Therefore adequate venting minimize porosity

This limitation can be overcome by making core with the use of thin wire to strength the core and for large cavity produced, the more number of small cores are used.

2. In a mold, core prints and chaplets must be required to position and assist the core.

2. Due to small weight of the core as compared to molten metal, core will get eroded due to molten metal, so core have sufficient hardness and strength to overcome this.

3. Due to fragile nature core will get fracture to impact of the molten metal when it will be poured in the mold

F = v_g (ƿ _n ƿ _c)

V = volume of core

that is, F ≤ 3.5 area of core

or its compressive strength should be:

3. Use wood flour or the saw dust to increase its permeability.

4. Use of plastic straw inside the cores to trap the generated gases.

3. It will make very low strength because after casting it will break to remove from casting and getting the desired product as per requirement.

6. Following are the three different core making process:

• HOT HARDENING PROCESS:

This curing operation occurs by the heating of mixture of sand resin or most probably by permitting it to interact with the pattern of heating instrument.