Note: Descriptions are shown in the official language in which they were submitted.
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MILLING CUTTER AND MILLING INSERT WITH COOLANT
DELIVERY
CROSS-REFERENCE TO EARLIER PENDING PATENT APPLICATION
[0001] This patent application is a divisional patent application of co-
pending United States Patent Application Serial No. 11/654,833 filed January
18,
2007 for a MILLING CUTTER AND MILLING INSERT WITH COOLANT
DELIVERY by Paul D. Prichard and Linn R. Andras. Applicants (Paul D. Prichard
and Linn R. Andras) hereby claim the benefit of the priority filing date of
said
above-referenced parent patent application (i.e., U.S. Serial No. 11/654,833
filed
January 18, 2007). Further, applicants hereby incorporate by reference herein
the
entirety of said parent patent application (i.e., U.S. Serial No. 11/654,833
filed
January 18, 2007).
BACKGROUND OF THE INVENTION
[0002] The invention relates to a milling cutter, as well as a milling insert,
used for chipforming and material removal operations. More specifically, the
invention pertains to a milling cutter, as well as a milling insert, used for
chipforming and material removal operations wherein there is enhanced delivery
of
coolant adjacent the interface between the milling insert and the workpiece
(i.e., the
insert-chip interface) to diminish excessive heat at the insert-chip
interface.
[0003] In a chipforming and material removal operation (e.g., a milling
operation), heat is generated at the interface between the cutting insert and
the
location where the chip is removed from the workpiece (i.e., the insert-chip
interface). It is well-known that excessive heat at the insert-chip interface
can
negatively impact upon (i.e., reduce or shorten) the useful tool life of the
milling
insert. As can be appreciated, a shorter useful tool life increases operating
costs and
decreases overall production efficiency. Hence, there are readily apparent
advantages connected with decreasing the heat at the insert-chip interface.
[0004] In this regard, U.S. Patent No. 6,053,669 to Lagerberg discusses the
importance of reducing the heat at the insert-chip interface. More
specifically,
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Lagerberg mentions that when the cutting insert is made from cemented carbide
reaches a certain temperature, its resistance to plastic deformation
decreases. A
decrease in plastic deformation resistance increases the risk for breakage of
the
cutting insert. U.S. Patent No. 5,775,854 to Wertheim points out that a rise
in the
working temperature leads to a decrease in hardness of the cutting insert with
a
consequent increase in wear of the cutting insert. Each one of the Lagerbeg
patent
and the Wertheim patent discuss the importance of delivering coolant to the
insert-
chip interface.
[0005] Other patent documents disclose various ways to or systems for
delivering coolant to the insert-chip interface. In this regard, U.S. Patent
No.
6,045,300 to Antoun discloses using high pressure and high volume delivery of
coolant to address heat at the insert-chip interface. U.S. Patent Application
Publication No. 2003/00820118 to Kreamer discloses grooves between the cutting
insert and a top plate. Coolants flows through the grooves to address the heat
at the
insert-chip interface. U.S. Patent No. 5,901,623 to Hong discloses a coolant
delivery
system for applying liquid nitrogen to the insert-chip interface.
[0006] It is readily apparent that in a chipforming and material removal
operation, higher operating temperatures at the insert-chip interface can have
a
detrimental impact on the useful tool life through premature breakage and/or
excessive wear. It therefore would be highly desirable to provide a cutter
assembly
(e.g., a milling cutter assembly), as well as a cutting insert (e.g., a
milling insert),
used for chipforming and material removal operations wherein there is an
improved
delivery of coolant to the interface between the milling insert and the
workpiece (i.e.,
the insert-chip interface, which is the location on the workpiece where the
chip is
generated).
[0007] In a milling operation, the chip generated from the workpiece can
sometimes stick (e.g., through welding) to the surface of the cutting insert
(e.g., a
milling insert). The build up of chip material on the cutting insert in this
fashion is
an undesirable occurrence that can negatively impact upon the performance of
the
cutting insert, and hence, the overall material removal operation.
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[0008] Thus, it would be highly desirable to provide a cutting assembly (e.g.,
a milling cutter assembly), as well as a cutting inert (e.g., a milling
insert), used for
chipforming and material removal operations wherein there is enhanced delivery
of
coolant to the insert-chip interface so as to result in enhanced lubrication
at the
insert-chip interface. The consequence of enhanced lubrication at the insert-
chip
interface is a decrease in the tendency of the chip to stick to the cutting
insert.
[0009] In a cutting operation such as, for example, a milling operation, there
can occur instances in which the chips do not exit the region of the insert-
chip
interface when the chip sticks to the cutting insert. When a chip does not
exit the
region of the insert-chip interface, there is the potential that a chip can be
re-cut. It is
undesirable for the milling insert to re-cut a chip already removed from the
workpiece. A flow of coolant to the insert-chip interface will facilitate the
evacuation of chips from the insert-chip interface thereby minimizing the
potential
that a chip will be re-cut.
[0010] Hence, it would be highly desirable to provide a cutting assembly
(e.g., a milling cutter assembly), as well as a cutting inert (e.g., a milling
insert), used
for chipforming and material removal operations wherein there is enhanced
delivery
of coolant to the insert-chip interface so as to reduce the potential that a
chip will be
re-cut. The consequence of enhanced flow of coolant to the insert-chip
interface is
better evacuation of chips from the vicinity of the interface with a
consequent
reduction in the potential to re-cut a chip.
SUMMARY OF THE INVENTION
[0011] In one form thereof, the invention is a cutting insert for use in
chipforming and material removal from a workpiece wherein coolant is supplied
to
the cutting insert from a coolant source. The cutting insert includes at least
one
discrete cutting location and at least one distinct internal channel that
corresponds to
the cutting location. The internal channel has an inlet to receive coolant and
an
outlet to exit coolant. The outlet is proximate to the cutting location, and
the inlet is
radial inward of the outlet.
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[0012] In another form thereof, the invention is a cutting insert for use in
chipforming and material removal from a workpiece wherein coolant is supplied
to
the cutting insert from a coolant source. The cutting insert includes a
cutting insert
body that presents a plurality of discrete cutting locations. The cutting
insert body
contains a plurality of discrete depressions corresponding to one of the
cutting
locations and extending toward its corresponding one of the cutting locations.
There
is a diverter plate that has a central body with a top face and a bottom face,
and a
plurality of tapered flanges. The diverter plate is affixed to the cutting
insert body
wherein each one of the tapered flanges is received within a corresponding one
of
the discrete depressions so that each one of the discrete depressions and its
corresponding one of the tapered flanges and a portion of the central body
define one
of a plurality of discrete internal channels. Each one of the discrete
internal channels
corresponds to one of the cutting locations. Each one of the internal channels
has an
outlet to exit coolant being proximate to the corresponding cutting location
and an
inlet to receive coolant being radial inward of the outlet.
