Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THE INVENTION
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~ his invention relates to a method ~or the preparatlon --
of multiple gauge metal strip by a shaving operation wherein
the strip workplece is drawn through the shavlng apparatus.
In many applications, such as the production of copper
strip ~or the formation o~ electrical connectors and the h~
likeg it is necessary to provide a multlple gauge thickness
in the metal strip. Hereto~ore, such conventional proced-
; ures as contlnuous mllling have been employed to produce
the desired variations in gauge. Such processes suffer
from the disadvantages of being time-consuming and generat-
~ - . .
ing an unfavorable form o~ scri~p.
Another procedure which has been investigated in the
ar~ comprises the reduction to gauge by a rolling opera-
~ tion. Rolling operatlons in production are unfavorably
iJ~ restricted to certain shapes, tend to involve complex and
costly tooling and are not good enough to prov~de products
meeting oommercial tolerances and that are free from
structural~de~ects.~
0~ The technique o~ shavlng as a form of metal reduction
has bee~n known ~Or~ BOme time, however its application
has~ been generally~limited to the finishing o~materials
;; of unl~orm~cros~s section by the reductlon in eros~s s~ctionalarea of the workpiece, wlth reduotion oonducted along the
-entire sur~ace area thereo~. This technique is illustrated
;Z~ in U.S. Patent No. 3,055,102 to~Shaw et al., wherein a
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shaving tool is applied against a rod or bar which reduces
cross sectional area along the entire surface thereof.
Certain problems would appear to arise if the shaving
technique exempli~ied by Shaw et al. were to be directly
applied to the manufacture of multiple gauge products
~rom rectangular strip stock. Specifically, the applica-
tion of shavlng force against only a portion-of the total
surface of the strip tends to magnify some of the problems
set forth in the aforenoted patent, particularly, the in-
ability to hold the workpiece properly centered with respect
to the tool, with the result that the workpiece wanders ~ -
- ~ and a wavy or broken surface may result. A further dif-
~iculty which i5 believed to be magni~led by the removal
of stock from only a portion of workpiece surface relates
to the excessive chattering and longitudinal vibration
that takes place as the strip passes through the tool,
which appears on the finished product as a galled or torn
surface. Finally, the uneven application of ~rictional
.
stress to the wor~piece can result in unwanted product
` i 20 uneveness or camber, which would require subsequent processes
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to eliminate.
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SUMMARY OF THE INVENTION
~.1
In accordance with this invention, it has been found
that a shaving;operation for the production of multiple
gauge me~al strip products may be conducted which comprises
drawing a metal strip of essentially rectangular initial
cross sectional conflguration, while maintaining said strip
under positive back tension, across a cutting tool disposed
at a predetermined angle with respect to the longitudlnal
, 30 direction of the strip, whereby the extent o~ surface
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reduction of the strip is confined to an area comprising from
about 5 to about 50% of total surface area, and the volume
removal of strip material ranges from about 10 to about 60%
measured in relation to initial strip cross sectional area. -~- The method of this invention may be practiced as both a multi~
pass and single-pass and single-pass procedure.
Further features of this invention comprise the
provision of an adjustable shaving apparatus comprising a
shaving tool holder including horizontal and vertical adjust-
ment means, which supports a shaving tool possessing a cutting
surface defining the desired multiple gauge configuration. The
shaving tool cutting edge is disposed at a critical rake angle
defined by the leading vertical edge of the tool and a vertical
plane extending in perpendicular relation to the longitudinal
direction of the strip. The rake angle may vary from 2-1/2 to
about 25, and preferably from 5 to about 18. The apparatus
, of the present invention rests upon a generally horizontal ;
support surface and is provided with laterally disposed strip
support guides which prevent unwanted movement of the strip
` 20 during the shaving operation. ;
In a further aspect of this invention there is provided
a multiple gauge metal strip product of rectangular cross-section
, ; ::
possessing regions of two or more variable thicknesses providing
a generally stepped surface configuration, the strip having been ;drawn while under bac~ tension through a shaving apparatus to
provide a uniform shaved surface whereby surface reduction of the -
strip is confined to an area comprising about five to about
fifty percent of total surface area, and volume removal of strip --
material ranges from about 10 to about 60% as measured in re-
lation to initial strip cross-sectional area, and wherein thick-
ness variations of said strip at said shaved surface are less
. . .. .
