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.
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[0027] 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 4A) 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.
[0028] The blades 9 may include one or more primary blades 9p (numbered in
Figure
5) 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 slight
spiral curvature
and generally longitudinally along the shoulder 8 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.
[0029] Referring specifically to Figures 2A and 2B, 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 3A) of
a
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respective shaped cutter 15. Each leading cutter pocket 4 may be defined by a
curved
sidewall 4s and a flat back wall 4b.
[ono]
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. Each row of
backup
pockets may extend into portions of the blades 9 in the nose section. 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.
[0031]
Referring specifically to Figures 1C, 2A, and 2B, the CNC machine tool 6 may
be further operated to drill a socket 11 extending from each leading cutter
pocket 4 into
the respective blade 9. Each socket 11 may be located at an edge of the
respective
leading cutter pocket 4 formed between the sidewall 4s and back wall 4b
thereof. Each
socket 11 may be located at a center of the respective edge.
[0032]
Figures 2C and 2D illustrate installation of a key 3k of the COS 3 into the
leading cutter pocket 4. The body 2 may be removed from the tool 6 and
delivered to a
work station (not shown). At the work station, a technician (not shown) may
mount each
key 3k into the respective socket 11. Each key 3k may be a pin, such as a
spring pin,
and each spring pin may have chamfered ends and an expanded diameter greater
than
a diameter of the respective socket 11. Engagement of one of the chamfered
ends with
the socket may compress the spring pin during insertion by the technician. The
bias of
each spring pin toward the expanded diameter may firmly engage the spring pin
into
engagement with the respective socket 11, thereby self-mounting into the
respective
pocket 4. Each spring pin may be the split-type (shown) or the coiled type
(not shown).
[0033]
Alternatively, each key 3k may be a solid pin interference fit into the
respective
socket or mounted therein using an adhesive.
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[0034] Referring specifically to Figure 1D, the body 2 may be moved from
the work
station 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).
[0035] 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.
[0036] The body 2 and shank 12 may be moved from the work 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.
[0037] Figures 3A-3C illustrate a shaped cutter 15 having keyways 3w of the
COS 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.
[0038] The cutting table 16 may have an interface 18 with the substrate 17
at a lower
end thereof and a non-planar working face at an upper end thereof. The
substrate 17
may have the interface 18 at an upper end thereof and a lower end for being
received in
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the leading cutter pocket 4. The pocket end of the substrate 17 may have an
outer
chamfered edge 17e formed in a periphery thereof.
[0039] 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.
[0040] The substrate 17 may have a keyway 3w formed therein for each ridge
19a-c.
Each keyway 3w may be located at the edge 17e of the substrate 17 and may
extend
from the pocket end thereof along a portion of a side 17s thereof. The portion
of the side
17s that each keyway 3w extends may range between fifteen and seventy percent
of a
length of the substrate 17. Each keyway 3w may be a slot inclined relative to
a
longitudinal axis of the cutter by an angle ranging between ten and seventy
degrees.
Each slot may have a width corresponding to a diameter of the key 3k, such as
equal to
or slightly greater than. Each keyway 3w may be angularly offset from the
associated
ridge 19a-c, such as being located opposite therefrom.
[0041] Figures 4A-4D illustrate brazing of the shaped cutter 15 into the
leading pocket
4 and engagement of the key 3k with one of the keyways 3w. 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 keyways 3w and key 3k do not engage.
[0042] Once delivered, a brazing material 20 may be applied to an interface
formed
between the respective pocket 4 and the cutter 15 using an applicator 22. As
the brazing
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 brazing material 20
throughout the
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interface. The articulator 21 may then be operated to align one of the keyways
3w with
the key 3k and engage the aligned members, thereby ensuring that the shaped
cutter 15
is properly oriented within the respective pocket 4. Proper orientation 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.
[0043] A heater (not shown) may then be operated to melt the brazing
material 20.
Cooling and solidification of the brazing 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 the each port 23 and mounted to the
body 2,
such as by screwing the nozzle therein.
[0044] 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.
[0045] Figure 5 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
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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.
[0046] 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 one of the
keyways 3w
of the unused ridges 19b,c may be engaged with the key 3k during re-brazing
thereof,
thereby extending the service life of the cutters 15.
