Structural Foam Molding FAQs

Structural foam molding is unique in the size, strength and versitility it provides. The range of opportunity it brings designers and engineers is just as great.

Along with the Q&As below, we’ve created a Structural Foam Molding Design Guide to help you get the most out of this valuable process.

Q: The tools are made from what materials?

A: Because structural foam is a lower pressure process we make tools out of aluminum.

Q: What materials do you mold?

A: Our most popular material is recycled high density polyethylene. Other popular materials are polypropylene, ABS, Styrene.

Q: How thick of a part can you make?

A: Suggested nominal wall section is .250 inches. Parts can be made with thicker wall sections but this increases cycle time and adds to the cost.

Q: How thin of a part can you make?

A: .180 inches is about as thin as you can make while still maintaining a cellular core.

Q: Can you get a flame retardant material for the molding?

A: Yes, structural foam materials can include flame retardant properties that meet various flammability specifications.

Q: Can the parts be painted?

A: Yes, if your product requires a more attractive and finished appearance the structural foam components can be painted.

Learn more about the part painting process and finishing options here.

Q: How long does it take to build the tools?

A: Generally 12-16 weeks after the CAD models are complete and the PO has been issued.

Q: How big of a part can you make?

A: Our largest machine can hold a tool up to 107 X 161 in size.

Q: How small of a part can you make?

A: Our smallest machine is 350 tons.

Q: What color is the material?

A: Recycled material is black. Virgin material can be just about any color you wish.

Q: How much does a tool cost?

A: Impossible to answer without seeing your part design but suffice it to say that tools of this size and complexity are usually many 10s of thousands of dollars.

Q: How much does a part cost?

A: Anywhere between 2x and 5x the material cost.

Q: How long does it take to get a quote?

A: About 3 weeks.

Q: How long does a structural foam tool last?

A: A well built structural foam tool will produce millions of parts.

Q: What is your minimum order?

A: 100 pieces.

Q: Can you insert mold steel bars or other reinforcements into structural foam parts?

A: Yes, however the difference in thermal expansion between the insert and the structural foam plastic material can cause issues with the heating and cooling cycle.

Q: Can the parts be printed with logos or identifying information?

A: Most often they are pad printed, painted or hot stamped.

Q: Can SF parts be glued together?

A: In similar fashion as typical thermoplastics, structural foam parts made out of the correct materials can be glued together.

Q: Can structural foam parts be screwed together?

A: Yes, you can drive screws directly into the structural foam panel or insert threaded fasteners.

Q: Who builds the tools?

A: We will request quotes from several highly qualified tool makers. From those bids we select the best candidate to build your tools. The price of the tools are not marked up. We send them as a straight pass through.

Q: Do you build tools in China?

A: No, we are unable to build the type of tools required for structural foam in China.

Q: What is gas assist and how is that different than structural foam?

A: Gas assist uses gas channels while structural foam molding uses a gas blowing agent. We sometimes will use both processes in the same part.

Q: What is RIM molding and how is that different than SF molding?

A: RIM molding is a chemical reaction where two different materials are combined to create a third material after molding. RIM is a very low pressure molding operation and the tools are much simpler than those used for structural foam molding. Structural foam is thermoplastic before, during and after the molding process.

Q: What is injection molding and how is that different than SF molding?

A: Structural foam molding is the cousin of injection molding. The major difference is how the molds are filled. Structural foam uses inert gas pressure to fill the tools while injection molding uses hydraulic or electric machine pressure.