Fabricating one-piece can bodies with controlled side wall elongation

New technology for fabricating a one-piece cup-shaped can body having a protective organic coating as formed. Such can body is formed free of side wall ironing from can stock comprising flat-rolled sheet metal substrate precoated with protective organic coating and forming lubricant. A plurality of successive diameter-reduction operations are carried out on a planar blank and cup-shaped work product under tension during which side wall height is increased and side wall substrate is decreased in thickness to provide controlled uniformity in side wall substrate thickness over about 85% to about 95% of side wall height for such can body. The fabricating tooling provides for a preselected clearance between a punch peripheral wall and a die cavity internal wall in each of such plurality of diameter-reduction operations to achieve a desired decrease in side wall thickness as the precoated substrate is moved into a die cavity by relative movement of its respective punch.

This invention relates to new tooling systems and methods for fabricating 
one-piece can bodies which provide sheet metal substrate thickness control 
during a plurality of diameter-reduction operations and, a selected 
uniformity in side wall substrate thickness without relying on side wall 
ironing. In particular, this invention is concerned with a new system for 
fabricating flat-rolled sheet metal substrate precoated with organic 
coating and lubricant while controlling thickness of the substrate to form 
a new onepiece can body having a protective organic coating on its 
interior and exterior surfaces as formed. And, in one of its more specific 
aspects, the invention enables production of precoated flat-rolled steel 
one-piece can bodies for carbonated beverages which are of lighter weight 
per can body than those previously produced commercially by "draw and 
iron" processing of flat-rolled steel can stock. 
The metal required per can body is a significant factor in optimizing 
container costs. Conventional draw-redraw practice increases metal 
thickness beyond container requirements along the side wall in approaching 
the open end of a one-piece sheet metal can body. And, when side wall 
ironing is used in forming one-piece can bodies, heavier gage starting 
material must be used; as a result the gage of the bottom wall metal in a 
drawn and ironed can body generally exceeds that required for container 
purposes. 
Another disadvantage is that precoated organic coating cannot be expected 
to withstand either such side wall thickening or side wall ironing and 
still provide the integrity required for comestibles. 
As taught herein, a one-piece sheet metal substrate can body has protective 
organic coating as formed in a process which is free of side wall ironing. 
Sheet metal substrate of predetermined starting gage is precoated with 
organic coating and lubricant; and, as part of the can body fabrication, 
side wall sheet metal substrate thickness is controllably decreased 
relatively uniformly over a selected major portion of side wall height. A 
specific flat-rolled steel substrate embodiment of the invention provides 
a structurally and economically practical alternative to the drawn and 
ironed sheet metal can bodies widely used commercially for carbonated 
beverage can packs.

Conventional redraw practice for fabricating one-piece can bodies has 
relied on "nesting" of curved clamping surfaces, as seen in the 
cross-sectional view of FIG. 1, on both the interior and exterior of the 
curved juncture between the endwall and side wall of a cup-shaped work 
product during redraw of a cup-shaped work product. 
In such practice, clamping sleeve 30 presents a curved transition zone 31 
between clamping endwall 32 and clamping sleeve cylindrical side wall 32. 
The attempt was made to match clamping surface 31 to the internal surface 
at the juncture between endwall 32 and side wall 33 of drawn cup 34. Also, 
redraw die 35 had a curved surface 36 for clamping the exterior surface at 
the juncture between endwall 32 and side wall 33; such matching was to 
continue as the sheet metal moved between the curved surfaces 31, 36 
toward the die cavity during the redraw of FIG. 2. 
In the theoretical "ideal" draw-redraw practice, the surface area of a 
drawn product does not increase as the flat-rolled planar sheet metal of a 
cut blank, or the endwall of a cup-shaped work product, is drawn into side 
wall height. However, in practice, the thickness gage of the side wall 
increases toward its open end as the metal is drawn and redrawn. For 
example, during conventional draw-redraw practice to form deep-drawn can 
bodies in which side wall height exceeds diameter, the metal increases as 
much as 15% to 30% in approaching the open end of the can body. 
The conventional draw die cavity entrance (such as 38 of FIGS. 1 and 2 as 
seen in cross section in a plane which includes the central longitudinal 
axis of the can body) was as large as possible while avoiding wrinkling 
(or buckle formation) in the sheet metal during movement of draw punch 40 
into draw die cavity 39. Further, in such prior practice, the curved 
surface at the "nose" portion 42 of punch 40 was made as small as possible 
while avoiding "punch-out" of metal at the start of reshaping a blank or a 
cup. 
For example, in such prior practice, after initial cup formation, typical 
radius of curvature dimensions for each such curved surface if used to 
form a can body for a 211 .times. 400 can (2 11/16" diameter by 4" 
height), would be as follows: 
______________________________________ 
clamping sleeve surface 32 
.125" 
cavity entrance surface 38 
.070" 
"punch-nose" surface 42 .125" 
draw die surface 36 .135" 
______________________________________ 
However, such conventional draw-redraw means thickened the sheet metal in 
approaching the open end of the can body. And, side wall ironing is not a 
good option because the cold forging characteristics of ironing were 
detrimental to the precoating of an organic coating. 
The fabricating system shown schematically in the general arrangement of 
FIG. 3 not only avoids thickening of side wall substrate while the 
diameter of a cup-shaped work product is progressively decreased in a 
plurality of sequential operations but also controls substrate thickness 
throughout such work product. In addition, the invention controllably 
decreases side wall substrate gage along side wall height free of side 
wall ironing. The result is a "thinned side wall" can body produced by 
controllably regulating tension in the substrate during side wall 
elongation. 
A relatively uniform decrease in side wall gage is achieved in each of a 
plurality of interrelated diameter-reduction operations. In a first phase 
of a specific embodiment (outlined by interrupted line 43 in FIG. 3), the 
diameter of a can stock blank is changed in two operations so as to form a 
cup-shaped work product of significantly decreased side wall diameter with 
relatively minor decreases in side wall gage. In a second phase of such 
specific embodiment (outlined by interrupted line 44 in FIG. 3), side wall 
thickness gage is more significantly decreased as side wall metal is 
elongated under increased tension with relatively minor changes in 
cup-shaped work product diameter. A one-piece can body with a side wall of 
controlled and lighter gage throughout its height is thus produced. The 
process significantly increases surface area of the work product over that 
of the starting blank as the side wall is elongated under tension free of 
any side wall ironing. 
Flat-rolled sheet metal of predetermined gage and surface characteristics 
is provided for producing the tension-elongated, thinned side wall, 
one-piece can bodies of the fabricating system shown diagrammatically in 
FIG. 3. Such sheet metal substrate is precoated on both its surfaces with 
organic coating and lubricant. The production operational rate of the 
fabricating system is preferably kept independent of the precoating 
preparation production rate. 
The organic coating applied to a surface-prepared sheet metal substrate 
embodies a "blooming compound"; that is, a lubricant which is activated by 
the heat and/or pressure of fabrication. And, the invention further 
provides for surface precoating of a lubricant which can be the type used 
for drawing can bodies. The precoated organic coating and lubricants 
(integral blooming compound and surface applied) are preselected, in 
particular for the internal surface of containers for comestibles, to meet 
requirements of governmental regulatory agencies such as the U.S. Food and 
Drug Administration. 
