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Manufacturing:
Metal Casting
Variation
of Green Sand Molding
Flaskless
Molding
One recent
innovation in green sand molding has been
the introduction of flaskless molding-with
both vertical as well as horizontal partings.
Contrary to any misconceptions,
a flask must be used on all green sand molding
primarily for containment of sand while
it is compacted about the pattern. In flaskless
molding (whether vertical or horizontal)
instead of using "tight" individual
flasks for each mold produced, the master
flask is contained as an integral unit of
the totally mechanized mold producing system.
Once the mold has been stripped from the
integral mold producing unit, it is held
against the other half of the mold with
enough pressure to allow pouring of the
metal.
Through advanced engineering
techniques as well as continuous modification
and improvements, vertical flaskless molding
has achieved notable production and casting
quality levels and has attained new heights
of casting dimensional tolerance and accuracy.
The vertical flaskless systems are suited
to gray, malleable and ductile iron as well
as steel, aluminum and brass castings.
In the vertical flaskless
systems, the completely contained molding
unit blows and squeezes a mold against a
pattern (or multiple patterns) which has
been designed for a vertical gating system.
Molds of this type can be produced in very
high quantities per hour, and of high density
(mold hardness ranging from 85-95 B scale)
with excellent dimensional reproducibility.
Advantages
- No expenditure is required
for flasks nor is there any cleaning or
maintenance of flasks.
- Working conditions are
improved and there is no handling, storing
or shakeout of flasks.
Disadvantages
- Restrictions apply to
size of casting, use of complicated cores
and core assemblies, and number of castings
per mold. Mold handling may be more difficult.
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