Sheet molding compound (SMC Process)

It is a new type of molding compound for a dry method to manufacture glass fiber reinforced polyester.

It uses multi-component of unsaturated polyester resin paste to impregnate the chopped glass fiber (or felt) and covers with polyethylene film to get the molding compound with sandwiched sheet.

Resin paste contains unsaturated polyester resin, initiator, chemical thickeners, low-shrinkage additives, powder fillers, pigments, release agents and so on.

Reinforcing material generally is untwisted glass rovings, which are chopped into the length of 20 ~ 50 mm.

The covered polyethylene film is to prevent air, dust, water vapor and impurities from polluting the material and to avoid the polyester resin’s cross-linking agent (styrene) to evaporate.

When use the SMC, we simply tear up the covered polyethylene film, then cut to the corresponding size and lay-up. Lastly, we put them into the mould and cure to get the required product.

Because the composition of sheet molding compound is complex, and the types, qualities, properties and ratio of each component have a significant impact on the production process, the properties of product and the cost.

SMC has various advantages. The operation of SMC is easy, molding time is short, the production efficiency is high, and it improves the processing environment and working conditions; the fluidity of forming is good, so that it can form the complex structure parts and large parts while keeping the good surface quality of the products.

Finally a diamond tipped flying cut-off saw cuts the finished profile into the required length, which are then handled by a take -off system