Sand Casting vs. Investment Casting
a) Sand casting raw materials are clay sand or chemical
self-hardening sand, the resources of the casting sand is rich and
the price is cheap.
b) The investment casting raw material
was to join the polyethylene material of paraffin wax, sodium
silicate, silicon sol, whose costs are higher than foundry sand.
a） After appropriate processing, the clay wet sand and chemical
self-hardening sand can be recycled, and the treatment process is
simple, and its cost is low.
b） The investment casting mold material
can be recycled, but the performance of the mold material will go
bad, fragility increases, ash content increased, decreased mobility,
increased shrinkage, color from white to brown, high processing cost
3. Casting cycle
a） The effective efficiency of the manual sand casting and resin
sand is low, but if you are using mechanical moulding equipments or
automatic moulding line, the moulding cycle is short and has high
b） The mold process of the investment
casting is cumbersome, and needs relatively long period.
Moulding material use time
a） Moulding sand can be used for a long time.
b） The materials of the investment
casting include wax, natural resin and plastic preparation, the mold
materials are easy to be cooling or melting, so can't be stored in
5. Casting appearance quality
a） The surface finish of the investment casting is higher than the
general casting, usually ranging from Ra.3.2 ~ 12.5μm.
b） The surface of the sand casting is
easy to be caused by the sand inclusion, sand wash, clip sand, air
hole and other casting defects.
a） Investment castings have very high dimensional tolerance,
normally could reach CT 4-6. This process could produce very complex
castings, and their min. wall thickness could reach 0.3mm.
b） Because of the characters of sand
moulds, so sand castings have lower dimensional tolerance, size
accuracy for CT10 ~ 13, the wall thickness of sand castings is
minimum of 3 to 5 mm.
a） The investment casting technology can ensure the consistency of
b） Unless by using moulding machines,
automatic moulding lines or shell molding process, otherwise, sand
casting process is difficult to ensure the consistency of the
8. Production range
a） In China, the investment casting is generally used to produce the
steel castings. It is generally used to product small castings with
unit weight under 20 kgs.
b） Sand casting can be used for the
production of cast iron and steel castings, and cast aluminum parts.
The adaptability of the sand casting is very broad, small, large,
simple, complex, single, large quantities can also be adopted.