Patent Application
20160368650
This disclosure relates to a metal elongated bottle and its method of production, and, in particular, to an elongated low-spread aluminum bottle and its method of production.
Beverage containers are often made from a metal sheet due to the robust structure, light weight, and good thermal conductivity of metal sheet materials. For example, aluminum cans are prevalent in the beverage industry and are made from aluminum sheet coils that are cut, drawn, formed, trimmed and coated to form cylindrical containers. The cylindrical containers are then filled with a beverage and sealed with a single-use lid.
Recently, metal sheet material has also been used to create aluminum, bottle-shaped containers that have a narrow neck and an open end that is either threaded to receive a cap or includes a crimped crown. The narrow neck and slender shape of aluminum bottles provide more comfort for drinkers holding the bottle and also provide an appealing visual appearance. However, the elongate shaped body and the narrow neck of aluminum bottles require increased plastic deformation of the original aluminum sheet material when the bottle is formed. The increased deformation of the aluminum sheet has resulted in increased manufacturing defects and higher rejection rates when compared with aluminum can manufacturing.
This disclosure presents a low-spread metal elongated bottle and its production method. As described in more detail below, the low-spread metal bottle and production method result in reduced rejection rates as compared with rejection rates when aluminum bottles are made using traditional aluminum can materials and manufacturing methods. The low-spread metal elongated bottle is formed from a low-spread metal and includes an elongated body shape and a narrow neck. The low-spread metal has a low spread between a yield state corresponding to the yield stress of the sheet metal and an ultimate tensile state corresponding to the ultimate tensile stress of the sheet metal.
In a specific aspect, the spread of the sheet metal equals to the arithmetic difference between the yield stress and the ultimate tensile stress. For example, in some embodiments, the difference between the yield stress and ultimate tensile stress of the low-spread sheet metal is about 22.4 MPa or 3.25 ksi. In some embodiments, the yield stress of the low-spread sheet metal is about 200 MPa or 29 ksi.
In another aspect, there is described a method for manufacturing an elongated bottle that includes providing a piece of sheet metal having a low spread between a yield state and an ultimate tensile state. The yield state corresponds to the yield stress of the sheet metal and the ultimate tensile state corresponds to the ultimate tensile stress of the sheet metal. The piece of sheet metal is formed into a circular cup. The circular cup is drawn into a cylindrical container having an open end and a closed end. The closed end of the cylindrical container is formed into a concave bottom portion. The open end of the cylindrical container is narrowed into a neck portion.
In one specific aspect, the method further includes trimming the open end for a straight edge prior to narrowing the open end into the neck portion.
In another specific aspect, narrowing the open end of the cylindrical container into a neck portion further includes applying a pressure perpendicular to the cylindrical axis of the central container near the open and.
In yet another specific aspect, the method further includes applying a layer of paint onto the outer surface of the elongated bottle. The layer of transparent seal is further applied onto the layer of paint.
In one specific aspect, the method further includes applying a film of seal onto the inner surface of the elongated bottle.
In another specific aspect, the spread of the sheet metal is the arithmetic difference between the yield stress and the ultimate tensile stress of the sheet metal. In some embodiments, the spread is within about 22.4 MPa or 3.25 ksi.
In another aspect, there is described an elongated bottle that includes a sheet metal formed body, wherein the sheet metal of the sheet metal formed body has a low spread between a yield state corresponding to the yield stress of the sheet metal and an ultimate tensile state corresponding to the ultimate tensile stress of the sheet metal. The body also includes a concave bottom portion that has a circular perimeter and a cylindrical portion that extends from the circular perimeter of the bottom portion. In some embodiments, the cylindrical portion has a uniform diameter. The bottle also includes a neck portion that has a varying diameter reduced from the uniform diameter of the cylindrical portion to form a tapered profile. The bottle also includes an opening.
In some embodiments, the arithmetic difference between the yield stress and the ultimate tensile stress of the sheet metal is between about 21 MPa or 3.05 ksi and about 23.1 MPa or 3.35 ksi.
In other embodiments, the arithmetic difference between the yield stress and the ultimate tensile stress of the sheet metal is between about 21.4 MPa or 3.1 ksi and about 22.8 MPa or 3.3 ksi.
In yet other embodiments, the arithmetic difference between the yield stress and the ultimate tensile stress of the sheet metal is about 22.1 MPa or 3.2 ksi.
In still other embodiments, the yield stress of the sheet metal is between about 196.5 MPa or 28.5 ksi and about 217.2 MPa or 31.5 ksi.
In another embodiment, the yield stress of the sheet metal is between about 29 ksi and about 31 ksi.
