Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to powder-compacting
apparatus and method and, more particularly, to an apparatus
and method producing compacted articles within very close
dimensional tolerances, with uniform density, and with sharp
edges. A particular application for which the present inven-
tion is specifically well suited is the production of index-
able throwaway cutting inserts for cutting tools, made of
powder metals and metal alloys which, after sintering,
requires very little grinding, if any, of the cutting edges
and tips.
The present invention is concerned with improved
tooling for use in powder-compacting presses such as are
disclosed in U.S. Patent Nos. 3,826,559, 3,775,032, 3,730,659,
3,726,622, 3,645,658, 3,574,892, 3,561,056, 3,516,142, 3,344,213
and 3,328,840, all of which are assigned to the same assignee
as the present application.
Moreover, the present application is an improvement
on the punch and die assemblies for compacting powder material
disclosed and claimed in U.S. Patent Nos. 3,775,043, 4,478,864,
4,061,452 and 4,061,563, all aæsigned to the same assignee as
the present application.
In the powder-compacting presses disclosed in the
aforementioned U.S. Patents, articles are compacted and formed
in a single- or multi-cavity die forming part of a punch and
die set, with the finished articles being automatically
ejected from the die cavities, picked up by a vacuum pick-up
head, and conveyed into suitable receptacles. A work station
positioner assembly, which is part of the press, is mounted
linearly or angularly movable transversely over the die plate.
The work station positioner carries a powder dispenser, an
l~Z6924
anvil and the pick-up head. The powder dispenser, which is
supplied with powder from a primary powder supply means
connected thereto by means of a flexible tubing or the like,
is first positioned over the die cavity or cavities which are
thus filled with powder as the punches are displaced downwardly
so as to draw a predetermined amount of powder into the die
cavity or cavities. The dispenser is then removed from above
the die cavity or cavities by the subsequent motion of the
station positioner assembly, and the anvil is, in turn,
positioned over the die cavities. The anvil is clamped over
the die cavity by means of a pivotable clamp supported above
the anvil and actuated in timed relation with the movement
of the punches. The anvil is held down with sufficient
pressure to permit the compaction of the powder against the
anvil as a result of an upward motion of the punches into the
die cavity or cavities. The anvil is then removed fror;~ its
position over the die cavity or cavities and is replaced by
the pick-up head as a result of a further linear or angular
motion of the work station positioner transversely across the
face of the die plate. The punches are displaced upwardly so
as to bring their upper ends in substantial flush alignment
with the upper surface of the die plate, such that the finished
compacted articles are e]ected from the die cavities and picked
up by the pick-up head. As the result of a return linear or
angular motion of the work station positioner to the initial
fill position, the pick-up head is removed from over the die
cavity and is disposed over one or, if a plurality of die
cavities are employed, a series of discharge apertures arranged
in a disposition similar to the arrangement of the die cavities
in the die plate, and the finished compacted article or
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articles are drawn, as by vacuum, through the discharge
aperture or apertures into a container or separate containers.
Alternatively, the compacted articles are drawn
directly into the pick-up head by suction and transported to
a remote discharge station by way of tubular conveyors through
which the compacted articles are propelled by suction, or a
flow of air, or a combination of both.
In Patent Nos. 3,775,032, 4,047,864, 4,061,452 and
4,061,453, tooling arrangements for compacting articles from
powder material are described in which a mold cavity is defined
partly by the end face of an upper punch projecting through an
anvil element above the die cavity, partly by the die bore
wall and partly by the end face of the lower punch.
The present invention is an improvement on the
tooling arrangements disclosed and claimed in the aforesaid
patents which permits to obtain compacted articles, generally
of a prismatic or pyramidal shape and having remarkably sharp
edges. The forming of sharp edges is an advantageous feature
where such sharp edges are desirable, as is the case when
compacting powder metals and powder alloys for forming a
"green" cutting tool insert or bit which is subsequently
sintered to a solid mass of ultra-hard material.
