Manufacturing – Casting methods - European Aluminium Association

1.9 Squeeze castings
1.9.1 Squeeze Casting – Characteristics
What is Squeeze casting?
This technique was initially similar to forging, with a mould made of a hollow lower dye and an
upper dye used as a stamp, which are set on a drop forging press. And the press is started as
soon as the liquid metal is poured in the lower dye.
This method is no more widely used, if ever, as 2 problems rise: the thickness of the cast part
depends on the quantity of metal poured; and parts must be of rather uniform thickness,
unless thinner areas, which solidify before thicker ones, will prevent pressure from applying
any more on areas subject to shrinkage.
As a matter of fact, "squeeze-casting", which is then sometimes said "indirect" SC, is now
commonly an evolution of pressure die casting, using the same machines, with differences
only on the injection speed and on the design of the pouring system:
the speed of the metal is drastically lowered, so as to avoid any turbulence – typically
0.5 m/s, against 30 to 60 m/s in HPDC – ;
the solidification must be progressive from the thinner area of the cast part to the
biscuit.
In other words the channels must be thicker than the cast part, and the gates set so as to
feed any area.
The high cooling speed and the pressure applied give the parts excellent mechanical
properties, and squeeze casting is therefore particularly suitable for suspension parts.
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