Aluminum beverage cans

Presented an almost complete information about aluminum cans Beer and soft drinks. Often referred to as simply “beer cans“:

design and component parts of aluminum cans
dimensions: height, diameter, wall thickness
weight (mass) of the can
built-in device “openers”
aluminum alloys – three different alloy
can manufacturing technology: from cutting a blank from an aluminum sheet to a can, filled with beer
equipment for the production of aluminum cans
recycling scrap aluminum cans

Aluminum packaging

Aluminum is widely used in various food packaging cans (Figure 1.1). Basic methods of manufacturing such aluminum cans – round and rectangular – shown in Figure 1.2.

Figure 1.1 – Variety of aluminum food cans [1]

Figure 1.2 – Methods of making cans from aluminum sheet [1]

Beer and beverages aluminum packaging

Aluminum cans for beer and other drinks are popular all over the world with a 60-ies of the last century. In the US, almost 100 % of beer is sold in aluminum cans, Europe - somewhere 50 %. Aluminum cans are consumed in huge quantities mainly in two types of containers: 0,33 and 0,50 l. Large production volumes justify the high-speed, high-precision production lines. Moreover, these various basic aluminum cans have the same diameter, they use the same cover and differ only in height.

The great advantage of aluminum beer cans before the main competitor – glass – the possibility of complete recycling of aluminum cans after their use in new beer cans.

Main elements and details

Aluminum beer cans (and for carbonated drinks too) must withstand internal overpressure up to 6 atmospheres. Therefore, banks structure includes a thick bottom and a dome-shaped rather thin walls, that, However, via bank of the internal pressure provides sufficient structural strength. A general view of a typical beer cans and assigning its various elements shown in Figure 1.3.

Figure 1.3 – Construction details of an aluminum can and their functions [2]

Dimensions of a beer aluminum can

Valid national regulations on the construction of aluminum cans – GOST 33748-2016 (instead of GOST R 51756-2001) “deep drawn aluminum cans with easy open lids”. is he, of course, consistent with similar international standards. According to it, the main parameters and dimensions of beer aluminum cans are as follows (accurate to 1 mm):

Beer can height:

cans 0,33 l – 115 mm
cans 0,5 l – 168 mm

Beer can diameter:

The bottom of the banks – 66 mm
cover jars – 59 mm.

The wall thickness of the beer cans

The housing is made of aluminum cans by drawing in two passes from a flat circular blank so-called "cup".
Then the walls of this cup are thinned during their successive rolling to a thickness of only one third of the original (Figure 2).
The bottom of the banks profiled in a special way not only, to withstand high internal pressure, but also for a good combination with a lower cover of aluminum cans – for easy packing.
Wall of the can is rolled to a thickness of 0,110 mm or less for almost the entire height. Currently, the minimum wall thickness, reported, already it comes to 0,08 mm.

Figure 2 – The wall thickness of the can has different thickness [1].

At the top of the can body wall is thicker and the thickness of beer cans in the place of 0,16 mm.
It is necessary for the convenience of the formation of the narrowed "neck", and to create a strong connection with the lid. The aluminum can lids are supplied separately and are installed on the body using the well-known double-lock seam immediately after filling the can with beer or other beverage (picture 3).

Figure 3 – The design of the jar lid connection with its body:
the seam “double lock” [1]

Cover of beer cans

The beginning of rapid growth in the popularity of aluminum beer cans refers to 1964 year, when it was invented design “easy open” cover (picture 4.1).

Figure 4.1 – Various types of easy-open aluminum covers [1]

On “beer” cans, these lids are opened with bare hands by simply turning a special "ear" (Figure 4.2a). Or even with one hand (!) (Figure 4.2b). The eyelet is installed on the lid using the so-called integral rivet (Figure 5). It is called the integral, because it is formed directly from metal cover.

Figure 4.2a – The lid opens easily and remains on the can [1]

Figure 4.2b – One-handed can opening [7]

Figure 5 – Technology of forming an integral rivet on a can lid [1]

The opening mechanism of beer cans

The task of the ear and the petal (it is also called “tongue”), make cotton escaping carbon dioxide gas at about effort on the eyelet 3 kilograms and completely pushing the petal (tongue) inside the can with an effort up to 7 kilograms, and the petal should remain hanging in banks.

This is achieved by making the perimeter lobe special notches of such depth, that can only 0,085 mm metal near the rivet and 0,110 mm on the opposite side (figure 6). In the same time, material at the cuts is strong enough, not to break during the manufacturing process or during unloading of the store.

Inside the petals can be seen another, inner row of notches. They are not as deep and serve, allegedly, for directional flow of metal in the main grooves and prevent ruptures the main sipes as they are formed.