The blooming compound incorporated in the organic coating and 
surface-applied augmenting lubrication are selected for each prepared 
surface; preferably, application of lubricant to the surface of the 
organic coating is carried out as part of coil precoat processing. Total 
lubricant coating weight on each surface is preselected in the range of 
about 15 to 20 mg/sq. ft. Fabricating line speed is kept independent of 
surface preparation line speed. However, lubrication requirements to meet 
fabricating stress on the public-side surface of the can stock differ from 
lubrication requirements on the product-side surface. And, organic coating 
requirements to maintain maximum product protection on such product-side 
surface can differ from organic coating objectives for the public-side 
surface. The present processing enables selective precoating required for 
product and/or public side surfaces and maintains the integrity of such 
coating during fabrication of the one-piece can bodies. Where carbonated 
beverage container specifications have required dual-stage treatment and 
lacquering of the product-side surface of a drawn and ironed can body, an 
internal spray coat or surface E-coat repair may suffice with the present 
processing and, such repair may not be necessary for many container 
products. The multiple stage washing and multiple surface coating 
finishing operations required of draw and iron processing are 
significantly diminished, with certain of such finishing operations being 
eliminated entirely because the protective characteristics of the 
precoated organic coating are substantially sustained on the interior and 
exterior of the can body during forming for most comestibles. 
Copending parent patent application U.S. Ser. No. 07/573,548, now U.S. Pat. 
No. 5,119,657, entitled "Draw-Process Methods, Systems and Tooling for 
Fabricating One-Piece Can Bodies," filed by the present applicant Aug. 27, 
1990, is incorporated herein to provide more detail on surface preparation 
practices for preparing flat-rolled steel as a substrate and, on organic 
polymeric materials used as a protective organic coating for specific 
embodiments of the present invention. Use of dual organic coating systems 
on sheet metal substrate and preselected coating weights for each surface, 
incorporating blooming compound and following up with preselected 
augmentation by surface lubrication, can be expected to provide sufficient 
protective organic coating integrity for the side wall thinning, 
diameter-reduction operations described herein; need for internal surface 
repair, if any, would likely be limited to internal side wall portions for 
certain container packs. 
For present purposes, the flat-rolled sheet metal is preferably work 
hardened. Double-reduced flat-rolled steel (see Making, Shaping and 
Treating Steel, 9th Ed., 1971, page 971, .COPYRGT.AISE, printed by Herbick 
& Held, Pittsburgh, PA) is a preferred type of tin mill product. Also, in 
a preferred composition for a flat-rolled steel specific embodiment, 
carbon content is decreased from conventional tin mill product practice of 
around 0.12% carbon to less than 0.02%C, with a range such as about 
0.002%C to about 0.01%C being preferable. And, manganese would preferably 
be decreased from the conventional tin mill product range (about 0.6%) to 
less than 0.2% Mn; for example, in a range of about 0.1% to about 0.2% Mn. 
Such compositions facilitate the tension-elongation stretching of side 
wall substrate taught herein. 
Referring to FIG. 3, surface preparation and precoating are carried out at 
46. Organic coating and lubricant precoating are described in more detail 
in applicant's copending U.S. application Ser. No. 07/573,366 entitled 
"Composite-Coated Flat-Rolled Sheet Metal Manufacture and Product," filed 
on Aug. 27, 1990, is incorporated herein by reference. Depending on end 
product and side wall gage reduction, surface coating for the 
"product-side" can be in the range of about 10 to about 20 mg/in.sup.2 and 
"public-side" surface coating can be in the range of about 5 to about 10 
mg/in.sup.2. 
Precoated flat-rolled can stock is accumulated at source 50; for example 
coiled continuous strip or, a moving strip accumulator can be provided in 
a manner to keep can stock preparation rate independent of fabricating 
line speed. Alternatively, can stock can be accumulated and supplied from 
source 50 to the fabricating line in cut sheet or blank form. 
Station 52 can comprise a blanking and cupping press into which 
continuous-strip or sheets are fed; or, alternatively, can comprise a 
cupping press into which cut blanks are fed. Using either alternative, a 
relatively shallow-depth, one-piece cup-shaped work product 54, with a 
flange 55 at the open end of side wall 56, is formed. In the specific 
embodiment, the diameter of the blank is decreased about thirty-five 
percent in forming the diameter for side wall 56 in such cupping 
operation. 
Cup formation and a subsequent diameter reduction of cup 54 at station 57 
are carried out to avoid increase in the side wall thickness gage. 
Avoiding increase in the gage of the side wall substrate is an important 
contribution to the control of side wall gage during side wall elongation. 
In the specific embodiment, side wall diameter for a one-piece can body is, 
to a large extent, established in a two step first phase. For example, a 
blank cut edge diameter of about 5.875" (for forming a final can body side 
wall diameter of 2.581") is formed in two diameter reduction operations 
into work product 60 having a side wall diameter of about 2.986". That is, 
cut edge diameter is decreased about 50% or more in such first phase while 
sheet metal substrate thickness in side wall 61 (excluding flange 62) is 
decreased only about 15%. Forming flange 62 at the open end of work 
product 60 establishes uniform side wall height along with providing other 
advantages. In a plurality of successive diameter-reduction operations, 
the diameter of a circular cut blank is decreased about one-third to 
provide the side wall diameter for the shallow-depth cup-shaped work 
product 54; such side wall diameter of the shallow-depth cup is then 
decreased about 25% at the second diameter reduction station 57 to produce 
work product cup 60 with side wall 61, open end flange 62 and closed 
endwall 63. 
In a controlled portion of the closed endwall the thickness gage is 
maintained at starting gage throughout the tension-regulated elongation of 
the side wall with diameter-reduction taught herein. For example, the 
planar portion of the closed endwall remains at starting gage in the first 
diameter reduction operation of the specific embodiment at cupping station 
52 and in the second operation at station 57. The side wall gage, in such 
specific embodiment, is decreased by a relatively minor and uniform amount 
during such first phase while the substrate of the curved surface juncture 
between closed endwall and side wall is in transition; that is, decreasing 
from such starting gage of the endwall to such uniform side wall gage. 
Flange 55 at the open end of shallow cup 54, and flange 62 at the open end 
of side wall 61, are oriented in a plane which is transverse (at or near 
perpendicular) to the central longitudinal axis of the work product; that 
is, the flange is properly oriented to support the work product for travel 
in the fabricating line. In a second fabricating phase (44) of the 
specific embodiment, greater elongations of the work product side wall 
under higher tensions are carried out with relatively minor diameter 
reductions. And, special measures are employed to provide for planar 
clamping of substantially solely uniform thickness gage material to enable 
higher-tension, greater side wall elongation notwithstanding the small 
surface areas of clamping due to such minor diameter-reductions in each of 
two higher-tension side wall elongation operations of such second phase. 
