Casting Methods
A manufacturing process where a solid is melted, heated to proper temperature, and is
then poured into a cavity or mold, which contains it in the proper shape during solidification.
Simple or complex shapes can be made from any metal that can be melted. The resulting product
can have virtually any configuration. Casting has marked advantages in the production of
complex shapes, parts having hollow sections or internal cavities, parts that contain irregular
curved surfaces (except those made from thin sheet metal), very large parts and parts made from
metals that are difficult to machine.





Centrifugal casting- A process by which a cylindrical part is produced by adding a
molten material to a mold that is rotated. Thickness is controlled by the amount of
material. No gating needed. Good dimensional accuracy. Produce large parts.
http://www.youtube.com/watch?v=3qKGx_AxHp0
Continuous casting- Continuous Casting is the process whereby molten steel is
solidified into a "semi-finished" billet, bloom, or slab for subsequent rolling in the
finishing mills. Shapes include I beams, billets, blooms and rounds.
http://www.youtube.com/watch?v=b-ox-ZN_YfE
Die casting- Die casting is a versatile process for producing engineered metal parts by
forcing molten metal under high pressure into reusable steel molds. Die casting is an
efficient, economical process offering a broader range of shapes and components than
any other manufacturing technique.
http://www.youtube.com/watch?v=1AgDGLNE6Es
Investment casting- An industrial process based on and also called lost-wax casting,
one of the oldest known metal-forming techniques. From 5,000 years ago, when beeswax
formed the pattern, to today’s high-technology waxes, the castings allow the production
of components with accuracy, repeatability, versatility and integrity in a variety of metals
and high-performance alloys. Primarily used in small parts.
http://www.youtube.com/watch?v=tyrXq_u1OH0
Evaporative-pattern casting- This is a class of casting processes that use pattern
materials that evaporate during the pour, which means there is no need to remove the
pattern material from the mold before casting.
http://www.youtube.com/watch?v=bvklUlD1YBo
Lost-foam casting is a type of evaporative-pattern casting process that is similar
to investment casting except foam is used for the pattern instead of wax. This process
takes advantage of the low boiling point of foam to simplify the casting process by
removing the need to melt the wax out of the mold.
Full-mold casting is an evaporative-pattern casting process which is a
combination of sand casting and lost-foam casting. It uses a expanded polystyrene foam
pattern which is then surrounded by sand, much like sand casting. The metal is then
poured directly into the mold, which vaporizes the foam upon contact.



Low pressure- The low-pressure casting process produces castings of exceptionally high
quality. In low-pressure casting, the furnace is pressurized whereby the molten metal is
brought into the casting die through a riser tube. The die is filled by slow and controlled
filling with a constant pressure. The filling process avoids the formation of oxidation, the
onset of cold currents and the danger of air inclusions. The solidification proceeds then
from the furthest point of the mold to the sprue. The furnace pressure is maintained and
ensures constant feeding of the castings. Through casting, technical measures and the
directed use of the die cooling, the ideal of a vectored freezing is reached.
http://www.youtube.com/watch?v=V4UA2-aWdEs
Permanent mold casting- The permanent mold process is a casting process where the
mold is manufactured from metal instead of sand. This allows the mold to be reused to
produce a large volume of castings. The molds are machined from grey iron or tool steel.
http://www.youtube.com/watch?v=xL8ZCp93ulU
Plastic mold- The most common type of plastic molding process used for large scale
manufacturing is the injection molding process. There are eight major types of plastic
molding processes:
1. Injection molding
2. Rotational molding
3. Thermoforming
4. Structural foam molding


5. Gas assist molding
6. Blow molding
7. Compression molding
8. Film insert molding
Resin casting- A method of plastic casting where a mold is filled with a liquid synthetic
resin, which then hardens. It is primarily used for small-scale production like industrial
prototypes and dentistry. It can be done by amateur hobbyists with little initial
investment, and is used in the production of collectible toys, models and figures, as well
as small-scale jewelry production. The synthetic resin for such processes is a monomer
for making a plastic thermosetting polymer. During the setting process, the liquid
monomer polymerizes into the polymer, thereby hardening into a solid.
http://www.youtube.com/watch?v=XPezK5RHgcc&feature=pyv&ad=5576394026&
kw=resin%20casting
Sand casting- Used to make large parts (typically Iron, but also Bronze, Brass,
Aluminum). Molten metal is poured into a mold cavity formed out of sand (natural or
synthetic). The processes of sand casting includes patterns, sprues and runners and
casting allowance (see below).
http://www.youtube.com/watch?v=rgL2Jn5mk1A
Metal
Pattern Oversize Factor (each
direction)
Finish Allowance
(smaller number for larger
sizes)
Min Wall
mm
(inches)
Aluminum
1.08 - 1.12
0.5 to 1.0 %
4.75
(0.187)



Shell molding- An expendable mold casting process that uses a resin covered sand to
form the mold. As compared to sand casting, this process has better dimensional
accuracy, a higher productivity rate, and lower labor requirements. It is used for small to
medium parts that require high precision. However, in shell mold casting, the mold is a
thin-walled shell created from applying a sand-resin mixture around a pattern. The
pattern, a metal piece in the shape of the desired part, is reused to form multiple shell
molds. A reusable pattern allows for higher production rates, while the disposable molds
enable complex geometries to be cast.
http://www.youtube.com/watch?v=xFb6rXNdrmo
Slush or slurry-Producing a hollow casting without a core in the mold by rotating a
liquid alloy in a hollow metal mold until a solid layer chills onto the mold, and then
pouring off the remaining liquid.
http://www.youtube.com/watch?v=oNZrxFvODtw
Spray forming-Also called spray casting or spray deposition, is the inert gas atomization
of a liquid metal stream into variously sized droplets (10-500 microns). The droplets are
interrupted by a substrate which collects and solidifies the droplets into a near fully dense
pre-form.
http://www.youtube.com/watch?v=Ihwboo9Ci2E