2. MOULDING
Molding or moulding is the process of
manufacturing by shaping liquid using a rigid
frame called mold or matrix.
3. INTRODUCTION
Shell moulding casting is a metal casting process
similar to sand casting, in that molten metal is poured
in to an expendable mold.
Shell moulding, also known as shell-mould
casting..however in shell moulding the mold is a thin-
walled shell created from applying a sand resin
mixture around pattern.
4. • As compared to sand casting ,this process
has better dimensional accuracy, a higher
productivity rate and lower labour
requirements.
• Shell mould casting allows the use o both
ferrous and non ferrous metals, most
commonly using castiron,carbon steel, alloy
steel, stainless steel ,aluminum and copper
alloys.
5. UTILITIES REQUIRED FOR THIS PROCESS
Metal pattern.
Oven.
Sand-resin mixture.
Dump box.
Molten metal.
7. PATTERN CREATION
A two piece metal pattern is created in the shape of
the desired part, typically from iron or steel
8. MOULD CREATION
First ,each pattern half is heated to 175-370 degree
centigrade and coated with a lubricant to facilitate
removal.
Next the heated pattern is clamped to dump box,
which contains a mixture of sand and resin binder.
9. MOULD ASSEMBLY
The two shell halves are joined together and securely
clamped to form the complete shell mould.
The shell mould is then placed in to a flask and
supported by a backing material.
10.
11. POURING
The mould is securely clamped together while the molten
metal is poured from the ladle into the gating system and
fills the mould cavity.
12. COOLING
After the mould has been filled, the molten
metal allowed to cool and solidify of the final
casting.
13. CASTING REMOVAL
After the molten metal has cooled, the mould
can be broken and casting removed.
Trimming and cleaning processes are required
to remove any excess metal from the feed
system and any sand from the mould.
14. ADVANTAGES
Can form complex shapes.
Very good surface finish.
High production rate.
Low labour cost.
Low tooling and equipment cost.
Scrap can be recycled.
15. DISADVANTAGES
High equipment cost poor material strength.
This process is useful for casting that may
range weight between 200gm to 200kg in both
ferrous an non ferrous metal.
Another is the resin for sand is expensive.
