A wax duplicate of the desired casting is created to be invested
into a "Ceramic Slurry".
The slurry covered investment can be dipped into alternating coatings
of sand and slurry until a suitable thickness of shell is achieved that can
hold the molten metal after the investment is burnt out.
The "Burn-Out" process requires that the investment and
coating are inverted in an oven that is fired to 1800F so that the investment
can flow out and be recovered. The refractory coating is also cured in this
procedure.
This process is beneficial for casting metals with high melting
temperatures that cannot be moulded in plaster or metal.
Principle
Method also called as precision investment casting. The method
involves the use of expendable Pattern with a shell of refractory material
surrounded to form a casting mould. Since the pattern made up of wax is melted
out and gets destroyed. That is why the name-"Lost wax method".