Patent Description:
In the metal container industry, substantially identically shaped beverage containers are produced massively. Dies have been used to neck the tops of the containers.

The document <CIT> relates to a necking system including a plurality of necking dies each necking dies having an at least partially non-polished necking surface and a non-polished relief following the necking surface. The document <CIT> relates to a method for manufacturing containers including providing a container having a first diameter, expanding the diameter of the container to a second diameter with at least one expansion die.

The present invention relates to a shaped aluminium container as defined by independent claim <NUM>, wherein a further development of the inventive container is provided in sub-claim <NUM>.

In some embodiments (not part of the claimed invention), the thickness of the sidewall in the top necked portions varies by at least <NUM> (<NUM> inch). In other embodiments (not part of the claimed invention), the sidewall thickness in either the top or bottom portions, or both, vary by at least <NUM> (<NUM>") or <NUM> (<NUM>").

In some embodiments (not part of the claimed invention), the shaped aluminum container is manufactured by a process comprising: necking a lower portion of the sidewall with a first necking die so that a working surface of the first necking die contacts a first section of the sidewall and reduces a diameter of the first section of the sidewall by at least <NUM>% in a single die stroke, wherein the thickness of the first section of the sidewall varies along the height of the sidewall by at least <NUM> (<NUM> inch); and necking an upper portion of the sidewall with a second necking die so that a working surface of the second necking die contacts a second section of the sidewall and reduces a diameter of the second section of the sidewall by at least <NUM>% in a single stroke. In some embodiments (not part of the claimed invention), the lower portion and/or the upper portion is necked with a series of necking dies. A series of necking dies may comprise two or more necking dies. In one embodiment, the lower portion is necked with two necking dies. In one embodiment (not part of the claimed invention), the first die to neck the lower portion reduces the diameter of the container by about <NUM>% and the second die to neck the lower portion of the container reduces the diameter of the container an additional <NUM>% of the original diameter. In some embodiments (not part of the claimed invention), a single necking die may reduce the diameter of the container <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or more.

In some embodiments (not part of the claimed invention), the process further comprises expanding the diameter of a middle portion of the sidewall before necking the upper portion of the sidewall. In some embodiments (not part of the claimed invention), a thickness of the middle portion varies by at least <NUM> (<NUM> inch). In some embodiments, the thickest portion is at or near the top of the container. In some embodiments (not part of the claimed invention), the thinnest or a thin portion can be at or near the top of the container.

In some embodiments (not part of the claimed invention), the first and the second necking dies are configured for use on metal bottle stock and comprise a necking surface and a relief. The necking surface comprises a land portion, a neck radius portion, and a shoulder radius portion, each having an inner diameter. The land portion is between the neck radius portion and the relief. The inner diameter of the land is a minimum diameter of the die. The inner diameters of the neck radius portion and the shoulder radius portion are greater than the inner diameter of the land. The relief comprises a relief surface, wherein an inner diameter of the relief surface is at least about <NUM> (<NUM> inch) greater than the inner diameter of the land portion and an inner diameter of the relief surface is no greater than a maximum diameter so as to reduce but not eliminate frictional contact between the sidewall and the relief surface while maintaining necking performance when necking the sidewall. In some embodiments (not part of the claimed invention), the diameter of the relief surface is about <NUM> to about <NUM> (about <NUM> to about <NUM> inch) greater than the inner diameter of the land portion. In other embodiments, the diameter of the relief surface is about <NUM>, <NUM> or <NUM> (<NUM>, <NUM> or <NUM> inch) greater than the inner diameter of the land portion. In some embodiments (not part of the claimed invention), the length of the land portion is between about <NUM> (<NUM>") to about <NUM> (<NUM>"). In other embodiments (not part of the claimed invention), the length of the land is about <NUM> (<NUM>") to about <NUM> (<NUM>"). In yet other embodiments (not part of the claimed invention), the length of the land portion is between about <NUM> (<NUM>") to about <NUM> (<NUM>"). In one embodiment (not part of the claimed invention), the length of the land portion is about <NUM> (<NUM>"). In some embodiments (not part of the claimed invention), the necking die is dimensioned so that when necking the metal bottle stock, the entire land and the relief travel relative to the sidewall in an axial direction and at least a portion of the relief travels beyond a top of the sidewall.

