20-04-2012, 04:38 PM
THE SAND PROCESS
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HOW IT WORKS
The Sand Casting ( Green Sand ) molding process utilizes a cope ( top half ) and drag ( bottom half ) flask set-up. The mold consists of sand, ( usually silica ), clay and water. When the water is added it develops the bonding characteristics of the clay, which binds the sand grains together. When applying pressure to the mold material it can be compacted around a pattern, which is either made of metal or wood, to produce a mold having sufficient rigidity to enable metal to be poured into it to produce a casting. The process also uses coring to create cavities inside the casting. After the casting is poured and has cooled the core is removed.
DEFINITIONS
1. POURING CUP: This is where the metal is poured into the mold.
2. SPRUE: The vertical channel from the top of the mold to the gating and riser system. Also, a generic term used to cover all gates, runners and risers.
3. RUNNER: The portion of the gate assembly that connects the sprue to the casting in gate or riser.
4. GATE: The end of the runner in a mold where molten metal enters the mold cavity.
5. RISER: A reservoir of molten metal provided to compensate for the contraction of the metal as it solidifies.
6. MOLD CAVITY: The impression in a mold produced by the removal of the pattern. When filled with molten metal it forms a casting.
7. COPE: Upper or top most section of a flask, mold or pattern.
8. PARTING LINE: A line on a pattern or casting corresponding to the separation between the parts of a mold.
9. DRAG: Lower or bottom section of a flask, mold or pattern.