Structural Foam Molding improves your products

What is Structural Foam Molding?

Structural foam is a low-pressure plastic injection molding process producing plastic parts and components that are lightweight and exceptionally strong. Rather than relying solely on machine pressure like the high-pressure/traditional process, this low-pressure technique introduces a chemical blowing agent into the plastic melt, which helps fill a mold. This blowing agent, along with the 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 low-pressure 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. 

Modern low-pressure injection technology is very advanced, and not all product designers and engineers are as familiar with the capabilities of this method as they are with conventional plastic injection molding. We created this guide to help demystify and explain the benefits of structural foam, with the goal of helping companies decide if this method of production is a good fit for their plastic products.

Advantages of Structural Foam Molding

Structural foam revolutionized manufacturing by offering benefits previously unavailable in plastic manufacturing. While its impressive capacity to fabricate large components – think large panels or machine structural components – initially gained recognition, the true potential of this molding technique extends far beyond size alone. The sections below detail some of these benefits.

Perfect for large, heavier plastic parts

Low-pressure injection molding is particularly well-suited for projects involving heavy parts, ranging from 8 pounds to an impressive 400 pounds. The reputed robustness and load-bearing capabilities of parts produced via this process make it an excellent choice when dealing with plastic products that are large, have multiple parts, and/or need an improved cycle time from rotational molding, sheet metal, or vacuum-formed processes.

Durable and strong components

Compared to other manufacturing processes, this plastic molding technique offers an exceptional strength-to-weight ratio and superior impact resistance with weight reduction up to 15% (by volume) compared to standard injection molding. These qualities provide a distinct advantage, ensuring your products are not only robust but also lightweight and impervious to the elements, enhancing overall performance and customer satisfaction.

Accommodates intricate, complex designs

When your design demands intricate features that surpass the capabilities of processes like vacuum forming, rotational molding, machining, or blow molding, low-pressure molding rises to the challenge. It allows for greater complexity and versatility in design, accommodating the diverse requirements of your products while decreasing the visibility of sink or read-through from thick sections or ribs.

Color control and consistency

Offering a complete range of colors, the low-pressure injection process allows for color consistency across products during production. Two colors can even be molded simultaneously – as well as two different materials – for the ultimate in creative freedom with respect to product design. Also, the consistent surface finish of plastic parts produced via this process is hard to beat. Note – this production technique can create a swirling or “silvering” effect that may not be ideal for certain products. For methods to eliminate this effect, please see our gas-assist molding page.

Efficient, cost-effective production

The low-pressure injection process provides cost-effective solutions by utilizing smaller machines to mold larger parts, reducing manufacturing expenses. Furthermore, compatibility with aluminum molds presents additional benefits, as aluminum molds require minimal maintenance when constructed correctly and maintained properly, resulting in extended tool life that can surpass that of steel molds. Structural foam molding also optimizes material usage for larger parts, allowing you to achieve efficiency and sustainability goals while maintaining product quality.

Dimensional accuracy

For industries that prioritize dimensional accuracy and reliability across large-scale production, structural foam excels. It ensures consistent dimensional precision, allowing for repeatable results across thousands of parts.

Enhances your competitive edge

Low-pressure foam techniques typically require no post-mold machining, resulting in faster cycle times and reducing costs. This molding process significantly reduces barriers to entry for large-scale production by lowering the capital requirements for tooling when compared with steel mold costs.

By leveraging the foam molding process, you gain access to a wide range of advantages that enhance the manufacturing process and the performance of your products. From versatility in assembly creation to durability against elements, handling heavyweights, and meeting design complexities, low-pressure molding proves its worth. It ensures dimensional reliability, superior strength-to-weight ratio, impact resistance, cost efficiency, and extended tool life. Embrace the benefits of low-pressure injection molding to elevate your manufacturing capabilities and create high-quality products.