[0013] In yet another form thereof, the invention is a cutting insert for use
in
chipforming and material removal from a workpiece wherein coolant is supplied
to
the cutting insert from a coolant source. The cutting insert includes a
cutting insert
body that presents at least one discrete cutting location. The cutting insert
body
contains at least one discrete depression that corresponds to the cutting
location and
extends toward the corresponding cutting location. There is a diverter plate
that has
a central body with a top face and a bottom face, and at least one tapered
flange. The
diverter plate is affixed to the cutting insert body wherein the tapered
flange is
received within the discrete depression so that the discrete depression and
the
corresponding tapered flange and a portion of the central body define at least
one
discrete internal channel that corresponds to the cutting location. The
internal
channel has an outlet to exit coolant that is proximate to the corresponding
cutting
location and an inlet to receive coolant being radial inward of the outlet.
[0014] In still another form thereof, the invention is a cutting insert for
use in
chipforming and material removal from a workpiece wherein coolant is supplied
to
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the cutting insert from a coolant source. The cutting insert includes a
mediate
cutting insert body that defines a peripheral flank surface and a peripheral
portion of
opposite rake surfaces wherein the peripheral flank surface intersects the
peripheral
portion of the opposite rake surfaces to form discrete cutting locations.
There is a
pair of rake plates attached to the mediate cutting insert body wherein each
one of
the rake plates defines in part its corresponding one of the rake surfaces.
The
mediate cutting insert body and the rake plates together define a first group
of a
plurality of discrete internal channels and a second group of a plurality of
discrete
internal channels. Each one of the first group of discrete internal channels
corresponds to one of the cutting locations at the intersection of one of the
rake
surfaces and the peripheral flank surface. Each one of the second group of
discrete
internal channels corresponds to one of the cutting locations at the
intersection of
other of the rake surfaces and the peripheral flank surface. Each one of the
first
group of the discrete internal channels has an inlet opening at the other of
the rake
surface and an outlet opening at the one rake surface adjacent to its
corresponding
cutting location. Each one of the second group of the discrete internal
channels has
an inlet opening at the one of the rake surface and an outlet opening at the
other rake
surface adjacent to its corresponding cutting location.
[00151 In still another form thereof, a milling cutter for use in chipforming
and material removal from a workpiece wherein coolant is supplied to the
milling
cutter from a coolant source. The milling cutter includes a milling cutter
body that
contains a coolant reservoir and a pocket that has a pocket opening in
communication with the coolant source. The milling cutter body contains a
fluid
passageway that provides fluid communication between the coolant reservoir and
the
pocket. There is a cutting insert that includes at least one discrete cutting
location
and at least one distinct internal channel that corresponds to the cutting
location.
The internal channel has an inlet to receive coolant and an outlet to exit
coolant
wherein the outlet is proximate to the cutting location and the inlet is
radial inward
of the outlet.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The following is a brief description of the drawings that form a part
of this patent application:
[0017] FIG. 1 is an isometric view of a specific embodiment of the milling
cutter assembly of the invention wherein the milling cutter body presents
pockets
spaced about the circumference thereof, and wherein some of the pockets are
shown
being empty (i.e., without a milling insert assembly therein), and two of the
pockets
are show as containing a milling insert assembly with the flow of coolant
shown by
arrows;
[0018] FIG. 2 is an isometric side view of one pocket contained in the
cutting rim of the milling cutter body showing the leading concave surface and
the
seating section, and wherein the pocket is illustrated in the environment of
the
milling cutter body shown in phantom;
[0019] FIG. 3 is an isometric view of the milling cutter assembly of FIG. 1
showing the milling cutter body with the reservoir cap and the retention knob
exploded away from the milling insert body to expose the central coolant
reservoir,
and wherein the flow of coolant is illustrated by arrows;
[0020] FIG. 4 is a side view of the lock screw of FIG. 3 with a portion
thereof cut away to show the central bore and auxiliary inclined bores
thereof, and
wherein the flow of coolant is shown by arrows;
[0021] FIG. 5 is a top view of the reservoir cap of FIG. 3;
[0022] FIG. 6 is a cross-sectional view of the reservoir cap taken along
section line 5-5 of FIG. 5;
[0023] FIG. 7 is an isometric view of the milling insert with the plate
exploded away from the milling insert body;
[0024] FIG. 8 is a plan view showing the rake surface of the milling insert
body that contains the discrete depressions therein;
[0025] FIG. 9 is a cross-sectional view of the milling insert body of FIG. 8
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taken along section line 9-9;
[0026] FIG. 10 is a plan view showing the top surface of the plate;
[0027] FIG. 11 is a cross-sectional view of the plate of FIG. 10 taken along
section line 11-11;
[0028] FIG. 12 is an isometric view of the plate showing the bottom surface
of the plate;
[0029] FIG. 13 is an isometric view of the milling insert assembly of FIG. 1
showing the bottom surface of the milling insert;
[0030] FIG. 14 is a cross-sectional view of the milling insert of FIG. 14
taken along section line 14-14 of FIG. 14;
[0031] FIG. 15 is an isometric view of the specific embodiment of the
milling insert assembly of FIG. 1 wherein the clamp, the milling insert body,
the
plate and the shim are exploded apart from one another;
[0032] FIG. 16 is an isometric view of a second specific embodiment of the
milling insert assembly wherein the top rake plate and bottom rake plate are
exploded apart from the milling insert body;
[0033] FIG. 16A is an isometric view of the top rake plate of FIG. 16;
[0034] FIG. 17 is a cross-sectional view of the milling insert assembly of
FIG. 14, when in an assembled condition;
[0035] FIG. 18 is an isometric view of a specific embodiment of a shim used
in conjunction with the milling insert of FIG. 7;
[0036] FIG. 19 is an isometric view of another specific embodiment of a
milling insert wherein the rake plate is exploded away from the milling insert
body;
[0037] FIG. 20 is an isometric view of the specific embodiment of FIG. 19
showing the bottom surface and the peripheral flank surface of the milling
insert;
[0038] FIG. 21 is a cross-sectional view of the milling insert of FIG. 19 with
the rake plate assembled to the milling insert body;
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[0039] FIG. 22 is a cross-sectional view of the milling insert of FIG. 19 with
the rake plate assembled to the milling insert body;
[0040] FIG. 23 is an isometric view of another specific embodiment of a
milling cutter assembly showing the milling insert of FIGS. 19-22 exploded
away
from the pocket of the milling cutter body;
[0041] FIG. 24 is an isometric view of the specific embodiment of the
milling cutter assembly of FIG. 23 wherein the milling cutter body is rotated
so that
the bottom surface of he milling inert is visible;
[0042] FIG. 25 is an isometric view of a portion of the milling cutter body of
still another specific embodiment of a milling cutter assembly wherein a shim
is not
necessary, and the milling insert has been removed from the pocket; and
[0043] FIG. 26 is another isometric view of the pocket of the milling cutter
body of FIG. 25.
DETAILED DESCRIPTION
[0044] Referring to the drawings, FIG. 1 illustrates a specific embodiment of
the milling cutter assembly of the invention generally designated as 40
wherein the
milling cutter assembly 40 is for use in chipforming and material removal
operations. In such an operation, the material is removed from a workpiece. In
operation, the milling cutter assembly 40 rotates in the direction indicated
by the
arrow "R".
