Casting Processes

Expendable mold

Permanent Mold

Cross section of mold

Plaster

Ceramics

Evaporative pattern

Shell

Investment

Sand casting

Basic Steps

3) Pouring Techniques

4) Solidification Process

2) Melting Process

5) Mold Removal

1) mold cavity is produced

6) Cleaning,finishing and inspection operation

cross section of mold

Sprue

Riser

Runner

Mold Cavity

Draft

Defects

Moulding Materials

Pouring Materials

Shrinkage Materials

Metallurgical

Gas

Air inclusion

Blow holes

Pin hole porosity

Cut and Washes

Metal penetration

Fusion

Run Out

Rat Tail and Buckles

Mis run

Cold shut

Slag inclusion

Hot Tear

Hot Spot

Pattern materials

Metal

Hard plastic

Wood

Sand Requirement

Collapsibility

Permeability

Cohesiveness

Refractoriness

Method of packing sand

Hand Ramming

Molding Machine

Mold Materials

Steel

Bronze

Graphite

Gray cast iron

Alloy cast iron

Frequently cast metal

Lead and its alloy

Magnesium and its alloy

Copper and its alloy

Aluminum and its alloy

Steel or iron ( mold : Graphite)

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Advantages

Disadvantages

Reusable molds

Good Surface finish

Little finish machining

Consistent dimension

Near net shapes

Directional solidification

High mold cost

Molds are not permeable

Limited to lower melting temperature alloy

Limited mold complexity

Types of permanent mold

Die

Centrifugal

Pressure

Squeeze

Slush

Semisolid

Hot chamber

Cold Chamber

hot chamber

cold chamber

Advantages

Very large parts can be produced

Difficult materials shape can be produced

Produce complex shapes with internal cavities

Economically competitive with other manufacturing processes