Utilizing double-reduced sixty-five pound per base box flat-rolled steel 
for fabricating a twelve ounce carbonated beverage can body, the cut blank 
diameter is decreased about 35% in forming shallow cup 54. In the specific 
embodiment, the side wall diameter (3.882") of shallow cup 54 is decreased 
about 25% to form work product 60 having a diameter of 2.986". In two 
subsequent higher-tension side wall elongation diameter-reduction 
operations of the illustrated embodiment, the diameter of the side wall is 
decreased in the range of about 2.5% to about 10% while the side wall is 
more significantly elongated and side wall thickness is more significantly 
decreased than in the two operations of the first phase. 
From station 57 (FIG. 3), the cup-shaped work product 60 travels open end 
down on flange 62 to station 64 for reshaping work product 60 in a third 
diameter-reduction operation in which side wall elongation is followed by 
a special countersinking of the endwall; the latter is preferably carried 
out in the same press station (64). 
In the specific embodiment, the diameter reduction in station 64 is less 
than in previous stations; for example, about 3% in processing such twelve 
ounce pressure-pack can body. A major portion of the clamping action is 
carried out on the substantially uniform gage side wall of the reshaped 
work product from station 57; then, upon completion of such first 
higher-tension side wall elongation of station 64, and upon release of 
clamping action, countersinking is carried out on the closed endwall. As 
shown in later FIGS., such countersinking returns at least that portion of 
the work product juncture substrate which is thicker than the relatively 
uniform thickness of the side wall just completed; also, a portion of such 
contiguous side wall is moved into the endwall. The result after such 
countersinking is that the uniform side wall gage from the operation at 
station 64 extends along side wall height into the curved surface juncture 
(where clamping will next occur) and into the closed endwall. 
At the open end of the work product, the small diameter flange (resulting 
from the small side wall diameter-reduction change at station 64), and the 
contiguous metal 65 leading to the open end of work product 66, will 
subsequently be removed by trimming. A portion of such clamped flange 
and/or such contiguous metal 65 to be removed will be at a thicker gage 
than the side wall of the just completed operation. 
The elongated side wall work product 66, with countersunk endwall 67, is 
then transferred for a further high-tension elongation of the side wall in 
a successive side wall diameter-reduction operation to be carried out at 
station 68 (FIG. 3). The minor diameter decrease is reflected in a small 
open end flange. Such small flange, and the contiguous metal leading to 
the open end, do not generally provide sufficient planar surface for 
adequate or stable support of a work product on its open end for in-line 
travel; therefore, other mechanical handling of work product, such as 
known side wall clasping techniques, can be used for work product transfer 
between stations 64 and 68, and subsequent thereto if required in line. 
Trimming at the open end of can body 70 is carried out at station 72; which 
in a specific embodiment is carried out in a manner to provide for 
beverage can formation. That is, the entire flange and contiguous metal 
leading to the open end are removed prior to station 74 where E-coat 
repair of the internal surface is carried out if required. Necking-in and 
flanging (utilizing commercially available apparatus) is carried out at 
station 76 prior to inspection at test station 78. Subsequent canning 
operations, such as filling and applying an end closure, can be carried 
out at station 80. 
The present invention eliminates several finishing steps required when 
fabrication of one-piece can bodies relies on side wall ironing. For 
example, the present invention eliminates (a) required washing of ironing 
lubricant from the can body, (b) external side wall protective coating, 
and (c) external base and bottom "rim" coating. Also, the internal surface 
lacquering (and curing) required by current ironing practice on beverage 
can bodies may be eliminated for certain products; repair of side wall 
internal surface, if required, is more readily adapted to being carried 
out in line. 
The fabricating steps of the specific embodiment are considered in greater 
detail starting with FIG. 4. Cut blank 84 is cut from can stock in which 
flat-rolled sheet metal substrate of predetermined thickness gage has been 
precoated; such blank has a predetermined cut edge diameter. In the 
cross-sectional partial view of cupping tooling in FIG. 5, cupping die 85 
defines die cavity 86 with entrance zone 87 between its internal side wall 
88 and planar clamping surface 89. Male punch 90 moves relative to die 
cavity 86, as indicated, as the blank 84 is clamped peripherally 
externally of male punch 90 between planar clamping surface 89 of die 85 
and planar surface 91 of clamping sleeve 92. Such planar clamping surfaces 
are oriented transversely to central longitudinal axis 93 at or near 
perpendicular to such axis. 
The cavity entrance zone 87, as viewed in vertical cross section (that is, 
in a plane which includes the central longitudinal axis 93), has a curved 
surface formed about a small radius of curvature to provide a "sharp edge" 
for multi-directional movement of can stock from a planar configuration 
into the die cavity. The radial projection of such cupping tooling cavity 
entrance zone on the clamping plane is about five times nominal sheet 
metal substrate starting gage. 
However, cavity entrance zone 87 is, preferably, formed about multiple 
radii of curvature. As described later in more detail, use of multiple 
radii of curvature increases curved-surface area of the cavity entrance 
zone without increasing such projection on the clamping plane surface. 
Designation of the use of multiple radii is indicated herein by setting 
forth the multiple radii used; in the specific embodiment, the multiple 
radii used for the cavity entrance zone 87 are about 0.05"/0.02"/0.05"; 
such mid-surface radius of about 0.02" provides a sharper edge 
configuration about which the can stock moves into the die cavity which is 
an important aspect in achieving the uniformity of side wall gage 
reduction and the extent of such reduction. Also, cavity wall 88 is 
slightly tapered to provide increasing diameter with increasing depth of 
such cavity. 
More uniform side wall gage over substantially full side wall height is 
facilitated by such cavity entrance measures and by selectively decreasing 
clearance, for such side wall diameter reduction operation, between the 
peripheral side wall of the punch and the cavity internal wall (at such 
entrance zone) to less than the gage of the substrate being elongated. As 
taught herein, selection of such clearance helps to control 
tension-elongation and the selected thickness uniformity along side wall 
height. For example, in the specific embodiment with a starting gage of 
0.0072" double-reduced steel, a clearance of about 0.007" (measured 
radially in cross section) provided around the circumference in the 
cupping die provides a side wall gage of about 0.0066" which is relatively 
uniform throughout side wall height between the closed endwall juncture 
and the open end flange. Such clearance is preselected in the plurality of 
successive diameter-reduction operations. 
Curved surface 94 at the peripheral (nose) portion of punch 90 is formed 
about as large a radius of curvature as can be used without causing 
buckling or wrinkling in the substrate, for the cupping operation. A punch 
nose radius of curvature of 0.300" (which is about forty times nominal 
starting gage) is used for cupping during fabrication of the 
above-mentioned can body for a twelve ounce beverage can using 
double-reduced sixty-five pound per base box precoated flat-rolled steel. 
Such large punch nose helps to overcome sheet metal inertia at the start 
of shaping a curvilinear side wall from flat-rolled substrate. 
Cup 96 (FIG. 6) includes endwall 97, side wall 98 which is symmetrical in 
relation to central longitudinal axis 99, flange 100 in a plane which is 
at or near perpendicularly transverse to axis 99, and juncture 101 between 
endwall 97 and side wall 98. Juncture 101 has a curved configuration in 
vertical cross section conforming to that of punch nose 94 of FIG. 5 which 
is formed about such 0.300" radius of curvature. 
During cup forming, central longitudinal axis 99 for cup 96 is coincident 
with central longitudinal axis 93 for the die; relative movement between 
tooling is carried out with such tool components being oriented in 
symmetrical relationships to axis 93. 