[0045] Milling cutter assembly 40 includes a generally cylindrical milling
cutter body generally designated as 42 that has a cutting rim 44 with a
peripheral
surface 46. Milling cutter 40 further includes a depending integral collar 48
that
depends downward (as viewed in FIG. 1) from the cutting rim 44. In this
specific
embodiment, milling cutter assembly 40 further contains a plurality of spaced-
apart
pockets generally designated as 52 in the peripheral surface 46 of the cutting
rim 44.
As will be described in more detail hereinafter, each pocket 52 receives and
securely
retains a milling insert assembly therein.
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[00461 It should be appreciated that the milling cutter body 42 may contain a
number of pockets different from that shown in this specific embodiment.
Further, it
should also be appreciated that the spacing between the pockets may be
different
from that disclosed herein. In this regard, the number and position of the
pockets
can vary depending upon the specific application for the milling cutter
assembly.
Applicants do not intend to limit the scope of the invention to the specific
geometry
of the milling cutter body and orientation of the pockets therein such as
those shown
in the drawings herein.
[00471 Each pocket 52 has a leading concave surface 54 and a seating section
(see bracket 60 in FIGS. 1 and 2) that is contiguous with and trails the
leading
concave surface 54. A transition region 58 provides a transition between the
concave surface 54 and the seating section 60. In the context of this
invention, the
terms "leading" and "trailing" (as well as like related terms) refer to the
relative
position of the structural aspects of the pocket and the milling insert
assembly in
reference to the operation of the milling cutter assembly. For example, in
reference
to the same component, a portion there of that is "leading" is rotationally
ahead of a
portion thereof that is "trailing" during the operation of the milling cutter
assembly.
The use of these relative terms is not intended to be restrictive of the scope
of the
invention, but only to define the various features of the structure relative
to one
another.
[00481 The seating section 60 includes a seating surface 62 at the trailing
end
of the seating section 60. Seating surface 62 has a radial disposition and an
axial
disposition. Seating surface 62 has a top edge 64 and a bottom edge 66. The
milling
cutter body 42 contains a closed threaded bore 68 that has a termination in
the
seating surface 62. The threaded bore 68 receives a threaded fastener as
described
hereinafter. The use of the terms "top" and "bottom" and the like are in
reference to
the relative orientation of the structural components as shown in the position
as
illustrated in FIG. 1. The use of these relative terms is not intended to be
restrictive
of the scope of the invention, but only to define the various features of the
structure
relative to one another.
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[0049] Seating section 60 further contains a trailing inclined seating surface
74 that joins the seating surface 62. The milling cutter body 42 contains a
coolant
passage 76 that opens at the trailing inclined seating surface 74 as shown by
an
opening 77. The opening 77 is offset from the geometric center of the seating
surface 62 so as to register (or be in alignment) with a selected lobe of the
central
coolant passage of the milling insert depending upon the position of the
milling
insert in the pocket. This aspect of the invention will be described in more
detail
hereinafter.
[0050] The coolant passage 76 provides a conduit for the flow of coolant to
the milling insert contained in the pocket as will be described hereinafter.
The
seating section 60 also contains a leading inclined seating surface 80 that is
contiguous with the trailing inclined seating surface 74. When the milling
insert
assembly is retained within the pocket, the milling insert rests on (and is
supported
by) the leading inclined seating surface 80 and the shim rests on and is
supported by
the trailing inclined seating surface 74. It should be appreciated that the
leading
inclined seating surface 80 and the trailing inclined seating surface 74 have
a radial
disposition and an axial disposition.
[0051] The seating section 60 further includes a clamp seating surface 84
that is adjacent to the leading inclined seating surface 80. A shoulder 86
joins the
leading inclined seating surface 80 with the clamp seating surface 84. Another
shoulder 88 provides a transition between the clamp seating surface 84 and the
transition 58. The clamp seating surface 84, as well as the shoulders 86 and
88, have
a radial and an axial disposition. The milling cutter body 42 contains a
threaded
hole (or aperture) 90 that opens at the clamp seating surface 84. Threaded
hole 90 is
designed to receive a retention pin that passes through a clamp wherein the
clamp
assists to securely retain the shim and milling insert in the pocket.
[0052] As illustrated in FIG. 3, the milling cutter body 42 further includes a
central coolant (or fluid) reservoir 94 that is in communication with a
coolant source
designated in FIG. 3 as COOLANT SOURCE. The central coolant reservoir 94 is
defined (at least in part) by a central upstanding wall 96 which has an upward
(or has
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a generally vertical orientation as viewed in FIG. 3). The upstanding wall 96
extends upwardly from the bottom surface 98 of the milling cutter body 42
wherein
the bottom surface 98 also defines (in part) the central coolant reservoir 94.
The
central upstanding wall 96 has a top edge 100 as viewed in FIG. 3.
[0053] The central upstanding wall 96 contains a coolant passage 76 that
provide fluid communication between the coolant reservoir 94 and the pocket
52.
Each coolant passage 76 corresponds to a pocket 52 in that coolant is supplied
to the
corresponding pocket 52 through the corresponding coolant passage 76. Although
applicants do not intend to be restricted to coolant passages 76 of any
specific size or
internal geometry, applicants contemplate that the dimension and geometry of
each
coolant passage 76 are such to provide for adequate flow of coolant to the
corresponding pocket, and hence, to the corresponding milling insert retained
in the
pocket. Further, applicants contemplate that as opposed to being a single
coolant
passage, there may be a plurality (e.g., a pair) of coolant passages that
supply coolant
to each pocket from the central coolant reservoir.
[0054] As shown in FIGS. 3 and 4, the milling cutter assembly 40 further
contains a lock screw generally designated as 106. Lock screw 106 has a top
end
108 and a bottom end 110 as viewed in FIG. 4. Lock screw 106 has an enlarged
diameter section 112, which defines a shoulder 114, adjacent to the top end
108
thereof. An elongate integral cylindrical shank 116 projects from the enlarged
diameter section 112. The lock screw 106 contains a central longitudinal
hexagonal
bore 118 therein that travels through the length thereof.
[0055] The lock screw 106 further contains a plurality of radial inclined
bores 124 disposed at an angle to the longitudinal axis Z-Z of the lock screw
106.
Each one of the inclined bores 124 provides fluid communication between
central
bore 118 and the top circular corner 122 of the lock screw 106. These inclined
bores
124 provide additional passages through which coolant can travel from the
coolant
source to the coolant reservoir. As shown in FIGS. 3 and 4 by the arrows,
coolant
enters the hexagonal bore 118 at the bottom end 120 thereof and flows through
bore
118 so that the coolant exits the hexagonal bore 118 at the top end 122
thereof. The
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coolant also exits the central bore 118 via the inclined bores 124 as shown by
the
arrows. The coolant that exits the lock screw 106 (whether via the central
bore 118
or the inclined bores 124) then flows to enter the central coolant reservoir
94 as
illustrated by the arrows.