The present invention accomplishes its objects by
providing a molding apparatus for compacting powder material
in a die or molding cavity having a bore in which is disposed
a reciprocably movable lower punch, and at least a pair of
coaxially disposed upper punches which are disposed movable
to a work position above the die bore from a position away
from the die bore. When disposed to their work position the
lower face of the center upper punch is displaced such as to
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be substantially flush with the surface of the die, while the
lower face of the peripheral upper punch abuts the surface of
the die. The end face of the central upper punch forms the
upper surface of the compacted article when the lower punch
is displaced upwardly to compact the powder material previously
placed in the die or mold cavity, and the peripheral upper
punch forms the upper surface of the article at its sharp
edges.
The many objects and advantages of the present
invention will become apparent to those skilled in the art
when the following description of an example of the best mode
contemplated for practicing the invention is read in conjunc-
tion with the accompanying drawing wherein:
Fig. 1 is a perspective view of an example of
compacted article, such as an indexable throwaway cutting
bit for a cutting tool, produced by the tooling arrangement
for powder-compacting press of the present invention;
Fig. 2 is a broken sectional view of an example of
apparatus for compacting the article of Fig. 1, with the
respective elements shown in their relative position at the
end of a compacting cycle;
Fig. 3 is a transverse section through line 3-3 of
Fig. 2;
Fig. 4 is a partial transverse section through
line 4-4 of Fig. 2;
Fig. 5 is a partial transverse section through
line 5-5 of Fig. 2;
Fig. 6 is a partial view thereof showing the relative
position of the lowerpunch in the die bore prior to compacting
the powder material disposed in the die cavity.
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Fig. 7 is a view similar to Fig. 6, but showing
the upper punch assembly placed over the die cavity prior
to the compacting step;
Fig. 8 is a view showing a portion of the structure
of Fig. 7 at the end of a compaction cycle, as also represented
at Fig. 2;
Fig. 8a illustrates a portion of the structure of
Fig. 7 shown in the same position at an enlarged scale;
Fig. 9 is a view similar to Fig. 7 and showing the
relative position of the diverse elements of the invention
after the article compaction step; and
Fig. 10 is a view illustrating the e~ection of the
compacted article from the die cavity.
The present invention is particularly well suited
for forming articles compacted of powder material, having a
prismatic, prismatoidal, wedge, frusto-conical or frusto-
pyramidal shape, more particularly where it is desired to
provide the article with a sharp peripheral edge. An example
of such article is illustrated at Fig. 1 which represents a
"green" indexable throwaway cutting insert 10 made for
example of tungsten carbide or carbides powder, particles or
other refractory metal carbides, nitrides, or the like, mixed
with a small quantity of softer metal particles and a binder,
compacted to an appropriate shape, such as the triangular
shape illustrated. After being formed to an appropriate
shape, for example to the shape illustrated, the relatively
fragile "green" cutting insert 10 is sintered at an appropriate
high temperature. Sintering causes the binder to evaporate,
carbonize and/or combine with the relatively low melting soft
metallic particles which are melted at the temperature of
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sintering such as to form an ultra-hard block of metallic
carbide particles or the like, structurally held together
by means of a lattice or matrix of the metallic cement
resulting from the melting of the fine particles of the
relatively low melting metal or metal alloy. The diverse
techniques and processes for obtaining ultra-hard metallic
alloy cemented cutting inserts are well known in the art,
and are not part of the present invention. Suffice it to
mention that after the "green" cutting inserts have been
sintered, and also generally quenched, with the sintering
operation causing considerable dimensional shrinkage, the
now-hard block o~ cemented carbide or the like is ground and
lapped to provide it with precise dimensions, a particular
shape and most importantly sharp cutting edges and tips.
The present invention presents the advantage of providing a
method and apparatus capable of obtaining "green" cutting
inserts, among other articles, which, after sintering, require
no or very little sharpening of the cutting edges and tips.