During subsequent diameter reductions of work product, curved clamping 
surfaces are eliminated and solely planar clamping is relied on. Also, the 
curved-surface juncture between the closed endwall and side wall of the 
work product (e.g. cup 96) is first reshaped about a smaller curved 
peripheral surface of the clamping tool. The start of such juncture 
reshaping is carried out in a manner which creates a force on the work 
product closed endwall metal which is directed in a transverse plane in a 
direction away from the central longitudinal axis (99). The importance of 
such reshaping of the curved-surface shallow-cup juncture (as well as in 
subsequent can body forming operations) is that reshaping the juncture 
adds to the surface area of the can stock available for clamping between 
planar surfaces during formation of a new cross section for the work 
product. 
FIG. 7 shows the juxtaposition of cup 96 with tooling approaching the 
closed endwall juncture prior to such juncture reshaping. Die 102 can be 
considered as stationary for purposes of understanding reshaping of the 
juncture of a cup-shaped work product -- it being understood that required 
relative movement between tooling components is carried out with their 
centerline axes coincident. 
It should also be noted that, in practice, such relative movement between 
upper and lower tooling is preferably selected so as to discharge the work 
product onto the pass line (travel path for the work product) without 
requiring removal of work product from tooling cavities or punch; and, 
without the necessity of accumulating work product off line for later 
reintroduction to the fabricating line. In the apparatus shown, the open 
end of the cup is oriented downwardly during formation for discharge of 
the work product for travel open end down in the pass line; travel from 
the first two press stations is carried out on the flange of each 
respective work product. 
The invention teaches use of a flat-faced die as shown in FIG. 7 (and also 
later illustrated dies). That is, die 102 presents solely planar clamping 
surface 103 and such planar clamping surface lies in a plane which is 
oriented to be transverse to central longitudinal axis 99. When such dies 
are made from sinter-hardened machineable material, such as tungsten 
carbide, and the clamping surface area is extended as in the first phase 
of the specific embodiment, a taper is provided between the planar 
clamping surfaces. For example, surface 103 can be tapered (opening 
outwardly) a fraction of a degree (such as 0.degree. 5') to facilitate 
movement of the can stock along such surface toward the cavity; for 
further details on use of taper with sinter-hardened tooling, see 
applicant's copending application Ser. No. 07/490,781, now U.S. Pat. No. 
5,209,099 entitled "Draw-Process Methods, Systems and Tooling for 
Fabricating One-Piece Can Bodies." 
Axially-movable clamping tool 104 has a sleeve-like configuration and is 
disposed to circumscribe male punch 106. The male punch is adapted to move 
can stock into cavity 108 as defined by die 102. The clearance between the 
internal wall of cavity 108 and the peripheral wall of punch 106 is 
selectively decreased in relation to the starting gage. Radial clearance 
about the circumference for cupping 65#/bb (0.0072") double-reduced 
flat-rolled steel of the specific embodiment can be selected at about 90% 
to 95% of substrate thickness, for example, between 0.0064" and 0.0068"; 
stated otherwise, such radial clearance about the punch is about 5% to 
about 10% less than substrate thickness. Elongation of the can stock by 
movement around the cavity entrance zone through such decreased clearance 
into the die cavity increases tension in the side wall substrate; the 
substrate is decreased in thickness by elongation under tension about the 
sharp edge of the cavity entrance-zone by movement of the punch into the 
die cavity. The result is a more uniform decrease in side wall gage along 
side wall height between juncture and flange of the cup. The work product 
side wall substrate gage is decreased about 10% to about 20% in station 57 
of FIG. 3; that is, to a thickness gage in the range of about 0.006" to 
about 0.0055" in such specific embodiment. 
Referring to FIG. 7, clamping sleeve 104 includes peripheral wall 110, 
planar endwall 111 and curved-surface transition zone 112 therebetween. 
The dimension of peripheral wall 110 of clamping sleeve 104 provides an 
allowance for tool clearance of about 0.0025" in relation to the internal 
side wall (98) dimension of a work product cup (96). 
The surface area of transition zone 112 of clamping sleeve 104 is 
significantly smaller than one-half the surface area of juncture 101 of 
cup 96; for example, about one fourth to about one-half. That is, in a 
specific embodiment, a projection of the transition zone 112 onto a 
clamping surface plane which is perpendicularly transverse to the central 
longitudinal axis occupies less than about 40% of the projection of cup 
juncture 101 on such plane. The interrelationship of these curved surfaces 
is selected to provide a difference of at least 60% in their radial 
projections on the transverse clamping plane; this translates into a 
corresponding increase in planar clamping surface area when juncture 101 
of cup 96 is reshaped about transition zone 112 (prior to otherwise 
starting metal movement into the die cavity due to movement of the punch). 
Reshaping of a work product juncture is shown and described in relation to 
FIGS. 8 through 11. 
In a specific cylindrical-configuration side wall embodiment for sizes set 
forth above, the transition zone surface on the cupping punch uses a 
0.300" radius of curvature to form cup juncture 101 so that the projection 
of such juncture on the transverse clamping plane is 0.300". The 
projection of transition zone 112 of the clamping sleeve curved surface 
using multiple radii of curvature teachings (as described in FIGS. 8-11) 
occupies 0.071" rather than the original 0.300" radius. This provides a 
radial difference of about 75%; that is, a projection of the clamping 
sleeve transition zone 112 onto the transverse clamping plane occupies 
less than about 25% of the projection of the 0.300" radius of curvature 
surface of juncture 101. Reshaping of the cup juncture thus significantly 
increases the planar clamping surface area (in which the clamping sleeve 
surface coacts with the planar clamping surface 103 of die 102); this 
feature is used in each operation in which a new diameter is formed. 
Referring to FIG. 8, as clamping sleeve 104 is moved against spring-loaded 
pressure its curved surface transition zone 112 comes into contact with 
the inner surface of juncture 101 of cup 96. With continued relative 
movement (FIG. 9) an outwardly directed (away from the central 
longitudinal axis) force is exerted on the sheet metal of cup 96 as 
juncture 101 is formed about a smaller radius of curvature (FIG. 9). Upon 
completion of such juncture, reshaping (FIG. 11) the can stock now 
available for clamping between planar clamping surfaces for forming a new 
diameter side wall has been substantially increased. And, clamping takes 
place solely over such extended planar surface area between the die planar 
clamping surface such as 103 of FIG. 7 and the clamping sleeve planar 
surface 111. The increase in planar clamping surface area over that 
previously available, due to such controlled reshaping of a work product 
juncture is indicated at 120 in FIG. 11. 
Such increased planar clamping surface is added to that made available by 
the earlier mentioned contribution of the invention which decreases the 
die cavity entrance zone surface; a smaller cavity entrance zone surface 
(described in more detail in relation to later FIGS.) increases the planar 
clamping surface area of the die for coaction with the planar surface of 
the clamping tool. Such die cavity entrance projection is from about five 
to about .5 times substrate gage in the sequence of operations. Combining 
the effect of reshaping the cup juncture and use of a smaller cavity 
entrance zone projection increases the planar clamping surface available 
by a factor of at least two over that available for corresponding can body 
sizes using conventional draw-redraw tooling. 
