Appeal No. 98-2559
Application 08/633,101
nonporous preformed skin and fusing the skin of the insert to
a metallic substance shell.7
The Kawai document teaches a casting method which
involves wrapping the perimeter of a core, formed from a
bubbled body of metal such as aluminum, with a layer of
Styrofoam. The bubbling magnification is about 10 times, with
the aluminum bubbled body being extremely lightweight. When
melt is poured into a mold with the wrapped core therein, the
7In appellant’s specification (page 5), it is indicated
that
[p]referably, but not necessarily, the insert 24
is preformed to a final or net shape in an
earlier operation such that a nonporous skin 26
forms completely about the exterior surfaces of
the cellular array. This skin 26 helps limit
over absorption or infusion of the molten metal
22 into the interstices of the insert 24.
As the molten metal 22 is poured or
otherwise introduced into the mold cavity
18, it contacts the skin 26 of the insert
24 and causes shallow or localized melting
of the skin 26. In this manner, the skin 26
(and perhaps a few layers of cells in the
foamed metal) fuses together with the
molten metal 22, forming a good mechanical
bond.
5
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Last modified: November 3, 2007