(Almost) Everything You Need to Know About Injection Molded Foam

If you’re looking for a versatile and durable foam material, injection-molded EVA foam may be the perfect choice for your next project. This type of molded foam is made by injecting molten EVA into a mold. The resulting product is a dense, closed-cell foam that has many benefits for product designers. In this article, we will discuss what molded foam is, the difference between injection-molded EVA foam and compression-molded EVA foam, and the benefits of using injection-molded EVA foam in product designs.

What is Molded Foam?

Molded foam is a type of foam that is made by dispersing material into a mold. The molded foam can be made from various materials, including polyurethane (PU), polystyrene (PS), and ethylene-vinyl acetate copolymer (EVA). Molded foams typically have a noticeable skinned surface which is a result of the reaction between the polymer and the tool surface.

Molded PU foams have two categories, flexible and reaction injection molding (RIM). Flexible PU tends to be softer and has a thin surface skin whereas RIM can have thick skin. Molded PS foams can be firm and strong compared to most flexible PU foams but the PU foams molded in RIM can be more durable.

What is EVA Foam?

EVA foam is a type of foam that is made from ethylene-vinyl acetate and blended copolymers. This type of foam is often used in footwear, sporting goods, and automotive applications. EVA foam has excellent cushioning properties and can be molded into a wide variety of shapes and sizes.

Why Use Injection Molded Foam?

Injection molded Foam is a modern technology that provides more control over the production and scaling process. It can achieve dimensional repeatability within reasonable ranges, ensuring parts are produced with workable specifications. This provides superior mechanical properties, improved product performance, reliability, and repeatability in production. The ability to quickly scale your project’s quantity by using injection molded foam is a key feature in product growth categories like sports, fitness and leisure products.

Injection molded foam produces precision parts that are lightweight and strong. Using a foaming agent reduces material consumption without sacrificing strength, making it environmentally friendly. This process also reduces production costs by optimizing material usage and increasing efficiency. Overall, injection molded foam is a cost-effective solution for producing high-quality flexible parts.

Injection-Molded EVA Foam vs Compression-Molded EVA

Injection Molded EVA foam is one of the most popular types of molded foam. It’s manufactured by combining ethylene-vinyl acetate with an organic peroxide catalyst. When the mixture is heated above its melting point, it becomes a liquid state, which allows it to flow easily into molds. Once inside the mold, the cycle happens and the part takes on the geometry of the tool cavity.

The process of making compression-molded EVA foam parts requires a pre-molded or fabricated shape to be hand loaded into the tool cavity prior to cycling with heat and pressure to gain the desired shape. The process can vary depending on raw material resources but generally is the same.

The main difference between injection-mold EVA foam and compression-molded EVA foam is that injection saves a step by going from raw material to the finished part in one step whereas compression has the premade materials that are then molded. Because of this, manufacturing with injection is more efficient.

Advantages of Using Molded EVA Foam

There are several advantages to using molded EVA foam in product design projects. One advantage is that it is extremely durable. It can withstand impact and extreme conditions without breaking down. Another advantage is that it is lightweight and easy to work with allowing complex forms and shapes.

Another advantage of using molded EVA foam is that it provides great chemical resistance and cleanability with common household cleaners.  

If you’re considering using molded foam in your next project, injection-molded EVA foam is a great option to consider. It’s versatile, durable, and resistant to water and chemicals, making it ideal for a wide range of applications. Contact us today to learn more about our molded foam solutions.