Referring once again to Fig. 1, the compacted
article 10 is an example of "green" cutting insert which,
due to its triangular shape, is provided with three indexable
sharp cutting tips 12 interconnected by sharp cutting edges
14, the upper surface 16 of the insert 10 being provided with
a continuous chip breaker groove 18 disposed proximate and
generally parallel to the cutting edges 14. A flat ledge 15
is disposed between the chip breaker groove 18 and the cutting
edges 14. The sidewalls 19 of the cutting insert 10 form
with the upper surface 16 and the flat ledge 15 an angle of
less than 90, thus defining a positive rake cutting insert
when mounted in a tool holder presenting a cutting tip 12 or
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a cutting edge 14 of the insert to a cylindrical workpiece
mounted in the chuck of a lathe with the plane of the top
surface 16 and of the ledge 15 of the cutting insert along
a diameter of the workpiece, as is also well known in the
metal cutting art.
In order to be effective as a metal cutting
implement, the insert cutting tips 12 and cutting edges 14
need be as sharp as possible, and this is accomplished
conventionally by finish grinding the top surface 16 and
ledge 15 and the side faces 19 of the insert, for the
insert 10 generally illustrated at Fig. 1. Sharp cutting
edges requiring no subsequent grinding or lapping are
generally impossible to achieve when cutting inserts are
compacted from powder materials by conventional techniques.
The present invention however by means of the structure
herein illustrated at Figs. 2-5 permits to achieve the
desirable results of compacting, among other articles,
cutting insert requiring no, or very little, grinding or
lapping as a finish manufacturing operation.
Referring now to Figs. 2-5, there is illustra-ted
an apparatus according to the present invention for molding
a generally pyramidal or prismatic article, such as the
"green" cutting insert ]0 of Fig. 1. The molding apparatus
comprises a die consisting of a die bushing 20 press-fitted,
cemented or otherwise disposed in a bore 22 in a die plate 24.
The die bushing 20 is preferably made of hard material, such
as tungsten carbide or the like, and the die plate 24,
although it may be made of a heat-treated tool steel, is
preferably also made of a carbide, and is provided with a
highly polished upper surface 25. Although the die plate 24
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may be made of a single thick plate, in the structure
illustrated at Fig. 2 the die plate 24 is shown as comprising
a block 26 of steel or tungsten carbide provided with a
blind bore 22 accepting the die bushing 20. The block 26
is in turn press-fitted or otherwise mounted in a recess 28
formed in a thick plate 30 mounted in the ~able ~ a p~w~e~-
compactin~ apparatus, not shown, of the type disclosed in
the aforementioned Letters Patent. In the structure illus-
trated, the upper surface of the thick plate 30 is provided
with a relatively thin plate 32 of highly polished hard
steel, tungsten carbide, or the like, fastened thereon by
any convenient means such as bolts or the like, not shown.
The die bushing 20 is provided with a bore 34 in
which is reciprocably disposed a lower punch 36 which is also
made preferably of an ultra-hard material such as tungsten
carbide, and which is reciprocable up and down in the die
bore 34 by means of a push rod 38, on the end of which it
is mounted, the push rod 38 being in turn connected to the
lower ram of the press~ not shown.
The die bore 34 has a peripheral shape conforming
to the peripheral shape of the lower punch 36 which, in the
example of structure illustrated, is in the form of an
equilateral triangle having rounded corners, the end face 40
of the lower punch 36 having an area corresponding to the
area of the lower face of the cutting insert 10 of Fig. 1.
The upper end of the die bore 36 is provided with tapered
walls 42, such as to form the tapered sidewalls 19 of the
frusto-pyramidal article or cutting insert 10 of Fig. 1,
the tapered walls 42 and the end face 40 of the punch 36
defining a die cavity 43.
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An upper punch anvil assembly 44 is disposed above
the die assembly 24, for controlled positioning over the die
cavity 43 and away from the die cavity 43 as operated by the
press mechanism in coordination with the motion of the lower
punch 36, during filling of the die cavity 43 with powder
material, compacting of the article 10 in the die cavity,
and ejection of the finished article from the die cavity.
For that purpose, the upper punch-anvil assembly 44 is
mounted in a work station positioner assembly, not shown,
in which are also mounted a powder dispenser and a pick-up
head, as disclosed and detailed in the aforementioned patents.
