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Патент USA US3058207

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Oct. 16, 1962
.1. M. KELLY ETAL
3,058,197
DIIIIE SHAVING WROUGHT COPPER AND ITS ALLOYS
Filed June 14, .1960v
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DIE RADIUS-R
WITNESSES
Fig. 3.
INVENTORS
James M. Kelly, Edward P. Kelly
and Herman H. Schmi?.
Mam
ATTORNEY
waited grates Fatent
fire
1
3,058,197
Patented Oct. 16, 1962
2
This indicated that the basic factors that contributed to
3,058,197
DIE SHAVENG ‘WRUUGHT COPPER AND ITS
ALLOYS
.larnes M. Keily, Tra?crd, Edward P. Kelly, Irwin, and
Herman H. Schmitt, Parker, Pa, assignors to Westing
the results were not fully understood, and that no con
sistent reliable results can be obtained as long as the meth
od of attack is one of trial and error.
The inventors have made exhaustive studies to get at
house Electric Corporation, East Pittsburgh, Pa, a
the basic factors involved to obtain consistent reliable re
corporation of Pennsylvania
Fiied June 14, 1960, Ser. No. 36,083
6 Qiaims. (Cl. 29-953)
shaving and shaving die design concerns itself with, (1)
sults.
Their studies reveal the basic key to successful
the radius on the cutting, or shaving, edge of the die, (2)
10 the relation of the hardness of the material to be shaved
This invention relates to apparatus and the technique,
to this radius, (3) the die clearance and the method of
or process, of shaving wrought metals, particularly copper
providing this clearance, (4) and the support and the
and its alloys.
alignment of the material to be shaved.
Wrought copper products used in the electrical indusa
In the drawings:
tries are, in general, formed to desired size and shaped by: 15
FIG. 1 shows a very much enlarged sectional view
of the cutting edge of the shave die;
(1) Casting wire bar;
FIG. 2 is a showing helpful in disclosing the cutting,
(2) Hot rolling; and
or shaving, edge of the shaving die;
(3) Cold rolling.
FIG. 3 shows a curve helpful in disclosing this inven
20 tion; and
Subsequently as a fourth step the ?nished product is
drawn through dies to dimension. Also certain modi
?cations of the mentioned procedures are known as ex
trusion instead of hot rolling.
FIG. 4 shows a longitudinal sectional view of a com~
plete shaving die.
FIG. 1 shows an insert AC of tool steel, tungsten
carbide, or other suitable hard and tough cutting material,
The mentioned procedures lend themselves to produc 25 in
the body of the die. The importance of the radius
tion line use and have for years produced reasonably
of curvature at the cutting edge cannot be overstressed
satisfactory copper products that have been accepted in
or overemphasized, because the proper grinding and form
the electrical industry and allied applications.
ing of this radius, its location in respect to the cutting
Recent trends in the electrical industry have raised the
edge CE and its physical size are important to successful
standard of acceptance and now a much improved 30 shaving operation.
Wrought copper product, particularly with reference to
FIG. 2, drawn to a smaller scale than FIG. 1, will per
surface ?nish, dimension, general appearance, and re
haps be helpful in disclosing the radius in question. Two
liability in use, must be provided.
lines x-—x and y—y are drawn as shown. The circle is
Further, new type insulations, new designs of electrical
added from the center 0, the intersection of the lines. The
apparatus, increased current loading per unit of weight 35 radius of this circle is chosen to be the radius giving the
and higher current ratings, demand wrought copper prod
best performance of the cutting tool, or die, in relation
ucts free from slivers, surface inclusions, copper dust,
to the hardness of the wrought copper to be shaved. In
rolled in and drawn oxides, and stain, etc., inherently
other words, this radius is R shown in FIG. 1 and the cut
common to a variable degree in most copper processed
ing
edge of the shave die is the point A, the intersection
by the techniques hereinabove mentioned.
40 between the circle and line x-—x.
One broad object of this invention is proper die shav
The physical size of this radius in inches has been
ing of the bars, rods, or wires of copper and its alloys and
found to be directly related to the hardness of the wrought
similar metals.
copper to be shaved. The curve shown in FIG. 3 shows
The process of die shaving is the removal of surface
this relation.
blemishes and material from one, or more, or all the sur 45
For unworked copper, that is, copper having no cold
faces of the wrought copper product thus yielding a prod
reduction and having a hardness of 40 as seen in FIG. 3,
uct of excellent surface ?nish, close dimensional tolerance
the length of the radius has to be .0302 of an inch and no
and high metal lustre. This is so because the very nature
greater ‘radius R will do. From FIG. 3, it is apparent that
of forming the bars and rods places the ‘blemishes in the
surface. Rolling or drawing through a die tends to in 50 the amount of cold reduction also determines the hardness.
