2. Casting since about 4000 BC…
2
Ancient Greece; bronze
statue casting circa 450 BC
Iron works in early Europe,
e.g. cast iron cannons from
England circa 1543

3. Two Categories of Casting
Processes
1. Expendable mold processes - mold is sacrificed to
remove part
2. Permanent mold processes - mold is made of metal
and can be used to make many castings

4. Casting Methods
• Sand Casting
High Temperature Alloy,
Complex Geometry,
Rough Surface Finish
• Investment Casting
High Temperature Alloy,
Complex Geometry,
Moderately Smooth Surface
Finish
• Die Casting
High Temperature Alloy,
Moderate Geometry,
Smooth Surface

5. Sand Casting
 Uses sand to hold the desired shape to be cast
 Bonded with chemicals or clay with water or oil
 Many different types of sand casting

6. Sand Casting

7. Sand Casting
Steps
cope: top half
drag: bottom half
core: for internal
cavities
pattern: positive
funnel  sprue 
 runners  gate 
 cavity 
 {risers, vents}

8. Investment Casting
 A refractory material (investment) is poured around
or built up on a pattern
 The investment is hardened by drying or heating
 The pattern is removed by melting or burning
 Metal is poured into the resulting cavity

9. Investment Casting

10. (a) Wax pattern
(injection molding)
(b) Multiple patterns
assembled to wax
sprue
(c) Shell built 
immerse into ceramic
slurry
 immerse into fine sand
(few layers)
(d) dry ceramic
melt out the wax
fire ceramic (burn wax)
(e) Pour molten metal (gravity)
 cool, solidify
[Hollow casting:
pouring excess metal before
solidification
(f) Break ceramic shell
(vibration or water
blasting)
(g) Cut off parts
(high-speed friction
saw)
 finishing (polish)
Investment Casting Steps

11. Die Casting
 Huge numbers of small, light castings can be
produced with great accuracy.
 Little surface finishing is required.
 Permanent mold (dies can be used over and over)

12. Die Casting

13. Die
Casting
Steps

14. •Reference:
 Metal Casting book
 http://en.wikipedia.org