The price difference between green sand, resin sand and shell
When we made quotations for some clients,
we will have to explain the price difference by various
sand casting processes,
in order to make our clients to know why our production costs were
higher or lower. Herein, let me make a brief introduction to the
castings costs by green sand,
resin sand and
shell molding processes.
1. Green Sand Casting Cost
Green sand is the cheapest casting process. As for
grey cast iron, the raw
casting cost is about 1206 USD/ton. As for
ductile cast iron, the raw
casting cost is about 1317 USD/ton.
Green sand includes three types of casting processes, one is manual
green sand. The foundry workers make the sand molds by their manual
operation. One is making sand molds by molding machines, and another
is by automatic molding lines. There is almost no difference for
these three types. The foundry just need to use them according to
the specific requirements and conditions.
2. Resin Sand Casting Cost
Resin sand casting process is suitable to produce middle and large
iron castings with higher surface quality, dimensional accuracy and
less casting defects. Because resin material is very expensive now
in China, so the resin castings are also very expensive now.
Moreover, resin casting process is slower than green sand,
therefore, its production costs will be higher too.
As for grey iron by resin sand, the raw casting cost is about 1365
USD/ton. As for ductile iron, the raw casting cost is about 1476 USD/ton.
3. Shell Molding Casting Cost
Shell molding use a kind of yellow resin sand, which is more
expensive than normal resin sand. Moreover, this type of resin sand
can not be recycled.
Shell molding castings could reach higher dimensional accuracy
(smaller tolerance), very good surface quality, more complex inside
and outside structures, thinner wall thickness and less casting
defects. However, this process can only produce small and middle
size and weight castings. The iron castings with over 500mm length
will be difficult to produce by it.
As for gray iron by shell molding process, the raw casting cost is
about 1460 USD/ton. As for ductile iron, the cost is about 1571 USD/ton.
The above prices are only production costs, the foundries need to
consider the other factors, so the final prices will be higher that
the above. The material costs cause the main difference between
these three casting processes, moreover, the size, complexity,
weight, annual demand and other technical requirements will also
cause some differences.