Resin Transfer Molding (RTM)

Varied reinforcements are loaded into matched mold, then
clamped closed. Catalyzed resin is forced through a sprue into
the mold at low pressure until filled, then left to cure. Suited for
lower volume molding of complex or large parts where high
structural strength is needed.

Advantages of Resin Transfer Molding

• good surface finish on all sides
• dimensional stability
• suited for rubber or metal bonding in molding process
• low tooling costs-mold can be made of composites for
  small production cycles.
• Standard and custom formulations of resins and
  reinforcing fibers available
• Very complex shapes or highly structural parts can be
  molded with closed internal passages
• Reinforcement loading can vary over the entirety of part.

Disadvantages of Resin Transfer Molding

• material waste in flashing, sprue & vents
• labor intensive process

Markets:

Best value for low production volume
structural, very large complex shapes such as wind turbine
blades, boat hulls, manifolds, defense & aircraft components and
internal pump/compressor components.