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A beverage can is a metal container designed to hold a fixed portion of liquid such as a carbonated soft drinks, alcoholic beverages, fruit juices, teas, tisanes, energy drinks, etc. Beverage cans are made of aluminium (75% of worldwide production) or tin-plated steel (25% worldwide production). Worldwide production for all beverage cans is approximately 475 billion cans per year worldwide, 52 billion per year in Europe.

History
Beginning in the 1930s, after an established history of success with storing food, metal cans were used to store beverages. The first beer was available in cans beginning in 1935. Not long after that, sodas, with their higher acidity and somewhat higher pressures, were available in cans. The key development for storing beverages in cans was the interior liner, typically plastic or sometimes a waxy substance, that helped to keep the beverage's flavor from being ruined by a chemical reaction with the metal. Another major factor for the timing was the end of Prohibition in the US at the end of 1933.

Canned beverages were factory-sealed and required a special opener tool in order to consume the contents. Cans were typically formed as cylinders, having a flat top and bottom. These would become known as "punch top" cans, they required an opener, typically a wedge shaped metal cutter known as a church key that latched onto the top rim for leverage where lifting it by hand would cut a triangular opening at the top edge of the can. A small second hole was usually punched at the opposite side of the top in order to let air in, allowing the beverage to flow freely.

In the mid-1930s, some cans were developed with caps so that they could be opened and poured more like a bottle. These were called "cone tops", as their tops had a conical taper up to the smaller diameter of the cap. Cone top cans were sealed by the same crimped caps that were put on bottles, and could be opened with the same bottle-opener tool. There were three types of conetops: high profile, low profile, and j-spout. The low profile and j-spout were the earliest, dating from about 1935. The "crowntainer" was a different type of can that was drawn steel with a bottom cap. These were developed by Crown Cork & Seal (now known as Crown Holdings, Inc.), a leading beverage packaging and beverage can producer. Various breweries used crowntainers and conetops until the late 1950s, but many breweries kept producing the simple cylinder-cans.

The popularity of canned beverages was slow to catch on, as the metallic taste was difficult to overcome with the interior liner not perfected, especially with more acidic sodas. But one significant advantage that the cans had over bottles is that they were discarded after use, unlike the deposit typically paid for bottles and not reimbursed until after consumers returned the empties back to the store. For the distributors, flat-top cans were more compact for transportation and storage, with cans also weighing less than bottles. By the time the US entered World War II, cans had gained only about ten percent of the beverage container market. And this was brought drastically down during the war to accommodate the strategic needs for metal.

In 1959, Ermal Fraze devised a can-opening method that would come to dominate the canned beverage market. His invention was the "pull-tab". This eliminated the need for a separate opener tool by attaching an aluminium pull-ring lever with a rivet to a pre-scored wedge-shaped tab section of the can top. It was like having an opener tool built into every can. The ring was riveted to the center of the top, which created a wedge opening long enough so that one hole served to both let the beverage flow out while air flowed in. Into the 1970s, the pull-tab was widely popular, however its popularity came with a significant problem as people would frequently discard the pull-tabs on the ground as litter. One technique that avoided littering was to drop the pull-tab into the drink. The littering problem was also addressed by the invention of the "push-tab".

Used primarily on Coors Beer cans in the mid-70s, the push-tab was a raised circular scored area used in place of the pull-tab. It needed no ring to pull up. Instead, the raised aluminium blister was pushed down into the can, with a small unsecured piece that kept the tab connected after being pushed inside. Push-tabs never gained wide popularity because while they had solved the litter problem of the pull-tab, they created a safety hazard where the person's finger upon pushing the tab into the can was immediately exposed to the sharp edges of the opening. (An unusual feature of the push-tab Coors Beer cans was that they had a second smalle r push-tab at the top as an airflow vent—a convenience that was lost with the switch from can opener to pull-tab.)

The safety and litter problems were both eventually solved later in the 1970s with Ermal Fraze's invention of the non-removing "pop-tab". The pull-ring was replaced with a stiff aluminium lever, and the removable tab was replaced with a pre-scored round tab that functioned similarly to the push-tab, however the raised blister was no longer needed as the riveted lever would now do the job of pushing the tab open and into the interior of the can.

In 2008, an aluminium version of the crowntainer design was adopted for packaging Coca-Cola's Caribou Coffee beverage. In 2004, Anheuser-Busch adopted an all-aluminium bottle for use with Budweiser and Bud Light beers.

Capacity
Various standard capacities are used throughout the world.

In Australia the standard can size is 375 ml. But for Energy Drinks, most commonly 500 ml
 * Australia

In New Zealand the standard can size is 355 ml.
 * New Zealand

In China the most common size is 330 ml.
 * China

Can dimensions may be cited in metric or imperial units. Imperial dimensions for canmaking are written as inches+sixteenths of an inch (e.g. "202" = 2 inches + 2 sixteenths). The US standard can is 4.83 inches high, 2.13 inches in diameter at the lid, and 2.60 inches in diameter at the widest point of the body.

