An integral three-dimensional article having interstitials therethrough,
the three-dimensional article comprises an unconstrained number of axially
successive stages. An apparatus and process for molding such a
three-dimensional article are also disclosed. The apparatus has members
extending into a mold cavity, each member having access to the periphery
of the mold cavity. Each stage may nest within an adjacent stage. The
nesting may be accomplished by having the end of one stage be convex,
while the mating end of an adjacent stage is complementary and concave.
The article may be useful as a static mixer, heat exchanger, etc.