In still another embodiment, the yield stress is about 29.8 ksi.
In some embodiments, the cylindrical portion of the bottle has a length between about 114 mm or 4.490″ and about 162 mm or 6.381″.
In other embodiments, the cylindrical portion has a length of about 162 mm.
In still other embodiments, the bottle has a total length between about 190 mm and about 238 mm.
In another embodiment, the bottle has a total length of about 238 mm.
In certain embodiments, the neck portion of the bottle includes a threaded portion.
In other embodiments, the threaded portion of the neck portion includes a folded flange.
In some embodiments, the bottle includes a threaded cap that is couplable with the threaded portion.
In another aspect, there is described a method for manufacturing an elongated bottle that includes providing sheet metal having a low spread between a yield state corresponding to the yield stress of the sheet metal and an ultimate tensile state corresponding to the ultimate tensile stress of the sheet metal. The method includes forming the sheet metal into a circular cup and drawing and ironing the circular cup into a cylindrical container having an open end and a closed end. The method also includes forming the closed end of the cylindrical container into a concave bottom portion and cutting the open end of the cylindrical container. The method also includes forming the open end of the cylindrical container into a neck portion.
In some embodiments, the method includes forming the container to have a total length between about 127 mm or 5″ and about 254 mm or 10″.
In other embodiments, the method includes forming the container to have a total length of about 238 mm.
In some other embodiments, an arithmetic difference between the yield stress and the ultimate tensile stress is about 22.4 MPa or 3.2 ksi.
In another aspect, there is provided a method for manufacturing a beverage bottle that includes forming sheet metal into a circular cup, wherein the sheet metal has a low spread between a yield state corresponding to the yield stress of the sheet metal and an ultimate tensile state corresponding to the ultimate tensile stress of the sheet metal. The arithmetic difference between the yield stress and the ultimate tensile stress of the sheet metal is about 22 MPa or 3.2 ksi and the yield stress is about 205.5 MPa or 29.8 ksi. The method also includes drawing and ironing the circular cup into a cylindrical container that has an open end and a closed end. The method also includes forming the closed end of the cylindrical container into a concave bottom portion and cutting the open end of the cylindrical container. The method also includes narrowing the open end of the cylindrical container into a neck portion and folding an edge of the open end outward to form a flange. In some embodiments, the bottle has a total length of about 238 mm.
In other embodiments, the method includes forming a shoulder portion at an angle of about 45 degrees to a body portion of the container.
Other aspects, features, and advantages will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are part of this disclosure and which illustrate, by way of example, principles of the disclosure.
Metal elongated bottles have many advantages over traditional can-shaped containers (as briefly discussed in the background). However, during manufacturing, rejection rates for elongated bottles may be higher than rejection rates of traditional cans due to the more complicated geometry of the bottle and the higher plastic deformation required for the elongated shape and narrower neck of the bottle. For example, rejections rates in the production of metal bottles may range from about 5% to about 95% due to defects such as excessive metal expansion and brim roll splitting.
It was previously thought that a wide spread between the yield stress and the ultimate tensile stress of the sheet aluminum used to form aluminum containers would provide lower rejection rates by allowing for increased operating latitude for metal forming properties. It has been found, however, that a low spread, i.e., a low difference between the yield stress and the ultimate tensile stress, of the sheet aluminum, such as the 3104 series aluminum, provides for lower rejection rates at high production speeds. In addition, it has been found that special post-forming thermal treatment of the metal, in conjunction with low spread metal, also helps to reduce manufacturing defects. For example, in some embodiments, a cup formed from a low spread metal is heat treated after a decorative printing coat is applied to the cup to dry the decorative printing. The cup is then necked and threaded, and a brim roll is applied to the bottle opening. In some embodiments, the heat treating of the metal, in conjunction with the low spread metal, removes a sufficient amount of work hardening to allow for necking, threading and brim rolling at high production speeds with low defect rates.
This disclosure presents a low-spread metal elongated bottle and a production method for reducing rejection rates associated with the production of aluminum bottles. In some embodiments, the production method described herein also allows for the production of an elongated bottle that is taller than previously available aluminum bottles. In some embodiments, the production method described herein also allows for a thinner side wall thickness and thus a lower aluminum material usage than previously available. Further, the disclosed processes and apparatuses may be used to form complicated bottle shapes that are less feasible with non-low-spread metals.