[0056] As illustrated in FIGS. 5 and 6, the milling cutter assembly 40 also
includes a reservoir cap generally designated as 126, which defines in part
the central
coolant reservoir 94. Reservoir cap 126 has a top surface 128 and a bottom
surface
130. The reservoir cap 126 contains a plurality of bolt holes 132, which are
located
in an equi-spaced fashion at the periphery of the reservoir cap 126. Each one
of the
bolt holes 132 is adapted to receive a bolt 134 (see FIG. 3) to affix the
reservoir cap
126 to the milling cutter body 42. The reservoir cap 126 further includes a
depending generally circular integral flange 136 that contains a plurality of
notches
138 wherein the notches 138 are equi-spaced about the circumference of the
flange
136.
[0057] Referring to FIG. 1, the milling cutter assembly 40 further includes a
plurality of milling insert (or cutting insert) assemblies wherein each one of
the
milling inserts is generally designated as 150. As is apparent from FIG. 1,
each one
of the pockets 52, and in particular the seating sections 60, receive and
retain a
milling insert assembly 150. The milling insert assembly 150 contains a number
of
components; namely, the milling insert (which can be more broadly considered
as a
cutting insert), the shim, the clamp and threaded members, which are described
in
more detail hereinafter. It should be appreciated that applicants contemplate
that the
term "cutting insert" is inclusive (without limitation) of milling inserts and
turning
inserts, as well as other styles and kinds of inserts used to engage the
workpiece and
remove material in a material removal operation such as, for example, a
chipforming
and material removal operation.
[0058] As mentioned above, the milling insert assembly 150 includes a shim
generally designated as 152. One specific embodiment of the shim 152 is
illustrated
in FIG. 15. Shim 152 presents a top surface 154, a bottom surface 156 and a
peripheral flank (or edge) surface 158. Shim 152 contains a pair of bores
therein.
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One of these bores is a fastener bore 160 that receives a threaded member 164
that
affixes the shim 152 and the milling insert to the milling cutter body 42 in a
fashion
known to those of ordinary skill in the relevant art. Shim 152 also presents
four
corners (162A, 162B, 162C, 162D) wherein corners 162B and 162C are sharp
corners and corners 162 A and 162D are flat corners defined by a flat surface.
[00591 The other bore 166 is a coolant bore in alignment with the pocket
opening 77 when the milling insert assembly 150 is affixed in the pocket 52.
As one
can appreciate from FIG. 18, the coolant bore 166 is offset from the geometric
center
of the top surface 154 of the shim 152. The nature of the offset of coolant
bore 166
is like that for opening 77 so that the coolant bore can register or align
with a
selected lobe of the central coolant passage of the milling insert depending
upon the
position of the milling insert in the pocket. As shown by the arrows in FIGS.
15 and
18, coolant flows from the coolant bore 166 bore 168 into the milling insert
as will
be described hereinafter.
100601 Referring to FIGS. 7 through 15, the milling insert assembly 150
includes a milling insert generally designated as 170. Milling insert 170 has
a
milling insert body 172 and a corresponding plate 174 wherein the plate 174
attaches
to the milling insert body 172 to form the milling insert 170.
[00611 The diverter plate 174 can be attached or affixed to the milling insert
body 172 in any one of a number of different ways. In this regard, these
components
(i.e., the milling insert body and the diverter plate) can be affixed together
by
adhesive or braze or the like. The milling insert body and the diverter plate
may be
sintered together to form a single milling insert. As still another
alternative, the
structure defined by the combination of the milling insert body and diverter
plate can
be formed as a monolithic body via a powder metallurgical technique that is
suitable
to make a body with an internal channel. In this regard, the following patent
documents are exemplary of powder metallurgical methods to make a body with
internal passages: U.S. Patent No. 4,881,431 to Bieneck for a Method of Making
a
Sintered Body having an Internal Channel, and U.S. Patent No. 6,860,172 to
Hecht
for a Method for Making a Powdered Metal Compact.
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[00621 The milling insert (including the milling insert body and the diverter
plate) may be made from one of any number of materials that are suitable for
use as
a cutting insert. The following materials are exemplary materials useful for a
cutting
insert: tool steels, cemented carbides, cermets or ceramics. The specific
materials
and combinations of materials depend upon the specific application for the
milling
insert. Applicants contemplate that the milling insert body and the diverter
plate
may be made from different materials.
[00631 In reference to tool steels, the following patent documents disclose
tool steels suitable for use as a cutting insert: U.S. Patent No. 4,276,085
for High
speed Steel, U.S. Patent No. 4,880,461 for Superhard high-speed tool steel,
and U.S.
Patent No. 5,252,119 for High Speed Tool Steel Produced by Sintered Powder and
Method of Producing the Same. In reference to cemented carbides, the following
patent documents disclose cemented carbides suitable for use as a cutting
insert:
U.S. Patent Application Publication No. US2006/0171837 Al for a Cemented
Carbide Body Containing Zirconium and Niobium and Method of Making the Same,
U.S. Reissue Patent No. 34,180 for Preferentially Binder Enriched Cemented
Carbide Bodies and Method of Manufacture, and U.s. Patent No. 5,955,186 for a
Coated Cutting Insert with A C Porosity Substrate Having Non-Stratified
Surface
Binder Enrichment. In reference to cermets, the following patent documents
disclose cermets suitable for use as a cutting insert: U.S. Patent No.
6,124,040 for
Composite and Process for the Production Thereof, and U.S. Patent No.
6,010,283
for a Cutting Insert of a Cermet Having a Co-Ni-Fe Binder. In reference to
ceramics,
the following patent documents disclose ceramics suitable for use as a cutting
insert:
U.S. Patent No. 5,024,976 for an Alumina-zirconia-silicon carbide-magnesia
Ceramic Cutting Tools, U.S. Patent o. 4,880,755 for a Sialon Cutting Tool
Composition, U.S. Patent No. 5,525,134 for a silicon Nitride Ceramic and
Cutting
Tool made Thereof, U.S. Patent No. 6,905,992 for a Ceramic Body Reinforced
with
Coarse Silicon Carbide Whiskers and Method for Making the Same, and U.S.
Patent
No. 7,094,717 for a SiAION Containing Ytterbium and Method of Making.
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[0064] Milling insert body 172 has a peripheral rake surface 178 that extends
about the periphery of the milling insert body 172, an opposite bottom surface
180,
and a peripheral flank surface 182. The peripheral rake surface 178 surrounds
a
plurality of discrete (generally concave) depressions (186, 188, 190, 192)
contained
in the milling insert body 172. Because each one of the discrete depressions
is
essentially alike, a description of discrete depression 186 will suffice for
the
description of the other discrete depressions (188, 190, 192). In this regard,
discrete
depression 186 has a radial inward boundary 196 and a radial outward boundary
198.
[0065] Milling insert body 172 further contains a central coolant passageway
200 in the bottom surface 180 thereof. Coolant passageway 200 has four equi-
spaced apart radial lobes (202, 204, 206, 208) wherein each lobe extends in a
radial
outward direction toward its corresponding cutting edge (or cutting location)
as
described hereinafter. Milling insert body 172 still further contains a
central
generally concave indention 212 that surrounds the central coolant passageway
200.