In most of Europe standard cans are 330 ml. In some European countries there is a second standard can size, 500 ml, often used for beer, cider and energy drinks.
 * Europe

In the UK 440 ml is commonly used for lager.

In Hong Kong most cans are either 355 ml or 330 ml.
 * Hong Kong

In India standard cans are 330 ml.
 * India

In Japan the most common sizes are 350 ml and 500 ml. Larger and smaller cans are also sold.
 * Japan

In Korea 250 ml cans are the most common for soft drinks. However, when accompanying take out food (such as pizza or chicken), a short 245 ml can is standard. Recently, some 355 ml cans which are similar to North American cans are increasingly available, but limited mostly to Coca-Cola and Dr Pepper. Finally, beer cans also come in 500 ml forms.
 * Korea

In both Malaysia and Singapore, the most commonly found cans are 300 ml. Larger 330 ml/350 ml cans are limited to imported drinks where it would usually cost a lot more than local ones.
 * Malaysia and Singapore

In North America, the standard can size is 12 USoz.
 * North America

In Canada, the standard size was previously 10 Imperial fluid ounces (284 ml), later redefined and labeled as 280 ml in around 1980. This size was commonly used with steel beverage cans in the 1970s and early 1980s. However, the US standard 355 ml can size was standardized in the 1980s and 1990s, upon the conversion from steel to aluminium.

South African standard cans are 330 ml and the promotional size is 440 ml. There is also the 500ml can. A smaller 200 ml can is used for "mixers" such as tonic or soda water. It has a smaller diameter than the other cans.
 * South Africa

Composition
Most metal beverage cans manufactured in the United States are made of aluminium, whereas in some parts of Europe and Asia approximately 55 percent are made of steel and 45 percent are aluminium alloy. Steel cans often have a top made of aluminium. The aluminium used in United States and Canada are alloys containing 92.5% to 97% aluminium, <5.5% magnesium, <1.6% manganese, <0.15% chromium and some trace amounts of iron, silicon and copper according to MSDS from aluminium producer Alcoa.

An empty aluminium can weighs approximately half an ounce (15 g). There are roughly 30 empty aluminium cans to a pound or 70 to a kilogram.

In many parts of the world a deposit can be recovered by turning in empty plastic, glass, and aluminium containers. Scrap metal dealers often purchase aluminium cans in bulk, even when deposits are not offered. Aluminium is one of the most cost-effective materials to recycle. When recycled without other metals being mixed in, the can–lid combination is perfect for producing new stock for the main part of the can—the loss of magnesium during melting is made up for by the high magnesium content of the lid. Also, reducing ores such as bauxite into aluminium requires large amounts of electricity, making recycling cheaper than producing new metal.

Aluminium cans are coated internally to protect the aluminium from oxidizing. Despite this coating, trace amounts of aluminium can be degraded into the liquid, the amount depending on factors such as storage temperature and liquid composition. Chemical compounds used in the internal coating of the can include types of epoxy resin.

How beverage cans are made
Ninety-five percent of all beer and soft drink  cans in the United States are made of aluminum. American can makers produce about 100 billion aluminum beverage cans a year, equivalent to one can per American per day. While almost all food cans are made of steel, aluminum's unique properties make it ideal for holding carbonated beverages. The typical aluminum can weighs less than half an ounce, yet its thin walls withstand more than 90 pounds of pressure per square inch exerted by the carbon dioxide in beer and soft drinks. Aluminum's shiny finish also makes it an attractive background for decorative printing, important for a product that must grab the attention of consumers in a competitive market.

Filling cans
Cans are filled before the top is crimped on. The key engineering issue is that can walls are about 80 micrometers thick, so empty cans are light, weak, and can easily be damaged. The filling and sealing operations need to be extremely fast and precise. The filling head centers the can using gas pressure, purges the air, and lets the beverage flow down the sides of the can. The lid is placed on the can, and then crimped in two operations. A seaming head engages the lid from above while a seaming roller to the side curls the edge of the lid around the edge of the can body. The head and roller spin the can in a complete circle to seal all the way around. Then a pressure roller with a different profile drives the two edges together under pressure to make a gas-tight seal. Filled cans usually have pressurized gas inside, which makes them stiff enough for easy handling.

Fabrication process
Modern cans are generally produced through a mechanical cold forming process that starts with punching a flat blank from very stiff cold-rolled sheet. This sheet is typically alloy 3104-H19 or 3004-H19, which is aluminium with about 1% manganese and 1% magnesium to give it strength and formability. The flat blank is first formed into a cup about three inches in diameter. This cup is then pushed through a different forming process called "ironing" which forms the can. The bottom of the can is also shaped at this time. The malleable metal deforms into the shape of an open-top can. With the sophisticated technology of the dies and the forming machines, the side of the can is significantly thinner than either the top and bottom areas, where stiffness is required. A single can-making production line can turn out up to 2400 cans per minute.

Plain lids (known as shells) are stamped from a coil of aluminium, typically alloy 5182-H48, and transferred to another press that converts them to easy-open ends. This press is known as a conversion press which forms an integral rivet button in the lid and scores the opening, while concurrently forming the tabs in another die from a separate strip of aluminium. The tab is pushed over the button, which is then flattened to form the rivet that attaches the tab to the lid.