The elongated bottle 100 shown in
The neck portion 105 is formed near the open end 191 of the bottle 100. The neck portion 105 has a varying diameter reduced from the uniform diameter 112 of the cylindrical portion 110. The varying diameter forms a tapered profile 107 that gradually constricts the neck portion 105 toward the opening 123. In some embodiments, a shoulder portion 111 of the neck portion 105 extends at an angle of about 45 degrees from the cylindrical portion 110. In some embodiments, a top neck portion 113 of the neck portion 105 extends at an angle of about 6 degrees from a center line 103 of the bottle 100. In some embodiments, the top neck portion 113 of the neck portion 105 extends at an angle of about 5.75 degrees from the center line 103 of the bottle 100.
The neck portion 105 includes a threaded portion 120 that has one or more threads 122 exposed on the outer surface of the threaded portion 120. The threads 122 enables a threaded cap 300 (
In some embodiments, a printed indicia 118 is applied onto the outer surface of the bottle 100. The print indicia 118 may be further sealed with a clear or transparent coat 119 applied to the outer surface of the bottle 100. An inner coating 130 may be applied to an inner surface of the elongated bottle 100 for separating a beverage from the sheet metal 101.
In some embodiments, the cylindrical portion 110 of the bottle 100 has a height of between about 114 mm or 4.490″ and about 162 mm or 6.381″. In some embodiments, the cylindrical portion 110 has a height of between about 120 mm or 4.7244″ and about 155 mm or 6.1024″. In other embodiments, the cylindrical portion 110 has a height of about 162 mm or 6.3779″. In some embodiments, the bottle 100 has an overall height of between about 190 mm or 7.48″ and about 238 mm or 9.37″. In other embodiments, the bottle 100 has an overall height of between about 200 mm or 7.874″ and about 220 mm or 8.661″. In other embodiments, the bottle 100 can have an overall height up to about 762 mm or 30″. As described in more detail below, bottles of this height were previously difficult to form on a consistent basis at high production rates due to high defect rates. For example, the increased amount of cold working of metal involved in forming a taller container caused the metal to become more brittle, leading to an increased rate of manufacturing defects. It has been found that the use of low spread metal in conjunction with heat treating allows for the creation of bottle-shaped containers at high speeds with low defect rates. The present disclosure allows for consistent, low-defect-rate production of bottles 100 with an overall height of about 238 mm (9.37″) or taller at high production speeds.
As shown in
In some embodiments, the ultimate tensile stress of the low-spread aluminum sheet material is between about 213.7 MPa or 31 ksi and about 241.3 MPa or 35 ksi. In some embodiments, the ultimate tensile stress of the aluminum sheet material is about 227.5 MPa or 33 ksi. In some embodiments, the yield stress of the aluminum sheet material is between about 196.5 MPa or 28.5 ksi and about 217.2 MPa or 31.5 ksi. In other embodiments, the yield stress is about 205.5 MPa or 29.8 ksi. It has been found that yield stress below about 193 MPa or 28 ksi may result in a loss of buckle strength of the bottle 100. In some embodiments, the arithmetic difference between the yield stress and the ultimate tensile stress of the low-spread metal is between about 21 MPa or 3.05 ksi and about 23.1 MPa or 3.35 ksi. In other embodiments, the arithmetic difference between the yield stress and the ultimate tensile stress in the low-spread metal is between about 21.4 MPa or 3.1 ksi and about 22.1 MPa or 3.2 ksi. In some embodiments, the arithmetic difference between the yield stress and the ultimate tensile stress in the low-spread metal is about 22.4 MPa or 3.25 ksi. In some embodiments, for example, the low-spread metal 210 may have a yield stress σy=200 MPa (or 29 ksi) and a tensile stress σuL=222.4 MPa (or 32.25 ksi). The low spread σuL−σY is therefore within about 22.4 MPa (or 3.25 ksi). As explained above, the arithmetic difference in non-low-spread metal between the yield stress and the ultimate tensile stress is typically about 255.1 MPa or 37 ksi.
During deformation, the achievable maximum plastic deformation of the low-spread sheet metal 210 is εL shown at numeral 233, wherein εT−εL is the elastic strain. Similarly, the maximum plastic deformation of the non-low-spread sheet metal 220 is εN shown at numeral 231, wherein εT−εN is the elastic strain. Because σuN is greater than σuL, and both metals 210 and 220 have the same elasticity modulus E 215, the achievable plastic deformation εL 233 is greater than εN 231. Therefore, it has been found that the low-spread metal 210 can withstand greater plastic deformation during high speed metal bottle production than non-low-spread metal 220. In addition, it has been found that the difference between εL 233 and εN 231 in low-spread metal reduces the rejection rates during production by reducing tearing and defects in the bottles. In some embodiments, for example, low spread metal having a spread of about 3.2 ksi has produced bottles 100 at a rate of about 1,200 bottles per minute with a defect rate of about 3%, as compared with defect rates from about 10% to about 60% with non-low-spread material.
