2. CENTRIFUGAL CASTING
In this process molten metal is poured in mould and allowed to
solidify while the mould is rotating. Metal is poured into the
centre of the mould at its axis of rotation. Due to centrifugal
force the liquid metal is thrown out towards the periphery.
4. PROCEDURE
1) The Mould wall is coated with a refractory ceramic coating (applying
Ceramic Slurry , spinning, dying , baking).
2) Starting rotation of the Mould at a pre determined speed.
3) Pouring of Molten metal directly into the Mould (no gating system is
employed).
4) The Mould is stopped after the casting has been solidified.
5) Extraction of Mould from the casting.
5. APPLICATIONS OF CENTRIFUGAL
CASTING
Pipes for water gas sewage.
Bearing Bushes.
Cylinder Liners.
Piston rings
Paper making rollers
Clutch Plates.
Pulleys.
8. SHELL MOULDING
Shell moulding, also known as shell-mould casting, is an
expendable mould casting process that uses a resin
covered sand to form the mould
10. PATTERN CREATION
A two piece metal pattern is created in the shape
of the the desired part typically from iron and
steel.
11.
12. First, each pattern half is heated to 175-370 °C
(350-700 °F) and coated with a lubricant to
facilitate removal. Next, the heated pattern is
clamped to a dump box, which contains a mixture
of sand and a resin binder.
MOULD CREATION
13.
14. MOULD ASSEMBLY
The two shell halves are joined and
securely clamped to form the complete
shell mould
16. The mould is securely clamped together while the molten is poured
from a ladle into the gating system and fills the mould cavity
Pouring
17. COOLING
After the mould has been filled the molten metal is allowed to solidify into
the shape of the final casting
18. CASTING REMOVAL
After the molten metal has been cooled , the mold can be broken and casting
can be removed
Trimming and cleaning process can be used to remove any excess metal from
the feed system and sand from the mould
20. ADVANTAGES & DISADVANTAGES
One of the greatest advantages of this process is that it can be completely
automated for mass production
The high productivity, low labour costs, good surface finishes, and precision of
the process can more than pay for itself if it reduces machining costs
One disadvantage is that the gating system must be part of the pattern
because the entire mould is formed from the pattern, which can be
expensive.
Another is the resin for the sand is expensive, however not much is required
because only a shell is being formed
