Lost foam casting (LFC) is a type of investment casting process that uses foam patterns as the investment. The method takes advantage of the properties of foam to simply and cheaply form castings that would be difficult or impossible, using normal "cope and drag" techniques.
Preparing Final Investment for Casting
Risers and gates are also likewise attached. (They must be part of the casting to minimize shrinkage.) Next, the foam cluster is coated with ceramic, either by dipping, spraying or pouring. The coating forms a barrier so that molten metal does not penetrate or cause sand erosion during pouring. Coating also helps to protect the structural integrity of the casting.
After the coating dries, the cluster is placed into a flask and backed up with un-bonded sand. Mold compaction is then performed, using a vibration table to ensure uniform and proper compaction. Once compacted, the mold is ready to be poured.
Automatic pouring is commonly used in LFC, as the pouring process is significantly more critical than in conventional foundry practice. With LFC process, cleaning is easier and requires fewer operations, since there are no fins or parting lines to remove.
From:http://www.china-die-casting.com/Lost-foam_casting.htm
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