
Since
aluminum as a metal is lightweight, strong and also recyclable, it is
strongly recommended for making packaging material. The packaging
material made out of aluminum is in the form of sheet, coil, plate or
foil. Pure aluminum is mainly used for making aluminum sheet or other
packaging material. Nowadays, non-heat treatable alloys of
aluminum-manganese or aluminum-magnesium are also used for higher
strength. With both pure aluminum and alloys, there are different
mechanical properties available in sheets and coils through varying
degrees of work hardening.
Making of aluminum sheet
To make sheet, first of all sheet ingots are formed out of aluminum
which are of different weights. These aluminum sheet ingots are then
flat rolled and rerolled till thickness, or gauge that is desired is
achieved. The gauge determines what sheet has been produced and what is
to be used for. Depending on the usage, the thickness varies. For
example, the aluminum sheet used for making panels in automobile bodies
or used in marine applications is thicker than the aluminum sheet used
in making packaging material.
Types of aluminum sheet
- Flat aluminum sheet : This as the name suggests
is the aluminum sheet which has a plain outlook and available in
different thickness.
- Chequered aluminum sheet : This type of sheet
does not have a plain or flat appearance. Rather, the aluminum sheet
has chequered pattern all over and hence the name. This type of
sheet is of varied types differing in their length, weight, grades
and thickness.
- Corrugated aluminum sheet : Like chequered
sheet, the corrugated aluminum sheet as the name suggests has
corrugated appearance and widely recommended to be used for roofing
& side cladding applications.
Properties tested for making aluminum sheet
- Density
- Melting Range
- Tensile Strength-Ultimate
- Tensile Strength-Yield
- Elongation
- Hardness
- Machinability
Features of aluminum sheets and coils
- Durable
- Lightweight
- Moderate to high strength
- Good welding characteristics
- High resistance to corrosion
- Resists stress cracking
Aluminum sheet as a packaging material
As a packaging material, aluminum sheet is used to make the following :
- Rigid Containers
- Beverage cans
- Closures for bottles and jars
- Collapsible tubes
One common product made out of aluminum sheet is rigid container.
This is a kind of stiff package, usually round in shape. It is also
known as "can". Rigid containers protect the product and bear
reasonable handling without deformation or breakage. The "can
industry" is considered to be the largest segment of the aluminum
packaging complex. Most rigid containers or cans are cylindrical, which
uses the container material efficiently. The shape also permits permits
manufacturing, drilling, and closing at high speeds with exact control.
Almost all beverage, beer, fruit, vegetable, dog food, and motor-oil
containers are cylindrical and made of aluminum sheet.