Please enable JavaScript.
Coggle requires JavaScript to display documents.
Slip Casting (water 30%-35%) (Form of Casting (Pressure Casting…
Slip Casting
(water 30%-35%)
Stages :
1) Pour slurry/ slip into a porous mould.
2) Extraction of water into moulds through voids/pores in mould
3) Forming of solid layer on surface of mould
4) Excess of slip/slurry removed.
Important Criterion
-Slip requires
high solid content with controlled of water
( high solid to water ratio) with suitable level of viscosity.
can be controlled by
3 parameters
Slip density
(mass/volume)
Viscosity
(relative internal stress in relation to movement at other positions)
Thixotropy
(ability of slip to be more viscous when remain undisturbed)
-Produced cast with
good properties such as dense
, solid with
good green strength
and not easily crack.
Deflocculant
(enable slip to be prepared with high solid content in a small amount of water without disturb viscosity)
Common deflocculant used:
-Na Silicate
-Calgon
-Na carbonate
-Dispex
-CMC
Deflocculant will affect 3 slip properties/parameters
Type of casting
Drain Casting
slip pored into moulds
cast layer formed in the inner layer of mould
Excess slip drained out
Partial drying ( cast can release from the wall of mould due to shrinkage during drying)
Trimming before glazing / firing
Solid Casting
cast layer is formed on both side of opposite walls of mould.
mould set-up from a few pieces are required.
Form of Casting
Bench Casting
Battery Casting
Pressure Casting
Advantages:
-high quality cast
-longer mould life
-Deform shape reduced
-Easy to change mould of mould
Factors
influencing
casting process
Solid Concentration/
rheology of slip
Distribution of
pore sizes in mould
Permeability of
cast layer
