Plaster mould technique

plaster mold process

1. Plaster Mould CastING

SUBMITTED TO : SUBMITTED BY :
DR. NANDITA GUPTA ABHIJEET
NIFFT,HATIA M.TECH(F.F.T)

2. INtroduCtIoN
Plaster mould casting is a metalworking casting process
similar to sand casting except the Moulding material is
Plaster of Paris(Gypsum-CaSO4•2H2O) instead of sand.
It can only be used with non-ferrous materials.
The Plaster is not pure Plaster of Paris, but rather has
additives to improve green strength, dry
strength, permeability, and castability.

3. ProCess
•Plaster is mixed and the pattern is sprayed with a thin
film of parting compound to prevent the Plaster from
sticking to the pattern.
•Plaster is then poured over the pattern and the unit
shaken so that the Plaster fills any small features.
•The Plaster sets, usually in about 15 minutes, and the
pattern is removed.

4. •The Mould is then baked, between 120 °C (248 °F)
and 260 °C (500 °F), to remove any excess water.
•The dried Mould is then assembled, preheated, and the
metal poured.
•After the metal has solidified, the Plaster is broken
from the cast part.

6. ADVANTAGES
•Excellent surface finish .
•Good dimensional accuracy.
•Allows the metal to fill thin cross-sections.
•the minimum possible cross-section is 0.6 mm
(0.024 in).
•It is used for castings as small as 30 g to as large as
45 kg .
•Complex shape product can be casted.
•It also produces minimal scrap material.
•Economical for complex shape component.

7. DISADVANTAGES
•It can only be used with lower melting temperature non-
ferrous materials, such as aluminium, copper, magnesium,
and zinc.
•Long cooling times restrict production volume.
•Factors(Like plaster composition, pouring procedure, and
curing techniques) should be monitored closely .
•Not stable as sand.

8. APPLICATION
•Parts that are typically made by plaster mold casting are
lock components, small gears, valves, fittings, tooling,
and ornaments.
•prototypes and short run production of aluminum and
zinc parts.
•Aircraft parts,small propeller,handles,small housing etc.