Also, the clamping sleeve peripheral transition zone (as viewed in cross 
section) is preferably manufactured about multiple radii. As described in 
relation to FIG. 12, a single radius of curvature for the clamping sleeve 
peripheral transition zone surface (as viewed in cross section) about a 
radius "R" would result in a projection on the transverse clamping plane 
of clamping endwall 102 dimensionally equal to "R." In place of such 
single radius, such curved surface is formed about multiple radii of 
curvature through selective usage of "large" and "small" radii of 
curvature in forming a curved surface transition zone for the clamping 
tool. 
In FIG. 12, clamping sleeve 124 includes a planar endwall 126 which is 
transverse to the centerline axis of the cup; clamping sleeve 124 also 
includes a peripheral side wall 127. In preferred fabrication of the 
curved surface transition zone for the clamping tool, a "large" radius R 
is used about center 128 to establish circular arc 129 which is tangent to 
the planar endwall surface 126. Extending circular arc 129 through 
45.degree. intersects with the extended plane of peripheral side wall 127 
at imaginary point 130. 
Using the radius R about center 132 establishes circular arc 134 tangent to 
side wall 127; extending arc 134 through 45.degree. intersects the 
transverse clamping plane of endwall 126 at imaginary point 136. 
Straight line 137 is drawn between imaginary point 136 and center 132; 
straight line 138 is drawn between imaginary point 130 and center 128; 
interrupted line 139 is drawn so as to be equidistant between parallel 
lines 137 and 138. Line 139 comprises the loci of points for the center of 
a "small" radius of curvature which will be tangent to both the circular 
arcs 129 and 134 so as to avoid an abrupt surface intersection at 
imaginary point 141. Using a radius of 1/2 R with its center 142 along 
line 139, circular arc 143 is drawn to complete a smooth, multiple radii 
curved surface for the transition zone of clamping sleeve 124. 
As a result of the clamping tool design of FIG. 12, the projection of the 
multiple radii curved surface on the transverse clamping plane of endwall 
102 is 0.0707 times R, resulting in further increase of almost 30% in the 
planar clamping surface over that available if a single radius R were used 
for the curved surface transition zone of clamping sleeve 124. Also, a 
more gradual curved entrance surface 144 into the transition zone is 
provided; and, a more gradual curved surface 145 from the transition zone 
onto the clamping surface 126 is provided. Curved surface 144 also 
provides for easier entrance of the clamping tool transition zone into 
contact with the internal surface of the curved juncture of a cup-shaped 
work product for such juncture reshaping step. 
In a specific cylindrical configuration embodiment for a multiple radii 
clamping sleeve transition zone for reshaping a 0.300" radius of curvature 
juncture for work product cup 76, R is selected to be 0.100"; therefore, 
the projection of clamping sleeve multiple radii transition zone on the 
transverse clamping plane comprises 0.0707", rounded off as 0.071". Other 
values for R can be selected; for example, a 1.25" radius of curvature for 
reshaping a cup juncture of substantially greater radius than 0.300"; or 
0.9" for reshaping a smaller radius of curvature juncture; in general 
selecting R as 0.100" will provide desired results throughout the 
preferred commercial range of can sizes designated earlier. 
As shown in cross section in FIG. 13, a funnel-shaped configuration 146 is 
established between planar surface 103 of die 102 and clamping sleeve 
transition zone 112 for movement of work product can stock into the 
axially transverse clamping plane without damage to the coating as male 
punch 106 moves into cavity 108. A further relief can be provided by 
having surface 103 diverge away from the clamping plane at a location 
which is external (in a direction away from axis 99) of the planar 
clamping surface. 
Male punch 106 includes endwall 147, peripheral side wall 148 and curved 
surface transition zone 149 between such endwall and side wall. A large 
surface area is provided at transition zone 149 (the punch nose) to the 
extent permitted by geometry requirements at the closed endwall juncture 
in later stages of the work product to facilitate starting each new 
diameter side wall. Coaction between such large surface area punch nose 
formed about a 0.200" radius of curvature for diameter reduction of the 
shallow-depth cup 96 (stage 57 of FIG. 3) in the specific example; also, a 
small projection cavity entrance zone surface 150 is used, preferably, 
formed about multiple radii of curvature 0.050"/0.020"/0.050" for 
increasing the planar clamping surface area for such diameter reduction 
stage. Such aspects also combine in subsequent stages to continue the 
control of the decrease in side wall gage initiated during the cupping 
stage. These measures also help to prevent surface damage ("galling") of 
organic coating surfaces. 
In accordance with teachings of the present invention, any significant 
increase in thickness gage of the side wall substrate is avoided during 
decrease in blank diameter and subsequent decreases in side wall diameter; 
and, side wall gage is controllably decreased in each such operation. From 
the cupping and second such operation (first phase) of the specific 
embodiment relatively uniform gage side wall substrate is made available 
for later higher-tension, greater side wall elongation operations. 
In a specific embodiment of such later operations, a portion of the 
substrate contiguous to the periphery of the closed end of the can body is 
used to provide a differing gage substrate to form a "bottom rim" about 
the closed endwall and extending to the can body side wall. Also, 
differing gage substrate is provided near the open end for flanging 
purposes; whereas, relatively uniform lighter gage side wall substrate is 
provided therebetween as described in more detail later herein. However, 
it should be noted that the side wall thickness control provided does not 
refer to the heavier gage portions of the flange and contiguous can stock 
leading to the open end of a can body (which may be of heavier gage than 
the finished relatively uniform gage portion of the side wall); such 
flange and contiguous portions are removed by trimming for purposes of 
fabricating carbonated beverage can bodies in the specific embodiment 
being described. 
The punch-nose radius after the cupping operation is selected to be about 
thirty times starting metal thickness gage in the second diameter 
reduction operation of the specific embodiment for a twelve ounce beverage 
can using 65#/bb double reduced TFS. That is, the radius of curvature for 
the punch-nose is about 0.200"; TFS refers to the tin free coating of 
chrome and chrome oxide applied to flat-rolled steel as a surfactant for 
later application of protective organic coating. 
The curved surface for the peripheral transition zone of the clamping tool 
uses the multiple radii of curvature teachings described earlier; for 
example, a surface which projects as 0.071" on the transverse clamping 
plane can be used during the second redraw in reshaping such first redraw 
curved surface juncture of the work product (which has an internal surface 
radius of curvature of 0.200"); or, a new surface based on R = 0.1" can be 
used in forming the multiple radii transition zone for the second redraw 
clamping tool as described above. 
