Materials

SMC – Sheet Molding Compound

Premix manufactures Sheet Molding Compounds (SMC) that are primarily used in compression molding. Premix offers SMC's that are suitable for molding a wide range of parts from very small to very large, from flat panel to very complex shapes. Through our Engineered Solutions, SMC's are tailored to specific customer needs providing part performance as well as manufacturing efficiency. The pliable sheet allows enough body for handling and cutting but enough rigidity for manual charge building or automation.

The SMC manufacturing process allows glass percentages from 15% to 65% to be incorporated into the matrix. The glass length can also be increased up to 2" vs. a BMC that may range between 1/8" and 1/2". SMC also offers the possibility of continuous strand or matte. SMC's come in a wide range of colors and can often be color matched. SMC's have excellent physical, thermal, flame and chemical resistance properties.

As with other thermosets, SMC is a mixture of polymer resin, inert fillers, fiber reinforcement, catalysts, pigments, stabilizers, release agents, and thickeners. Manufacturing of SMC is a continuous in-line process. The base components of liquids and solids (paste) are bulk mixed and continuously metered onto to the surface of a carrier/barrier film, coating the film surface. Two mirror imaged metering stations operate simultaneously. One of the paste-coated carrier films are then layered with chopped fibers. The 2 carrier webs, paste & fiber are then brought together in the compaction section, where the sandwich-like layered components are kneaded into one homogenous compound sheet. The sheet is then fan folded into a container and stored in a controlled environment where maturation takes place, on its way to a specified viscosity.