Finally, the top rim of the can is trimmed and pressed inward or "necked" to form a taper conical where the can will later be filled and the lid (usually made of an aluminium alloy with magnesium) attached.

Opening mechanisms


Early metal beverage cans had no tabs; they were opened by a can-piercer or churchkey, a device resembling a bottle opener with a sharp point. The can was opened by punching two triangular holes in the lid—a large one for drinking, and a second (smaller) one to admit air.

As early as 1922, inventors were applying for patents on cans with tab tops, but the technology of the time made these inventions impractical. Later advancements saw the ends of the can made out of aluminium instead of steel.

Cans are usually in sealed paperboard cartons, corrugated fiberboard boxes, or trays covered with plastic film. The entire distribution system and packaging need to be controlled to ensure freshness.

Pull-tab


Mikola Kondakow of Thunder Bay, Ontario, Canada, invented the pull tab version for bottles in 1956 (Canadian patent 476789). Then, in 1962, Ermal Cleon Fraze of Dayton, Ohio, United States, invented the similar integral rivet and pull-tab version (also known as ring pull in British English), which had a ring attached at the rivet for pulling, and which would come off completely to be discarded. He received US Patent No. 3,349,949 for his pull-top can design in 1963 and licensed his invention to Alcoa and Pittsburgh Brewing Company, the latter of which first introduced the design on Iron City Beer cans. The first soft drinks to be sold in all-aluminium cans were R.C. Cola and Diet-Rite Cola, both made by the Royal Crown Cola company, in 1964.

The early pull-tabs detached easily. The Journal of the American Medical Association noted cases of children ingesting pull-tabs that had broken off and dropped into the can.

Full-top pull-tabs were also used in some oil cans and are currently used in some soup, pet food, tennis ball, nuts and other cans.

Stay-on-tab


The Easy-open ecology end was also invented by Ermal Fraze and Omar Brown. This design reduced injuries and reduced roadside litter caused by removable tabs. The mechanism uses a separate tab attached to the upper surface as a lever to depress a scored part of the lid, which folds underneath the top of the can and out of the way of the resulting opening.

Such "retained ring-pull" cans supplanted pull-off tabs in the United Kingdom in 1989 for soft drinks and 1990 for alcohol.

Wide Mouth
One of the more recent modifications to can design was Mountain Dew's introduction of the "wide mouth" can in the late 1990s. The American Can Company, now a part of Rexam, and Coors Brewing Company have owned wide mouth design patent (number D385,192) since 1997. Other companies have similar designs for the wide mouth. Ball Corporation's from 2008 has a vent tube to allow direct airflow into the can reducing the amount of gulps during the pour.

Sustainable Beverage Ends
The SuperEnd® from Crown Holdings launched in 2000 was designed to use 10% less metal in production than standard beverage ends.

Press button can
One unsuccessful variation was the press button can, which featured two pre-cut buttons—one small and one large—in the top of the can,c sealed with a plastic membrane. These buttons were held closed by the outward pressure of the carbonated beverage. The consumer would open the can by depressing both buttons, which would result in two holes. The small hole would act as a vent to relieve internal pressure so the larger button could then be pressed down to create the hole used for drinking the beverage. Consumers could also easily cut themselves on the edges of the holes or get their fingers stuck.

Press button cans were used by Pepsi in Canada from the 1970s to 1980s and Coors in the 1970s. They have since been replaced with pull tabs.

Full Aperture End
A recent innovation to the beverage can is the full aperture end, where the entire lid is removed turning the aluminum can into a cup. Crown Holdings first designed the "360 End" for use by SABMiller at the 2010 FIFA World Cup in South Africa. It has been used by Anheuser-Busch InBev in China and Brazil  and most recently by Sly Fox Brewing Company  in the United States.

Collecting
Beer can collecting was a minor fad in the late 1970s and 1990s. However, the hobby waned rapidly in popularity. The Beer Can Collectors of America (BCCA), founded in 1970, was an organization supporting the hobby, but has now renamed itself Brewery Collectibles Club of America to be more modern.

As of late 2009, membership in the Brewery Collectibles Club of America was 3,570, down from a peak of 11,954 in 1978. Just 19 of the members were under the age of 30, and the members' average age had increased to 59.



The Future
Worldwide production of aluminum beverage cans is steadily increasing, growing by several billion cans a year. In the face of this rising demand, the future of the beverage can seems to lie in designs that save money and materials. The trend towards smaller lids is already apparent, as well as smaller neck diameters, but other changes may not be so obvious to the consumer. Manufacturers employ rigorous diagnostic techniques to study can sheet, for example, examining the crystalline structure of the metal with X-ray diffraction, hoping to discover better ways of casting the ingots or rolling the sheets. Changes in the composition of the aluminum alloy, or in the way the alloy is cooled after casting, or the thickness to which the can sheet is rolled may not result in cans that strike the consumer as innovative. Nevertheless, it is probably advances in these areas that will lead to more economical can manufacture in the future.