THE LOST FOAM CASTING THE LOST FOAM CASTING

PROCESSPROCESS

Lost-foam castingLost-foam casting Lost-foam castingLost-foam casting ( (LFCLFC) is a type ) is a type

of of evaporative-pattern casting process that is similar  process that is similar to investment casting except to investment casting except foam is  is used for the pattern instead of wax. used for the pattern instead of wax. This process takes advantage of the This process takes advantage of the low boiling point of foam to simplify low boiling point of foam to simplify the investment casting process by the investment casting process by removing the need to melt the wax removing the need to melt the wax out of the mold.out of the mold.

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections.1. Mould foam pattern sections. 2. Age pattern to allow dimensional 2. Age pattern to allow dimensional

shrinkage. shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern. pattern. 4. Build cluster (multiple patterns per 4. Build cluster (multiple patterns per

cluster). cluster). 5. Coat cluster. 5. Coat cluster. 6. Dry coating. 6. Dry coating. 7. Compact cluster in flask. 7. Compact cluster in flask. 8. Pour metal. 8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

THE LOST FOAM CASTING PROCESS

1. Mould Foam Pattern Sections

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections. 1. Mould foam pattern sections. 2. Age pattern to allow dimensional 2. Age pattern to allow dimensional

shrinkage.shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern. pattern. 4. Build cluster (multiple patterns per 4. Build cluster (multiple patterns per

cluster). cluster). 5. Coat cluster. 5. Coat cluster. 6. Dry coating. 6. Dry coating. 7. Compact cluster in flask. 7. Compact cluster in flask. 8. Pour metal. 8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

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.

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections. 1. Mould foam pattern sections. 2. Age pattern to allow dimensional shrinkage. 2. Age pattern to allow dimensional shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern.pattern. 4. Build cluster (multiple patterns per cluster). 4. Build cluster (multiple patterns per cluster). 5. Coat cluster. 5. Coat cluster. 6. Dry coating. 6. Dry coating. 7. Compact cluster in flask. 7. Compact cluster in flask. 8. Pour metal. 8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

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.

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections. 1. Mould foam pattern sections. 2. Age pattern to allow dimensional shrinkage. 2. Age pattern to allow dimensional shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern. pattern. 4. Build cluster (multiple patterns per cluster).4. Build cluster (multiple patterns per cluster). 5. Coat cluster. 5. Coat cluster. 6. Dry coating. 6. Dry coating. 7. Compact cluster in flask. 7. Compact cluster in flask. 8. Pour metal. 8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

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.

Moulded sprue is manufactured similar to foam pattern • •

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections. 1. Mould foam pattern sections. 2. Age pattern to allow dimensional 2. Age pattern to allow dimensional

shrinkage. shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern. pattern. 4. Build cluster (multiple patterns per 4. Build cluster (multiple patterns per

cluster). cluster). 5. Coat cluster.5. Coat cluster. 6. Dry coating. 6. Dry coating. 7. Compact cluster in flask. 7. Compact cluster in flask. 8. Pour metal. 8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

THE LOST FOAM CASTING PROCESS5. 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.

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections. 1. Mould foam pattern sections. 2. Age pattern to allow dimensional 2. Age pattern to allow dimensional

shrinkage. shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern. pattern. 4. Build cluster (multiple patterns per 4. Build cluster (multiple patterns per

cluster). cluster). 5. Coat cluster. 5. Coat cluster. 6. Dry coating.6. Dry coating. 7. Compact cluster in flask. 7. Compact cluster in flask. 8. Pour metal. 8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

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.

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections. 1. Mould foam pattern sections. 2. Age pattern to allow dimensional 2. Age pattern to allow dimensional

shrinkage. shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern. pattern. 4. Build cluster (multiple patterns per cluster). 4. Build cluster (multiple patterns per cluster). 5. Coat cluster. 5. Coat cluster. 6. Dry coating. 6. Dry coating. 7. Compact cluster in flask.7. Compact cluster in flask. 8. Pour metal. 8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

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.

