Atlas Foundries

THE Process:

Lost Foam Casting is a type of evaporative pattern casting. This method is quite similar to investment casting which uses wax instead of foam in the pattern making process. This process takes advantage of the low boiling point of polymer foams to simplify the investment casting process by removing the need to melt the wax out of the mold. All other steps in the casting process are similar to sand casting. Lost Foam casting process can be said to combine the quality and surface benefits of investment casting with the economical production costs of Sand-Casting process. It is most advantageous for complex castings that would regularly require cores and are difficult to produce in the traditional green sand or no bake process.

EPS Beads Pre-forming

EPS is the primary raw material that is steam treated in order to make patterns which will be later used to cast the actual product

Forming/Moulding

Preformed beads are then injected in a custom-made die to produce the patterns by application of steam and pressure. These patterns are an exact replica of the actual product required.

Assembly

Patterns are inspected for deformities or imperfections as any error in the pattern will result in a like error in the final product. They are glued to formed cluster and dried to make them stable for next process.

Coating

Patterns are then coated with refractory which acts as a barrier medium between sand and liquid metal during pouring. Coated patterns are dried in heating rooms..

Compaction

Patterns are compacted in free-flowing sand in a sandbox using a 3-axis vibration on a compaction table. This gives strength to the assembly to withstand pressure during pouring resulting in accurate dimensions of castings and zero defects due to deformities.

Vacuum

This is a critical step in the entire process. Pouring of liquid metal is done under high vacuum pressure to ensure all gas generated during evaporation of foam pattern is extracted.

Differences with Sand casting process

1. No usage of cores.
2. No additives, binders, resins etc for treating sand.
3. No risers.
4. Sand is 100% recycled.

Advantages of Lost Foam Casting process

1. Outstanding results with complex/engineered castings involcing multiple cores.
2. Excellent surface finish.
3. Dimensionally accurate. Near net-shape castings achievable.
4. Defects of blowholes, pinholes, flash etc eliminated completely.
5. Requires no draft in removal of castings.
6. Flexible process due to inherent nature of foam which is easier to handle.
7. Economical. As the complexity increases, overall costs of a casting reduces as compared to sand casting.
8. Substantially reduced machining saving further costs in the production lifecycle of a casting.
9. Combines the benefits of investment casting and sand casting process beautifully.
10. Environmentally friendly by reducing overall sand requirement and carbon generation. Less polluting than a conventional sand foundry.

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Lost Foam Manufacturing