In some embodiments (not part of the claimed invention), the land has a surface finish Ra ranging from about <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to about <NUM> × <NUM>-<NUM> mm (<NUM>µ in). In some embodiments (not part of the claimed invention), the relief has a surface finish Ra ranging from about <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to about <NUM> × <NUM>-<NUM> mm (<NUM>µ in), from about <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to about <NUM> × <NUM>-<NUM> mm (<NUM>µ in) or from about <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to about <NUM> × <NUM>-<NUM> mm (<NUM>µ in). In some embodiments (not part of the claimed invention), the neck radius portion and the shoulder radius portion have a surface finish Ra ranging from about <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to about <NUM> × <NUM>-<NUM> mm (<NUM>µ in).

In some embodiments (not part of the claimed invention), an expansion die for manufacturing metal containers expands the diameter of the middle portion of the sidewall. The expansion die for manufacturing metal containers comprises a working surface and an undercut portion, wherein the working surface is configured to expand a diameter of a metal container having a closed bottom. The work surface comprises a progressively expanding portion and a land portion. The land portion is between the progressively expanding portion and the undercut portion. The outer diameter of the land portion is a maximum diameter of the die. In some embodiments, the length of the land portion is a minimum <NUM> (<NUM>"). In some embodiments (not part of the claimed invention), the length of the land portion is between about <NUM> (<NUM>") to about <NUM> (<NUM>"). In some embodiments, the length of the land portion is between about <NUM> (<NUM>") to about <NUM> (<NUM>"). In other embodiments (not part of the claimed invention), the length of the land is about <NUM> (<NUM>") to about <NUM> (<NUM>"). In yet other embodiments (not part of the claimed invention), the length of the land portion is between about <NUM> (<NUM>") to about <NUM> (<NUM>"). In one embodiment, the length of the land portion is about <NUM> (<NUM>"). The undercut portion comprises an undercut surface having an outer diameter. The outer diameter of the undercut surface is at least approximately <NUM> (<NUM> inch) smaller than the outer diameter of the land portion and no less than a minimum diameter so as to reduce but not eliminate frictional contact between the undercut surface and the metal container. The outer diameter of the undercut surface is dimensioned to minimize collapse, fracture, wrinkle and all other physical defects, which may occur during expansion. The work surface is dimensioned so that when inserted into the aluminum container the entire land portion and at least a portion of the undercut portion enter the aluminum container causing the diameter of the middle portion of the sidewall to expand.

In some embodiments (not part of the claimed invention), an initial portion of the work surface of the expansion die has a geometry for forming a transition in a container from an original diameter portion to an expanded diameter portion. In some embodiments (not part of the claimed invention), the transition is stepped or gradual. In some embodiments (not part of the claimed invention), the land portion of the expansion die has dimensions to provide an expanded diameter of a container stock worked by the work surface.

In some embodiments (not part of the claimed invention), at least a portion of the work surface of the expansion die has a surface roughness average (Ra) of approximately <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to <NUM> × <NUM>-<NUM> mm (<NUM>µ in). In some embodiments (not part of the claimed invention), at least a portion of the undercut portion has surface roughness average (Ra) of approximately <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to <NUM> × <NUM>-<NUM> mm (<NUM>µ in). In some embodiments (not part of the claimed invention), the outer diameter of the land portion of the expansion die is substantially constant along the length of the land.

In some embodiments (not part of the claimed invention), the diameter of the middle portion of the sidewall is expanded with a series of expansion dies.

In some embodiments (not part of the claimed invention), the top of the container is dimensioned to accept a closure. In some embodiments (not part of the claimed invention), a closure covers an opening on top of the container. In some embodiments (not part of the claimed invention), the closure comprises one of: a lug, a crown, a roll-on pilfer proof closure or a threaded closure.

In some embodiments (not part of the claimed invention), a can end having a severable pour spout encloses a top of the container.

A process for forming a metal container comprises: providing a container having a sidewall, wherein the sidewall has a thickness and a height, and wherein the thickness varies along the height of the sidewall by at least <NUM> (<NUM> inch); and necking the container with a necking die so that a working surface of the necking die contacts a section of the sidewall and reduces a diameter of the section of the sidewall by at least <NUM>% in a single stroke, wherein the thickness of the section of the sidewall varies along the height of the sidewall by at least <NUM> (<NUM> inch) before and after necking.

In some embodiments (not part of the claimed invention), the necking die used in the process of forming a metal container comprises: a necking surface and a relief; wherein the necking surface comprises a land portion, a neck radius portion, and a shoulder radius portion, each having an inner diameter;.

In some embodiments (not part of the claimed invention), the process of forming a metal container further comprises expanding the diameter of a portion of the sidewall.

In some embodiments (not part of the claimed invention), the process of forming a metal container further comprises necking the container with a series of necking dies.

In some embodiments (not part of the claimed invention), the process of forming a metal container further comprises expanding the diameter of the portion of the sidewall with a series of expansion dies.

