Foam molding takes small plastic pellets, then steams and adds pentane gas to make them up to 40 times their original size. After the pellets have expanded, they are re-heated and steam is used to inject them into a mold. This process creates light objects with low density, a lot like packaging peanuts.
Foam molding works pretty fast, usually 1–2 minutes to create each object. It creates various light-weight items like bicycle helmets, packaging supplies and surfboards. Foam molding is excellent for objects that need to be light but also large.