To show this relation the percent cold reduction is shown
crease rather than decrease the surface blemish.
at the right and the hardness scale at the left. Unusually
It has been known for some time that the removal
the copper has received some cold reduction in area before
of the surface layer from a copper rod, or bar, would im
it
gets to the mill for shaving. In fact, this reduction in
prove its appearance, and reliability in use. Surface
area may be well over the 50%.
grinding had been tried but such a procedure is rather ex 55
Assuming that the reduction in area from the cold Work
pensive.
ing is 60%. This corresponds to a hardness number of
Die shaving has been tried in the past with some meas
100. The very best radius R for the cutting edge CE is one
ure of suceess, but never with a consistent reliable result.
At one time it was thought a blunt-nosed die for sur
of .0225 inch. This is, however, not too critical. What
FIG. 3 actually shows that in no case should the radius R
face shaving was desired. This type of die pushed and 60
be less than .02 of an inch nor more than .0302 of an inch.
rubbed the copper rod surface rather than shaved off a
Within this range there is thus some choice. The best
selected layer as was intended.
At other times a die with a sharp cutting edge was
used and still no consistent reliable results were obtained.
radius to use for a copper of a particular hardness is the
radius indicated by curve RC, but as long as the radius
falls within the range .02 of an inch and .0302 of an inch
3,053,197
3
coppers of a fairly wide range of hardness can be properly
We claim as our invention:
.
1. A cutting die for shaving a surface layer off of a
metal bar, a cutting edge on the die conforming generally
to the transverse peripheral shape of the said metal bar
that is to be shaved by moving said metal bar perpendic
shaved.
Now the die must also have a clearance so that no parts
of it act as a wire die, that is, a cold reduction die. From
FIG. 1 it will be apparent that the radius R emanates from
a center that is the same distance from the axis of the die
ularly toward the cutting edge of the die, said cutting edge
being shaped at the front thereof to a curvature deter
as the cutting edge CE, considering a die for a cylindrical
mined by a circle whose center lies less than .0302 of an
rod CR, is from the axis of the die. Or in other words
inch from the cutting edge and the radius of the center
it emanates from the surface of the shaved rod CR. From
the front of the cutting edge toward the rear, the die has 10 of the circle determining the curvature lies substantially
in the intersection line of the shaved surface of the metal
a small but increasing clearance C. This clearance, while
being shaved and a plane perpendicular to the shaved sur
not too critical, cannot be chosen at random, and for
face of the metal being shaved.
proper consistent results increases from Zero at the cutting
2. In a die for shaving a surface layer off of a metal
edge to from .025 of an inch per inch distance from the
bar, a cutting edge on the die conforming generally to
cutting edge toward the rear to .032 of an inch per inch
the transverse peripheral shape of the said metal bar that
distance toward the rear from the Cutting edge. This means
is to be shaved by moving said metal bar perpendicularly
the inner surface of a circular die is in the shape of a
toward the cutting edge of the die, said cutting edge being
frustum of a cone with the angle between the axis of the
shaped at the front thereof to a curvature determined by
cone and a straight line in the surface of the cone and
intersecting the axis, having an average angle of 1° 38', 20 a circle whose center lies less than .0302 of an inch from
the cutting edge and the radius of the center of the circle
and a range of about twelve minutes of an are above or
determining the curvature lies substantially in the inter
below this average angle.
section line of the shaved surface of the metal being
The die D has the annular cutting insert AC and the
curvature at region CU above, or removed, from the
cutting edge CE, is so shaped by suitable grinding to pro
shaved and a plane perpendicular to the shaved surface
25 of the metal being shaved, said die having an increasing
clearance from the cutting edge toward the rear between
the die and the material being shaved that increases per
inch distance toward the rear from the cutting edge no
vide a reverse curve for the proper breaking of the shaved
material into small chips, CH.
In operation the die, shown complete in axial section
less than a selected relatively small distance.
3. In a die for shaving a surface layer off of a metal
in FIG. 4, is rigidly mounted in a suitable wire, rod or
bar drawing machine and the part to be shaved, as cylin
drical rod CR is drawn through the die with the axis of
the rod in coincidence with the axis of the die.