In some embodiments (not part of the claimed invention), at least one of the expansion dies comprises: a work surface comprising a progressively expanding portion and a land portion; and an undercut portion; wherein the land portion is between the progressively expanding portion and the undercut portion and an outer diameter of the land portion is a maximum diameter of the die; wherein the undercut portion comprises: (a) an undercut surface; and (b) an outer diameter of the undercut surface, wherein the outer diameter of the undercut surface is: (i) at least approximately <NUM> (<NUM> inch) smaller than the outer diameter of the land portion; and (ii) no less than a minimum diameter so as to reduce but not eliminate frictional contact between the undercut surface and the aluminum container; and wherein the work surface is dimensioned so that when inserted into the metal container the entire land portion and at least a portion of the undercut portion enter the metal container causing the diameter of the at least a portion of the sidewall to expand.

In some embodiments (not part of the claimed invention), a process for forming a metal container comprises: providing a container having a sidewall, wherein the sidewall has a thickness and a height, and wherein the thickness varies along the height of the sidewall by at least <NUM> (<NUM> inch); and expanding the diameter of the container with an expansion die so that a working surface of the expansion die contacts a section of the sidewall and expands a diameter of the section of the sidewall by at least <NUM>% in a single stroke, wherein the thickness of the section of the sidewall varies along the height of the sidewall by at least <NUM> (<NUM> inch) before and after expanding. In some embodiments (not part of the claimed invention), the process further comprises necking the container. In some embodiments (not part of the claimed invention), the process further comprises expanding the diameter of the container with a series of expansion dies. In some embodiments (not part of the claimed invention), the expansion die comprises: a work surface comprising a progressively expanding portion and a land portion; and an undercut portion; wherein the land portion is between the progressively expanding portion and the undercut portion and an outer diameter of the land portion is a maximum diameter of the die; wherein the undercut portion comprises: (a) an undercut surface; and (b) an outer diameter of the undercut surface, wherein the outer diameter of the undercut surface is: (i) at least approximately <NUM> (<NUM> inch) smaller than the outer diameter of the land portion; and (ii) no less than a minimum diameter so as to reduce but not eliminate frictional contact between the undercut surface and the aluminum container; and wherein the work surface is dimensioned so that when inserted into the metal container the entire land portion and at least a portion of the undercut portion enter the metal container causing the diameter of the at least a portion of the sidewall to expand.

The following detailed description, given by way of example and not intended to limit the invention solely thereto, will best be appreciated in conjunction with the accompanying drawings, wherein like reference numerals denote like elements and parts, in which:.

For the purposes of this specification, terms such as top, bottom, below, above, under, over, etc. are relative to the position of a finished metal container resting on a flat surface, regardless of the orientation of the metal container during manufacturing or forming steps or processes. A finished metal container is a metal container that will not undergo additional forming steps before it is used by an end consumer. In some embodiments, the top of the container has an opening.

The term "bottle stock" is used throughout this specification, However, all of the processes, products and apparatuses disclosed herein are applicable to all metal containers including beverage cans and cups, aerosol cans and food containers. A quotation mark or "in" designates inches.

<FIG> depicts a bottle stock after each stage of necking by a necking system in accordance with the one embodiment present invention, in which the inventive necking system provides for a more aggressive necking reduction scheme than was previously available with prior necking systems and the ability to neck a container through thick wall and thin wall portions, i.e. containers having sidewalls that vary in thickness by at least <NUM> (<NUM> inch) and the necking die travels past the thick wall portion and into the thin wall portion in a single stroke. <FIG> depicts the progression of necking from an initial necking die to produce the first necked bottle stock <NUM> to a final necking die to produce the final necked bottle stock <NUM>. Although <FIG> depicts a necking system including <NUM> stages, the following disclosure is not intended to be limited thereto, since the number of necking stages may vary depending on the material of the bottle stock, the bottle stock's sidewall thickness(es), the initial diameter of the bottle stock, the final diameter of the bottle, the required shape of the neck profile, and the necking force. Therefore, any number of necking dies has been contemplated, so long as the progression provides for necking without collapse or other physical defect of the bottle stock.

<FIG> depicts a cross sectional view of a necking die including at least a partially textured necking surface <NUM> and a textured relief <NUM> following the necking surface <NUM>. In one embodiment, the partially textured necking surface <NUM> includes a shoulder or body radius portion <NUM>, a neck radius portion <NUM>, and a land portion <NUM>.