As also mentioned in the aforesaid patents, the work station
positioner assembly is linearly or arcuately movable by an
appropriate mechanism of the press apparatus such as to
sequentially place over the die cavity 43 the powder dispenser
for filling the die cavity with powder material, the punch-
anvil assembly 44 for compacting in the die cavity the powder
material to a finished article, and for replacing the punch-
anvil assembly 44 by a pick-up head or other ejection mechanism
during ejection of the finished article from the die cavi~y.
The work station positioner assembly, the powder dispenser
and the ejection mechanism are not represented in the drawing
for the sake of simplification, and as they are not necessary
for a proper understanding of the present invention.
Alternatively, the upper punch-anvil assembly 44 may be
mounted on the end of the upper ram of a powder-compacting
press of the type disclosed in U.S. Patent No. 4,061,453,
and in such arrangement, the woxk station positioner assembly
carries only the powder dispenser and the ejection mechanism,
the whole assembly 44 being removed from over the die cavity 43
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during the upstroke of the press upper ram. The latter
arrangement has been arbitrarily chosen in the representation
of Fig. 2, wherein the upper punch-anvil assembly 44 is
directly mounted on the end of the upper ram 46 of the press
apparatus.
The ram 46 is provided on its end with a shouldered
mounting plate 48 fastened thereon by any convenient means
such as screws, bolts or the like, not shown. The shouldered
mounting plate 48 has a circular periphery, and the assembly
44 is fastened to the end face of the mounting plate 48 by
means of a mounting ring 50 having a threaded bore 52 thread-
ably engaging the threaded periphery 54 of a retainer ring 56
having a stepped inner bore 58 engaging the stepped outer
surface 60 of the upper portion 62 of a cylindrical tubular
housing 64. The tubular housing 64 has a lower portion 66.
The lower portion 66 is fastened at its top to the bottom of
the upper portion 62 of the housing 64 by means of screws or
bolts, not shown, and is provided at its lower end face with
an annular plate 68 preferably made of hard steel or tungsten
carbide or the like, and having a highly polished face 70
engageable with the upper surface 25 of the die plate 24.
The annular plate 68, or shoe, is attached to the lower
surface of the lower portion 66 of the housing 64 by any
convenient means such as bolts or screws, not shown. The
housing 64 is made in two sections, 62 and 66, for convenience
of manufacturing and assembly.
A pair of concentric telescopic punches 72 and 74
are disposed slidably within the housing 64. The punch 72,
or outer punch, is circularly cylindrical and its peripheral
surface 76 slidably enages the wall of a reduced diameter bore
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portion 78 of the upper portion 62 of the housing 64. The
upper portion 62 of the housing 64 has an enlarged diameter
bore portion 80, such that an annular abutment surface 82 is
formed between the enlarged diameter bore portion 80 and the
reduced diameter bore portion 78. The outer punch 72 has
an enlarged diameter portion 84 freely disposed in the
enlarged diameter bore 80 of the housing upper portion 62,
and forming an annular abutment surface 86 engageable with
the annular abutment surface 82 in the housing for limiting,
in a downward direction, the displacement of the outer
punch 72 relative to the housing 64.
The per.iphery of the upper outer punch 72 being
circular for simplification of manufacturing, an anti-rotation
device 88 is provided for linearly guiding the outer punch 72
and preventing rotation around its longitudinal axis. The
anti-rotation device 88 comprises a steel or tungsten carbide
ball 90 placed in a radial bore 92 in the upper housing
portion 62. The outer end of the radial bore 92 is internally
threaded, as shown at 94, such as to accept a set screw 96,
preferably a dog point set screw, which, according to the
setting imparted on the set screw 96, urges the ball 90 with
more or less pressure into a longitudinal groove 98 formed
in the peripheral surface 76 of the outer punch 72.
