SEIATSU... the process for producing consistently perfect moulds.
The process sequence.
The SEIATSU air flow squeeze moulding process is a
method of compacting moulding sand. The required quantity
of sand is released when the louvre shutters of the sand dosing hopper are opened. The mould is formed by a pattern
plate mounted on a pattern bolster. A guiding frame on top
of the moulding box guides the sand into the box (fig. 1).
The sand dosing hopper underneath the sand storage hopper then moves to the side and simultaneously the squeeze
head moves in position over the mould. The machine table
rises thus pressing the bottom bolster (including the moulding box and filling frame) against the squeeze head, hermetically sealing the system. The SEIATSU air flow valve is
then opened. The air is passed through the moulding sand
from the back of the mould and towards the pattern. Vents
provided on the pattern plate or on the pattern itself facilitate
the air flow simultaneously through all the components
The mould is then compacted by applying pressure in an
arrangement that may use a squeeze plate, an elastic
squeeze plate or a multi-ram press (fig. 3). Whilst the compacting process is proceeding the dosing hopper is refilled.
To separate the mould and the pattern the machine table
is lowered and the sand dosing hopper and the squeezing
head are moved back to their datum position (fig. 4).
The sand is filled into the mould box to cover the pattern
The SEIATSU AIRFLOW Squeeze Moulding Process is applied
Mould example: Brake drum, Ø approx.: 500 mm
Mould example: Cylinder heads, flasksize: 1550 x 1100 mm
When penetrating the moulding sand the air flow results in
a downward force on every grain of sand. Thus the air flow
forces the sand into every recess in the mould pattern. The
packing density increases in the direction of the flow, layer
by layer, in such a way that the sand is most tightly compacted in the zones that are closest to the pattern.
To demonstrate this excellent compacting effect 35 mm high
layers of sand of different colours were built up around a
pattern. After the air flow was applied the thickness of the
layer at the bottom was reduced to 20 mm whilst that at the
top was 30 mm. With the subsequent pressing, a uniform
compaction of the entire mould is achieved.
After-compacting by multi-ram press
Separation of pattern and mould
Mould example: Bottom Flask for a flow clutch, rib width 2.5 mm, dia. approx. 400 mm Previously made using sand cores,
now with green sand mold insert. After the finishing pressure is applied an even mold is formed.
The advantages of the SEIATSU process.
Squeeze Moulding Process
Jolt Squeeze Machine
Jolting + squeezing
Airflow + squeezing = SEIATSU
Sand height (in mm)
Mould hardness (GF units)
Uniformly high mould hardness.
Fewer cores required.