An efficient tool design is crucial to the employment of
RTM.
Compositech typically designs and manufactures RTM tooling from
metal. Metals like aluminium and tool steel are used to make the
best use of their properties like hardness, heat conductivity,
thermal expansion and machinability.

Factorization
The thermal expansion of a typical carbon/epoxy laminate is very
low compared to the metals used to cast it. Typically a RTM mould
is heated to cure the component. The heating leads the metal tool
to expand. To compensate for the difference in expansion the tool
is made smaller than the parts final dimensions. As the tool
expands up to the cure temperature it will gain the correct
dimensions and the part will have the desired geometry as the resin
solidifies at the cure temperature.
This process is called factorization and makes it possible to
use dissimilar tool and part materials to obtain a correct part
geometry.