Central indention 212 defines four sealing surfaces (214, 216, 218, 220),
which have
an arcuate (or concave) surface, between adjacent discrete depressions. These
sealing surfaces extend from the central coolant passage 200 to the peripheral
rake
surface 178. More specifically, sealing surface 214 is between discrete
depression
186 and discrete depression 188, sealing surface 216 is between discrete
depression
188 and discrete depression 190, sealing surface 218 is between discrete
depression
190 and discrete depression 192, and sealing surface 220 is between discrete
depression 192 and discrete depression 186.
[0066] The sealing surfaces (214, 216, 218, 220) are locations where the
milling insert body and the diverter plate join. As will be described
hereinafter, in
the case of a two-piece (i.e., the milling insert body and the diverter plate)
milling
insert, these seals in the vicinity of the sealing surfaces may be formed via
secure
surface-to-surface contact in the case of a strong force (e.g., a clamping
force)
exerted against the milling insert to urge the diverter plate against the
milling insert
body. In the case where a single piece milling insert is formed by joining
together
the milling insert body and the diverter plate, the seal in the vicinity of
the sealing
CA 02750361 2011-08-24
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surfaces could be formed due to the joinder, such as, for example, by
sintering or
brazing, of the components together along the adjacent surface areas. The same
is
true in the case of where the components are joined along adjacent surface
areas by
adhesive or the like. In the case where the milling insert is a monolithic
body, the
discrete internal channels (which could have a geometry like that of the
interior
channels formed via the assembly of the milling insert body and the diverter
plate)
would be formed by as internal channels in the interior of the part during
formation
wherein the volume of material in the vicinity of the sealing surfaces would
function
as barriers to define the discrete internal channels.
[00671 A specific lobe of the central coolant passageway 200 intersects each
one of the discrete depressions. In this regard, lobe 202 intersects discrete
depression 186, lobe 204 intersects discrete depression 188, lobe 206
intersects
discrete depression 190, and lobe 208 intersects discrete depression 192. In
reference to discrete depression 186, which has application to the other
discrete
depressions, there is a boundary 224 at the intersection between the discrete
depression 186 and the lobe 202 of the central coolant passageway 200.
[00681 Milling insert body 172 presents four cutting edges (228, 230, 232,
234) at the juncture between the peripheral flank surface 182 and the
peripheral rake
surface 178. When in operation, the milling insert has an orientation such
that one
of the cutting edge (i.e., a selected one of the cutting edges) engages the
workpiece
so as to perform a chipforming and material removal operation. The vicinity
where
the cutting edge engages the workpiece can be considered to be the cutting
location.
[00691 As mentioned above, milling insert 170 further includes a diverter
plate 174. Diverter plate 174 has a central body 240 that presents a generally
frusto-
conical shape. Central body 240 further has a top face 242 and a bottom face
244.
Four tapered flanges (246, 248, 250, 252) extend in a radial outward direction
from
near the bottom face 244 of the diverter plate 174. Since each one of the
tapered
flanges (246, 248, 250, 252) is alike, a description of tapered flange 246
will suffice
for a description of the other tapered flanges. Tapered flange 246 has an
inclined top
surface 256 disposed at an included angle "C" with respect to the top surface
242 as
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shown in FIG. 11. Tapered flange 246 has an inclined bottom surface 258
disposed
at an included angle "D" with respect to the top surface 242 as shown in FIG.
11.
Inclined top surface 256 and inclined bottom surface 258 intersect to define a
peripheral edge 260.
[00701 In this specific embodiment, the complete milling insert 170 is
formed by the assembling together of the milling insert body 172 and the
diverter
plate 174. As mentioned above, the milling insert body 172 and the diverter
plate
174 can be affixed together by any one of a number of techniques. In addition,
it
should be appreciated that the milling insert body may be made from one
material
and the diverter plate made from another material. In other words, the milling
insert
body and the diverter plate can be made from different materials. By making
the
milling insert body and diverter plate from different materials, in certain
instances an
advantage can be gained over an assembly (i.e., milling insert body and
diverter
plate) made from the same materials.
[00711 To assembly together these components, the central body 240 of the
diverter plate 174 is positioned within the cavity in the rake surface of the
milling
insert body, and the diverter plate 174 is firmly pushed against the milling
insert
body 172 so that there is close contact between the two components. Such close
surface-to-surface contact is shown in FIG. 14 wherein the sealing surface 214
and
its proximate surface area of the central body 240 (which is designated as
region 254
in FIG. 12 and 14) are in intimate contact.
[00721 When there is intimate close contact between the selected surface
areas of the diverter plate 174 and the milling insert body 172, a seal is
formed
between each one of the sealing surfaces (214, 216, 218, 220) and the
proximate
surface area of the central body portion 240 of the diverter plate 174. These
seals
help define each one of a plurality of discrete internal channels that are
essentially in
fluid isolation from one another. Each discrete internal channel is defined
between
the discrete depression, the corresponding tapered flange (of the diverter
plate) and
the proximate surface area of the central body portion of the diverter plate.
CA 02750361 2011-08-24
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[0073] It should be appreciated that in the case of a two-piece (i.e., the
milling insert body and the diverter plate) milling insert, these seals may be
formed
via secure surface-to-surface contact in the case of a strong force (e.g., a
clamping
force) exerted against the milling insert to urge the diverter plate against
the milling
insert body. In the case where a single piece milling insert is formed by
joining
together the milling insert body and the diverter plate, the seal could be
formed due
to the joinder, such as, for example, by sintering or brazing, of the
components
together along the adjacent surface areas. The same is true in the case of
where the
components are joined along adjacent surface areas by adhesive or the like.
Finally,
in the case where the milling insert is a monolithic body, the discrete
internal
channels (which could have a geometry like that of the interior channels
formed via
the assembly of the milling insert body and the diverter plate) would be
formed by as
internal channels in the interior of the part during formation.
[0074] In this specific embodiment, there are four discrete internal channels
wherein FG. 14 shows a representative one of these internal channels
designated as
266. Since the internal channels present essentially the same geometry, the
following description of internal channel 266 will suffice for a description
of the
other internal channels. Discrete internal channel 266 has an inlet 268 (see
FIG. 13)
that opens adjacent to the bottom surface 180 (of the milling insert body 172)
and
the bottom face 244 of the diverter plate 174. Inlet 268 is offset in the
radial
outward direction from the central axis H-H of the milling insert 170. As can
be
seen in FIG. 13, each one of the inlets of the other internal channels is
offset from
the central axis H-H.
[0075] Internal channel 266 has an outlet 270 for the exit of coolant as
shown by the arrows in FIG. 14. Each one of the outlets 270 opens adjacent to
the
peripheral rake surface 178 and the corresponding tapered flange that extends
from
the diverter plate. Each internal channel corresponds to a cutting edge so
that when
the internal channel is in fluid communication with the coolant source, the
internal
channel will provide for the flow of coolant toward the corresponding cutting
edge.
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As shown in FIG. 14 the coolant exits the internal channel in the form of a
fan-
shaped spray (see arrows in FIG. 14).