, than plus or minus 0.002 inches.
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The method of this invention possesses certain
advantages over conventional milling procedures, in that scrap
retrieval is made easier and higher speeds of operation are
possible. Scrap retrieval is made easier, as the removed
stock is usually obtained in the form of a long continuous
coil, whereas the scrap generated by conventional cutting
processes is obtained in random shapes and sizes which are
bothersome to gather and contain. Likewise, shaving to a
specified gauge can be achieved with
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greater ease than with conventional milling procedures,
and with ~ewer p~sses and in less time than with conven-
tional rolllng techniques.
It is, accordingly, a principal ob~ect of the present
invention to provide an improved method for the manu~ac-
ture of multiple gauge metal strip products which employs
a shaving operation.
It is another obJect o~ the present invention to
provide a method as a~oresaid which may be practiced with
a single pass reduction procedure.
It is a further obJect of the present inven~ion to
provlde an apparatus ~or the per~ormance of the shaving
method as aforesaid which is o~ simple construction and
which prevents aberrant strip movement during the per~or~
mance of said method.
Other ob~ects and advantages will become apparent
to those skilled in the art ~rom a consideration o~ the
description which proceeds with re~erence to the ~ollowing
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drawings.
BRIE~ DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a shaving apparatus -~
employed in accordance with the invention;
Figure 2 is a~side view o~ the shaving apparatus
hown in Figure l; -~
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igures 3, 4 and 5 are schemat1c cross s~ect1onal views
o~ multiple gauge strip con~igurations prepared ln accord-
ance with the invention.
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DE~A_L~D ~3CRIPTION
In accordance with the present invention, the fore-
going ob~ects and advantages are readily attained.
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The method of this ln~ention comprises drawing a
strip of generally rectangular cross section which is
malntained under back tension through a shaving apparatus
whereby a shaving tool defining a cutting edge possessing
regions of two or more variable levels of depth located
therein engages the surface o~ said strip so as to con-
tinually inscribe the corresponding pattern thereon. The
shaving method of this invention may be conducted contin-
uously to achieve strip sur~ace reductions confined to an
area comprising from about 5 to about 50% of total surface
area, and preferably from about 10 to about 40% of total
surface area, and strip volume removal ranging from about
10 to about 60%, and preferably ~rom about 15 to about 50%,
said volume removal measured in relation to the measured
change in strip cross sectional area. The foregolng may
be achieved in one shaving pass, and products produced
thereby will possess ~avorably uniform shaved sur~aces. ;
The shaving apparatus employed in accordance with the
presen~ invention comprises an ad~ustable shaving tool pro-
vided with a cuttln~ edge de~ining a pattern corresponding ~-
~;~ to the multiple gauge surface desired in the final strip
product. The shavlng tool is primarily ad~ustable in two
respects to enable shaving to be conducted to successfull~
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achieve maxlmum possible strip reductions measured primar-
ily in terms of volume removal. As noted in our earlier
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co-pending parent applioation, maximum volume removal per
shaving pass may be generally determined in relation to the
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`~ yield strength o~ the strip and then coordinated with the
cross sectional conflguratiQn of the desired end product.
This being done, the appara~us is then appropriately
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ad~usted to achieve the extent of volume removal desiredO
The apparatus will be described in greater detail herein-
below.
Referring to Figure l, a shaving apparatus useful in
accordance with the presen~-invention is illustrated in
perspective. Apparatus 10 comprises a bar-shaped shaving
tool 11, which is positioned in the Figure with cutting
edge 12 located ad~acent and on top of respective metal
strip M. As noted above, cutting edge lZ defines a cutting
pattern 13 whose configuration serves as the template for
the final configuration of the multiple gauge strip product.