FIG. 13 shows the apparatus of FIG. 7 during formation of a new side wall 
cross section. Tooling dimensions for a cylindrical-configuration 
one-piece can body for twelve ounce carbonated beverage can, using 
precoated 65#/bb flat-rolled double reduced TFS, in accordance with the 
invention are as follows: 
______________________________________ 
Multiple 
Radii of 
Work Punch- Curvature 
Product Nose Cavity For Cavity 
Diameter 
Radius Diameter Entrance 
______________________________________ 
Circular 5.875" -- -- -- 
blank 
Shallow cup 
3.882" .300" 3.896" .05"/.02"/.05" 
(FIG. 6) 
Second cup 
2.986" .200" 2.998" .05"/.02"/.05" 
(FIG. 14) 
______________________________________ 
Punch and die cavity clearances in such cupping phase are approximately 
equal to desired side wall sheet metal thickness, for example, about 
0.007" per side (radial cross section). Use of such clearance stretches 
side wall substrate to provide a relatively uniform substrate gage of 
about 0.0066" along such side wall. In the twelve ounce cylindrical can 
body embodiment, the diameter of a circular sheet metal blank is decreased 
about 34.2% during cupping. And, the shallow cup work product side wall 
diameter is decreased about 23% in the second operation; radial clearance 
of about 0.006" can be selected for such second diameter-reduction 
operation. 
The multiple radii of curvature shaping of the die cavity entrance zone is 
combined with tapering of the cavity internal wall to help eliminate 
adherence of can stock to the die cavity internal wall. The 
multi-directional movement required of the metal substrate in establishing 
a new cross sectional area can result in a type of "spring-back" action in 
the overall product side wall. Such recessed taper for the internal wall 
surface of the die cavity, along with other aspects, helps minimize or 
substantially eliminate galling of the outer surface organic coating. 
FIG. 15 is an enlarged vertical cross-sectional partial view of a cavity 
entrance zone for die 165 formed about a single radius of curvature 166, 
selected in accordance with earlier presented teachings (about five times 
sheet metal starting gage for the cupping stage and decreasing in 
subsequent operations). Single radius curved surface 168 for the entrance 
cavity is spaced from central longitudinal axis 170 and extends 
symmetrically between planar clamping surface 171 and internal side wall 
surface 172. Curved surface 168 is tangential (as viewed in such cross 
section) at each end of its 90.degree. arc; that is, tangential to planar 
surface 171 and to the cavity internal surface 172, respectively. 
In FIG. 16, such curved surface 168 (about single radius of curvature 166 
of FIG. 16) is shown as an interrupted line; a 45.degree. angle line 173, 
between the planar clamping surface and cavity side wall, is also shown by 
an interrupted line. Such 45.degree. angle line 173 meets the respective 
points of tangency of single radius curved surface 168 with the planar 
clamping surface 171 at 174 and the internal side wall 172 at 175. The 
planar clamping surface 171 and the cavity internal surface 172 (as 
represented in cross section) would, if extended, define an included angle 
of 90.degree.. 
A larger surface area 176 (FIG. 16) for the entrance zone is provided by 
the present invention. The multiple radii cavity entrance zone concept is 
carried out, in the specific embodiment being described, by selecting a 
radius of about 0.050" as the "larger" radius (RL) for the multiple radii 
surface. Placement of such larger radius (RL, FIG. 17) surface provides 
for the more gradual movement of can stock from the planar clamping 
surface into the cavity entrance zone and, also, for the more gradual 
movement from the entrance zone into the interior side wall of the cavity. 
A smaller radius (Rs) for the specific embodiment, selected at about 
0.020", is used to establish a curved surface which is intermediate, such 
larger radius (RL) portions located at the arcuate ends of the entrance 
zone surface. That is, the Rs surface is centrally located of such 
entrance zone. The interior cavity wall 172 is recessed slightly, about 
one-half degree to about 1.degree., in progressing from the curved surface 
entrance zone into the cavity. 
A portion (181) of the curved surface 176 of FIG. 16 is formed in FIG. 17 
about center 177 and uses the larger radius RL (0.050"); such surface 
portion 178 is tangential to the planar clamping surface 171 of the draw 
die. Such larger radius is used about center 180 to provide curvilinear 
surface 181 leading into the internal side wall of the cavity. 
To derive the loci of points for the centrally located smaller radius (Rs) 
of curvature portion of the curved surface, the arcs of the larger radii 
surfaces 178, 181 are extended to establish an imaginary point 184 at 
their intersection. Connecting imaginary point 184 with midpoint 185 of an 
imaginary line 186 between the R centers 177, 180 provides the remaining 
point for establishing the loci of points (line 188) for the center of the 
smaller radius (Rs) of curvature; the latter will provide a curvilinear 
surface 190 which is tangential to both larger radius (RL) curvilinear 
surfaces 178 and 181. In the specific embodiment for a twelve ounce 
beverage can body, the larger radius (RL) of curvature is selected at 
about 0.05" (in a range of 0.040" to 0.060") and, the smaller radius (Rs) 
of curvature is selected at about 0.02" (in the range of 0.015" to 
0.025"). A specific example for the cupping cavity entrance zone and the 
second operation cavity entrance zone is 0.050"/0.020"/0.050"; a specific 
example for the later higher-tension operations which provide increased 
side wall elongation and gage reduction is 0.012"/0.003"/0.012". 
In such multiple radii configurations, the smaller radius (Rs) curved 
surface is located intermediate the two larger (RL) surfaces, e.g. 
0.05"/0.02"/0.05" and provides the edge about which the can stock moved 
into the cavity as the side wall is stretched for passage through the 
preselected clearance. 
In order to provide a 1.degree. recessed taper (FIG. 17) for the die cavity 
internal surface, the arc between the planar clamping surface and such 
internal surface is increased by 1.degree.; such 1.degree. arc increase 
being added at the internal surface end of the arc, Such added 1.degree. 
of arc enables such internal surface to be tangent to the curved surface 
at point 191; that is, 1.degree. beyond the 90.degree. point of tangency 
(175), A tangential recess-tapered internal side wall cannot be provided 
without such added arc provision as described immediately above. The 
location of a 1.degree. taper internal side wall surface, in a vertically 
oriented plane which includes the central longitudinal axis of the draw 
cavity, is shown at line 192 in relation to a non-tapered side wall 
surface indicated by line 172, 
In the specific embodiment of flat-rolled steel can body for a twelve ounce 
carbonated beverage can, can body weight is less than that required by 
draw and iron processing of a can body having the same dimensions; for 
example, steel can bodies in accordance with the invention result in a 
weight of about fifty-three pounds per thousand can bodies compared to a 
weight of about fifty-eight pounds per thousand drawn and ironed steel can 
bodies. 
The second phase (FIG. 3) is carried out in multiple reshaping operations. 
In each stage a relatively minor diameter reduction is utilized while side 
wall gage is decreased significantly as the side wall is significantly 
elongated. Several measures are taught to enable accomplishing such 
objectives: (a) providing for planar clamping of more uniform thickness 
can stock substantially throughout clamping metal, (b) minimizing the 
decrease in side wall diameter in each stage, and (c) controlling 
clearance between the punch peripheral wall and the internal wall entering 
die cavity. 
The closed endwall 194, shown in interrupted lines in FIG. 18, is an 
intermediate configuration of the work product endwall during the third 
diameter-reduction operation in the specific embodiment of the fabricating 
system (carried out at station 64 of FIG. 3). That is, interrupted line 
194 of FIG. 18 depicts the closed endwall configuration before endwall 
countersinking. Work product 195 of FIG. 18 includes elongated side wall 
196, flange 197 and flange associated metal 198 leading to the open end of 
work product 195. The resulting countersunk endwall is shown in a solid 
line at 199. The radial dimension of the flange is represented at 200 
which also represents the radial decrease in side wall cross section. The 
central longitudinal axis is represented at 202. 