In some embodiments, a necking die includes a partially textured necking surface <NUM>, which reduces surface contact between the necking surface and the bottle stock being necked in a manner that reduces the force that is required to neck the bottle (hereafter referred to as "necking force"). It has unexpectedly been determined that a necking surface having a textured surface provides less resistance to a bottle stock being necked than a non-textured surface. As opposed to the prior expectation that a smooth, non-textured, highly polished surface would provide less resistance and hence require less necking force, it has been determined that a surface with a relatively low Ra value, i.e. <~ <NUM> × <NUM>-<NUM> mm (<~<NUM> micro inches) has greater surface contact with the bottle being necked resulting in greater resistance and requiring greater necking force. In some embodiments, the increased surface roughness (higher Ra value) reduces the surface contact between the necking surface and the bottle being necked, hence reducing the required necking force.

Reducing the necking force required to neck the bottle stock allows for necking dies having a greater percent reduction than previously available in prior necking dies. It also helps to enable the die to neck through varying thicknesses of metal sidewall.

In one embodiment, a textured surface has a surface roughness average (Ra) ranging from more than or equal to <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to less than or equal to <NUM> × <NUM>-<NUM> mm (<NUM>µ in), so long as the textured necking surface does not disadvantageously disrupt the aesthetic features of the bottle stock's surface (coating) finish in a significantly observable manner. In one embodiment, a non-textured surface has a surface roughness average (Ra) finish ranging from <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to <NUM> × <NUM>-<NUM> mm (<NUM>µ in). <FIG> represents a surface mapping of one embodiment of a non-textured land portion <NUM> of the necking die generated by ADE/Phase Shift Analysis and MapVue EX - Surface Mapping Software. In this example, the surface roughness (Ra) value was approximately <NUM> × <NUM>-<NUM> mm (<NUM>µ in). <FIG> represents a surface mapping of one embodiment of a textured land portion <NUM> of the necking die, in accordance with an embodiment of the present invention generated by ADE/Phase Shift Analysis and MapVue EX - Surface Mapping Software. In this example, the surface roughness (Ra) value was approximately <NUM> × <NUM>-<NUM> mm (<NUM>µ in).

Referring to <FIG>, in one embodiment, the partially textured necking surface <NUM> includes a textured land portion <NUM>, a non-textured neck radius portion <NUM>, and a non-textured shoulder radius portion <NUM>. In another embodiment, the at least partially textured necking surface <NUM> may be entirely textured. Referring to <FIG>, the contact angle α of the bottle stock <NUM> to the necking surface <NUM> may be less than <NUM>°, wherein the contact angle is the included angle between <NUM> (the ray extending perpendicular to the land) and <NUM> (the ray extending perpendicular from the plane tangent to the point of contact by the bottle stock with the necking surface). In some embodiments, the working surface and/or relief may be entirely non-textured. In some embodiments, the working surface and/or relief is hard turned and lightly polished to knock off rough edges to obtain a surface finish of about <NUM> × <NUM>-<NUM> mm to <NUM> × <NUM>-<NUM> mm (<NUM>-<NUM> micro inches), or about <NUM> × <NUM>-<NUM> mm to <NUM> × <NUM>-<NUM> mm (<NUM>-<NUM> micro inches) or about <NUM> × <NUM>-<NUM> mm to <NUM> × <NUM>-<NUM> mm (<NUM> to <NUM> micro inches).

The textured land portion <NUM> in <FIG> in conjunction with the knockout (not shown) provide a working surface for forming an upper portion of the bottle stock into a bottle neck during necking. The knockout (not shown) fits inside the container or bottle stock during necking and helps the container to be removed from the die after necking. In one embodiment, the textured land <NUM> extends from tangent point of neck radius portion <NUM> of the die wall parallel to the center line of the necking die. The textured land portion <NUM> may extend along the necking direction (along the y-axis) by a distance Y1 being less than <NUM> (<NUM>"), or being on the order of approximately <NUM> (<NUM>"). In some embodiments, the length of the land portion is between about <NUM> (<NUM>") to about <NUM> (<NUM>"). In some embodiments, the length of the land portion is between about <NUM> (<NUM>") to about <NUM> (<NUM>"). In some embodiments, the length of the land portion is between about <NUM> (<NUM>") to about <NUM> (<NUM>"). In some embodiments, the length of the land portion is approximately <NUM> (<NUM>").

Another aspect of some embodiments of the present invention is a relief <NUM> positioned in the necking die wall following the necking surface <NUM>, The dimensions of the relief <NUM> are provided to reduce, but not eliminate, frictional contact with the bottle stock and the necking die, once the bottle stock has been necked through the land <NUM> and knockout. Therefore, in some embodiments, the relief <NUM>, in conjunction with the partially textured necking surface <NUM>, contributes to the reduction of frictional contact between the necking die wall and the bottle stock being necked, wherein the reduced frictional contact maintains necking performance while reducing the incidence of collapse, buckling, rupturing, wrinkling and other physical defects, and improving stripping of the bottle stock.

