We are all familiar with disposable packaging products. Our computer monitors, laptops and televisions are usually shipped individually in styrofoam. Basic bags can be supplied with bubble wrap or dirty peanut ships. If you are packing highly sensitive devices or devices that will be shipped many times, reusable packaging materials should be considered.
In reusable packaging products, polystyrene foam, bubble wrap and peanuts are usually replaced by stronger foams. The two most used types of foam in reusable packaging are polyurethane and polyethylene foams.
Polyurethane (polyurethane, also called polyester) is a sponge foam, such as the consistency of foam used in pillows or mattress covers. This is a material with an open cell, which means that it will absorb liquids. This foam is used to pack very light weight units and is used when the foam is in contact with sensitive areas of the units that are prone to scratches — for example, on the front of an LCD display or plasma TV and computer monitors.
Polyethylene (PE) is more rigid than polyurethane. This is closer to the properties of styrofoam, but much more flexible and flexible. Expanded polystyrene can be easily broken if bending, but polyethylene foam will not be crushed or broken during bending. Polyethylene foam has closed cells, so it will not absorb liquids. This foam can be used to pack most units, and many packaging designers prefer to use it because it does not absorb liquid.
Colour
Polyurethane dark gray. Polyethylene black. (both have many colors - white, yellow, blue, etc.)
Density
There are different densities of both. The most common density is two pounds per cubic foot. A cubic foot is 12 "x 12" x 12 ", so a two-pound denotes the weight of a solid foot cubic block.
Four, six and nine pounds per cubic foot are also available. The nine-pound polyethylene foam is a softwood density. It will be used in applications where the unit weighs several hundred pounds.
Cost of
The cost of polyurethane and polyethylene is very similar, but the cost increases with the use of higher density foam.
Foams used for typical units
Polyurethane - Hard drives, cameras, lenses, lights, music recorders, microphones and sensitive electronic components.
Polyethylene - large plotters, rugged devices such as metal lights, microphone stands, heavy industrial parts, large loudspeakers or amplifiers, heavy cables or cords.
Anti-static
In highly sensitive environments where static electricity is a problem, antistatic foams are available. Both standard polyurethane and polyethylene foams can have antistatic properties that help dissipate electrical charge inside the package.
Antistatic density
Antistatic foams have the same densities as standard polyurethanes and polyethylene foams.
Antistatic color
Antistatic foam comes in pink color to stand out from standard foams.
Antistatic cost
Antistatic foam usually doubles the cost of standard foam.
Cross reference
Cross-reference Polyethylene is used in cases where the problem of contamination of foreign objects (FOD). Standard polyethylene foams have air pockets, but Cross Link has a flat surface. This helps to reduce foam particles, which are created by friction between the foam and the block when it is removed and placed in the foam.
Cross-reference color
Cross Link can be found in light gray, as well as in black or charcoal.
Cost of cross references
Cross Link can be three to four times as much as standard foam costs.
Cross Link Alternative
Standard polyethylene foam can be heat treated to reduce the amount of particles. The surface of the foam is treated with a high power heat gun. Heat melts pockets in the open air and creates a shiny, smooth surface that helps reduce particle count. This will add some labor to the interior cost of the foam, but is a less expensive option than using a cross reference. There are also small variations of PE foam cells, such as SoftFoam, that mimic some properties of Crosslink without the high cost.
High density plastic sheets
High density polyethylene sheets (HDPE) can be used in foam pillows where a heavy object has a small surface area in contact with the foam. The failure nose, the sharp end of the drill tool, or the sharp metal edges of industrial blocks are all examples of small areas.
HDPE can also be used as a support in a removable tray. HDPE will give the tray some stiffness when removed from the enclosure.
HDPE color
The color is usually black, but may be white or gray. You can also use ABS.
HDPE thickness
HDPE is available in several different thicknesses, the most common are 1/8 ", 1/4" and 1/2 "thick sheets.
A good packaging specialist will ask a few questions about the packaged units and the environments in which they will travel to select the right foam for your application. Price, lead time and ease of assembly are all areas that the designer will consider when designing the right packaging for a project.