[0047] Figures 6A-6C illustrate a mold 25 of a casting assembly 26 (Figure
8A) for
manufacture of a matrix body fixed cutter drill bit (not completely shown, see
alloy body
drill bit 1) having a second COS 27 (Figure 10B), according to another
embodiment of the
present disclosure. Figure 7A illustrates a typical leading cutter
displacement 28 of the
casing assembly 26. Figures 7B and 7C illustrate installation of the cutter
displacement
28 into a displacement pocket 29 of the mold 25. Figure 8A illustrates the
casting
assembly 26.
[0048] 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.
[0049] The mold 25 may be fabricated with a displacement pocket 29 for each
leading
cutter pocket 34 (Figure 9A) 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.
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Each keyway 29w may include a semi-cylindrical mid-section and a pair of
quarter-
spherical end-sections.
[0050] 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.
[0051] Each leading cutter displacement 28 may also have a key-former 28m
formed
therein. The key-former 28m may be located at an edge of the front face 28f
and may
extend therefrom along a portion of the side 28s. The key-former 28m may be a
slot
inclined relative to a longitudinal axis of the displacement 28 by an angle
ranging between
ten and seventy degrees. Each slot may have a length and a width corresponding
the
length and width of the keyway 3w, such as equal to or slightly less than. The
key-former
28m may be angularly offset from the key 28k, such as being located opposite
therefrom.
[0052] 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 9C) 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 9C) of the matrix drill
bit. The port
displacements 31 may be removed after infiltration to form respective ports
35n (Figure
9C) of the matrix drill bit.
[0053] 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
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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 10A).
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).
[0054] 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.
[0055] 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.
[0056] 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
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
14
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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.
[0057] Figure 8B 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.
[0058] Figures 9A and 9B illustrate the typical leading cutter pocket 34 of
the matrix
drill bit. Figure 9C 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.
[0059] 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 a key 27k formed
therebetween
by the key-former 28m. A center of each key 27k may be located at an edge of
the
CA 3004127 2018-05-07
1
respective leading cutter pocket 34 formed between the sidewall 34s and back
wall 34b
thereof. Each key 27k may be located at a center of the respective edge. Each
key 27k
may be wedge-shaped in order to mate with one of the keyways 3w of the shaped
cutter
15.
[0060] Figures 10A-10C illustrate brazing of the shaped cutter 15 into the
pocket 34
and engagement of the key 27k of the second COS 27 with one of the keyways 3w.
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
keyways 3w and
key 27k do not engage.
[0061] Once delivered, the brazing material 20 may be applied to an
interface formed
between the respective pocket 34 and the cutter 15 using the applicator 22. As
the brazing
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 brazing material 20
throughout the
interface. The articulator 21 may then be operated to align one of the keyways
3w with
the key 27k and engage the aligned members, thereby ensuring that the shaped
cutter
15 is properly oriented within the respective pocket 4. Proper orientation may
be that the
operative ridge 19a is perpendicular to a projection (not shown, see
projection 24) of the
leading edge of the respective blade 36 through the leading cutter pocket 34.
[0062] A heater (not shown) may then be operated to melt the brazing
material 20.
Cooling and solidification of the brazing 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 the each port 35n and mounted to the
matrix
body 41, such as by screwing the nozzle therein.
16
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1
[0063] Figures 11A-11C illustrate a second shaped cutter 43 for use with
either COS
3, 27, 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.
[0064] The cutting table 44 may have an interface 46 with the substrate 45
at a lower
end thereof and the working face at an upper 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.
[0065] 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.
[0066] 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-
17
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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.
[0067] 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.
pow The substrate 45 may have the interface 46 at an upper end thereof
and a lower
end for being received in either leading cutter pocket 4, 34. The substrate
upper 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 11C). A height of the mounds may be
greater
than an elevation of the ribs 49a-c. The substrate 45 may have a keyway 3w
formed
therein for each ridge of the respective rib 49a-c. Each keyway 3w may be
located at the
edge of the substrate 45 and may extend from the pocket end thereof along a
portion of
a side thereof. Each keyway 3w may be angularly offset from the associated
ridge, such
as being located opposite therefrom.
[0069] Alternatively, a ridge of each mound may be level with or slightly
below the
bases 47a-c.
[0070] Figures 11D and 11E illustrate a third shaped cutter 50 for use with
either COS
3, 27, according to another embodiment of the present disclosure. The third
shaped cutter
50 may include a concave cutting table 51 attached to a cylindrical substrate
52. The
cutting table 51 may be made from a superhard material, such as
polycrystalline diamond,
18
CA 3004127 2018-05-07
attached to a hard substrate, 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 VI I IB metal-tungsten carbide. The group VIIIB metal may be cobalt.
