Green-Sand molding utilizes a mold made of compressed or compacted moist sand. The sand is called "green" because of the moisture present. The mold is not baked or dryed. The mold materials consist of silica sand mixed with a suitable bonding agent(moist clay). To produce the mold, a metal or wood frame is placed over the pattern to produce a cavity representing one half of the casting. Compaction or ramming of the sand is achieved by either jolting or squezzing the mold. The opposite half of the mold is made by same manner. The two flacks are positioned to form the complete mold.
(Rapid Tooling Guideline for Sand Casting, Wanlong Wang,Henry W. Stoll,James G. Conley, p.g. 4-5)
Gas Metal Arc Welding
Gas Metal Arc Welding is an arc welding process that uses an arc between a consumeable electrode and the welding pool with a shielding from externally supplied gas without any application of pressure. In Europe GMAW is also called metal inert gas (MIG) and metal active gas (MAG). GMAW is used for welding the aluminium under Ar gas for shielding the metal.
(Modeling, Sensing and Control of Gas Metal Arc Welding, Desineni S. Naidu,Selahattin Ozcelik,Kevin L. Moore, pg.2)
Shielded Metal Arc Welding
Shielded Metal Arc Welding process is a process in which the heat for joining is obtained from an electric arc between a covered metal electrode and the workpiece. The groove is filled by the melting of the electrode core. The molten weld pool is protected from the atmosphere by the gases formed from decomposition of the electrode covering. The molten weld metal is cleaned by the scavenging action of the molten flux. Some of the more common names for SMAW are "stick" welding and "arc" welding.
(Shielded Metal Arc Welding, P E William L Ballis, pg. 23-24)
Plaster Molding
Plaster mold casting is similar to sand casting except that the mold is made of plaster of Paris (gypsum, CaSO4-2H2O) instead of sand. Additivies such as tale adn silica flour are mixed with the plaster to control contraction and setting time, reduce cracking and increasing strength. To make the mold, the plaster mixture combined with water is poured over a plastic or metal pattern in a flask and allowed to set. Wood pattern are oftenly unsatisfactory due to the extended contact with water in the plaster. The fluid consistency permits the plaster mixture to readily flow around the pattern, capturing its details and surface finish. Thus, the cast product in plaster molding is noted for these attributes.
(Fundamentals of Modern Manufacturing: Materials, Processes, and Systems,
Mikell P. Groover, pg. 235)
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