Figure 6 – Notches provide crafty
reliable opening of the can in two stages:
first gas outlet, then pushing the petal inside the can [1]

The Ingenious Design of the Aluminum Beverage Can

Materials aluminum cans

Material requirements

The main requirement to the materials of beer cans is their ability to molding large plastic deformations. Aluminum alloys suitable in this sense is ideally. Moreover, for beer cans lids important ability to predictably burst of incisions. Aluminum handles this much better, than steel. Another positive point is that, and that the housing, and Cover - aluminum, that minimize any potential galvanic effects, which could lead to accelerated corrosion.

Body material

Details of beer cans are made of aluminum-manganese and aluminum-magnesium alloys (table). To apply tape can body thickness 0,30 mm from an aluminum alloy 3004 or a modification thereof – aluminum alloy 3104 – able to H19.

Materials of lids and keys

Lids are produced from lacquered 3104 aluminum alloy strip 5182 in temper H48 by thickness 0,26 mm, and for the production of "ears" – keys easy opening – strip of aluminum alloy 5042 in temper H18 by thickness 0,45 mm.

Table – Aluminum alloys of aluminum beer cans

Technology

aluminum cans production cycle

The figure below shows a cycle of production of aluminum cans for beer and soft drinks.

Figure 7.1 – Typical production cycle for aluminum beer cans [4]

Figure 7.2 – Deep drawing press [1]

Figure 7.3 – Extraction and reeling banks walls in “bodimeykere” [1]

Aluminum sheet rolls

Factories for producing aluminum beer cans consume large amounts of aluminum sheet, which comes in large rolls. The housing and cover are made of aluminum cans sheets – of different aluminum alloys. Each roll weighs about 11 tons and at its unwinding sheet travels a distance 9-13 kilometers.

Aluminum rolls fed to the plant for production of aluminum cans and loaded into “uncoiler” (uncoiler). This is a machine , which unwinds the aluminum sheet at the beginning of the production line for cans. Here on the aluminum sheet applied special lubricant. This lubricant makes aluminum sheet more “smooth”, without damage, through all shaping operations.

Body manufacturing

A typical process sequence for the manufacture of the can body shown in Figure 7. The first step in the manufacture of cans is cutting round billets, for example, diameter 140 mm. Naturally, this felling produces waste: these losses amount to about 12-14 %. They immediately sent to be melted down to manufacture new leaf and new beer cans.

An intermediate blank is obtained from the original round billet by deep drawing (stamping) – shallow “cup” (drawings 8 and 9). from this “cup” by rolling are almost ready can body, and also form a dome of the bottom (figures 8, 10, 11). Then, the bank-finished wash, drawings are applied to it and varnished, and only after that its mechanical shaping is completed - the formation of the throat and flanging (figure 8).

Figure 8 – Aluminum can body manufacturing technology (0, 33 mm) [1]

Figure 9 – deep-drawing – forming “cup” [2]

Figure 10 – Rolling out the can wall [2]Figure 11- Bottom molding [2]

Making beer can lids

Aluminum sheet supplied in rolls of up to 8 tonnes. Each roll is made up 2,5 millions of caps. aluminum sheet, which has a pre-paint coating, served in a special press, in which the dies are almost ready to cover. Then produce complex edges forming a cover, which then provides a reliable connection with its banks housing.

Figure 12 – Not yet fully finished cover [3]

Making beer cans abalone

Manufacturing process abalone - key-openers – It includes about 13 operations (figure 13), before it can be installed on the cover.

Figure 13 – Technological operations for making an eyelet [3]

Scrap aluminum cans

How many cans are in 1 kilogram of scrap?

The average weight of various cans of various capacities for low alcohol drinks, including, beer:

0,33 l - 13 g - 77 cans on 1 kg of aluminum scrap
0,5 l - 15-20 g - 50-66 cans on 1 kg of aluminum scrap

How much is 1 kg of aluminum cans for scrap?

The cost of scrap aluminum cans (in Moscow at the end of April 2020 of the year):

35-50 rub

Do not crush aluminum can

Large waste recyclers usually ask not to crush empty aluminum cans. The thing is, that household or, as they call him, municipal waste is sorted automatically by special sorting machines. These machines identify aluminum cans by their shape: round and smooth. The machine accepts the crumpled can for irreplaceable waste and sends it to the landfill.

Remelting aluminum cans

Plain remelting of aluminum cans gives on average the following aluminum composition:

Si - 0,26 %
Fe - 0,40 %
Cu - 0,20 %
Mn - 0,86 %
Mg – 1,22 %
Ti - 0,04 %
other - Al.

“Aluminum” such chemical composition is well within the range of chemical composition of alloys 3004 and 3104 (cm. (see table above), which is used for making the can body. Therefore, the overwhelming part of the scrap of aluminum cans is remelted and returned to their manufacturers (figures 14 and 15) .