The outer punch 72 has a longitudinal circularly
cylindrical bore 100 slidably receiving the inner punch 74
provided with a corresponding circularly cylindrical peripheral
surface 102. The upper end of the inner punch 74 is fastened
to the lower surface of a mounting pl.ate 104 by means of a
bolt 106 disposed in a countersunk bore 108 through the
mounting plate 104 and having a threaded end engaging a
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threaded longitudinal blind bore 110 disposed centrally at
the end of the inner punch 74, a relatively thick spacer
washer 112 being disposed between the upper end face of the
inner punch 74 and the lower surface 105 of the mounting
plate 104. The upper face 114 of the inner punch mounting
plate 104 engages the lower face of the mounting plate 48
on the end of the ram 46, and its lower face 105 engages the
upper face of the housing portion 62, when the assembly 44
is mounted on the end of the ram 48 and the mounting ring 50
is appropriately tightened.
A plurality of compressed Belleville springs 116
are disposed around the periphery of the spacer washer 112
and the periphery of the upper end of the inner punch 74, in
the annular space formed between such peripheries and the
enlarged inner diameter bore 80 of the upper housing portion
62. The Belleville springs 116 constantly urge the outer
punch 72 downwardly relative to the inner punch 74, the
amount of permissible motion of the outer punch 72 relative
to the inner punch 74 being determined by the di.stance
between the annular abutment 5urface 86 of the outer punch 72
and the annular abutment surface 82 separating the reduced
diameter bore 78 and the enlarged diameter bore 80 of the
housing upper portion 62. Annular shims, not shown, may
be disposed in that space 118 to adjust the amplitude of
such relative motion, and an appropriate thickness of annular
shims 120 is generally disposed between the lower Belleville
spring 116 and the upper end face of the outer punch 72 to
appropriately set to a desirable value the pressure exerted
by the Belleville springs 116 on the upper end face of the
outer punch 72.
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The inner punch 74 is preferably made of tungsten
carbide, or like material, and is provided proximate its
lower end with a generally triangularly shaped reduced
diameter portion 122, best shown at Figs. 3 and 4, to conform
with the shape of the article 10 compacted from powder
material by way of the apparatus of the invention. It will
be appreciated that when it is desired to compact from powder
material an article having a shape other than triangular,
the reduced diameter portion 122 of the inner punch 74 i5
provided with an appropriately conforming shape. The reduced
diameter portion 122 of the inner punch 74 has a generally
triangular end face 124, for forming the upper surface 16
of the article 10, Fig. 1, which is provided at its perimeter
with a continuous ridge 126 for forming the groove 18 of the
article 10.
The lower end 128 of the outer punch 72 is also
provided with a triangular shape on its periphery and carries
a similarly shaped plate 130 made of carbide or like material,
highly polished at its lower face 132, and provided at its
center with a tria.ngular bore 134 slidably accepting the
triangular end 122 of the inner punch 74. As the triangular
end 122 of the inner punch 74 is disposed in the triangular
bore 134 of the end plate 130, the inner punch 74 is
restrained against rotation around its longitudinal axis
relative to the outer punch 72 which in turn is restrained
against rotation by the anti-rotation device 88.
Although it is evident that the end plate 130
mounted at the lower end of the inner punch 74 need not have
a triangular periphery, with rounded corners, for the sake
of precision in dimensions and density and for the sake of
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precision in dimensions and density and for the sake of
applying even pressure on the upper surface 25 of the die 24,
it is preferable to have a shape for the end plate 130 which
corresponds to the shape of the die bore opening, to provide
equal areas of engagement between the lower surface 132 of
the plate 130 and the surface 25 of the die 24 to balance the
pressure applied to the die surface 25 around the die cavity
43.
Figs. 6-10 illustrate the relative positions of
the moving elements of the apparatus of the invention, at
successive steps from the filling of the die cavity 32 with
powder material 136, Fig. 6, to khe ejection from the die
cavity of the finished compacted article 10, Fig. 10. At
Fig. 6, the die cavity 43 is shown after filling with powder
material 136 from a primary dome-shaped powder hopper or
dispenser 138 placed in communication with a secondary powder
dispenser, not shown, by means of a flexible tubing 140. The
powder dispenser 138 is mounted on the press apparatus work
station positioner, not shown, as explained in detail in the
aforesaid patents, and is linearly or arcuat:e:Ly dlsplaceable
over the surface 25 of the die and die pla-te, to the position
over the die cavity 43 shown in phantom line in the drawing,
such as to fill the die cavity with the powder material 136.
