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METALWORKING EQUIPMENT AND TOOLS
carried out by reducing and then turning off the
vacuum (as the conveyor belt leaves the zone of
connection to the vacuum system), transferring
sand from the stony state to loose.
In the invention [5], it was proposed not
to carry cooling castings on the conveyor in
loose sandy medium, but to feed them into a
closed inclined trench (as a continuation of the
conveyor), along the walls of which the castings in
sand move by sliding under their own weight and
are in the trench until the temperature reaches,
at which prescribed the embossing of sand forms.
This significantly reduces the power conveyor. Let
us consider in more detail the design of foundry
conveyor systems.
The layout of the VFM installation for
obtaining simple shaped and continuously cast
castings is shown in Fig. 1a [3]. The installation
consists of a movable conveyor-crystallizer 1, on
which a uniform layer of sand 2 is poured from the
hopper 3. A synthetic film 5 from roll 6 is applied
to the roll 4, and then the film is laid on the sand
layer with this roll. A casting bucket 7 is installed
above the mold.
For the manufacture of simple shaped
castings on roll 4 (Fig. 1b), models of the gating
system 8 and shaped castings 9 are mounted,
with the help of which cavities 10 are obtained
(Fig. 1a). To perform continuous profiles, ring
models 11 and 12 are used, with the help of which
cavities with profiles 13 and 14, respectively,
are molded (Fig. 1d, 1e). During molding, the
model is pressed into the sand by a rotating
roller and leaves a film 5 on it, the remains of
which can be wound into a roll at the end of
the sand-lined section of the conveyor (see
Fig. 1a to the right). A model similar to a
combination of model constructions
(Fig. 1b, 1d) can be mounted on
roll 4, which gives an imprint (a
cavity in the sand) with a variable
surface both in longitudinal and in
cross section. That is, it is possible to
pour, for example, in semi-continuous
mode a rail with teeth of different
profiles and simultaneously with rows
both along and across conveyor, etc.
To improve the lining of the film with
models, the synthetic film 5 can be heated at the
time of lining (in this and other forming methods
discussed below) by airless or air spraying such
a coolant as heated non-stick paint onto this film
[8]. The latter increases the productivity of the
molding process by combining the traditional
operations of VFM: heating the film with heat-
transfer fluid and painting the film with non-stick
paint. In addition, since heated ink particles are
more energy-intensive heat carriers than the
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METALWORKING EQUIPMENT AND TOOLS
previously known method of blowing with bias towards the knockout. to use a plate one, and the sand 6 is poured on a model
heated air, the heating time of the film is After filling the cavities with plates of such a conveyor 2, a film 7 from a roll 8 is
reduced. And heating the paint reduces metal and cooling the casting can be made with cavities laid on a roll counter 9 with a
the drying time, and this complex lining- sand and castings are removed and vacuum valves 22 (Fig. simultaneous molding of filling
painting operation easily fits into the from the mold, sand is fed into 1h) by alternately connecting funnels 10. Usually, a frame
continuous molding process. The degree the cooling - recycling system, these cavities to an external device is used to apply film
of compaction of sand can be increased traditionally used for VFM. vacuum system 23 [7]. to Model 2. The description
by applying vibration of the roll, or other For the manufacture of Conveyor plates can have [4] shows an example of a
known methods. semi-continuous thick-walled hollow perforated sidewalls design 5 of a frame type with
The sand layer is vaccumed through profiles, a rotary mechanism 24 and longitudinal partitions a rotating frame with double-
the mesh filters 15 (Fig. 1f), mounted can be used (Fig. 1g) in 25, the latter, it is advisable to sided film suction cups. With
in the tape 1 and having valves 16, the form of a frame 19 with mount on multi-strand molds. each rotation of 180º around
which are connected to the system 17 of a drive 20, on which two The mold is transported on an axis perpendicular to
pipelines for vacuum tracking the moving rolls with models of various rollers 26. the direction of movement
tape, after which the sand acquires the configurations are installed. To obtain castings in of the conveyor, the frame
strength inherent in VPM. The thickness When exposed to the sand of a continuous vacuum form, alternately spreads the film on
of the sand layer from the bottom of one of the rolls, cavities are consisting of two half-molds, the model one after the other.
formed, and when the rolls the following installation was The lower half-mold is
are removed from the sand developed, the scheme of assembled from segments
and the horizontal position of which is shown in Fig. 2a [4]. 11. For pouring, use a bucket
the frame 19, a partition 21 is The installation consists of a 12. After pouring, the mold is
obtained between the cavities conveyor 1 of model plates smoothly placed in a closed
[6]. In this case, instead of a with models 2, onto which a inclined chute 13, where the
conveyor belt for a movable synthetic film 3 is laid from a casting is cooled and fed to
mold, it is more convenient roll 4 using a device 5. Then conveyor 14, and the sand
the casting cavity
to the surface of the
tape is 0.05 ... 0.10
m. To facilitate the
indentation efforts of
the models in the molding section,
minimum vacuum is maintained,
increasing it when moving to the
pouring and cooling areas. This is
achieved by connecting the system 17
to the valves 16 so that the nearest
connected belt filter is at a distance
of 0.5 ... 1.0 m from the molding
position. In addition, the roll 4 with
models forms sand, mostly poured on
it from above from the hopper 3, and
is almost on the verge of vacuum in
the sand, however, after the film is
laid with the roll, the sand remains
stationary. In some cases, a compact
sand cultivator or a device for creating
a pseudo-boiling layer can be installed
in the hopper 3 above the roll. When
moving, the tape rests on the rollers Fig. 2. Installation of VFM for the production of castings in the sand
18 and may have a slight downward a form of two half-forms obtained continuously.
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