The relationship the radius should have to the hardness
of the copper above described may be ampli?ed by con
bar, a cutting edge on the die conforming generally to
the transverse peripheral shape of the said metal bar that
is to be shaved by moving said metal bar perpendicularly
toward the cutting edge of the die, said cutting edge being
shaped at the front thereof to a curvature determined by
sideriug for soft copper, substantially unworked copper, 35 a circle Whose center lies less than .0302 of an inch from
the cutting edge and the radius of the center of the circle
determining the curvature lies substantially in the inter
Vickers Hardness Number__ 40
Radius
“0302:1323
For hard copper,
Vickers Hardness Number__ 120 z 6000
Radius
section line of the shaved surface of the metal being
40 shaved and a plane perpendicular to the shaved surface
— .020
of the metal being shaved, said die having an increasing
clearance from the cutting edge toward the rear between
the die and the material being shaved that increases from
no less than .025 of an inch to no more than .032 of an
Thus, it can be stated that, so long as the ratio of the
Vickers hardness number to the shaving die radius is 45 inch per inch distance from the cutting edge toward the
rear.
within the numerical range of 1323 to 6000 successful
shaving results are achieved.
4. In a die for shaving a surface layer off of a metal
Since :the radius is rather small and the insert AC is of
bar, a cutting edge on the die conforming generally to
extremely hard and tough material the radius is formed
the transverse shape of the said metal bar that is to be
by the use of diamond dust and a suitable lapping
shaved by moving said metal bar perpendicularly toward
technique.
the cutting edge of the die, said die being shaped at the
The technique hereinabove described is not limited to
the simple shape shown in FIG. 4, nor is the procedure
con?ned to basic copper. A variety of metals as alumi
front of the cutting edge to a curvature determined by a
circle whose center lies less than .0302 of an inch from
In practice bars, as rods and wires circular in transverse
section need shaving most frequently. Also often bars
having a transverse section that is either square, oval, or
rectangular need to be shaved. The invention is, of course, 60
shaved and a plane perpendicular to the shaved surface
of the metal being shaved, said die having an increasing
clearance from the cutting edge toward the rear between
the die and the material being shaved that increases per
the cutting edge and the radius of the center of the circle
num, nickel, etc., and their alloys could be processed in 55 determining the curvature lies substantially in the inter
section line of the shaved surface of the metal being
the manner herein disclosed.
not limited to a bar having a particular transverse section.
The die properly shaped at the cutting edge and the proper
clearance of the rear of the cutting edge, lends itself to
inch distance toward the rear from the cutting edge no
less than a distance of .025 of an inch.
5. An annular die for shaving a surface layer off of a
metal rod, said die having a front circular cutting edge
the shaving of one or more surfaces of bars that have
any one of the following transverse cross sections: 65 of a selected radial dimension with the inner surface being
that of a frustum of a cone with the portion with the
‘C-shaped, D-shaped, H-shaped, T-shaped, etc.
Extruded shapes where ?nish and dimension tolerance
is not su?iciently exacting are ideal applications for direct
larger diameter ?aring outwardly by a relatively small
angle, as from a fraction of a degree to no more than a
very few degrees, and the cutting edge in any longitudinal
subsequent shaving procedure. Soft coppers may, with
the die herein disclosed, be shaped to precision tolerance 70 sectional plane including the axis of the frustum of the
and provided with excellent surface finish without hot
cone has a curvature at the front away from the cutting
rolling, cold rolling and subsequent draw-anneal proce
that is determined by a radius no greater than .0302 of
an inch and Whose center, or rear end, falls at‘ a point
away from the axis of the cone a distance equal to the
dures.
’
All these suggested dies and alternate procedures fall
within the scope of this invention.
radius of the circular cutting edge.
3,058,197
5
6. A shaving die for shaving a surface layer of a
selected thickness 011° of the surface of a bar of metal,
said die having a cutting edge which at its front curves
away from the metal being shaved on a radius parallel
to the shaved metal surface and whose length may be 5
selectively varied from .020 of an inch for relatively hard
6
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,392,481
Kaplan et a1 ____________ __ Jan. 8, 1946
2,679,680
Hanks _______________ __ June 1, 1954
505,442
Great Britain _________ __ May 10, 1939
FOREIGN PATENTS
and well cold worked metal to .0302 of an inch for sub
stantially unworked metal, said die having a clearance
between the die and the shaved metal that may be selec
tively varied from .025 of an inch to .032 of an inch per 10
inch distance toward the rear from the cutting edge.
OTHER REFERENCES
American Machinist, pages 190-494, March 12, 1956.
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