| Foundry
and Production Technology |
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Foundry: Foundry is a factory which produces metal casting
from either ferrous or non-ferrous materials. It includes basic
production processes such as melting of metal, manufacture of
moulds, pouring of the metal into moulds, solidification, shakeout
and fettling of the castings. |
Pattern : It is a model of an object to form a cavity
of a sand mould for casting. Materials used to make pattern
are : wood, metals, plaster, plastic compounds, wax, etc. |
Molding Sand : It is the principal raw material which
is used in molding. |
Core : The portion of the mould which forms the hollow
interior of the castings or hole through the castings. |
Furnaces :
- Blast Furnace : Used in steel plants. Its charge consists
of iron ore, coke and lime stone. The product is pig iron.
- Cupola : Its charge consists of pig iron and used cast
iron. Coke and limestone. Product is cast iron.
- Electric Arc Furnace : It makes use of electric current
at low voltage and high amperage. To produce arc graphite
electrodes are used.
- Converters : They are used in steel production.
- Oil fired furnace : They are generally used for castings
of non-ferrous materials.
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Sand used in foundry shop : Green sand is the only sand
in its natural state and is quite moist. It has excellent property
of conformability because of its dampness. The mould should
be properly vented which is made of green sand. |
Dry Sand : The green sand is called dry sand when moisture
is removed from it. Dry sand is used for large size castings.
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Loam Sand : The mixture of clay and fireclay, sand with
water obtains a thin plastic paste that is plastered on moulds
with soft bricks and hardness on drying. |
Facing Sand : Applied on the face of the mould and comes
in contact with the molten metal. |
Backing Sand : The used sand which is prepared from mould
and is used time and again. |
Parting Sand : It is fine sharp dry sand which is used
to keep the green sand from sticking to the pattern and also
to keep the boxes separated. |
Hard Ramming : This method has low initial cost and it
is laborious and slow. |
Squeezing : It is suitable for relatively small work
and best for shallow flakes. |
Sand Slinger : The process which is fast and produces
uniform ramming. It has a high initial cost. |
Power Press Operations : The operation in which shearing
is the most common action. |
Metal Blanking : This is the process of punching, cutting
or shearing a piece out of stock to a predetermined shape. In
this process the black should be flat and thus punch is made
flat and shear provided on the die. |
Hole Punching : In this process the scrap is punched
out, the die is kept flat and shear provided on punch. For clear
cut and durability, clearance between the punch and die is required.
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Metal Bending : Performed in a variety of presses, brakes,
forming rolls, roll straighteners etc. Spring back may be compensated
for by overbending due to the elasticity of the metal and amount
of the bend. |
Metal Drawing : In this process flat sheets or blanks
are pulled or drawn in suitable containing tools through a die.
In this process metal is drawn into cylindrical cup or rectangular
or irregular shapes, deep or shallow. |
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