[0071] 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. The substrate 52 may have a plurality
of keyways
(not shown) formed therein and spaced therearound. Each keyway may be located
at
the edge of the substrate 52 and may extend from the pocket end thereof along
a portion
of a side thereof. Since the third shaped cutter 50 is symmetric, either COS
3, 27 may
be used as an indexing system (should the cutter develop a wear flat) instead
of an
orienting system.
[0072] Alternatively, sides of the cutting table 51 and substrate 52 may
each be
elliptical instead of circular. Either COS 3, 27 may then be used to orient
the major axis
of the cutter to the proper orientation. Additionally, the concavity present
in the working
face may be defined by a curved or parabolic shape oriented along the major
axis
extending from end to end to form a parabolic (or hyperbolic paraboloid)
concavity. The
thickness of the cutting table may be thicker towards the outer edge thereof
at the
opposed ends and along the major axis and thinner towards a center of the
cutter and
along the minor axis. The concave working face may present a continuous curve
from
end to end along and in the direction of the major axis.
[0073] In another aspect of this alternative, the concavity present in the
working face
may be defined by a curved or parabolic shape oriented along the minor axis
extending
from end to end to form a parabolic or hyperbolic paraboloid concavity. The
concave
cutter face may present a continuous curve from end to end along the minor
axis. The
19
CA 3004127 2018-05-07
I
thickness of the cutting table may be thicker towards the outer edge thereof
at the
opposed ends and along the minor axis) and thinner towards the center of the
cutter and
along the major axis. For this aspect, either COS 3, 27 may then be used to
orient the
minor axis of the cutter to the proper orientation.
[0074] In another aspect of this alternative, the concavity present in the
working face
may be defined by a curved or parabolic shape oriented along each of the major
axis and
minor axis which results in the formation of spherical, elliptical paraboloid
or ovoidal
concavity. The concave working face may present a continuous curve along any
selected
orientation from end to end across the face. The thickness of the cutting
table may be
thicker towards the outer edge thereof at all locations therealong and
thereabout while
being thinner towards the center of the cutter. For this aspect, either COS 3,
27 may then
be used to orient either the major or minor axis of the cutter to the proper
orientation. The
concavity on the face may presents a first counter angle in the direction of
the major axis,
and a second counter angle in the direction of the minor axis. These counter
angles need
not be equal to each other.
[0075] Alternatively, for circular sides of the cutting table 51 and
substrate 52, the
concavity present in the working face may be defined by a curved or parabolic
shape
oriented along the first axis extending from end to end to form a parabolic or
hyperbolic
paraboloid concavity. The concave working face may present a continuous curve
from
end to end along the first axis. The thickness of the cutting table may be
thicker towards
the outer edge thereof at the opposed ends and along the first orientation
axis and thinner
towards the center of the cutter and along a second axis orthogonal to the
first axis. For
this alternative, either COS 3, 27 may then be used to orient the first axis
of the cutter to
the proper orientation. The concavity on the face may present a counter angle
in the
direction of the first axis.
[0076] Alternatively, for circular sides of the cutting table 51 and
substrate 52, the
concavity present on the working face may be defined by a curved or parabolic
shape
oriented along each of the two orthogonal axes which results in the formation
of spherical,
elliptical paraboloid or ovoidal concavity. The concave working face may
present a
CA 3004127 2018-05-07
I
continuous curve along any selected orientation from end to end across the
face. The
thickness of the cutting table may be thicker towards the outer edge thereof
at all locations
therealong and thereabout while being thinner towards the center of the
cutter. For this
alternative, either COS 3, 27 may then be used to orient either axis of the
cutter to the
proper orientation. The concavity on the working face may present a first
counter angle
in the direction of the first axis, and a second counter angle in the
direction of the second
axis. These counter angles need not be equal to each other.
[0077] Alternatively, for circular sides of the cutting table 51 and
substrate 52, The
concavity present on the working face may be defined by a curved or parabolic
shape
oriented along the first axis extending from the center towards a first end to
form a
parabolic (or hyperbolic paraboloid) concavity at that end and a planar
surface at an
opposite second end. The concave working face may present a continuous curve
extending along the first axis from the flat surface associated with the
second end and
center and terminating at the first end. The thickness of the cutting table
may be thicker
towards the outer edge thereof at only the first end along the first
orientation axis and
thinner towards the center and towards the second end along the first
orientation axis.
