Hot Chamber
Die Casting Machine:
•
It is also called a
gooseneck machine because of the shape of the metal passage way.
PROCESS:
•
In this machine the
melting pot, usually made of cast iron, is a part of the machine.
•
The gooseneck containing a cylinder and metal
passage way is kept immersed in the metal pot.
•
The plunger in the
gooseneck cylinder is actuated either hydraulically or pneumatically. In
operation the plunger is withdrawn letting the liquid metal into the gooseneck cylinder
through the port provided.
•
When the die halves are
closed and ready for casting the plunger forces the liquid metal entrapped in
the cylinder into the die through the gooseneck passage and a nozzle
•
After a predetermined
time interval the plunger is retracted allowing the liquid metal in the
gooseneck channel and nozzle to fall back into cylinder
•
The die halves are opened
and the solidified casting is ejected from the die. Hot chamber machines are
designed to operate almost automatically and fast
•
A press button operation
will make the machine go through a complete cycle of activities including
closing the die halves, forcing the metal into the die, holding the pressure
for a predetermined time, withdrawing the plunger, opening the die, ejecting
the casting and stop ready for the next cycle
•
When the die halves are
closed and ready for casting the plunger forces the liquid metal entrapped in
the cylinder into the die through the gooseneck passage and a nozzle
•
After a predetermined
time interval the plunger is retracted allowing the liquid metal in the
gooseneck channel and nozzle to fall back into cylinder
•
The die halves are opened
and the solidified casting is ejected from the die. Hot chamber machines are
designed to operate almost automatically and fast
•
A press button operation
will make the machine go through a complete cycle of activities including
closing the die halves, forcing the metal into the die, holding the pressure
for a predetermined time, withdrawing the plunger, opening the die, ejecting
the casting and stop ready for the next cycle
•
The operator then removes
the casting, inspects the dies, gives spray lubrication to the dies and starts
the next cycle. Metal injection speeds and pressures can be controlled to suit
different metals and castings
•
Since the melting pot
plunger and cylinder of a hot chamber die casting machine are made of cast iron
and cast iron reacts with metals like aluminium at elevated temperatures, only
low melting-point metals can be cast by this method
•
There is also a limit on
the maximum pressure which can be applied. Hot chamber machines are mostly
operated below 14 kPa. Alloys of lead, tin and zinc are the most common metals
cast by this process
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COLD Chamber Die Casting Machine:
•
The
metal in this case is melted in a separate furnace and the required quantity of
metal is ladled to the machine
•
A
plunger operated hydraulically forces the metal into the die. Injection
pressures of 28 kPa to 250 kPa are possible in cold chamber machines
•
The
machine is semiautomatic, once the metal is ladled into the cold chamber the
rest of the operation is automatic.
1 Comments
Awesome article!
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