Smart Mandrels™ for
Composite Tooling (US Patent No. 7,422,714)
How Smart Tooling Works
Smart Mandrels are reusable mandrels created to
reduce the complexity and hassle of the composite tooling process.
With this ground-breaking technology, commercial filament winders
and composite manufacturers now have access to an inexpensive
solution to the high labor and materials costs normally associated
with trapped tooling.
CRG has invented fully cured, high-performance
thermoset systems (Veriflex®)
that are elastic above set transition temperatures and recover
to a "memory" shape when left unrestrained. Mandrels
made with these thermoset systems provide distinct advantages
over conventional approaches. Smart Mandrels can be easily
molded, extracted, and reused.
The smart tooling process is being commercialized through SmartTooling.com.
Advantages of Shape Memory Properties
When heated above the transition temperature, the mandrel
becomes elastic and can easily be molded into a desired shape.
Once cooled, the material will become rigid and retain the
new shape. The mandrel can then be filament wound and the resulting
part cured on the mandrel. Heating the mandrel above its transition
temperature after the part is cured makes the mandrel elastic
again and easily extractible from the part. Because of the
mandrel's shape memory properties, it can be returned to its
original tubular shape and reused.
Benefits of Smart Mandrels
• Faster fabrication process, reduced
cycle time
• Reduced material and mandrel
creation costs
• Reduced labor costs
• Simple extraction process
• Reusability
• Lower environmental impact, cleaner
process
• Tremendous shape versatility
Current
Characteristics
Transition temperature..........................85°C/185°F
Cure temperature of part
Mandrel process........up
to 40°C/104°F
Bladder process...... up
to 140°C/284°F
Demold temperature.. up to 130°C/266°F
Comparison with Conventional Tooling:
Feature
Smart Mandrels
Salt/
Sand
Metal
Reusability
High
None
High
Materials Cost
Low
Low
High
Labor Cost
Low
Medium
High
The
Smart Mandrels Trapped Tooling Process
Step 1: A shape memory polymer Smart
Mandrels mandrel.
Step 2: The mandrel is placed into a clamshell
mold, heated above its transition temperature,
and blown into its complex shape under air
pressure. While still under air pressure, the
mandrel is cooled in its new, rigid complex
shape.
Step 3: Once cooled, the mandrel is removed
from the
mold and installed on a filament winder.
Step 4: The rigid mandrel is
filament-wound.
Step 5: After the filament-wound composite part
cures,
the mandrel is heated above its transition
temperature. This allows it to return to its
"memorized" tubular shape in an elastic state
and be easily removed from the composite part.
Step 6: The composite part is completed.
The Smart Mandrels tube can then be remolded
and reused with no degradation in material properties.
Smart Mandrels™ for
Composite Tooling
