Industry breakthroughs in fibers, resins and molding techniques create new opportunities for sheet molding compounds.

What do ambulance transport cots and high-tech drones have in common? Some of their parts may have been manufactured from sheet molding compounds.

SMCs are thermoset, semi-finished composites that combine chopped strands of fibers, traditionally glass, with various types of resins. Produced in sheets between 1 mm and 3 mm thick, SMC is a highly versatile, dimensionally stable material. It’s often used in the automotive industry to compression mold everything from Class A body panels to semi-structural components. But cars and trucks aren’t the only applications benefitting from SMC’s fast cycle times, corrosion resistance, durability and moldability.

Citadel Plastics produces SMC parts for ambulance transport cots for Ferno, a supplier of medical equipment. The cots incorporate independently operated motorized legs to raise and lower them, which in turn reduces the strain on emergency medical technicians caused by lifting heavy patients. SMC provides the cot legs structural integrity and encloses the moving mechanism. Rapid Composites uses a hybrid SMC, combining higher tow carbon fibers and glass fibers, for production of an amphibious, tricopter/quad configurable drone called the Bullray. It weighs just 4.4 kilograms and can be molded in less than 10 minutes to its net shape.

Major markets

Because a one-piece SMC part can often replace a multi-piece metal assembly, the material is sought after in many markets. Perhaps the most talked about is automotive.

OEMS rely on SMC as a lightweight replacement for steel and aluminum, producing large parts such as exterior body panels and underbody shields as well as smaller items like electric vehicle battery box enclosures.