Solid Freeform Fabrication technologies have demonstrated the potential to
produce tooling with cooling channels, which are conformal to the molding c
avity. 3D Printed tools with conformal cooling channels have demonstrated s
imultaneous improvements in production rate and part quality as compared wi
th conventional production tools. Conformal cooling lines of high performan
ce and high complexity can be created, thus presenting a challenge to the t
ooling designer. A systematic, modular approach to the design of conformal
cooling channels is presented. Cooling is local to the surface of the tool,
so the tool is divided into geometric regions and a channel system is desi
gned for each region. Each channel system is itself modeled as composed of
cooling elements, typically the region spanned by two channels. Six criteri
a are applied, including: a transient heat transfer condition, which dictat
es a maximum distance from mold surface to cooling channel; considerations
of pressure and temperature drop along the flow channel; and considerations
of the strength of the mold. These criteria are treated as constraints, an
d successful designs are sought that define windows bounded by these constr
aints. The methodology is demonstrated through application to a complex cor
e and cavity for injection molding.