Sheet moulding compound

Sheet Molding Compound (SMC ), English, called plate-shaped dough molding compounds of thermosetting reaction resins and glass fibers for the production of fiber - reinforced polymer composites. In SMC all the necessary components are fully pre-mixed, ready for further processing before. Typically polyester or vinyl ester resins. The reinforcing fibers are in mats, rare in fabric form, whose typical fiber length is 25-50 mm. Properties and names of SMC are regulated in EN 14598.

This fiber-matrix semis has been known since about 1960. In the early 1960s succeeded in the U.S. to produce by the addition of polyethylene powder, SMC with low shrinkage. In the late 1960s, could be fully compensated by the addition of styrene and thermoplastic components, the shrinkage of the polyester resin part.

There are the following SMC types:

• SMC - LP low profile: System with high surface quality
• SMC -LS low shrink: System response with low shrinkage
• C- SMC: system with endless, oriented fibers.

In LS systems (low shrink ) the shrinkage of between 0.05 % and 0.15 % must be. For LP- systems ( low profile ), a shrinkage of between 0.05 % and -0.5 % is required. Painted surfaces in the automotive industry must have Class -A quality. SMC systems for this application have a shrink smaller -0.05 %.

In Europe, in 2012 about 258,000 t SMC and BMC were prepared with glass fibers as a reinforcing fiber, which represents a market share of approximately 26 % for glass fiber reinforced plastics.

The SMC- mass contains about:

The fully automatic mixing the Harzfüllstoffgemisches with the glass fibers, the SMC semi -finished product in sheet form. This can then be cut and processed by extrusion to finished parts on. SMC is used to produce body parts for cars, sports equipment, electrical industry, plumbing industry and in aviation and aerospace industry. During pressing fasteners may already be inserted in the mold. This makes SMC particularly economical. The fillers are used to weight and cost reduction.