[0076] Milling insert assembly 150 further contains a clamp 280 that
contains an aperture 282 and a peripheral surface 284. The aperture 282 is
designed
to receive a threaded member to affix the clamp 280 to the clamp seating
surface 84
wherein the threaded member passes through the aperture and engages the
threaded
hole 90 in the clamp seating surface 84.
[0077] The milling insert assembly 150 is affixed in the pocket 52 of the
milling cutter assembly 40 in such a fashion that the shim 152 is secured to
the
seating surface 62 via a threaded member that passes through fastener bore 160
and
engages threads in the threaded bore 68. The bottom surface 156 of the shim
152
presses firmly against the seating surface 62. Shim 152 has an orientation
such that
the coolant bore 166 is in alignment with the opening 77 (and coolant passage
76).
[0078] Milling insert 170 is positioned within the pocket 52 so that the
bottom surface 180 thereof is securely against the top surface 154 of the shim
152.
The milling insert 170 has an orientation so that a selected one of the lobes
(202,
204, 206, 208) of the central coolant passage 200 is in alignment with the
coolant
bore 166 in the shim 152. The milling insert 170 is in fluid communication
with the
coolant source via the coolant passage 76 and the central coolant reservoir 94
whereby coolant may flow into the milling insert 170. Then, coolant flows
through
the milling insert 170 via the discrete internal channel that corresponds to
the lobe
aligned with the coolant passage 166.
[00791 When in the orientation illustrated by FIGS. 13 through 15, coolant
from the coolant source passes through the milling cutter body 42 in that it
flows via
the passages (118, 124) in the lock screw 106 into the central coolant
reservoir 94.
Coolant passes out of the coolant reservoir 94 via the coolant passages 76 and
through the coolant bore 166 through the inlet 268 into the discrete internal
channel
266 that corresponds to lobe 206, which is the lobe aligned with the coolant
passage
166. Coolant travels through the discrete internal channel 266, and then exits
the
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internal channel 266 at the outlet 270 thereof. Coolant exits along the length
defined
by a portion of the peripheral edge of the corresponding flange 250 of the
diverter
plate 174 (see the arrows adjacent to flange 250 in FIG.14). The coolant exits
in
such a fashion so as to comprise a direct spray on the corresponding cutting
edge
232, and thus, there is provided a flow of coolant directly to the vicinity of
the
engagement of the cutting edge with the workpiece.
[0080] As can be appreciated, there will come a point during the milling
operation that the milling insert 170 will need to be indexed or repositioned
to
present a new cutting edge for engagement with the workpiece. In the case of
the
indexable milling insert, this means that the milling insert 170 will be
rotated in the
pocket 52 to present a new cutting edge. By rotating the milling insert 170 in
the
pocket 52, the coolant bore 166 in the shim 152 will be in alignment with a
different
discrete internal channel wherein this internal channel corresponds to the new
cutting edge. When in operation, coolant will be supplied in the vicinity
where the
new cutting edge engages the workpiece.
[0081] The fact that the coolant bore 166 of the shim 152 and the lobes of
the milling insert 170 are offset from the geometric centers of the shim and
the
bottom surface 180 of the milling insert 170, respectively, provides for the
feature
that a different discrete internal channel (which corresponds to the new
cutting edge)
receives coolant to supply to the new cutting edge in engagement with the
workpiece.
[0082] Referring to FIGS. 16 and 17, there is shown another specific
embodiment of a milling insert 290 that is illustrated as a multi-component
structure
in that there is a mediate milling insert body and a pair of opposite rake
plates that
can be affixed to the mediate milling insert body. The opposite rake plates
can be
attached or affixed to the mediate milling insert body in any one of a number
of
different ways. In this regard, these components can be affixed together by
adhesive
or braze or the like. The milling insert body and the diverter plate may be
sintered
together to form a single milling insert. As still another alternative, the
structure
defined by the combination of the milling insert body and rakes plates can be
formed
CA 02750361 2011-08-24
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as a monolithic body via a powder metallurgical technique that is suitable to
make a
body with an internal channel. The above-referred patent documents that are
exemplary of powder metallurgical methods to make a body with internal
passages
are applicable to this milling insert.
[00831 It should be appreciated that the mediate milling insert body may be
made from one material and one or both of the rake plates made from another
material. In other words, the milling insert body and either one or both rake
plates
can be made from different materials including each rake plate made from a
different
material. By making the milling insert body and the rake plates (one or both)
from
different materials, in certain instances an advantage can be gained over an
assembly
(i.e., milling insert body and one or both rake plates) made from the same
materials.
[00841 Milling insert 290 defines eight cutting edges that comprise four
cutting edges adjacent to one rake surface of the milling insert and four
cutting edges
adjacent to the other rake surface of the milling insert 290. Milling insert
290 also
contains discrete internal channels wherein each internal channel is
essentially in
fluid isolation from the other internal channel. These internal channels
comprise a
first set of four discrete internal channels wherein each one of these
channels of the
first set corresponds with one of the cutting edges adjacent to the one rake
surface.
These internal channels comprise a second set of four discrete internal
channels
wherein each one of these channels of the second set corresponds with one of
the
cutting edges adjacent to the other rake surface.
[00851 Milling insert 290 includes a mediate milling insert body 292. The
milling insert body 292 has a peripheral flank surface 294, as well as
opposite faces
296 and 298. The mediate milling insert body 292 further presents a peripheral
portion of the rake surface 300 on one face 296 and another peripheral portion
of the
rake surface 302 on the other face 298. The intersection between the
peripheral
flank surface 294 and the peripheral portion of the rake surface 300 define
cutting
edges 304, 306, 308 and 310 wherein these cutting edges are adjacent to one
rake
surface of the milling insert. The intersection between the peripheral flank
surface
294 and the peripheral portion of the rake surface 302 define cutting edges
312, 314,
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316 and 318 wherein these cutting edges are adjacent to another rake surface
of the
milling insert.
[00861 Milling insert body 292 further contains a central aperture 320 that
passes completely through the milling insert body. Milling insert boy 292
further
contains a plurality of peripheral apertures that pass completely through the
milling
insert body 292 and are located adjacent to the periphery of the milling
insert body
292 wherein these apertures can be considered to comprise a first set of
apertures
and a second set of apertures. Referring to FIG. 17, the first set of
apertures
comprises apertures 322, 324, 326 and 328, and the second set of apertures
comprises apertures 332, 334, 336 and 338.
[00871 Milling insert 290 further includes one rake plate 342 that has an
exterior surface 344 and an interior surface 346. One rake plate 342 contains
a
central aperture 348, as well as a plurality of passages (350, 352, 354, 356)
located
adjacent to the periphery of the one rake plate. Each one of these passages
(350,
352, 354, 356) passes completely through the one rake plate 342. One rake
plate 342
further contains a plurality of troughs (360, 362, 364, 366) (see FIG. 16A)
wherein
each one of the troughs is adjacent to one of the apertures.
