The lost foam casting process involves (1) molding foam patterns that are aged, assembled, and clustered together. (2) The cluster is then coated and dried before (3) being compacted in a flask filled with sand. Molten metal is then poured, displacing the foam to create a casting, which is later extracted from the sand mold.

1. THE LOST FOAM
CASTING PROCESS
Copyright 2003 © Austin Group, LLC. All rights reserved.

2. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

3. THE LOST FOAM CASTING PROCESS
1. Mold Foam Pattern Sections
Copyright 2003 © Austin Group, LLC. All rights reserved.

4. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

5. THE LOST FOAM CASTING PROCESS
2. Age Patterns
• The foam material used to create the pattern
shrinks in much the same manner as a typical
casting.
• Patterns are “aged” by allowing them to rest at
room temperature for a period of 5 to 7 days.
• Patterns may also be force aged in a drying oven
to allow for quicker use.
Copyright 2003 © Austin Group, LLC. All rights reserved.

6. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

7. THE LOST FOAM CASTING PROCESS
3. Assemble the Pattern
• Production patterns are
assembled using a
precision, automated
gluing machine.
• Glue is printed to one
section of the foam and
then pressed against the
adjoining piece.
• Multiple piece parts can
be built up in this way
and produce very
complex geometry
Copyright 2003 © Austin Group, LLC. All rights reserved.

8. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

9. THE LOST FOAM CASTING PROCESS
4. Clustering
• Glue individual patterns
to sprue.
• Number of patterns per
sprue is dependent on
part size and/or
configuration.
• Molded sprue is
manufactured similar to
foam pattern
Copyright 2003 © Austin Group, LLC. All rights reserved.

10. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

11. THE LOST FOAM CASTING PROCESS
5. Coating
• Coating parameters are
verified before coating
cluster.
• Coating is mixed
continuously to maintain
properties.
• Cluster may be hand
dipped or by automated
robot station.
Copyright 2003 © Austin Group, LLC. All rights reserved.

12. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

13. THE LOST FOAM CASTING PROCESS
6. Drying
• Coating is dried in an
oven at 120-140°F(49-
60°C) for 3 to 5 hours.
Copyright 2003 © Austin Group, LLC. All rights reserved.

14. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

15. THE LOST FOAM CASTING PROCESS
7. Compaction
• Cluster is delivered to
the pouring line by
conveyor.
• Cluster is placed into
flask and held in position
by a fixture
• Fixture is timed to
release the cluster during
the compaction cycle.
Copyright 2003 © Austin Group, LLC. All rights reserved.

16. THE LOST FOAM CASTING PROCESS
7. Compaction (Cont.)
• Sand is rained into flask
from overhead bin.
• Compaction tables can be
either vertical or horizontal
in orientation and vibrate
the flask during filling.
• Sand is compacted from
approximately 90lb/ft³ to
100 lb/ft³ by the
compaction table.
Copyright 2003 © Austin Group, LLC. All rights reserved.

17. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

18. THE LOST FOAM CASTING PROCESS
8. Metal Pour
• Metal is poured to
displace the polystyrene
pattern.
• Metal may be poured by
hand or with an
automatic ladle.
Copyright 2003 © Austin Group, LLC. All rights reserved.

19. THE LOST FOAM CASTING PROCESS
Process Steps
1. Mold foam pattern sections.
2. Age pattern to allow dimensional shrinkage.
3. Assemble pattern if it is a multiple piece pattern.
4. Build cluster (multiple patterns per cluster).
5. Coat cluster.
6. Dry coating.
7. Compact cluster in flask.
8. Pour metal.
9. Extract cluster from flask.
Copyright 2003 © Austin Group, LLC. All rights reserved.

20. THE LOST FOAM CASTING PROCESS
9. Extraction
• Casting is allowed to
cool in sand for a
predetermined period.
• Flask is then dumped
on to a shakeout
conveyor.
• Loose sand around the
casting cluster helps
protect the parts from
damage.
Copyright 2003 © Austin Group, LLC. All rights reserved.

21. THE LOST FOAM CASTING PROCESS
9. Extraction (Cont.)
• Castings proceed through
shakeout to remove loose
sand and coating
Copyright 2003 © Austin Group, LLC. All rights reserved.

22. THE LOST FOAM CASTING PROCESS
Final Casting
Copyright 2003 © Austin Group, LLC. All rights reserved.