molding is a mature and good
casting process. The foundries use the
core shooter machines to make the hot
resin sand shell and core, the assembly
the shell and core, and pour the melted
iron into the assembly.
The shell molding is using a kind of
resin sand, but this type of resin sand
is yellow, and very fine. After heating
metal patterns, the resin sand
will become a harden shell or core.
Shell molding can make the castings with
good surface quality, good dimensions,
thin wall thickness. The dimensional
tolerance of shell molding is just a
little lower than
lost wax investment
casting process, so it is much higher
than resin sand and
green sand casting
process. If you have high requirements
to your products, and your parts are not
very large and heavy, the shell molding
should be a very good choice for you.
The disadvantage of shell molding is the
process has to use the metal patterns
and the production cost is higher than
resin sand casting process. It is about
75USD/TON higher than resin sand casting
process. Moreover, its production rate
has limitation. If you annual demand is
very large, such as over 50,000 pieces,
you should check your supplier if they
could complete them. For the large order
volume, you will have to choose the
automatic molding line.
For the shell molding, there is no min.
weight limited, even 0.2kg can still be
made by shell molding, yes, it is
possible for making several pieces in
one mold. However, it is not common to
steel castings by shell
molding in China, most of foundries make
iron castings by shell molding,
including Dandong Foundry.
The castings usually have the size
limitation of under 400mm, too large can
not be made by shell molding. The common
weight for shell molding is under 20kg,
to large or too heavy is better to
choose other process. Of course, you
should talk with your casting suppliers
and check if they could make your
products by shell molding.
The attached are some photos for
shooting machine, resin shells and cores
for your reference.
Dandong Foundry is
using shell molding process to produce
the stove burners,
differential cases for car and other