Sheet Moulding Compound / Bulk Moulding Compound
|The process |
SMC and BMC are names of the raw-materials of which products are pressed under pressure and heightened temperature (150 ºC).
SMC consists of glass-fiber layers 20 to 30 mm enclosed between to layers of polyester-resin. Mostly, the glass-fibers are not oriented.
BMC consists of a polyester-resin-mass with short glass-fibers (approx. 6 mm.).
When to use?
- SMC is especially suited for middle-sized shell-shaped products, e.g. dish antennas and spoilers.
- Through applying a coating in the mould (In Mould Coating) a very good surf-quality can be established with SMC.
- BMC is more suitable for smaller products. It allows for more freedom in shaping the products, like with the forging of metals.
- Products are high-temperature resistant and can therefore be applied in for instance the automotive industry and for electronic equipment.
- High stiffness, but lower than for for instance RTM because short fibers are applied.
- Because of the relative high mould-costs the process is suited for series from approx. 3000, for smaller series RTM is an alternative for SMC. The mould costs are significantly lower than for e.g. injection-moulding.