Advanced Composite Bulk Molding

Toray Advanced Composites designs and develops advanced composite materials for use in a myriad of industries including aerospace, recreational, energy and transportation.

Bulk Molding Compounds (BMC)

Bulk molding compounds are produced from advanced fibers like carbon and S-2 glass coated with a high-performance resin system. These fibers are then cut into lengths of 12 to 50 mm and then utilized for molding composite parts. Toray supplies bulk molding compounds with thermoplastic resins like PEEK, PPS and nylon, or with thermoset resins including epoxy or cyanate ester. The company also offers products made from intermediate and high modulus fibers.

Product Name Resin Type Fiber Modulus Tg Description Tensile Strength (RTD) Tensile Modulus (RTD) Bulk Molding Compounds MS-1A Epoxy HM 327°F/164°C High Modulus Epoxy 42 ksi (290 MPa) 19 Msi (131 GPa) MS-1H Epoxy IM 327°F/164°C Fast Cure Intermediate Modulus Epoxy 37 ksi (255 MPa) 10 Msi (69 GPa) MS-4A Epoxy SM 327°F/164°C Standard Modulus Epoxy 45 ksi (310 MPa) 9 Msi (62 GPa) MS-4H Epoxy SM 379°F/193°C Standard Modulus Epoxy 44 ksi (303 MPa) 6 Msi (41 GPa)

BMC offers the following benefits:

• Lighter weight of composite parts with stiffness and strength of metallic parts
• Enables composite part fabrication with complex geometry
• Enables precise composite structure fabrication

BMC Molding Guidelines

• Pre-weigh the required quantity of molding compound
• Preheat the molding compound to make it more formable
• Form a mold charge to roughly fit the mold cavity
• Place the charge within the mold cavity
• Cure under pinch pressure for material consolidation
• Close mold and continue with designated cure cycle
• Post curing needed for full properties under fixture

BMC Facilitates Complex Parts Fabrication

BMC facilitates designing and production of complex parts.

These compounds feature:

• High fiber content (normally 50%)
• Controlled resin content fibers
• Designing more complicated geometries is easier when compared to continuous fiber composites
• Resin systems customized for compression molding
• Lengths: 6.35 mm, 12.7 mm, or 50.8 mm
• Typical width: 3.2 mm

BMC is an Alternative to Metal

Advanced composite BMC has a very low density of 1.5 g/cc and has tensile strengths akin to aluminum, making it suitable to fabricate lighter weight components when compared to metals.

Though steel and titanium have greater ultimate strength, bulk molding compounds far exceed these metals in specific strength, a measure of strength that accounts for density, allowing for the creation of strong part at a fraction of the weight of metal.

Advantages of BMC over metals are as follows:

• Higher Strength
• Lighter Weight
• Corrosion Resistance

This information has been sourced, reviewed and adapted from materials provided by Toray Advanced Composites.

For more information on this source, please visit Toray Advanced Composites.