Introduction to Casting Process
● Casting Process is the most widely used
Manufacturing Process in the Industries.
● Products of varied sizes, from small to very
large can be manufactured using this
● Some examples of items manufactured
using Casting Process include Engine
blocks, Machine tool bases, Cylinder heads,
Pump housings, Valves, etc.
Pattern in Casting Process
● It is a replica of the object
to be made.
● Mould Cavity is made with
the help of Pattern.
● They are usually made
from Wood, Plastic, Sugar
Pine and Wax.
Types of Pattern
● Single Piece Pattern
● Two Piece Pattern
● Multi Piece Pattern
● Match Plate Pattern
● Gate Pattern
● Skeleton Pattern
● Sweep Pattern
● Loose Piece Pattern
● Cope and Drag Pattern
● Shell Pattern
● Difference in dimensions of Pattern
and Casting are due to Allowances.
● Allowances are provided to avoid any
damage to the Mould Cavity and
desired Casting Product is obtained.
● It gives a compensation to the
drawbacks of the Casting Process.
Core in Casting Process
● Cores are compact mass of core sand used to produce hollowness in
● The core is placed inside the mould cavity, at the right location and
● It can also be used to strengthen the mould.
● Cores are placed on the extra projections on the pattern called the
● Sometimes cores are placed with Chaplets that provide adequate
support to and avoid it from sagging. These Chaplets are made from
same material as that of the Casting.
● To provide continuous, uniform
feed of molten metal into mould
cavity and to reduce the turbulence
● Proper directional solidification.
● To fill the mould cavity in a less
time to avoid thermal gradient.
● To provide minimum excess metal,
and erosion of mould walls.
Elements of Gating System
POURING BASIN :
● It is the conical hollow element or tapered
hollow vertical portion of the gating system.
● It makes easier for the ladle operator to
direct the flow of molten metal from crucible
to pouring basin and sprue.
● It helps in maintaining the required molten
● It reduces turbulence and vortexing at the
A Casting Defect is an undesired irregularity in
a metal casting process.
Some defects can be tolerated while others
can be repaired, otherwise they must be
Types of Casting Defects are:
1) Gas Porosity 2) Shrinkage defects
3)Mould material defects 4) Pouring metal
-defects 5) Metallurgical defects
● Moulding is a manufacturing process that involves
shaping a liquid or malleable raw material by using
a fixed frame.
● The mould is obtained from the initial pattern or
template of the desired object.
● Then, multiple copies of the final product are
produced using that mould.
● As the liquid cools and hardens inside the mould,
the final product is obtained. It’s removal is
facilitated by release agents or ejection pins.
It is used for preparing Mouldings for the
Constituents Of Moulding Sand are:
● Silica Sand
Properties of Moulding Sand
● Green Strength
● Dry Strength
● Flowability or Plasticity