In one embodiment, the relief <NUM> extends into the necking die wall by a dimension X2 of at least <NUM> (<NUM> inch) measured from the base 13a of the land <NUM>, in other embodiments, at least <NUM> (<NUM> inch) or <NUM> (<NUM> inch). In some embodiments, the relief extends into the die wall no more than <NUM> (<NUM>"). The relief <NUM> may extend along the necking direction (along the y-axis) the entire length of the top portion of the bottle stock that enters the necking die to reduce, but not eliminate, the frictional engagement between the bottle stock and the necking die wall to reduce the incidence of collapse, buckling, rupturing, wrinkling and other physical defects, yet maintain necking performance. In one embodiment, the relief <NUM> is a textured surface. The transition from the land to the relief is blended, with no sharp corners, so that the metal bottle stock can travel over the land in either direction without being damaged.

In some embodiments of the present invention, a necking system is provided in which at least one of the necking dies of the systems may provide an aggressive reduction in the bottle stock diameter. Although <FIG> represents an introductory die, the above discussion regarding the shoulder radius <NUM>, neck radius <NUM>, land <NUM> and relief <NUM> is equally applicable and may be present in each necking die of the necking system. The geometry of the necking surface of at least one of the successive dies provides for increasing reduction, wherein the term "reduction" corresponds to decreasing the bottle stock diameter from the bottle stock's initial diameter to a final diameter.

In one embodiment, the introductory die reduced the diameter of the container being necked by more than <NUM>% in a single necking stroke, or more than <NUM>% in a single necking stroke. The level of reduction that is achievable by the dies of the necking system is partially dependent on the surface finish of the necking surface, necking force, bottle stock material, required neck profile, and sidewall thickness(es). In one embodiment, an introductory necking die provides a reduction of greater than <NUM>%, wherein the initial necking die is configured for producing an aluminum bottle necked package from an aluminum sheet composed of an Aluminum Association <NUM> alloy, having an upper sidewall thickness of about <NUM> (<NUM> inch) or less and a post bake yield strength ranging from about <NUM> MPa to <NUM> MPa (<NUM> to <NUM> ksi). In some embodiments, the upper sidewall thickness may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> inch), just to name a few examples. In some embodiments, the thickness of the sidewall in the bottom necked portions varies by at least <NUM> (<NUM> inch). In some embodiments, the thickness of the sidewall in the top necked portions varies by at least <NUM> (<NUM> inch). In other embodiments, the sidewall thickness in either the top or bottom portions, or both vary by at least <NUM> (<NUM>") or <NUM> (<NUM>") In some embodiments, the sidewall thickness varies by no more than <NUM> (<NUM>"), <NUM> (<NUM>"), <NUM> (<NUM>"), <NUM> (<NUM>") or <NUM> (<NUM>").

<FIG> depicts one embodiment of an intermediate die in accordance with the present invention, in which the intermediate necking die may be employed once the bottle stock has been necked with an initial necking die. In comparison to the introductory necking die depicted in <FIG>, the intermediate necking die depicted in <FIG> provides a less aggressive reduction. In one embodiment, a plurality of intermediate necking dies each provide a reduction ranging from <NUM>% to <NUM>%. The number of intermediate necking dies depends on the bottle stock initial diameter, required final diameter, neck profile, sidewall thickness and variability of the thickness of the sidewall.

<FIG> depicts one embodiment of a final necking die in accordance with the present invention. The final necking die is utilized once the bottle stock has been necked by the intermediate necking dies. The final necking die has a necking surface that results in the neck dimension of the finished product. In one embodiment, the final necking die provides a reduction of less than <NUM>%. In one embodiment, the final necking die may have a reduction of <NUM>%.

In one embodiment, a necking system is provided in which the plurality of necking dies include an introductory necking die having a reduction greater than <NUM>%, <NUM> intermediate dies having a reduction ranging from <NUM> to <NUM>%, and a final necking die having a reduction of <NUM>%.

In one embodiment of the present invention, a method of necking metal containers, utilizing a necking system as described above, is provided including the steps of providing an aluminum blank, such as a disc or a slug; shaping the blank into an aluminum bottle stock; and necking the aluminum bottle stock, wherein necking comprises at least one necking die having an at least partially textured necking surface.

Some embodiments of the present invention provide a necking system including a reduced number of dies and knockouts, therefore advantageously reducing the machine cost associated with tooling for necking operations in bottle manufacturing.

