MOLDING SAND

The general sources of receiving molding sands are the beds of sea, rivers, lakes, granulular elements of rocks, and deserts. The common sources of molding sands available in India are as follows:

1 Batala sand ( Punjab)

2 Ganges sand (Uttar Pradesh)

3 Oyaria sand (Bihar)

4 Damodar and Barakar sands (Bengal- Bihar Border)

5 Londha sand (Bombay)

6 Gigatamannu sand (Andhra Pradesh) and

7 Avadi and Veeriyambakam sand (Madras)

Molding sands may be of two types namely natural or synthetic. Natural molding sands contain sufficient binder. Whereas synthetic molding sands are prepared artificially using basic sand molding constituents (silica sand in 88-92%, binder 6-12%, water or moisture content 3-6%) and other additives in proper proportion by weight with perfect mixing and mulling in suitable equipments.

Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. It is relatively cheap and sufficiently refractory even for steel foundry use. A suitable bonding agent (usually clay) is mixed or occurs with the sand. The mixture is moistened with water to develop strength and plasticity of the clay and to make the aggregate suitable for molding. The term “sand casting” can also refer to a casting produced via the sand casting process. Sand castings are produced in specialized factories called foundries.

Molding is the operation necessary to prepare a mold for receiving the metal. It consists of ramming sand around the pattern placed in support, or flask, removing the pattern, setting cores in place, and creating the gating/feeding system to direct the metal into the mold cavity created by the pattern, either by cutting it into the mold by hand or by including it on the pattern, which is most commonly used. Copied from A Textbook of Basic Manufacturing Processes and Workshop Technology by Rejender Singh. For more related it then check our daily post.