Pointarticle.com

Lost Foam Costing is a sub type of Investment Casting. This
type of casting method uses foam pattern as the investment. This method
benefits from the advantages of the foam properties helpful to make simple and
cheap castings. These types of simple castings are impossible using the regular
cope and drag method.

Casting process:

Foam Shaping: The
original foam pattern of the Polystyrene is generally molded or carved.

Carving
Polystyrene: The formed foam or polystyrene is then carved using
traditional carving tools or the new-age hot-wire cutting tools. It can also be
sanded easily.

Injecting
Polystyrene in a Mold: Polystyrene contains pentane as a blowing agent
and is commonly used for beads. The beads are pre-extended, stabilized and then
blown into the mold to form pattern sections. A steam cycle forces the beads to
expand fully, after this the fuse together and then it undergoes an in-mold
cooling cycle. The final shape if very complex, then it is molded in sections.
A cluster is formed by aging and gluing together the shaped foam sections. 

Preparing Final
Mold (Investment) for Casting: Gates and Raisers are generally attached
to the pattern, they are also the part of the casting as this helps reduce the
shrinkage. Pouring, dipping or spraying are the different methods used for
coating the foam cluster with ceramic investment. The reason for this coating
is that it forms a barrier and helps to prevent the molten metal to penetrate
or cause sand erosion while pouring. Structural integrity of the casting is
protected thanks to the coating. The cluster when dried is backed up with
un-bonded sand and is placed in a flask. Proper and uniform compaction is then
achieved by performing mold compaction using a vibrating table. After all this
process and after proper compaction, the mold is ready to be poured.

Automatic pouring is the preferred method in Lost Foam
Casting. This is the most critical process and also a bit difficult than the
traditional foundry practice. As there are no parting lines or fins to remove
the cleaning is easier and requires far more less time and operations in the
Lost Foam Casting process.

Advantages of Lost
Foam Casting: Due to its unique properties, foam is easy to carve glue
and manipulate. It also provides accurate dimensions as Lost Foam Casting is
more accurate and effective than sand casting. There are no fins or parting
lines the finishing process is easy and less time consuming. The elimination of
cores makes complex casting designs easy. Lost Foam Casting also allows us to
control the wall thickness and thus no core prints are required thus
eliminating shifts or fins and also saves the trouble of sand mixing and core
defects. As there are no drafts multiple levels of casting is possible. Precise
gate and riser replacements are achieved. Unconventional forms of casting that
are difficult or impossible to achieve in traditional cope and drag method are
easily achieved in Lost Foam Costing. 
Due to simpler process and easy finishing work , the process is very cost
effective and lowers the overall price of the final product.

About the author

Tags: beads, blowing agent, carving tools, castings, cutting tools, flask, foam properties, fuse, gates, hot wire, integrity, mold, molten metal, new age, polystyrene, proper compaction, sand erosion, shape, shrinkage, steam cycle

Share This

Related Posts

• Bronze Casting Information and the process of Bronze Casting
• Metal Casting Associations and Metal Casting Groups
• Best Hair Styling Foam Ideas
• Injector Torch, Cutting Torch, and other Metal Casting Torches Described
• Sieger Objects Muse Giftware

« SITE NAVIGATION AND ARCHTECTRURE | Best Hair Styling Foam Ideas »