How Expanded Polystyrene Products are Made

Expanded polystyrene products, otherwise known as packing foam, can come in a variety of shapes and sizes depending on the consumer’s needs. It is feather-light, cost-effective, and is an excellent shock-absorber for securing the merchandise. Expanded polystyrene comes in tiny pellets, but can be shaped into any shape you can imagine for endless and creative commercial uses.

How Packing Foam is Made:

  1. The polystyrene pellets need to be steamed in a chamber in order to expand. When the chamber reaches about 400°F, pentane gas pellets escape and allow air to enter the chamber. The pellets inflate about 40x their original size!
  2. Next, the factory packages the pellets into huge sacs. The expanded pellets are poured into a block mold machine. The greater amount of pellets the manufacturers use, the denser the product will be.
  3. The pellets are now steam-fused together, molding the polystyrene into massive blocks. These blocks are roughly 5x1x3/4 meters, and the process takes about 5-20 minutes to complete, depending on the desired density.
  4. The conveyor belts used in this process typically have built-in scales within the belt. The blocks of polystyrene need to be weighed to make sure they meet important specifications. The blocks can weigh anywhere from 100-450 pounds!
  5. At this point, the block is ready to be cut into whatever shape the client has ordered, using a copper and nickel wire that is electrically heated. As the heat generates, the polystyrene melts on contact, enabling fine precision cuts. The cutting is often guided by computer software, allowing virtually any shape to be cut.

As mentioned, expanded polystyrene has many uses other than packaging. In this video, for example, the blocks are being sliced into insulation panels that may be used to insulate a basement wall or a roof. Indoor and outdoor signs are commonly made out of expanded polystyrene and coated with a protective exterior paint for withstanding harsh weather conditions.