The cutting table may have a substantially constant thickness from the second
end toward
the center along the first axis and then may increase from the center towards
the first end
along the first orientation axis. For this alternative, either COS 3, 27 may
then be used to
orient the first end of the cutter to the proper orientation. The concavity on
the working
face may present a counter angle in the direction of the first axis.
[0078] Alternatively, for elliptical sides of the cutting table 51 and
substrate 52, the
cutter may be severed along the minor axis and each half used as a separate
cutter. The
concavity present on the working face may be defined by a curved or parabolic
shape
oriented along each of the major axis and minor axis which results in the
formation of
spherical, elliptical paraboloid or ovoidal concavity associated with the
included half. The
concave working face may present a continuous curve along any selected
orientation
from end to end across the face. The thickness of the cutting table may be
thicker towards
the outer edge thereof at all locations therealong and thereabout while being
thinner
towards the center at the cut-off flat edge of the cutter along the minor
axis. For this
21
CA 3004127 2018-05-07
alternative, either COS 3, 27 may then be used to orient the end opposite to
the cut-off
flat edge of the cutter to the proper orientation. The concavity may present a
first counter
angle in the direction of the major axis, and a second counter angle in the
direction of the
minor axis. These counter angles need not be equal to each other.
[0079] Alternatively, for elliptical sides of the cutting table 51 and
substrate 52, the
cutter may be severed along the minor axis and each half used as a separate
cutter. The
concavity present on the working face may be defined by a curved or parabolic
shape
oriented along the major axis extending from center to end to form a parabolic
or
hyperbolic paraboloid concavity. The concave cutter face may presents a
continuous
curve from center to a first end along the major axis. The thickness of the
cutting table
may be thicker towards the outer edge of the cutter 30 at the first end along
the major
axis while being thinner towards a center of the cutter at the cut-off flat
edge of the cutter.
For this alternative, either COS 3, 27 may then be used to orient the first
end opposite to
the proper orientation. The concavity on the face may present a counter angle
in the
direction of the major axis.
mom Alternatively, for elliptical sides of the cutting table 51 and
substrate 52, the
cutter may be severed along the major axis and each half used as a separate
cutter. The
concavity present on the working face of the cutter may be defined by a curved
or
parabolic shape oriented along the minor axis extending from center to a first
end to form
a parabolic or hyperbolic paraboloid concavity. The concave working face may
present a
continuous curve from center to the first end along the major axis. The
thickness of the
cutting table may be thicker towards the outer edge thereof at the first end
along the minor
axis while being thinner towards the center at the cut-off flat edge. For this
alternative,
either COS 3, 27 may then be used to orient the first end to the proper
orientation. The
concavity on the face may present a counter angle in the direction of the
minor axis.
[0081] Alternatively, for circular sides of the cutting table 51 and
substrate 52, the
cutter may be severed in half and each half used as a separate cutter. The
concavity
present on the working face may be defined by a curved or parabolic shape
oriented
along the first axis extending from center to a first end opposite the cut-off
flat edge to
22
CA 3004127 2018-05-07
form a parabolic or hyperbolic paraboloid concavity. The concave working face
may
present a continuous curve from center to the first end along the first axis.
The thickness
of the cutting table may be thicker towards the outer edge thereof at the end
along the
first axis while being thinner towards the center of the cutter at the cut-off
flat edge. For
this alternative, either COS 3, 27 may then be used to orient the first end to
the proper
orientation. The concavity on the face may present a counter angle in the
direction of the
first axis.
[0082] Alternatively, for circular sides of the cutting table 51 and
substrate 52, the
cutter may be severed in half and each half used as a separate cutter. The
concavity
present on the working face may be defined by a curved or parabolic shape
oriented
along each of the first axis extending from center to a first end opposite the
cut-off edge
and the cut-off edge which results in the formation of spherical, elliptical
paraboloid or
ovoidal concavity associated with the included half. The concave cutter face
may present
a continuous curve along any selected orientation from end to end across the
face. The
thickness of the cutting table may be thicker towards the outer edge thereof
at all locations
therealong and thereabout while being thinner towards a center of the cutter
along the
cut-off edge. For this alternative, either COS 3, 27 may then be used to
orient the first
end to the proper orientation. The concavity may present a first counter angle
in the
direction of the first axis, and a second counter angle in the direction of
the second axis.
These counter angles need not be equal to each other.