100881 Milling insert 290 further includes another rake plate 370 that has an
exterior surface 372 and an interior surface 374. The other rake plate 370
contains a
central aperture 376, as well as a plurality of passages (378, 380, 382, 384)
located
adjacent to the periphery of the one rake plate. Each one of these passages
(378,
380, 382, 384) passes completely through the other rake plate 370. Other rake
plate
370 further contains a plurality of troughs (388, 390, 392, 394) wherein each
one of
the troughs is adjacent to one of the apertures.
[00891 When the rake plates (342 and 370) are assembled to the mediate
milling insert body 292, there are formed a first set of discrete internal
channels
wherein a representative channel of the first set of discrete channels is
designated
400 in FIG. 17. The more detailed description of channel 400 will suffice for
such a
description of the other channels of the first set since they are essentially
the same.
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[0090] In reference to FIG. 17, internal channel 400 comprises peripheral
aperture 328, passage 384 contained in the other rake plate 370 and the trough
366
contained in the one rake plate 342. The exterior opening for passage 384
functions
as an inlet for the internal channel 400 through which coolant enters from the
coolant source when the internal channel 400 is in fluid communication with
the
coolant source. When in this condition, coolant flows through passage 384 and
peripheral aperture 328 and into trough 366 where it is directed over the
notches 286
and away from the milling insert toward the vicinity of the cutting edge 310.
It can
thus be seen that internal channel 400 provides a pathway for coolant to flow
so as to
provide a direct spray of coolant in the vicinity of the corresponding cutting
edge.
[0091] As can be appreciated, each one of the internal channels in the first
set of discrete internal channels has an inlet in the other rake plate 370 and
an outlet
in the one rake plate 342. Each one of the channels of the first set of
discrete
internal channels has a corresponding one of the cutting edges (304, 306, 308,
310)
adjacent to the one face 296. Referring to FIGS. 16 and 16A, the four interior
channels of the first set of interior channels are described below.
[0092] The first one of the interior channels comprises passage 378 in the
other rake plate 370, the peripheral aperture 322 in the mediate milling
insert body
and the trough 360 in the one rake plate 342. The first interior channel
correspond to
cutting edge 304. The second one of the interior channels comprises passage
380 in
the other rake plate 370, the peripheral aperture 324 in the mediate milling
insert
body and the trough 362 in the one rake plate 342. The second interior channel
corresponds to cutting edge 306. The third one of the interior channels
comprises
passage 382 in the other rake plate 370, the peripheral aperture 326 in the
mediate
milling insert body and the trough 364 in the one rake plate 342. The third
one of
the interior channels corresponds to cutting edge 308. The fourth one of the
interior
channels (which is illustrated as channel 400 in FIG. 17) comprises passage
384 in
the other rake plate 370, the peripheral aperture 328 in the mediate milling
insert
body and the trough 366 in the one rake plate 342. The fourth interior channel
correspond to cutting edge 310.
CA 02750361 2011-08-24
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[0093] When the rake plates (342 and 370) are assembled to the mediate
milling insert body 292, there is also formed a second set of discrete
internal
channels wherein a representative channel of the second set of discrete
channels is
designated 402 in FIG. 17. The more detailed description of channel 402 will
suffice
for such a description of the other channels of the second set since they are
essentially the same.
[0094] In reference to FIG. 17, internal channel 402 comprises peripheral
aperture 334, passage 352 contained in the one rake plate 342 and the trough
390
contained in the other rake plate 370. The exterior opening for passage 352
functions as an inlet for the internal channel 402 through which coolant
enters from
the coolant source when the internal channel 402 is in fluid communication
with the
coolant source. When in this condition, coolant flows through passage 352 and
peripheral aperture 328 and into trough 390 where it is directed over the
notches 286
and away from the milling insert toward the vicinity of the cutting edge 314.
It can
thus be seen that internal channel 402 provides a pathway for coolant to flow
so as to
provide a direct spray of coolant in the vicinity of the corresponding cutting
edge.
[0095] As can be appreciated, each one of the internal channels in the second
set of discrete internal channels has an inlet in the one rake plate 342 and
an outlet in
the other rake plate 370. Each one of the channels of the second set of
discrete
internal channels has a corresponding one of the cutting edges (312, 314, 316,
318)
adjacent to the other face 298. Referring to FIGS. 16 and 16A, the four
interior
channels of the second set of interior channels are described below.
[0096] The first one of the interior channels (of the second set of channels)
comprises passage 350 in the one rake plate 342, the peripheral aperture 332
in the
mediate milling insert body and the trough 388 in the other rake plate 370.
The first
interior channel corresponds to cutting edge 312. The second one of the
interior
channels (which is illustrated as internal channel 402 in FIG. 12) comprises
passage
352 in the one rake plate 342, the peripheral aperture 334 in the mediate
milling
insert body and the trough 390 in the other rake plate 370. The second
interior
channel corresponds to cutting edge 314. The third one of the interior
channels
CA 02750361 2011-08-24
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comprises passage 354 in the one rake plate 342, the peripheral aperture 336
in the
mediate milling insert body and the trough 392 in the other rake plate 370.
The third
one of the interior channels corresponds to cutting edge 316. The fourth one
of the
interior channels comprises passage 356 in the one rake plate 342, the
peripheral
aperture 338 in the mediate milling insert body and the trough 394 in the
other rake
plate 370. The fourth interior channel corresponds to cutting edge 318.
[00971 The above description shows that coolant is supplied to any one of
the cutting edges that is selected to be in engagement with the workpiece. In
this
regard, when affixed to the pocket of a milling cutter body such as generally
shown
in FIG. 1, a threaded member passes through the central aperture 320, as well
as a
central passage in an optional shim (not illustrated), so as to engage a
threaded bore
in the seating surface of a pocket that carries a milling insert assembly that
uses
milling insert 290. The seating surface of the pocket that is generally
parallel to the
rake plates contains an opening to a coolant passage that is, in turn, in
communication with the coolant source through the central coolant reservoir.
The
position on the seating surface of the opening to the coolant passage is such
that the
inlet to the internal channel corresponding to the selected (or engaged)
cutting edge
is in alignment with the opening to the coolant passage.
[00981 In operation, coolant is supplied through the internal channel to the
selectively engaged cutting edge. When it is necessary to present a new
cutting
edge, the milling insert is indexed to another position to present the new
cutting
edge. When in the new position, the internal channel that corresponds to the
new
cutting edge is now in alignment, and hence, fluid communication with the
opening
of the coolant passage. Thus, coolant is supplied to the new cutting edge that
is
engagement with the workpiece.
[00991 Referring to FIGS. 19 through 22, there is shown still another specific
embodiment of a milling insert generally designated as 410. Milling insert 410
has a
milling insert body 412 that presents a peripheral flank surface 414 and a
peripheral
rake surface 416. Milling insert body 412 defines cutting edges (418, 420,
422, 424)
CA 02750361 2011-08-24
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at the intersection between the peripheral flank surface 414 and the
peripheral rake
surface 416. Milling insert body 412 has a bottom surface 426.
