Making Cores Of Sand Casting Process

Cores are used to obtain the internal configurations of different castings. Cores are usually made of synthetic sand, although clean, natural sand containing only 1 to 2 % clay can be used. Cores may also be made of green sand used in the dried condition. Most frequently, however, they are bonded with organic agent such as linseed oil, cereals, molasses etc may be added to make the raw mixture stronger. The basic advantage of organic core binders (as compared to clays) is that they break down under the heat of metal (have collapsibility) and so can be easily removed from the casting as shakeout.

Equipment:

1. Core Box
2. Rammer
3. Chemicals / Materials:

Chemicals / Materials:

Moulding Sand (mixture of sand & molasses).

Procedure:

• Take a core box and fill it completely with molding sand (mixture of sand & molasses).
• Insert iron wires for reinforcement.
• Then ram the molding sand present in the core box with the help of a rammer.
• Continue adding and ramming the moulding sand until the sand is densely and fully packed in the core box.
• Then, open the core box and carefully remove the core from it.
• Bake this core in an oven at about 230oC to develop the strength in core and to remove gases.
• After baking, wash the core with refractory slurry to improve the casting surface finish.