As will be seen in greater detail in Figure 2, cutting edge
12 is disposed at a critical angle with respect to strip M
which facilitates the continuous operation o~ the method
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of this invention.
;
Referring ~uxther to Figure 1, shaving tool 11 is
supported by ad~ustable tool holder 14 comprising tool
support structure 15 held within adjustable housing 16.
Housing 16 i5 ~astened to a ~lat supporting surface through
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~ 20 ~ base 17, which is provided with a tunnel-like channel for
~ ., .
the passage therethrough o~ strip M. Housing 16 is pro-
vided with a horizontal ad~ustment 18 and a ver~ical ad~ust-
~i ment 19 comprising, respectively, calibrated screw-driven
slide connections. Ad~ustments 18 and 19 are fine ad~ust-
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ments provlded ln addition to a gross ad~ustment which
comprlse~ slidable tool support structure 15 located
within tracks 21. Thus, when the appropriate vertical
'`' position is determined in gross, support structure 15 is
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held stationary and fixed in position by tightening screw
threaded nut 22 against shaving tool 11, whereby the back
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plate of support structure 15, not shown, is brought into
~irm engagement with tracks 21~ Thereafter, fine adjust-
ments of both vertical and horizontal position can be made
with ad~ustments 18 and 19 noted earlier.
As stated above, ad~ustments of depth o~ cut or maxi-
mum stock removal are determined with respect to the yield
strength of the strip and the particular con~iguration
desired. In addition to the aforenoted ad~ustments of
vertical and horlzontal position of the shaving tool, a
further critical ad~ustment is made which relates to the
rake angle of the tool edge. The rake angle may be de~ined ~ -
a~ the angle which the plane o~ the vertlcal leading surface
cutting tool or blade defines with respect to an imaginary
vertical plane perpendicular to the direction of strip
travel. Referrlng to Figure 2, tool 11 is shown in greater
detall wherein an angle ~ is cle~ined which is measured from
plane 20, shown in phantom which is parpendicular to the
direction of strip M, and the inclined surface 23 employed
at the lower portion of tool 11 closest to strip M. In
accordance with the presenk lnvention, it has been found
that a certain critical rake angle exists, which exceeded,
results in a loss of oontrol of the thickness o~ the finished
strip product. Often, a rake angle in excess o~ the criti-
cal ~alue~causes the workpiece to ride up the tool, with
the result that excessive strip material is removed. The ;~
rake angle found to be use~ul in the present method may
range ~rom about 2-1~2 to about 25~ and pre~erably from
about 5 to about 18. Accordin~ly, and as illustrated in
.. . . .
Figure 2, tool 11 is constructed such that the desired
shape lnoludlng the rake angle is machined into the tool
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tip or cutting edge 12. The vertical leading ~ace of
the tool integral with cutting edge 12 is thus lnclined
at an angle lying ~ithin the range of rake angles noted
above.
; After the appropriate ad~ustments of shaving tool 11
have been made, shaving of strip M is accomplished by
pulling the strip across cutting edge 12 with the neces-
sary force to overcome the shaving resistance at the tool.
As noted earlier, strip M is supported and guided in part
by the flat surface supporting tool holder 14. In addition,
further supports or guides, not shown, could be employed
in lateral relation to the edges of strip M to prevent
lateral wandering from occurring during the shaving opera- -
tion.
As stated be~ore, the method o~ this invention may be
practiced as a multi-pass or single-pass operation. Thus,
when the amount of stock remo~al deslred exceeds the maxi-
mum possible stock removal pex pass, the desired amount
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~ may be divided so that lesser amounts are conducted in two
;.
-~ 20 or more passes. In this way, the yield strength of the
strip will not be exceeded and strip rupture ls prevented.
