AIM Processing Small Plastic Parts Blog

Structural foam molding is a process in which an inert gas is added to a melted polymer which is then injected into the standard injection molding tool. In this process, the blowing agent activates and pushes resin uniformly into the cavity pockets.  As the part cools, a solid skin forms against the mold. On the interior, the foaming action produces a honeycomb structure and reduces post-mold shrinking.

The result is a part that is significantly lighter than one produced by a standard plastic injection molding process. But 10-30% lower weight isn’t the only advantage. Structural foam molding can provide a number of benefits you may want to consider as you plan your next project. They include:

Increased strength and stiffness. The honeycomb structure within the parts gives them very high strength-to-weight and stiffness-to-weight ratios.

No sink marks on thick parts. You can break a lot of the old rules of thumb regarding part thickness. This leaves you with the chance to make thick and complex parts without depressions.

Low stress and warpage. The low pressure process eliminates these issues.

Superior impact resistance. This, again, due to the honeycomb structure.

Sound deadening and electrical/thermal insulating properties. Thanks to the tiny air pockets within the part.

Lower cost aluminum molds. Since lower pressures are used, aluminum works well.

Faster cycles. This is thanks to the better heat transfer of aluminum molds.

Lower cost materials. Recycled post-consumer materials can be used in this process, and parts produced are also recyclable.

Appealing surface characteristics. Parts have a consistent surface finish, picking up the texture you want.

An excellent replacement for other materials. Parts can replace a wide range of materials, from concrete to sheet metal to fiberglass to wood.

Long life expectancy for tooling. Although aluminum tooling is used, it often lasts as long as steel due to the lower pressures used.

Of course, not every part is an ideal candidate for structural foam molding. But if you need a lower weight, high strength part that can be made quickly and cost effectively, structural foam may be the way to go.

Have questions about this process and whether it’s right for your project? Give us a call or stop by. Being a plastic injection company, we’ve got extensive expertise in this area and are happy to share our insights.