Sheet Molding Compounds

Sheet molding compounds (SMC) are fiber-reinforced thermosetting semifinished products. They are produced in thin uncured and thickened sheets that can be handled easily before their forming process. To a larger extent, SMC is a generic term that designates such types of compounds together with the process to convert them into large composite parts, which mainly display shell-like geometry. This process is usually compression molding. SMC are widely used in a large diversity of fields of applications (aerospace, agricultural, rail and marine, electrical and energy, domestic appliance, building and construction, and medical sectors), but the automotive and truck industries remain the drivers of SMC technology. After a short introduction, this article gives successively detailed descriptions of (i) the materials used in SMC, (ii) their compounding, (iii) the compression molding process, (iv) the final properties of SMC, and (v) SMC recycling. Keywords: sheet molding compounds (SMC); compression molding; short fiber-reinforced polymer composites; hermoset polymer matrix