By reducing the number of necking die stages, the present invention advantageously reduces the time associated with necking in bottle manufacturing.

Although the invention has been described generally above, the following examples are provided to further illustrate the present invention and demonstrate some advantages that arise therefrom. It is not intended that the invention be limited to the specific examples disclosed.

Table <NUM> below shows the reduction provided by a <NUM> stage die necking schedule, in which the necking die geometry was configured to form an aluminum bottle necked package from an aluminum bottle stock having a upper sidewall sheet thickness of approximately <NUM> (<NUM> inch) and a post bake yield strength ranging from about <NUM> MPa to <NUM> MPa (<NUM> to <NUM> ksi). The aluminum composition is Aluminum Association (AA) <NUM>. As indicated by Table <NUM>, the bottle stock is necked from an initial diameter of approximately <NUM> (<NUM>") to a final diameter of <NUM> (<NUM>") without failure, such as wall collapse.

As depicted in Table <NUM> the necking system includes a first necking die that provides a reduction of approximately <NUM>%, <NUM> intermediate dies having a reduction ranging from approximately <NUM> to <NUM>%, and a final necking die having a reduction of <NUM> %. <FIG> represents a cross-sectional side view for the shoulder necking surface of each necking die of the <NUM> stage necking system represented in Table <NUM>. In this example, the portion of the bottle stock being necked has a substantially uniform thickness.

<FIG> depicts the force required to neck a bottle into a necking die having a textured land in accordance with the invention, as indicated by reference line <NUM>, and the force required to neck an aluminum container into a non-textured necking die, as indicated by reference line <NUM>, wherein the non-textured necking die represents a comparative example. The geometry of the necking die having the textured land and the control die is similar to the necking die depicted in <FIG>. The bottle being necked had an upper sidewall sheet thickness of approximately <NUM> (<NUM> inch), a post-bake yield strength of approximately <NUM> MPa to <NUM> MPa (<NUM> to <NUM> ksi), and an aluminum composition being Aluminum Association <NUM>.

Referring to <FIG>, a significant decrease in the necking force is realized beginning at the point in which the bottle being necked contacts the textured land, as illustrated by data point <NUM> on the reference line <NUM>, as compared to a non-textured necking surface, depicted by reference line <NUM>.

Now turning to the expansion die, a gradual expansion of a container comprised of a hard temper alloy using multiple expansion dies of increasing diameters, as opposed to using one expansion die, allows the diameter of the container to be expanded up to about <NUM>% without fracturing, wrinkling, buckling or otherwise damaging the metal comprising the container. When expanding a container constructed of a softer alloy, it may be possible to expand the container <NUM>% using one expansion die. The number of expansion dies used to expand a container to a desired diameter without significantly damaging the container is dependent on the degree of expansion desired, the material of the container, the hardness of the material of the container, and the sidewall thickness of the container. For example, the higher the degree of expansion desired, the larger the number of expansion dies required. Similarly, if the metal comprising the container has a hard temper, a larger number of expansion dies will be required as compared to expanding a container comprised of a softer metal the same degree. Also, the thinner the sidewall, the greater number of expansion dies will be required. Progressive expansion using a series of expansion dies may provide increases in the container's diameter on the order of <NUM>%, wherein greater expansions have been contemplated, so long as the metal is not significantly damaged during expansion. In some embodiments, the diameter of the container is expanded more than <NUM>%. In other embodiments the diameter of the container is expanded less than <NUM>%, greater than <NUM>%, greater than <NUM>%, greater than <NUM>%, greater than <NUM>%, or greater than <NUM>%. Other percentages of expansion are contemplated and are within the scope of some embodiments of the invention.

Further, when expanding a coated container, a gradual expansion will help to maintain the integrity of the coating. Alternatively, a container may be expanded before coating.

Necking an expanded container formed in accordance with some embodiments of the invention to a diameter greater than or equal to the container's original diameter X does not require the use of a knockout because the container's sidewall is in a state of circumferential tension following expansion. In some embodiments of the invention, a knockout can be used when necking the container.

Referring to <FIG>, in some embodiments, the expansion die is comprised of A2 tool steel, <NUM>-<NUM> Rc harden, <NUM> finish, although any suitable container shaping die material may be used. In some embodiments, the expansion die <NUM> includes a work surface <NUM>, having a progressively expanding portion <NUM>, a land portion <NUM>, and an undercut portion <NUM>. An initial portion <NUM> of the work surface <NUM> in the depicted embodiment has a geometry for gradually transitioning the diameter of the container <NUM> sidewall <NUM>. The progressively expanding portion <NUM> has dimensions and a geometry that when inserted into the open end of a container <NUM> works the container's sidewall <NUM> to radially expand the container's diameter in a progressive manner as the container travels along the work surface <NUM>. In some embodiments, the expansion die <NUM> provides the appropriate expansion and forming operations without the need of a knockout or like structure. In some embodiments, a knockout may be used.