[0083] Alternatively, for elliptical sides of the cutting table 51 and
substrate 52, the
concavity present on the working face may be defined by a curved or parabolic
shape
oriented along the major axis extending from center towards first end to form
a parabolic
or hyperbolic paraboloid concavity at that end and a planar surface at
opposite second
end. The concave cutter face presents a continuous curve extending along the
major axis
from the flat surface associated with the first end and center and terminating
at the second
end. The thickness of the cutting table may be thicker towards an outer edge
thereof at
the first end along the major axis and thinner towards the center and at the
second end
along the major axis. The cutting table may have a substantially constant
thickness from
the second end toward the center along the major axis. The thickness of the
cutting table
23
CA 3004127 2018-05-07
may then increase from the center towards the first end along the major axis.
For this
alternative, either COS 3, 27 may then be used to orient the first end to the
proper
orientation. The concavity on the face presents a counter angle in the
direction of the
major axis.
[00841 Alternatively, for elliptical sides of the cutting table 51 and
substrate 52, the
concavity present on the working face may be defined by a curved or parabolic
shape
oriented along the minor axis extending from center towards a first end to
form a parabolic
(or hyperbolic paraboloid) concavity at that end and a planar surface at an
opposite
second end. The concave cutter face presents a continuous curve extending
along the
minor axis from the flat surface associated with the second end and center and
terminating at the first end. The thickness of the cutting table may be
thicker towards the
outer edge thereof at the first end along the minor axis and thinner towards
the center of
the cutter and the second end along the minor axis. The cutting table layer
may have a
substantially constant thickness from the second end toward the center along
the minor
axis. The thickness of the cutting table may then increase from the center
towards the
first end along the minor axis.
[0085] Alternatively, for elliptical sides of the cutting table 51 and
substrate 52, along
the major axis thereof, the working face may be divided into two halves. A
first half may
extend from the center towards a first end. A second half may extend from the
center
towards a second end. The concavity present on the working face may be defined
in only
the second half by a curved or parabolic shape oriented along the major axis
extending
from center towards the second end to form a parabolic or hyperbolic
paraboloid
concavity in the second half while the first half presents a planar surface.
The concave
working face may present a continuous curve extending along the major axis
from the
center and terminating at the second end. The thickness of the cutting table
in the first
half may be substantially constant. However, the thickness of the cutting
table in the
second half may be thicker towards the center and the outer edge thereof at
the second
end along the major axis while being thinner at points between the center of
the cutter
and the second end along the minor axis. The thickness of the cutting table in
the first
half may be generally equal to the maximum thickness of the cutting table in
the second
24
CA 3004127 2018-05-07
half. For this alternative, either COS 3, 27 may then be used to orient the
major axis and
the second end to the proper orientation.
[0086] Alternatively, for elliptical sides of the cutting table 51 and
substrate 52, along
the major axis of the elliptical cutter, the face may be divided into two
halves. A first half
may extend from the center towards a first end. A second half may extend from
the center
towards a second end. The concavity present on the working face may be defined
such
that each of the first half and second half presents a separate or distinct
concave cutter
shape defined by a curved or parabolic shape oriented along the major axis
extending
from center towards either the first end or the second end to form a distinct
parabolic or
hyperbolic paraboloid concavity in each of the first half and the second half.
Each concave
cutter face may present a continuous curve extending along the major axis from
the center
and terminating at either the first end or the second end. The thickness of
the cutting table
in each of the first half and second half may be thicker towards the center
and the outer
edge thereof at the first end along the major axis and thinner at points
between the center
of the cutter and the first end along the minor axis. With respect to the
second half, the
cutting table may be thicker towards the center and the outer edge thereof at
the second
end along the major axis and thinner at points between the center of the
cutter and the
second end along the minor axis. For this alternative, either COS 3, 27 may
then be used
to orient the major axis and either the first or second end to the proper
orientation.
[0087] Figure 11F illustrates a fourth shaped cutter 54 for use with either
COS 3, 27,
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 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.
[0088] The cutting table 55 may have an interface 57 with the substrate 56
at a lower
end thereof and the working face at an upper end thereof. The working face may
have an
CA 3004127 2018-05-07
1
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).
[0089] The substrate 56 may include a keyway 3w for each operative portion
of the
ridge 58. Each keyway 3w may be located at the edge of the substrate 56 and
may
extend from the pocket end thereof along a portion of a side thereof. Each
keyway 3w
may be angularly offset from the associated operative portion, such as being
located
opposite therefrom.
[0090] 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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I
