foundry machinery casting for lost foam casting production line

foundry machinery casting for lost foam casting production line

Product Description

The lost foam casting process originated in 1958 when H.F. Shroyer was granted a patent for this cavityless casting method, using a polystyrene foam pattern imbedded in traditional green sand. The polystyrene foam pattern left in the sand is decomposed by the molten metal. The molten metal replaces the foam pattern, precisely duplicating all of the features of the pattern. Like investment casting (lost wax process), a pattern must be produced for every casting made.

First a foam pattern and gating system are made using a molding press.

Secondly, the foam pattern and gating system are assembled into a cluster.

Then the cluster is coated with a permeable refractory coating.

The next step is to invest the dry coated cluster in loose unbonded sand that is vibrated in and around the foam cluster.

The final step in the casting process is to pour the molten metal directly into the foam cluster, decomposing the foam in the system and replacing it with metal. The balance of the casting cleaning operations (cut off, grind, heat treat, straightening and blast) are straight forward and quite similar to other casting processes.

The composition of lost foam sand processing line

Lost foam sand processing can be divided into: screening, magnetic separation and cooling, including dust removal equipment, elevator, sand hopper, electric control and so on.

• Screening equipments: vibrating conveyer screening (There are many kinds of types and models, adopting different types according to different spatial layout).

• Magnetic separation equipments: through magnetic separation, suspended magnetic separation.

• Cooling equipments: boiling bed, spiral elevator (as auxiliary equipment, not main cooling equipment), water cooling roller (adopting roller external water spray principle cooling), sand temperature regulator.

Seen from cooling effect, boiling bed and water cooling roller is better, comparing with each other: boiling bed is high consumption power, excessive noise, small occupied area, low water consumption, otherwise water cooling roller is low power, low noise, large occupied area, high water consumption.

Lost foam casting process (EPC process) is to let foamed plastic beads (good EPC material) become prepared casting shape according to foaming molding, bury in the dry sand after baking coating, vacuum pumping, pouring metal liquid, becoming casting or craft after cooling.

The advantage of the casting process

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

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

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

• Risers are not usually required due to the nature of the process; because the molten metal vaporizes the foam the first metal into the mold cools more quickly than the rest, which results in natural directional solidification.

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

• The flexibility of LFC often allows for consolidating the parts into one integral component; other forming processes would require the production of one or more parts to be assembled.