Foam extrusions are made through a process that involves extracting a product with several variables that relate to each other. Through this process, one variable results in a ripple effect in order to create a final product. Foam extrusions are made possible with the use of precision equipment, because special foam controls the process variables. As a result, uniform quality can be maintained.
The process of creating foam extrusions has been around for many years. During World War II, Styrofoam logs were made using foam extrusion processes. These logs were used as floats for anti-submarine nets, as well as for rafts for the military troops.
The Dow Company marketed the first commercialized extruded foam, uncross-linked foam, in 1958. Two years later, the Japanese were able to extrude cross-linked foam with the use of chemical blowing agents. France also pioneered the extrusion of polyvinyl chloride (PVC), which involved cooling the surface to form a solid skin. This method is widely known as the Celuka process.
The Celuka process was discovered in 1989. Today, it remains one of the most popular methods for foam extrusions. It is commonly used for creating moldings, boards, and foam-core doors. Other products made from foam extrusions include backer rods, swimming pool noodles, and splines used to secure doors, windows, and patios.
Extruded polyethylene foam is one of the more popular foam extrusions because it is a self-contained material. It involves a complex molding process that requires the control of interrelated variables. Heat, pressure, additives, resins, and density are part of the foam extrusions process. All of the variables are capable of combining at the molecular level. Therefore, each must be controlled in order to create the product.
Melt pumps are commonly used to improve foam extrusions. The primary way melt pumps assist in the process is by stabilizing the mass flow. Usually, extruding foam products also requires accurate control from melt temperature. If the plastic temperature varies, it may reshape the foam. Even if the temperature is off by only a few degrees, the product can be a total failure. A high quality foam product is produced only when all of the variables are properly controlled.