It was previously thought that a low spread between the yield stress and the ultimate tensile stress of metal sheets used to form cans and bottles would increase defect rates and slow production. Specifically, it was previously thought that a wide spread was necessary to provide increased operating latitude for metal forming properties. However, it has been found that using sheet metal with a low spread between the yield stress and the ultimate tensile stress is well suited to form elongated aluminum bottles at high speeds.
As described above, the low-spread sheet metal 260 has a lower spread than the non-low-spread sheet metal 270, or, in other words, σuL−σyL<σuN−σyN. In the example illustrated in
At step 404, the sheet metal is formed into a cup. The cup is then drawn into a cylindrical container at step 406. The cylindrical container has an open end and a closed end. At step 408, a concave bottom portion is formed at the closed end of the cylindrical container. In some embodiments, the open end is trimmed for a straight edge prior to narrowing the open end into the neck portion. At step 410, a decorative coating and sealer are applied to the cup. In some embodiments, a layer of paint is applied onto the outer surface of the elongated bottle 100 and a layer of transparent sealer 119 may further be applied onto the layer of paint. A film of sealer 130 may be applied onto the inner surface of the elongated bottle 100 for separating the drink from the sheet metal. At step 412, the cylindrical container may be heat treated to remove some or all of the work hardening effect incurred at previous steps and to dry the decorative coating or sealer applied to the cup. At step 4114, a neck portion is formed near the opening 123 of the cylindrical container 100. The neck portion 105 may be formed in a necking operation and may have a varying diameter forming a narrowing tapered profile 107.
At step 416, a threaded portion 120 is formed on the neck portion 105 by deforming or indenting a portion of the neck portion 105 to form one or more threads 122. The threads 122 are exposed on the outer surface of the elongated bottle 100. At 418, a flange 125 at the edge of the opening 123 is folded outwardly to provide a rounded rim.
In some embodiments, the temperature set points and cycle duration during step 412 are configured to cure any decorative coating applied to the bottle and to thermally recover the metal. For example, the coated bottle 100 may pass through a washer dry-off oven, a pin oven, and a bake oven. In some embodiments, the coated bottle 100 may travel at about 5-17 ft/min through the washer dry-off oven at about 275-500° F. Then the coated bottle 100 may travel at the rate of about 200-1500 cans/min through the pin oven at about 390-500 F. And finally the coated bottle 100 may travel through the bake oven at a maximum speed of about 12-22 ft/min. The inside oven temperature can be about 290-340° F. in a first zone, 410-500° F. in a second zone, and 400-500° F. in a third zone.
In a different embodiment, the coated bottle 100 may travel at about 6-14 ft/min through the washer dry-off oven at about 280-350° F. Then the coated bottle 100 may travel at the rate of about 400-1300 cans/min through the pin oven at about 425-485° F. And finally the coated bottle 100 may travel through the bake oven at a maximum speed of about 14-20 ft/min. The inside oven temperature can be about 300-330° F. in a first zone, about 450-490° F. in a second zone, and about 440-490° F. in a third zone.
In some other embodiments, the coated bottle 100 may travel at about 7-12 ft/min through the washer dry-off oven at about 300-320° F. Then the coated bottle 100 may travel at the rate of about 600-1200 cans/min through the pin oven at about 460-470° F. And finally the coated bottle 100 may travel through the bake oven at a maximum speed of about 16-18 ft/min. The inside oven temperature can be about 310-320° F. in a first zone, about 465-475° F. in a second zone, and about 460-470° F. in a third zone. It has been found that, in some embodiments, the above temperatures and travel rates recover at least some of the work hardening of the material to allow the low spread metal to be formed into the shape of a bottle with a neck-shaped portion, as described above.
In the foregoing description of certain embodiments, specific terminology has been chosen for the sake of clarity. However, the disclosure is not intended to be limited to the specific terms selected, and it is to be understood that each specific term includes other technical equivalents which operate in a similar manner to accomplish a similar technical purpose. In this specification, the word “comprising” is to be understood in its “open” sense, that is, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise”, “comprised” and “comprises” where they appear.
In addition, the foregoing describes some embodiments of the disclosure, and alterations, modifications, additions and/or changes can be made thereto without departing from the scope and spirit of the disclosed embodiments, the embodiments being illustrative and not restrictive.
Furthermore, the disclosure is not to be limited to the illustrated implementations, but to the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the disclosure. Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment.
This application is a continuation of application Ser. No. 14/292,686, filed May 30, 2014, entitled “Low Spread Metal Elongated Bottle and Production Method,” now pending and incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14292686 | May 2014 | US |
| Child | 15250388 | US |
