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Case Glossary

Anti-Static Foam

An open cell polyurethane foam with the addition of antistatic chemical additives. Anti-static foam is available in 1.2 lb. - 2.0 lb. densities and is pink in color.

Blow Molded

A manufacturing process by which hollow plastic parts are formed. In general, there are three main types of blow molding; Extrusion Blow Molding, Injection Blow Molding, and Stretch Blow Molding.

Cushioning Curve

A graphical representation of the dynamic cushioning properties of a packaging media. It is determined by dropping varying masses of a specific size from a defined height onto a specimen of the product to be tested. Defined for each curve is the drop height and the specimen thickness. Through the use of varying specimen thickness drop heights, a product's dynamic cushioning characteristics are depicted. Drop Height Based on the probable handling environment of the package and its delivery system, the distance it is likely to be dropped.

ELE Foam (Ether-like Ester)

Open cell, low cost polyurethane foam that has the look and feel of polyester foam. Available in 1.6 lb. density. It is gray in color and is the most common foam used in the shipping case industry.

Fragility Index

The fragility of an item is measured and reported numerically as its Fragility Index (Expressed in G's) It provides a basic parameter for packaging engineers to use in the selection of cushioning materials. The fragility index is the maximum G force that an item to be packaged can withstand without sustaining damage.

G Force

The acceleration of gravity (32.19ft/sec/sec)

Impact Dissipation

The ability of packaging material to provide deceleration, or absorb the force of impact across its available space, thus preventing damage to the product it protects.

Injection Molded

A manufacturing technique for making parts from plastic material. Molten plastic is injected at high pressure into a mold, which is the inverse of the desired shape and is then clamped together and solidified into the shape of the mold creating the part.

Internal Dimension (I.D.)

These are the internal dimensions of the case. Load Bearing Area Calculated by dividing the highest static load into the weight of the product.

Outside Dimension (O.D.)

These are the external dimensions of the case.

Parting Line

The section in which the lid and base separate from each other.

Polyethylene Foam (aka HDPE)

Closed cell, high density foam that is resistant to solvents, oils, greases and most common chemicals. This material is available in densities ranging from 2.0 lb. density to 9 lbs. This foam meets the PPC-1752D specification and is also available in a special Military grade.

Pressure Relief Valve

A purge valve that provides you the ability to release any built-up internal air pressure. A more accurate term would be a pressure equalization valve.

Rotationally Molded

The rotational molding process is a high temperature, low pressure plastic forming process that uses heat and biaxial rotation (i.e. rotation on two axes) to produce hollow, one piece parts.

The rotational molding process consists of four distinct phases:

  1. Loading a measured quantity of polymer (usually in powder form) into the mold.
  2. Heating the mold in an oven while it rotates, until all the polymer has melted and adhered to the mold wall. The length of time the mold spends in the oven is critical - too long, and the polymer will degrade, reducing impact strength. If the mold spends too little time in the oven, melting of the polymer may be incomplete. The polymer grains will not have time to fully melt and coalesce on the mold wall, resulting in large bubbles in the polymer. This has an adverse effect on the mechanical properties of the finished product.
  3. Cooling of the mold, usually by fan. This stage of the cycle can be quite lengthy too - the polymer must be cooled to a temperature where it solidifies and can be handled safely by the operator. This typically takes tens of minutes. The part will shrink on cooling, coming away from the mold, and facilitating easy removal of the part. The cooling rate must be kept within a certain range- very rapid cooling (e.g., by water spray) would result in the part cooling and shrinking at an uncontrolled rate, producing a warped part.
  4. Removal of the part.

Static Loading

The weight of the product distributed over the foam surface area expressed in pounds per square inch (psi).

Thermal Formed

See vacuum formed.

TSA Lock

TSA-accepted padlocks work two ways: a combination lock for the owner, and a separate TSA coded keyhole for access by airport baggage screeners. This way officials can inspect your baggage without ruining the lock or case they are trying to get into.

Vacuum Formed

Asimplified version of thermoforming, whereby a sheet of plastic is heated to a forming temperature, stretched onto or into a single-surface mold, and held against the mold by applying vacuum between the mold surface and the sheet.