FIG. 19 shows the juxtaposition of tooling for starting the operation 
resulting in work product 195 of FIG. 18. The closed end of the work 
product 60 from station 57 of FIG. 3 (after reshaping of the juncture) is 
identified as 204; an integral punch 205 comprises a core 206 and an 
insert 207 which are joined. Use of such parts (which are bolted together 
to form the integral punch) makes machining easier; such parts act as a 
unitary punch during fabrication. Such integral punch defines a recessed 
contour 209 in its endwall; the latter is utilized in later countersinking 
of endwall 194 to form endwall 199 (FIG. 18). 
Punch 205 is moving toward the cavity 212 defined by die 214 in FIG. 19 
with relative movement of tooling components as indicated. The juncture 63 
between endwall and side wall of work product 60 (FIG. 3) has been 
reshaped to form a new juncture 216 for increased planar clamping (as 
described earlier) by clamping tool 218. A portion of the endwall 204, 
represented by the planar portion of width 200 of flange 197 in FIG. 18 
can therefore include the start of "transition thickness" metal between 
endwall and side wall from juncture 63 which is initially clamped between 
the planar surfaces of die 214 and clamping sleeve 218. Such substrate is 
in transition to the side wall (61) gage resulting from the operation at 
station 57 (FIG. 3). Side wall 61 is free of any significant increase in 
thickness throughout its height (which does not include the flange 61). 
Such side wall thickness is less than starting gage and is of relatively 
uniform thickness with such thickness dimension depending on the tooling 
selected for such previous station (57). Thus, reshaped juncture 216 can 
be of varying thicknesses in going from endwall wall gage through a 
portion of the "transition thickness" metal of juncture 63. 
At the start of a new diameter formation in FIG. 20, a portion of such 
varying thickness juncture 216 substrate, designated 220, is adjacent to a 
side surface (punch nose) portion of contour 208. To facilitate the start 
of a new diameter, such partially heavier substrate portion 220 is in the 
space between die internal wall 222 and such side surface portion of 
contour 208; such space, which is larger in radial dimension than the 
clearance between die cavity wall and punch peripheral wall, .leads into 
the controlled tighter clearance between cavity wall 222 and punch wall 
224. 
The work product side wall, which is at a decreased relatively uniform gage 
from the previous operation (station 57 of FIG. 3), is after such initial 
start clamped for side wall elongation. The clearance between punch wall 
224 and cavity wall 222 is preselected for the specific embodiment. Such 
clearance is less than such side wall gage; the can stock must be 
elongated through such clearance in order to move from the cavity entrance 
zone 226 into the side wall as punch 205 moves into the cavity. 
The cavity entrance zone 226 for this higher tension side wall elongation 
is formed about multiple radii of curvature of 0.012"/0.003"/0.012". The 
nose portion of contour 208 of punch 205 has a radius of curvature of 
about 0.050" to about 0.070". The substrate is elongated under tension by 
stretching about such sharp edge (0.003" radius) through the clearance 
provided between the cavity internal wall and the punch peripheral wall. 
Such elongation and thickness reduction by tension-elongation is free of 
side wall ironing and is free of "cold forging" (also referred to as 
surface "burnishing") aspects of side wall ironing. The clearance is 
selected at about 0.0045" for this third diameter-reduction operation of 
the specific embodiment for a twelve ounce beverage can; the resultant 
height of side wall 196 (of work product 195 FIG. 18) to flange 197 is 
about three and seven-eighths to about four inches. 
Upon reaching desired side wall height, clamping at flange 197 (FIG. 21) is 
released as male countersinking member 230 comes into contact with endwall 
194 (FIG. 18); and, by coacting with recessed endwall contour means (such 
as 209 of punch 205) the countersunk endwall 199 (FIG. 18) is formed. 
Such countersinking to form closed endwall configuration 199 is important 
to side wall thinning in the next stage (68 of FIG. 3). In such subsequent 
stage, the side wall is again elongated under high tension and the side 
wall metal is thinned through a selected clearance (about 0.004" in the 
final side wall forming operation of the specific embodiment). It is 
important, since planar clamping is to be exercised over a relatively 
small surface area, that such clamping be carried out on relatively 
uniform gage material. 
As the work product of FIG. 18 is formed in the die cavity before endwall 
countersinking, the substrate thickness at the juncture 220 is 
dimensionally in transition. The object of the countersinking of FIG. 21 
is to move such "transition gage" substrate 220 into the endwall so as to 
avoid later clamping (FIG. 24) of non-uniform gage material in the final 
side wall reshaping operation to form the nontrimmed can body of FIG. 23. 
In such configuration of the final side wall reshaping operation, the 
radial dimension indicated at 263 is equal to the radial change in side 
wall cross section and defines flange 238 (FIG. 23). 
With relatively small surface area planar clamping available, uniform gage 
metal is important for purposes of achieving desired side wall thinning. 
Such countersinking of the initial endwall configuration 194 (shown as 
interrupted lines in FIG. 18) into the countersunk configuration 199 is 
carried out after releasing flange clamping at the opposite end (FIG. 21). 
The latter enables the thicker material from the juncture to move into the 
endwall (out of the clamping range for the next diameter reduction 
operation). And, also, a controlled portion of the thinner, relatively 
uniform gage, side wall material to be "pulled" into the endwall 199 by 
such countersinking step. The resulting configuration peripheral of the 
endwall 199 is shown by the exploded cross-sectional view of substrate as 
shown in FIG. 22. The material clamped during the next operation will be 
at the relatively uniform side wall gage of the operation of FIG. 20. And, 
after the side wall diameter reduction portion of the next operation 
(FIGS. 24, 25), a controlled slightly heavier gage substrate will be in 
position as the "bottom rim" in the specific embodiment of a carbonated 
beverage can body configuration. 
Referring to FIG. 22, a portion of side wall 196 has been pulled into the 
new peripheral portion 242 of the endwall; and, countersunk profile 
portion 244 presents what had been varying thickness gage transition zone 
substrate (previously 220 in FIG. 21); such substrate extends into the 
remaining panel portion 245 with increasing thickness equal to initial 
starting gage for the substrate. 
The final operation work product 247 of FIG. 23 depicts the final reduction 
in cross-sectional dimension at 263 and flange 238. Side wall substrate in 
approaching the flange has passed the sharp edge cavity entrance but does 
not have the full benefit of the stretch being provided to the remainder 
of the side wall and, thus can provide slightly thicker substrate (about 
0.004"). Such slightly heavier substrate provides for subsequent necking 
and flanging of the trimmed can body and helps to avoid edge cracking 
during chime seam formation. Clamping takes place between the planar 
surface of clamping sleeve 250 (252 represents the reshaping radius) and 
the planar surface 254 of die 256 (FIG. 24). 
At the closed endwall, inboard of such clamping, a portion of countersunk 
endwall 199 with varying thickness substrate, contiguous to location 244 
in FIGS. 22 and 24, is reshaped gradually to form the rim 262, which is 
contiguous to the periphery of the closed end as shown in the 
cross-sectional view of FIG. 23. 
