 
Rapid Composite Manufacturing
Molds
Injection molding poses several challenges:
the cost of tool and die for mold makes design changes difficult,
the mold must be kept in good condition, large production
quantities are required to recoup cost, a mold can only produce
one part at a time, and the mold or the part being made can
be damaged in demolding. CRG has developed a tooling process
for rapidly and inexpensively manufacturing composites. This
patent pending process replaces expensive metal molds with
Veriflex®,
the registered trade name for CRG’s shape memory polymer
(SMP) resin systems.
Creating molds with SMP provides several advantages
over metal molds:
- Relatively inexpensive
- Versatile, producing a range of geometrically
different parts from one sheet
- Increased production rates
- Capability of fabricating many molds
- Prototype production possible
- Gentle demolding process
CRG's SMP system is capable of
being thermally formed into a precise negative image of a
master part, cooled, and made to retain the new shape. Veriflex
functions on thermal activation customizable from -20°F
to 520°F. This material can withstand the elevated temperatures
needed to cure composite parts without deformation and offer
a gentle, simple demolding process. After the composite part
has cured, the mold is raised above the transition temperature
(Tg), which allows it to retract to its memorized shape. SMP
tooling processes provide the opportunity to mitigate the
drawback of traditional fabrication techniques for advanced
composite parts. This tooling system also possesses versatility
in size variations, including being capable of micro (nanometers)
to macro (meters) replication.
Mandrels
An object with a diameter larger in the center
than at either end is a problematic shape for current fabrication
techniques, because rigid mandrels cannot be extracted after
the composite is cured. Conventional approaches to this problem
include multipiece or water-soluble mandrels. Rigid multi-piece
mandrels are complex and labor-intensive, and water-soluble
mandrels require the disposal of hazardous or noxious waste
and are costly and time-consuming.
 CRG's
Veriflex is a fully cured, high-performance thermoset system
that is elastic above set transition temperatures. The SMP
can be placed in a clamshell mold, shaped into a complex curved
mandrel, and cooled. The SMP mandrels, trade named Smart Mandrels,
can be filament-wound, cured, and then the mandrels heated
and removed. CRG’s patent-pending mandrel process allows
composites with problematic geometry to be easily fabricated
and the mandrels removed. This technology offers the filament
winding industry an improved process with relatively low-cost
and reusable material components.
Advantages to an internal thermoset mandrel
system include:
- Speeds up fabrication process
- Reduces cost of developing and removing
mandrels
- Offers a simple extraction process
- Allows for reusable mandrels with shape
versatility
See
Smart Mandrels™
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