Structural foam molding is a low-pressure plastic injection molding process that offers unique qualities and opportunities compared to conventional injection molding by injecting plastic & an inert gas or foaming agent into a mold cavity
What is Structural Foam Molding?
Structural foam molding is a low-pressure plastic injection molding process that offers unique qualities and opportunities compared to conventional injection molding by injecting plastic & an inert gas or foaming agent into a mold cavity. Modern structural foam molding technology is very advanced. However, some product designers and engineers are less familiar with the capabilities of structural foam than conventional plastic injection molding.
We have created this page to help demystify and explain the process which produces very robust ridged parts and not a soft foam product as the name could suggest. The benefits of structural foam are also outlined to help companies decide if structural foam molding is a good fit for their products.
Medium to Large-Sized Parts
Ideal for Many Applications
Structural foam product parts and components are produced by using low-pressure injection molding. Rather than relying solely on machine pressure like high-pressure/traditional injection molding, low-pressure structural foam molding introduces a chemical blowing agent into the plastic melt which helps fill a mold. This blowing agent, along with possible use of gas-assist, aids in the fill and pack out of the mold.
The process produces a cellular ‘foam’ core with solid outer surfaces known as the skin. The unique properties of finished structural foam molded material make it more rigid because of the solid outer skin. The cellular core adds to the strength and impact resistance. Plus, the density reduction of the core means parts are 10% to 15% lighter in weight compared to solid injection molded plastic.
The low pressure molding of thermoplastics allows for:
- Larger part size – Shot sizes up to 200 lbs.
- Durability, strength, and manufacturing efficiency
- Dimensional accuracy over the entire production run
- Weight reduction up to 15% (by volume) compared to standard injection molding
- Superior impact resistance
- Parts that are impervious to the elements
- Color consistency and complete range of colors
- Two different materials can be molded simultaneously
- Ability to mold two colors simultaneously
- Consistent surface finish
- Parts are recyclable and returnable for supply chain cost effectiveness
- Aluminum molds are less costly than steel