Die Casting Process
High pressure die casting, the
process used by Del Mar Industries,
is widely regarded as the most
technologically advanced of all
casting processes. Die casting
machines, as well as the dies
that run in them, are designed
for medium to high-volume production
requirements.
Die casting machines consist of
two vertical platens, one fixed
and one moving. The steel die
is built in two halves with the
desired part machined into a cavity
(or multiple cavities) centered
in the die and typically split
between the two halves. The die
halves are bolted to each platen
on the machine, and when closed,
a measured amount of molten metal
is filled into a shot sleeve and
then driven into the die cavity
using a hydraulically actuated
piston. Once the metal has solidified
(usually a matter of seconds),
the moving platen slides horizontally
away from the fixed platen, opening
the die to allow for ejection
of the part. The moving platen
then closes again against the
fixed, and the process repeats
the cycle. Cycle times are measured
in seconds and vary depending
upon the shot size and type of
machine.
Hot chamber machines used to
run most zinc and magnesium alloys
are the fastest to cycle. The
shot sleeve and piston are submerged
in molten metal in a furnace
attached to the machine, fully
integrating the metal injection
portion of the cycle. Cold chamber
machines used to run some zinc
alloys run slower cycle times
because of the use of a detached
furnace. A measured amount of
metal is poured into the shot
sleeve via an automated ladling
system and the shot is produced.
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