The land portion <NUM> has dimensions and a geometry for setting the final diameter of the container being formed by that expansion die <NUM>. In one embodiment, the land portion <NUM> may extend a distance of <NUM> (<NUM>") or more. In other embodiments, the land may extend <NUM> (<NUM>"), <NUM> (<NUM>"), <NUM> (<NUM>"), <NUM> (<NUM>"), <NUM> (<NUM>") or <NUM> (<NUM>") or more or less. An undercut portion <NUM> follows the land portion <NUM>. The transition from the land portion <NUM> to the undercut portion <NUM> is blended. The undercut portion <NUM> extends at least beyond the opening of the container when the die is at the bottom of the expansion stroke to enable the die to maintain control of the metal as it expands and to minimize the container becoming out-of-round.

The work surface <NUM> may be a non-textured surface or a textured surface. In one embodiment, a non-textured surface has a surface roughness average (Ra) finish ranging from <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to <NUM> × <NUM>-<NUM> mm (<NUM>µ in). In one embodiment, the work surface <NUM> may be a textured surface having a surface roughness average (Ra) ranging from more than or equal to <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to less than or equal to <NUM> × <NUM>-<NUM> mm (<NUM>µ in), so long as the textured work surface <NUM> does not significantly degrade the product side coating disposed along the container's inner surface.

In some embodiments, immediately following the land portion <NUM> the surface of the expansion die transitions smoothly to an undercut portion <NUM> in order to reduce, but not eliminate, the frictional contact between the container <NUM> and the expansion die <NUM> as the container is worked through the progressively expanding portion <NUM> and land portion <NUM> of the work surface <NUM>. The reduced frictional contact minimizes the incidence of collapse, buckling, rupturing, wrinkling and other physical defects, and improves stripping of the container <NUM> during the expansion process. In some embodiments, the undercut portion <NUM> is a textured surface having a surface roughness average (Ra) ranging from more than or equal to <NUM> × <NUM>-<NUM> mm (<NUM>µ in) to less than or equal to <NUM> × <NUM>-<NUM> mm (<NUM>µ in). In some embodiments, the undercut portion <NUM> may extend into the expansion die wall by a dimension L of at least <NUM> (<NUM> inch), in other embodiments, at least <NUM> (<NUM> inch) or <NUM> (<NUM>"). In some embodiments, the undercut portion extends into the die wall no more than <NUM> (<NUM>").

A die system for producing containers is provided including the expansion die <NUM>. The die system includes at least a first expansion die <NUM> having a work surface <NUM> configured to increase a container's diameter, and at least one progressive expansion die, wherein each successive die in the series of progressive expansion dies has a work surface configured to provide an increasing degree of expansion in the container's diameter from the previous expansion die. In one embodiment, the die system may also include one or more necking dies.

Although the invention has been described generally above, the following example is provided to further illustrate the present invention and demonstrate some advantages that may arise therefrom. It is not intended that the invention be limited to the specific example disclosed.

In one example, the four expansion dies depicted in <FIG> are utilized to increase the internal diameter of the container <NUM> from about <NUM> (<NUM>") to a diameter of about <NUM> (<NUM>"), as depicted in <FIG>. The expansion die <NUM> depicted in <FIG> can be used to expand the <NUM> (<NUM>") diameter container to a <NUM> (<NUM>") diameter container. The expansion die shown in <FIG> can be used to expand the <NUM> (<NUM>") diameter container to a <NUM> (<NUM>") diameter container. The expansion die shown in <FIG> can be used to expand the <NUM> (<NUM>") diameter container to a <NUM> (<NUM>") diameter container. The expansion die shown in <FIG> can be used to expand the <NUM> (<NUM>") diameter container to a <NUM> (<NUM>") diameter container. It should be noted that as the diameter of the container expands, it also becomes shorter.

In one embodiment, the containers of <FIG> are comprised of <NUM> aluminum alloy having a H19 temper. The sidewall thickness is about <NUM> (<NUM>"). It should be noted that using some embodiments of the invention, it is possible to expand thin walled (equal to or less than about <NUM> (<NUM>")), hard-temper (H19, H39) drawn and ironed aluminum cans varying amounts including expanding these containers greater than <NUM>% in diameter, greater than <NUM>%, greater than, <NUM>%, and greater than <NUM>%.