THE LOST FOAM CASTING PROCESS

7. Compaction (Contd.) ••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.

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections. 1. Mould foam pattern sections. 2. Age pattern to allow dimensional 2. Age pattern to allow dimensional

shrinkage. shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern. pattern. 4. Build cluster (multiple patterns per 4. Build cluster (multiple patterns per

cluster). cluster). 5. Coat cluster. 5. Coat cluster. 6. Dry coating. 6. Dry coating. 7. Compact cluster in flask. 7. Compact cluster in flask. 8. Pour metal.8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

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. •

THE LOST FOAM CASTING THE LOST FOAM CASTING PROCESSPROCESS

Process StepsProcess Steps 1. Mould foam pattern sections. 1. Mould foam pattern sections. 2. Age pattern to allow dimensional 2. Age pattern to allow dimensional

shrinkage. shrinkage. 3. Assemble pattern if it is a multiple piece 3. Assemble pattern if it is a multiple piece

pattern. pattern. 4. Build cluster (multiple patterns per cluster). 4. Build cluster (multiple patterns per cluster). 5. Coat cluster. 5. Coat cluster. 6. Dry coating. 6. Dry coating. 7. Compact cluster in flask. 7. Compact cluster in flask. 8. Pour metal. 8. Pour metal. 9. Extract cluster from flask.9. Extract cluster from flask.

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.

THE LOST FOAM CASTING PROCESS

9. Extraction (Contd.)

••Castings proceed through shakeout to remove loose sand and coating.

THE LOST FOAM CASTING PROCESS

Final Casting

DETAILS Commonly cast metals include cast Commonly cast metals include cast

irons, aluminium alloys, steels, irons, aluminium alloys, steels, and nickel alloys; less frequently stainless and nickel alloys; less frequently stainless steels and copper alloys are also cast. steels and copper alloys are also cast.

The size range is from 0.5 kg (1.1 lb) to The size range is from 0.5 kg (1.1 lb) to several tonnes (tons). several tonnes (tons).

The minimum wall thickness is 2.5 mm The minimum wall thickness is 2.5 mm (0.098 in) and there is no upper limit. (0.098 in) and there is no upper limit.

Typical surface finishes are from 2.5 to Typical surface finishes are from 2.5 to 25 µm (100 to 1000 µin)25 µm (100 to 1000 µin)

Typical linear tolerances are Typical linear tolerances are ±0.005 mm/mm (0.005 in/in).±0.005 mm/mm (0.005 in/in).  

AdvantagesAdvantages

This casting process is advantageous This casting process is advantageous for very complex castings that would for very complex castings that would regularly require cores. regularly require cores.

It is also dimensionally accurate, It is also dimensionally accurate, maintains an excellent surface finish, maintains an excellent surface finish, requires no draft, and has no parting requires no draft, and has no parting lines so no flash is formed.lines so no flash is formed.

As compared to investment casting, it As compared to investment casting, it is cheaper because it is a simpler is cheaper because it is a simpler process and the foam is cheaper than process and the foam is cheaper than the wax. the wax.

AdvantagesAdvantages Risers are not usually required due to Risers are not usually required due to

the nature of the process; because the the nature of the process; because the molten metal vaporizes the foam the molten metal vaporizes the foam the first metal into the mold cools more first metal into the mold cools more quickly than the rest, which results in quickly than the rest, which results in natural directional solidification.natural directional solidification.

Foam is easy to manipulate, carve and Foam is easy to manipulate, carve and glue, due to its unique properties. glue, due to its unique properties.

DisadvantagesDisadvantages

The main disadvantage is that The main disadvantage is that pattern costs can be high for low pattern costs can be high for low volume applications.volume applications.

The patterns are easily damaged or The patterns are easily damaged or distorted due to their low strength.distorted due to their low strength.

If a die is used to create the patterns If a die is used to create the patterns there is a large initial cost.there is a large initial cost.

TimelineTimeline Lost-foam casting was invented in Lost-foam casting was invented in

1964 by M.C. Flemmings.1964 by M.C. Flemmings. Public recognition of the benefits of Public recognition of the benefits of

LFC was made by LFC was made by General MotorsGeneral Motors in  in the mid 1980s when it announced its the mid 1980s when it announced its new car line, new car line, SaturnSaturn, would utilize LFC , would utilize LFC for production of all for production of all engine blocksengine blocks, , cylinder headscylinder heads, , crankshaftscrankshafts, , differential carriersdifferential carriers, and , and transmissiontransmission cases cases

Thank YouThank You

PAWAN KUMAR VERMAPAWAN KUMAR VERMA

B.Tech 2B.Tech 2ndnd Yr Yr

ME-BME-B

R.No.- 0900140072R.No.- 0900140072

Anand Engg College, AgraAnand Engg College, Agra