Though the ~oregoing description has proceeded with
~ ~ re~erence to a particular shaving apparatus, the present
`-`~; ~ inventlon should not be~so limited, as variations ln
apparatus are contemplated within the scope o~ the present
method. Thus, the~ shaving tool support structure could
. ~ ~
- assume a dif~erent shape and size and could employ adjust- ~
ment means varying in both number and size. Likewise, ~ -
the shaving tool may comprise a plurality o~ cuttlng edges
placed in side-by-side or sequential relation to each other.
.
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In order to gain a fuller understanding of the method
of this invention and to illustrate the undexlying prlnci-
pals thereof, the following examples are presented which
were conducted to prepare multiple gauge products resembl-
ing, respectively, the con~igurations set forth in Figures
39 4 and 5.
The following examples are presented for purposes of ~-
lllustration only and should not be construed as limitative
of the invention. -~
EXAM~LE I
Samples of C.D.A. Alloy 260 in both soft and extra
hard tempers were shaved to prepare a product possesslng
the configuration shown in Figure 3. An apparatus was
employed which comprised a shaving tool in accordance with
the invention and a strip guicLe together with coiler and
reco ler reels to pay off and wind up the strip. The pay
off reel was controlled so as to exert a back tension on
the strip entering the shaving apparatus. Successively
larger cuts were taken until yielding occurred, and the
volume of removal ~as measured at that point. The alloy
samples comprised flat ribbons o~ strip measuring 1.203 x
0.096". The configuration of Figure 3 posse~ses a surface
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~ removal of approximately 29% and a volume removal of 26.5~.
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The slanted edge de~ining the trough is inclined at a 45
angle, and total depth of cut is 0.042". The results o~
the experiment are set forth ln Table I, below. Variations
ln maximum cut depth and, there~ore, volume remo~al between
samples A and B is attributible to the di~ference ln the
yield strengths of the respective samples.
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EXAMP-LE II
A multiple gauge strip part was desired with a con- -
; figuration conslsting of three truncated pyramidal protru-
sions in the central region of one ma~or face thereof. The
cross sectional conflguration of the product is shown in
Figure 4. The product was prepared by the method of the
invention as ~ollows:
A flat rectangular strip of Alloy 260 having a width
o~ 0.620" and a thickness of 0.092" as well as reasonable
camber tolerances was provided. A formed tool consisting
of the negative of the strip configuration required was
prepared wherein appropriate relief and cuttin~ angles
wsre included. The strip was draw-shaved after the tool
had penetrated the strip to the required depth. The moving
~trip was shaved to the desired configuration in two passes,
each of which achieved an 18% reduction of the metal volume
90 that the total volume remo~al was cloæe to 36%. The
final strip thickness at its minima was 0.040"9 whlle its
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~; maxima, comprising the height of the protrusions, remained
;~ . . . .
-i~ 20 at 0.092". The sur~ace removal was approximately 45% of ~ ~ -
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` total strip sur~ace. As the protrusions were desired on
; ~; on~ face alone, surface removal ~or this shape was confined
~ to the top broad ~ace of the strip.
.~ . . ...
EXAMPLE III
A further confi~uration was prepared as illustrated in
! Flgure 5 whlch consisted of a flat strip 1~ ~ide, o. o80
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thick wlth ~our 1/16~ rectangular grooves 0.030" deep in ;-
which about 12% o~ the surface area has been removed. The
draw-shavlng process described in Example I was employed
however shaving was limited to one pass. The ~otal ~olume
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removed in this test was about 9%.
EXAMPLE IV
A strip product possessing a configuration similar
to that of Example II was prepared employing the same appa-
ratus, with the difference being that Alloy 638, R copper-
aluminum-silicon cobalt alloy was employed as the starting
material. Rather than uslng two passes, one pass was em-
ployed to prepare the product which developed a drawlng
~orce equivalent to the yield strength of the alloy. The
~oregoing technique resulted in a single pass reduction of
38%.
Shaving speeds in the continuous experlments were in
the range o~ 50 - 200 ~t/min., but speed control was not
maintained. The shaved sur~ace o~ the strip had à good
appearanae and thickness variations were measured to be
+ 0.002", while width variations were 0.005".
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