When displaced away from the die cavity 43, the lower lip 142
of the dome-shaped powder dispenser l.38, whi.ch is constantly
in engagement with the surface 25 of the die and die plate,
leaves in the die cavity 32 a predetermined volume of powder
material 136 which is in part depending upon the position of
the end face 40 of the lower punch 36, the lip 142 of the
powder dispenser 138 evening the load of powder 136 in the die
~lZ~9Z4
cavity 43 to a level flush with the surface 25.
After the die cavity 43 has been filled with powder
136, and the powder dispenser 138 linearly or arcuately
displaced out of the way, the upper punch-anvil assembly 44
is in turn placed over the die cavity 43 as illustrated at
Fig. 7. In arrangement where the assembly 44 is mounted on
a work station positioner, the assembly 44 is linearly or
arcuately displaced with the lower surface 132 of the end
plate 130 of the outer punch 72 constantly in sliding engage-
ment with the upper surface 25 of the die and die plate,to a position corresponding to the position illustrated at
Fig. 7. In the example of structure illustrated however, the
assembly 24 being directly mounted on the end of the ram 46
of the press, as illustrated in detail at Fig. 2, is raised
out of the way by the ram 46 during filling of the die cavity
43 with powder, Fig. 6, and when the finished part, after
compaction, i5 ejected from the die cavity, Fig. 10. Appropri-
ate guiding columns, not shown, are used for supporting and
guiding the housing 64 of the assembly 44 during the recipro-
cating motion of the press ram, as particularly disclosed inU.S. Patent No. 3,826,599. Toward the end of the downward
stroke of the ram, the end plate 130 of the outer punch 72 is
the first to engage its lower face 132 with the die and die
plate surface 25, Fig. 7, because the Belleville springs 116
constantly urge the outer punch 72 downwardly, with the
annular shoulder surfaces 86 and 82 respectively of the outer
punch 72 and of the housing 64 in engagement with each other,
causing the lower surface 70 of the housing end plate 68 and
the end face 124 of the outer punch 74 to be substantially at
the same level and out of contact respectively with the upper
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surface 25 of the die and die plate and the level of the
powder material 136 in the die cavity 43.
As further shown at Fig. 7, the end of the bore 134
in the end plate 130 of the outer punch 72 is disposed over
the die cavity 43, and the end face 132 of the end plate 130
is engaged securely with the die and die plate surface 25
around the periphery of the die cavity opening as a result of
the further compression of the Belleville springs 116 when
the press ram continues its downward stroke. At the end of
the ram downward stroke, the lower surface 70 of the housing
end plate 68 has been advanced to also engage the die and
die plate surface 25, while simultaneously the end face 124
of the inner punch 74 has been advanced such as to engage the
level surface of the load of powder material 136 in the die
cavity 43, Fig. 8. Simultaneously therewith, the lower punch
36 is displaced upwardly such that, at the end of the compac-
tion stroke, the diverse elements occupy the position illus-
trated in detail at Fig. 2 and partially at Figs. 8 and 8a.
In that position, namely at the end of the compaction .step,
the lower surface 7t) of the housing end plate 68 is in Ei~m
engagement with the die and die plate surface 25, and the
lower surface 132 of the outer punch end plate 130 is also
in firm engagement with the surface 25. The inner upper
punch 74 remains stationary at the end oE its downward stroke
such that the upward stroke of the lower punch 36 compacts
the powder material 136 against the end face 124 of the inner
upper punch 77 which thus forms the upper face 16 of the
article or cutting insert 10, while the ribs 126 on the end
face 124 of the inner upper punch form the groove 18 in the
upper surface 16 of the article 10. As best shown in the
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enlarged view of Fig. 8a, the lower edge surface of the outer
upper punch end plate 130 which overlaps the opening of the
die cavity 43, identified by numeral 144 which was positioned
in that overlapping position over the opening of the die
cavity 43 prior to the compaction step, forms with the tapered
wall 42 of the die cavity 43 a very sharp edge 14 for the
article 10, and a smooth ledge 15 between the groove 18 and
the sharp edge 14. For forming an article 10 such as the
cutting insert of Fig. 1, the end face 40 of the lower punch
36 is preferably slightly convex, as also best shown at Fig.
