Notes on Thermoset Composites and Manufacturing Techniques

Thermosets: Cannot be reprocessed after curing.
Primary Thermoset Matrix Materials: Polyester, Epoxy, Bismaley Imide, Phenolic, Polyimide.
Polyester: Least strong, heat-resistant; cost-effective; widely used in commercial applications.
Epoxy and Others: Superior mechanical performance and heat resistance.

Improvement of Mechanical Properties: Strength and rigidity enhanced significantly with long-oriented reinforcement fibers.
Common Reinforcement Fibers: E glass, Aramid, Carbon (Graphite).
Forms of Fibers: Strand, Toe, Fabric, Prepreg tape, Preforms.

Types of Methods: Manual layup, Automated layup, Spray up, Filament winding, Pultrusion, Resin transfer molding (RTM).
Manual Layup: Involves cutting reinforcement and applying resin; gel coat may be used.
Automated Layup: Utilizes tape laying machines; allows for large and complex parts.
Spray Up: Resin is sprayed while reinforcement is chopped for application; allows for automated systems.
Filament Winding: Used for hollow shapes; involves wrapping resin-impregnated fiber around a mandrel.
Pultrusion: Continuous process for producing long shapes; efficient with low waste.
Resin Transfer Molding: Efficient for large, complex parts; involves infusing resin into a mold filled with reinforcement.

Common Curing Methods: Curing at room temperature, in ovens, or in autoclaves; may require vacuum assistance.
Vacuum Bag Molding: Involves sealing a nonadhering plastic film around the layup to remove air.

Machining Composite Parts: Can be cut, drilled, and otherwise fabricated similar to metals; special tools needed to prevent damage.
Machining Tools Recommended: Tungsten carbide or diamond tipped; coolant usage advised.

Adhesive Bonding: Uses adhesives for permanent joints; surface cleanliness is crucial.
Mechanical Fastening: Involves rivets, pins, bolts; requires precision hole making.