Structural foam molding can offer processors another option for customers who are seeking a part that offers strength and durability with reduced weight.
Generally reserved for medium- to high-volume production runs, structural foam is run on injection molding machines, with a foaming agent introduced to produce the internal wall sections of the part. The end result is a part with a hard outer surface and a softer inner layer. The interior is a bone-like structure that offers strength and a lighter weight.
The low-pressure process requires a blowing agent or nitrogen, which is introduced into the material along with any colorants and additives before it is injected into the mold.
A solid wall is created and the core is then retracted so the pressurized gas can expand, creating a uniform cellular structure. This versatile process can be easily used with any thermoplastic that can be injection molded.
The process allows processors to use aluminum molds instead of more expensive steel tooling.
The process offers weight reduction without losing the high rigidity features of a material. Moreover, the molded material doesn’t warp and there are no sink marks. In addition to dimensional stability, the process offers high-impact strength for increased processing flexibility. Processors can produce parts that feature a smooth and solid exterior and a foam structure on the inside.
The automotive end market is a key customer base for structural foam molded products. Different blends of polycarbonate, ABS and polyesters are used in these applications. Designers also can work with complicated designs. Parts can be 4 mm thick or greater, allowing for an array of designs.
There are several advantages that can make structural foam molding an attractive option. The biggest is the ability to produce lightweight, strong products.
Parts molded using structural foam molding also feature increased durability. However, the part’s surface often will need to be painted for a better aesthetic appearance.