8a, such that the lower face of the insert, even after
sintering, is slightly concave. This pxovides a more stable
seating of the cutting insert in the receiving pocket of a
tool holder, where the insert is supported by the pocket flat
bottom surface engaging the lower surface of the insert
proximate the outer edge thereof, thus giving the insert
maximum support directly below where most of the load is
applied to the insert, namely close to or directly below the
cutting edge 14 as feasible.
Fig. 9 represents the relative position o the
movable elements of the apparatus of the invention after the
article 10 has been compacted and the ram of the press appara-
tus has relieved the pressure applied on the mounting plate
104 of the upper punch assembly 44. The end plate 68 of the
housing 64 has been lifted from the die surface 25, and the
end face 124 of the inner punch 74 has simultaneously been
lifted from the upper face 16 of the article 10 as a result
of allowing the Belleville springs 116 to expand. However,
while the pulling away of the end face 68 of the housing 64
and of the end face 124 of the inner punch 74 was taking
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place, the lower face 132 of the end plate 130 of the outer
upper punch 72 remains in contact with the die and die plate
surface 25, thus continuing to hold the article 10 in the
die cavity 43 by engaging the marginal ledge 15 of the
article, while the end face 124 of the inner punch 74 and
the ridge 126 on the punch end face are disengaged respect-
ively from the top surface 16 and from within the groove 18
of the compacted article 10. In arrangement where the
housing 64 is mounted on a work station positioner, the whole
upper punch assembly 44 is then displaced away from over
the die cavity 43, with the lower surface 143 of the outer
punch end plate 130 remaining engaged with the die surface 25,
and in arrangement like the one illustrated in the drawing,
subsequent upstroke of the press ram lifts the whole assembly
44 away from over the die cavity 43.
The lower punch 36 is subsequently advanced
upwardly until its end face 40 is substantially flush with,
or slightly above, the die and die plate surface 25, as
illustrated at Fig. 10, to eject the article 10 Exom the
die cavity. The rake por-tion of an appropriate mechanical
ejection device, not shown, removes the article to a
receptacle or, alternatively, a vacuum pick-up head, not
shown, is placed over the die cavity to pick up the finished
compacted article 10, as explained in detail in the herein-
before referred to U.S. patents.
Although the present invention has been described
and illustrated as an apparatus and method specifically
adapted to compact from powder material a "green" cutting
insert for use in a cutting tool, such cutting insert having
a well-defined geometry, it will be readily apparent to
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1 1 Z~7~ ~
those skilled in the art that the principle and the structure
for practicing the present invention are directly adaptable
to a compacting '7green" cutting insert of any geometry differ-
ent from that disclosed herein for illustrative purpose only,
and for compacting articles of diverse powder materials,
metallic and non-metallic, and of diverse configurations,
where it is desired to provide the compacted article with
a sharp edge at the junction of two surfaces of said article.
Where it is desired to provide the compacted article with an
aperture extending from a surface to another surface of the
article, as is often the case for cutting inserts held in
a tool by means of a screw or eccentric pin, such an aperture
is formed in the article by means of an appropriate core rod
generally disposed concentric with the lower punch and
stationarily held in an adjustable fixed position, as also
disclosed in detail in the aforesaid U.S. patents.
In arrangements where, for example, the aperture
134 in the outer upper punch 72 end plate 130 is circular,
and the end portion 122 of the inner punch 74 is circularly
cylindrical, an anti-rotation dev:ice alike the anti-rotation
device 88 may be disposed through the wall of the outer
punch to prevent rotation of the inner punch relative to
the outer punch, or any other anti-rotation device may be
used such as a key and co-operating keyway.
In the appended claims, the term "punch" is used
to designate the lower punch and the terms "counterpunches"
are used to designate the upper punches.
Having thus described the invention by way of an
example of structural embodiment thereof, modification whereof
will be apparent to those skilled in the art, what is claimed
as new is as follows:
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