[0100] Milling insert body 412 contains a central aperture 428 that passes
completely through the body. Milling insert body 412 contains a central cavity
430
that further contains troughs (432, 434, 436, 438). Milling insert body 412
contains
a coolant passage (440, 442, 444, 446) adjacent to each one of the troughs
(423, 434,
436, 438). A description of coolant passage 442 is sufficient for a
description of the
other coolant passages wherein coolant passage 442 has an inlet 448 and an
outlet
450. Coolant enters the passage through the inlet and exits the passage
through the
outlet.
[0101] Milling insert 410 further includes a milling rake plate 470. Milling
rake plate 470 has an exterior surface 472 and an interior surface 474, as
well as
contains a central aperture 476 therethrough.
[0102] Milling insert 410 affixes to the pocket of the milling cutter body in
a
fashion generally like that for milling insert 290 in that a threaded member
passes
through the central aperture to engage a threaded bore in the seating surface
of a
pocket that carries a milling insert assembly that uses the milling insert.
More
specifically, FIGS. 23 and 24 show a milling cutter assembly generally
designated as
480. Milling cutter assembly 480 includes a milling cutter body 482 that has
an
axial forward end 484 and an axial rearward end 486. There is a head portion
488 at
the axial forward end 484 ad a shank 490 depends from the head portion 488.
The
head portion 488 contains a pocket 494 that has a bottom seating surface 496
and a
pair of upstanding side seating surfaces 498 and 500. The head portion 488
contains
a threaded hole (or aperture) 502 that opens in the bottom seating surface 496
of the
pocket 494. The milling cutter body 482 contains a coolant passage 504 that
opens
at the bottom seating surface 496 of the pocket 494.
[0103] In reference to the attachment of the milling insert 410 to the milling
cutter body 482, the milling insert 410 is positioned in the pocket 494 so
that the
central apertures (428 and 476) of the milling insert body 412 and rake plate
470,
CA 02750361 2011-08-24
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respectively, are in alignment with the threaded hole 502. The screw 506 is
passed
through the central apertures (428 and 476) and into engagement with the
threaded
hole 502 whereby the screw 505 is tightened down to secure the milling insert
410 to
the milling cutter body 482.
[0104] It should be appreciated that the milling insert 410 is oriented in the
pocket 494 so that a selected one of the cutting edges is positioned to be in
engagement with the workpiece. In this regard and as shown in FIGS. 23-24, the
milling insert 410 is oriented so that cutting edge 420 is in position to
engage the
workpiece and the corresponding coolant passage 442 is in alignment with the
coolant passage 504 opening in the bottom seating surface 496. When in this
position, coolant passes into the milling insert 410 via coolant passage 442
and flows
through the milling insert 410 so as to exit in a spray adjacent to the
cutting edge
420.
[0105] In operation, the coolant passage that corresponds to the cutting edge
(420) selected to be in engagement with the workpiece is in alignment with the
opening to the coolant passage in the seating surface. Coolant is supplied to
the
engaged cutting edge through the coolant passage 442 in the milling insert.
When it
is necessary to present a new cutting edge, the milling insert is indexed to
another
position to present the new cutting edge. When in the new position, the
internal
channel that corresponds to the new cutting edge is now in alignment, and
hence,
fluid communication with the opening of the coolant passage. Thus, coolant is
supplied to the new cutting edge.
[0106] Referring to the structure in FIGS. 25-26, there is shown another
specific embodiment of a milling cutter body generally designated as 510.
Milling
cutter body 510 contains a plurality of pockets 514 at the periphery thereof.
Each
one of the pockets 514 has a side seating surface 516 and a bottom seating
surface
518. Each pocket 514 also has a leading surface 520. A clamp 522 is secured to
the
milling cutter body 510 at a point rotationally ahead of the pocket 514, but
close
enough to the pocket 514 to be able to bias against the surface of a milling
insert
retained within the pocket 514. The side seating surface 516 contains a cut
out
CA 02750361 2011-08-24
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portion 526 that surrounds the coolant passage 532 that opens at the side
seating
surface 516.
[0107] In reference to the attachment of the milling insert 170 in the pocket
514, the bottom surface 180 of the milling insert 170 is placed against the
side
seating surface 516 so that one of the lobes (202, 204, 206, 208) is in
alignment with
(or opens into) the volume defined by the cut out 526. The clamp 522 is
positioned
so that it acts against the milling insert 170 whereby upon being tightened,
the clamp
securely maintains the milling insert 170 in the pocket 514. Coolant passes
into the
milling insert 170 through the coolant passage 532 and the volume defined by
cut
out 526. Coolant then passes through the milling insert 170 as described
hereinabove, and exits in a spray adjacent to the selected cutting edge that
is in
engagement with the workpiece.
[0108] The milling cutter assembly has a number of advantages because it
provides coolant to the underneath side of the cutting edge at the interface
of the
cutting edge and the workpiece. As a result, the coolant provides for a
reduction of
the negative impact of the heat build-up at the milling insert-workpiece
interface. As
a further result, the presence of the coolant provides for an improvement in
the
lubrication at the milling insert-chip interface to avoid or reduce
accumulation of
workpiece material on the milling insert. In addition, the coolant stream
facilitates
the evacuation of the chips from the vicinity of the milling insert-chip
interface to
avoid re-cutting the chip.
[0109] For the specific embodiments shown herein, it an be seen that the
coolant exits at a location on the underneath side of the cutting edge at the
interface
of the cutting edge and the workpiece. As a result, the coolant provides for a
reduction of the negative impact of the heat build-up at the milling insert-
workpiece
interface. As a further result, the presence of the coolant provides for an
improvement in the lubrication at the milling insert-chip interface to avoid
or reduce
accumulation of workpiece material on the milling insert. In addition, the
coolant
stream facilitates the evacuation of the chips from the vicinity of the
milling insert-
chip interface to avoid re-cutting the chip.
CA 02750361 2011-08-24
-29-
[01101 It is apparent that the present invention provides a milling cutter, as
well as a milling insert, used for chipforming and material removal operations
wherein there is an improved delivery of coolant to the interface between the
milling
insert and the workpiece. A number of advantages exist as a result of the
improvement in the coolant delivery.
[0111] In this regard, the present invention provides a milling cutter, as
well
as a milling insert, used for chipforming and material removal operations
wherein
there is an improved delivery of coolant to the interface between the milling
insert
and the workpiece (i.e., the location on the workpiece where the chip is
generated).
As a result, the coolant provides for a reduction of the negative impact of
the heat
build-up at the milling insert-workpiece interface. As a further result, the
presence
of the coolant provides for an improvement in the lubrication at the milling
insert-
chip interface to avoid or reduce accumulation of workpiece material on the
milling
insert. In addition, the coolant stream facilitates the evacuation of the
chips from the
vicinity of the milling insert-chip interface to avoid re-cutting the chip.
[0112] The patents and other documents identified herein are hereby
incorporated by reference herein. Other embodiments of the invention will be
apparent to those skilled in the art from a consideration of the specification
or a
practice of the invention disclosed herein. It is intended that the
specification and
examples are illustrative only and are not intended to be limiting on the
scope of the
invention. The true scope and spirit of the invention is indicated by the
following
claims.