In one example <FIG>, shows a container <NUM> having a sidewall <NUM> with a thickness that varies between about <NUM> (<NUM>") and about <NUM> (<NUM>"). The container <NUM> is aluminum in this example but may be comprised of any metal, such as steel, for example.

<FIG> shows a necking die <NUM> necking a lower portion <NUM> of the sidewall <NUM>. A bottom necked portion <NUM> is also illustrated as well as a knockout <NUM>. <FIG> and 21a show a necking die <NUM>, shown in <FIG>, representing a series of two necking dies used to create the bottom necked portion <NUM> of the container <NUM>. The table shown next to <FIG> and 21a show the dimensions that vary between the first and second dies, which comprise the series of two dies used to form the bottom necked portion <NUM> (shown in <FIG> and <FIG>) of the container <NUM>. Part of the working surface <NUM> of the necking die <NUM>, including the land <NUM> has a textured surface with an Ra value of about <NUM> × <NUM>-<NUM> mm (<NUM> micro inches). The Ra value of the working surface <NUM> that was not textured had a Ra value of about <NUM> × <NUM>-<NUM>-<NUM> × <NUM>-<NUM> mm (<NUM>-<NUM> micro inches).

<FIG> shows a knockout <NUM> representative of the two knockouts used in conjunction with the necking dies <NUM> shown in <FIG>, <FIG> and 21a. The table shown next to <FIG> shows the dimensions that vary between the first and second knockouts <NUM>, which were used with the series of two dies to form the bottom necked portion <NUM> of the container <NUM>.

The table below shows the dimensions of the container <NUM> before and after each necking step in necking the lower portion <NUM> of the sidewall <NUM>.

The dimensions are in inches. The "gap" is the radial distance between the inner diameter of the land <NUM> of the necking dies <NUM> and the outer diameter of knockouts <NUM>. The "estimated metal thk" is the maximum thickness of the metal being formed by the necking die. As mentioned earlier, the metal thickness of the sidewall <NUM> of the containers formed in this example varies by about <NUM> (<NUM>") in the portion of the sidewall <NUM> being formed, i.e. the necking dies <NUM> travel over metal that varies in thickness by about <NUM> (<NUM>"). The necking dies <NUM> and the accompanying knockouts <NUM> are designed to accommodate the thickest metal, as well as the thinnest metal they pass over in the necking process. The thickest metal in the sidewall <NUM>, in this example, is near the top of the container <NUM>. This information also applies to tables appearing later in this specification.

<FIG> and <FIG> show an expansion die <NUM> used to expand the diameter of a middle portion <NUM> of the sidewall <NUM> of the container <NUM> after the two necking steps. In this example, two expansion steps followed the two necking steps. The table shown under <FIG> shows the dimensions that vary between the first and second expansion dies <NUM>, which comprise a series of two expansion dies. None of the expansion dies <NUM> were textured in this example.

In the table below, "body rad. " and "neck rad. " refer to radii of the expansion dies.

<FIG> and <FIG> show the container after necking with the two necking dies shown in <FIG>, <FIG> and 21a and expanding with the two expansion dies shown in <FIG> and <FIG>. The thin wall portion <NUM> and thick wall portion <NUM> are shown. The transition between the thin wall and the thick wall can be short or long and gradual. The necking steps followed by expansion steps form a pinch <NUM> in the container <NUM>.

<FIG> shows a necking die <NUM> forming the top necked portion <NUM> in an upper portion <NUM> of the container <NUM>. Because of the scale of the drawing, the land and relief in the necking die is not shown. The top necked portion <NUM> was necked in multiple necking stations with a series of multiple different necking dies. Additional necking stations and dies may be used to obtain a bottle or other desired shape. A die representative of the five dies used in stations <NUM>-<NUM> is shown in <FIG>. The dimensions that vary between each of the five dies used to produce the top necked portion are shown in the table labeled "Profile 'I'" under <FIG>. None of the dies in this series of five were textured. <FIG> shows a knockout <NUM> representing the knockouts used in conjunction with the five necking dies represented in <FIG>. The table next to <FIG> lists the dimensions that vary between the five knockouts <NUM>. In this example, the outer diameter of the top of the container before necking was about <NUM> (<NUM> inches).

Claim 1:
A shaped aluminum container (<NUM>), comprising:
a sidewall (<NUM>) including an upper sidewall having a thickness of about <NUM> (about <NUM> inch) or less, wherein the sidewall (<NUM>) includes a top necked portion (<NUM>) and a bottom necked portion (<NUM>), wherein thickness of the sidewall in the bottom necked portion (<NUM>) varies from the thickness of the upper sidewall by at least <NUM> (<NUM> inch) to not greater than <NUM> (<NUM> inch).