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Casting with Resin
The process of casting with resin has decades of
years history, and is very common in the
recent years. The resin sand casting has
many advantages, such as better surface
quality, better dimensional tolerances
and can produce very large castings.
There are two kinds of resin used for
casting
processes, and another kind for
making the patterns.
1. Fruan resin for the
resin casting process.
Furan resin is a kind of
black resin, the iron foundries can mix
the resin with sand together, after
burning the mixed sand, the resin sand
will become very hard, and we called
them as the hard molds. This kind of
resin sand molds are normally used for
producing large iron castings from 30kg
to 2tons.
The resin sand casting process can keep
good surface quality and better
dimensions than green sand. Some iron
foundries use the resin sand casting
equipment for mixing and shooting the
resin sands, and some foundries use the
traditional simple mixing methods. Since
the resin is costly, so the resin sand
casting process is more expensive than
green sand casting process.
2. Phenolic resin sand
for the shelling molding process.
When you heard someone to use the
shelling
molding process or hot shell and
core casting process, then they will use
the
phenolic resin sand as the
molding material. This kind of resin
sand is yellow, and normally, this kind
of resin sand has been well mixed and
packed, so metal foundries do not need
to mix them by themselves, and just buy
the resin sand and inject the sand into
metal molds, then heat the resin sand
into solid shells or cores.
The surfaces
of resin shells and cores are very
smooth, the dimensions are very accurate
, and there is less sand residual,
therefore, the quality of castings are
very good. The casting tolerance can
reach the same level as the lost-wax
investment casting. Many people think
the lost-wax investment casting process
will be replaced by the shell molding
process in the future. It is mainly
because the shell molding process can
reach higher production rate and less
pollution.
Since the resin shells and cores can not
be reused, so the costs are even higher
than the furan resin sand castings.
3. Epoxy resin for
patterns.
The
epoxy resin patterns are made
by the epoxy resin and glass fiber,
which has good lifetime and strength,
but lower costs than metal patterns, so
are widely used.
The process
of casting with resin must be well used
in the future, but the low production
rate and high costs will still restrict
its development.
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