“Lost Foam” casting
To see the process, press the buttons below

Tooling
The die is machined out of split aluminium
block creating a negative impression,
split cavity into which the foam is injected.
Since Poly-Styrene is non abrasive, the
tooling will continue to produce sharp,
precise patterns indefinitely.

Pattern Production
Patterns are produced by injecting poly-styrene into
the cavity of the tooling, separating the tooling
pieces and removing the pattern. The result is a positive,
exact replica of the final desired part out of foam.
Metal will later evaporate the foam, so for every
part needed a foam pattern must be produced.

The Gating System
The foam pattern and gating system are assembled
into a cluster (for mass production of the part).

Coating
After the patterns are glued to the sprue, the tree
then must be coated in a liquid slurry that is intended
to cover the surface of the foam. This creates the
incredible detail and surface finish by creating a smooth
shell covering the entire surface of the pattern, and
subsequently provides the surface finish on the casting.
Careful care is taken to coat the entire pattern, and to
prevent dents and dings in the foam, thus avoidingcasting anomalies.

Investing
After the coated trees are dry, they are invested
in sand which provides the support and rigidity to
the thin slurry shell. First the trees are put inside
a barrel shaped flask, and attached to a special lid.
Sand is rained into the flask. The flask will vibrate
as it is filled, liquefying the sand, which enables the
sand to fill every void surrounding the tree. When
the vibration of the flask is over, the sand inside is
extremely compact providing rigid and equal support
to the foam tree.

Pouring
A basin is placed in the sand surrounding the
exposed foam sprue. When the metal has reached
the correct temperature, it is poured into the basin.
The metal evaporates the foam, following the sprue
to the in-gate, then into the pattern. The foam
evaporates as the metal replaces it, creating an exact
metal replica of the foam pattern.

Finishing
The sand and hot metal are spilled into a cooling bin.
The cooled metal is then retrieved and the castings are
cut off the tree and the in-gate is ground flat. The casting
are then ready for blasting, machining, and shipment.

For More Information...
...please feel free to call us!
206.623.7147
Our manufacturing facility is located at:
45 South Spokane Street
Seattle WA 98134