In the embodiment as shown in FIG. 24, a portion of the substrate (from a 
radially outboard portion of 242 of FIG. 22) has been reshaped by clamping 
sleeve curved surface 252. In such embodiment, clamping sleeve 250 clamps 
can stock substrate which is at the relatively uniform thickness of the 
previous operation side wall (about 0.0045") to form a relatively small 
diameter reduction forming flange 238 (FIG. 23) at completion of the 
diameter reduction portion of this final stage. The planar portion of 
flange 238 is clamped between planar surface 254 of final die 256 and the 
planar endwall of clamping tool 250. 
As such planar clamping takes place initially as shown in FIG. 24, punch 
260 (which includes core 261, a bottom ring portion 261[a], and spacer 
261[b]) moves in the relative direction indicated to side wall elongation; 
also, substrate at and near to location 244 as seen in FIG. 24. (which 
includes substrate at the slightly heavier gage indicated in FIG. 22) is 
in a position to form rim 262 along surface 265 (FIG. 24) of cone portion 
267. Surface 265, in cross-sectional view is tapered toward the endwall 
and the central longitudinal axis; and, extends at an angle toward a 
"dolphin nose" shaping portion 268 (FIGS. 24, 25) of bottom ring 261[a]. 
The side wall substrate is thinned in gage (to about 0.0035" in the 
specific embodiment) by stretching through a radial clearance of about 
0.004" between the internal cavity wall and the punch peripheral wall. 
And, side wall height is elongated to form the configuration of FIG. 23 
while substrate from contiguous to the closed end "dolphin nose" to the 
side wall is of controlled thickness to add to the strength of rim 262; 
and, in a preferred embodiment, side wall substrate contiguous to the open 
end is slightly heavier (about 0.004") than the relatively uniform 
thickness thinned side wall major portion as tabulated for the specific 
embodiment; such slightly heavier substrate facilitates later formation of 
a chime seam after trimming of the FIG. 23 work product. 
As side wall elongation is completed, clamping of flange 238 (shown in FIG. 
23) is discontinued and endwall (dome) profile tooling 270 (FIG. 25), with 
relative movement as indicated, reshapes the planar endwall portion 272 of 
FIG. 24 forming the dome-shape 274 of FIG. 25; spring loaded rim tooling 
266 holds the contour of rim 262 against surface 265 of the rim portion 
267 of core 261. The "dolphin nose" shaped portion 268 of punch insert 
261[a] forms a bottom support 274 (FIG. 26), which in plan view presents a 
ring shaped configuration in a cylindrical-configuration side wall 
embodiment. 
The data tabulated below relates to such specific embodiment utilizing 
65#/bb double-reduced TFS precoated with protective organic coating and 
lubricant and, comprises substrate thickness data measurements carried out 
at a location in the rolling direction ("with grain") and at a location 
90.degree. to the rolling direction (90.degree. to grain) around the 
perimeter of the can body. Such measurements were made along side wall 
height starting with the closed endwall 274 thickness (0.0073"- 0.0074"); 
then at the rim 262 (0.0051") and continuing at 1/4 intervals along side 
wall height to a height of 4 3/4. 
The tabulated thickness of the closed endwall is within nominal gage for 65 
lb/bb double-reduced flat-rolled steel which is 0.0072" .+-. 5% (about 
0.0068" to about 0.0076"). The thickness of rim 262 is controlled as 
described earlier to provide desired anti-bulging strength between endwall 
support 275 and side wall 263. In the final side wall reshaping operation 
such material is lain, as described earlier, along tooling portion 263 
between the peripheral wall 276 and dolphin nose 264 of punch 260 (FIG. 
24). 
Note in the tabulated data that the side wall substrate, from such rim to a 
location contiguous to the open end, has a thickness gage which is within 
about one to three ten thousandths of an inch of such 0.0035" value 
throughout such major portion of side wall height. An average thickness 
within about two ten thousandths along about 85% to about 95% of side wall 
height defines the "relatively uniform side wall gage" achieved by the can 
body fabricating system taught herein. In the specific embodiment a final 
thickness along side wall height of about 0.0035" was the objective in 
preselecting the clearance between the cavity internal wall and the punch 
peripheral wall. Such 0.0035" represents a side wall gage reduction of 
about 52.5% in working with 0.0074" double-reduced TFS; and, the average 
departure is within about two ten thousandths (0.0002") from 0.0035" to 
provide relatively uniform gage over such major portion of side wall 
height. 
Such "tension-regulated" side wall elongation achieves a uniformity of side 
wall gage in the fabrication of onepiece can bodies which had not been 
conceived of previously other than by side wall ironing. However, the new 
process disclosed is free of side wall ironing and free of "cold forging" 
or "burnishing" effects of side wall ironing which are completely 
detrimental to the integrity of a protective organic coating required for 
sheet metal canning of comestibles. The tension-regulated side wall 
elongation of the present invention achieves a decrease in side wall gage 
and a desired uniformity in side wall thickness without such 
disadvantages. 
______________________________________ 
TABULATED DATA 
Thickness Gage 
Side Wall 
Height With Grain 
90.degree. to Grain 
______________________________________ 
43/4 .0040" .0036" 
1/2 .0038" .0036" 
1/4 .0036" .0036" 
4" .0036" .0035" 
33/4 .0036" .0036" 
1/2 .0035" .0035" 
1/4 .0035" .0035" 
3" .0035" .0035" 
23/4 .0034" .0035" 
1/2 .0034" .0034" 
1/4 .0033" .0034" 
2" .0035" .0035" 
13/4 .0035" .0034" 
1/2 .0035" .0035" 
1/4 .0035" .0035" 
1" .0036" .0035" 
3/4 .0034" .0034" 
1/2 .0037" .0037" 
Rim 1/4 .0052" .0051" 
Closed .0074" .0073" 
endwall 
______________________________________ 
The surface area of such can body, after trimming such flange and 
contiguous metal, is about forty-five square inches; which is about 40% 
greater than the surface area of the 5.875" cut-edge starting blank. The 
Percentage increase in surface area is greater when trimmed metal is 
considered; and, will increase as blank edge is optimized so as to 
decrease trim; or, will be increased by forming smaller diameter can 
bodies so as to Provide a surface area which is in the range of about 40% 
to about 50% greater than the starting blank area. The relatively uniform 
thickness along the side wall is substantially uniform around the 
circumference at each such level; the increased thickness of about 0.005" 
near the closed end helps to prevent bulging of the rim. 
In completing a can, the flange 238 and remaining metal leading to open end 
276 (FIG. 23) are trimmed. Internal surface E-coat repair, if any, is 
carried out at E-coat station 72 (FIG. 3) which also includes curing of 
such E-coat; then, the can body is directed to necking and flanging 
apparatus 74 (FIG. 3) to form the necked-in portion indicated at 280 of 
FIG. 26 and the flange needed for the chime seam. Testing is carried out 
at 76. After filling, end closure structure 282 (FIG. 26) is applied by 
forming chime seam 284. 
While specific materials, steps and dimensional values have been set forth 
for purposes of explaining this new can body fabricating technology, it 
should be recognized that changes in such specifics can be made in the 
light of the above teachings without departing from the concepts entitled 
to patent protection; therefore, for purposes of determining the scope of 
the patentable subject matter reference shall be made to the appended 
claims.