The investment casting process begins by creating wax or plastic patterns of the desired casting shape. These patterns are assembled and surrounded by a refractory slurry mold. The mold is then heated, melting out the pattern and leaving a clean cavity. Molten metal is then poured into the mold to create the casting, which is then separated from the mold. This lost wax process allows for intricate details and smooth surfaces in castings of alloys that are difficult to machine.

1. INVESTMENT CASTING
BY
ARAVINDKUMAR B

2. INVESTMENT CASTING PROCESS
 To create intricately detailed shapes
 Also called lost wax process begins with the production of wax
replicas or patterns of the desired shape of the castings.
 The patterns are prepared by injecting wax or polystyrene in a
metal dies.
 A number of patterns are attached to a central wax sprue to
form a assembly.
 The mold is prepared by surrounding the pattern with
refractory slurry that can set at room temperature.
 The mold is then heated so that pattern melts and flows out,
leaving a clean cavity behind.
 The mould is further hardened by heating and the molten
metal is poured while it is still hot.
 When the casting is solidified, the mold is broken and the
casting taken out

3. METHODOLOGY
 Pattern is made up of wax / polystyrene polyethylene
 Dipping is done in extremely fine silica and
water/gypsum solution.
 Baked in a oven for 2 hours to melt out the wax (100-
120 C)
 Mold is cured for sometime at 800-900 C

5. ADVANDAGES
 Intricate details can be cast
 smooth surface /no parting line
 high accuracy
 unmachinable alloys ( HRS + Nimonic alloys)
 mininimum wall thickness of 1-2mm

7. The basic steps of the investment casting process are
 Production of heat-disposable wax, plastic, or
polystyrene patterns
 Assembly of these patterns onto a gating system
 “Investing,” or covering the pattern assembly with
refractory slurry
 Melting the pattern assembly to remove the pattern
material
 Firing the mold to remove the last traces of the
pattern material
 Pouring
 Knockout, cutoff and finishing

8. APPLICATIONS
 Parts for aerospace industry / aircraft engines
 Food / beverage machinery
 m/c tools, scientific instruments, sewing machine
 nozzles, vanes, blades for gas turbines.