From a conversion perspective, structural foam molding can replace wood, metal, concrete and fiberglass. It can also have significant advantages in relation to alternative processes such as rotational molding, die cast, stamped metal, smc, thermoforming, rim and fiberglass layup. . The results? Significant reduction in cost and increases in productivity.

Structural foam plastic molding is an injection molding process that utilizes a foaming agent that mixes with the base resin in the polymer melt before being injected into the mold. This mixture becomes a combined polymer/gas melt. This process allows for less volume of plastic than a solid injection molded part to completely fill the mold, or a “partial fill” method. The lesser polymer volume requires less clamping pressure on the molds. This is often described as a low-pressure molding process. Due to the lower pressure and forces involved, the structural foam process allows very large parts and/or multiple parts to be produced on a single machine and in a single cycle. Additionally, cost effective tooling solutions can be utilized for these large or multi-cavity molded products.

Key Benefits of the Structural Foam Molding Process

  • 20% less weight than a high pressure part
  • 3-4 times more rigid than a solid part
  • Cost reductions are significant
  • Low mold cavity pressure
  • Reduced part weight
  • Capable of molding large, complex parts
  • Low cavity pressure allows lower cost tooling
  • Low part stress and warpage
  • Multiple molds can be run at the same time
  • Capable of molding parts .1875î thick or greater
  • Functions as excellent substrate for high quality painted finish applications
  • High dimensional stability
  • Virtually any thermoplastic can be foamed
  • High stiffness to weight ratio

As the foamed plastic flows through the mold, the surface cells burst and a solid skin is formed against the walls of the mold while the core of the part cools to a cellular structure. This results in a part that typically weighs 20% less than a solid plastic part, is 3 to 4 times more rigid, and is produced with less molded-in stresses. Parts may weigh up to several hundred pounds.