Question

(a) Describe the process steps in sand casting? Compare to die casting, what are some major advantages and disadvantages of sand casting?

(b) Describe the process steps in investment casting?

(c) Describe the process of hot-chamber and cold-chamber die casting. What are the most attractive features for each process?

Answer 1

Ans A ). Process steps in sand casting :-

1. You must place a pattern in sand , to create a mould.

2. Incorporate the pattern and sand in a gating system.

3. You must remove the pattern you have placed to create mould, remove that.

4. The mould cavity is to be filled with the molten metal.

5. Now leave , and wait until the molten metal gets cooled.

6. Break that mould and Remove the casting .

And B ). Process steps in investment casting

1. Firstly there should be a produtipro for heat-disposable wax, plastic, or polystyrene pattern.

2. These pattern are to assemble onto gating system.

3. The pattern assembly is to be covered with refactory slurry.

4. Melting the pattern assembly to remove the pattern material.

5. Remove the last traces of pattern material by firing the mold.

6. Pouring.

7.cutoff and give finishing .

Ans C ). Hot chamber die casting

:- the injection mechanism of a hot chamber machine is immerei in molten state . The furnanf is attached to machine by a metal feel system.

The die is closed and piston rises , opening the port

Next , the plunger seals the port pushing the molten state metal through the metal feed system and nozel into the die cavity .

The die opens

Ejector pins push the casting out of the ejector die as the plunger uncover the filling hole, molten metal flows through the inlet to refill the metal feed system

Ejector pins push the casting out of the ejector die . As the plunger uncover the fillufi hole.

cold chamber die casting

1. The allumina is liquefied through a furnace.

2. Molten aluminum is then ladled into the die casting chamber.

3. Plunger forces the aluminum into the cavity .

4 . Plunger moves forward and die opens .

5.ejector pins force the die casting part out of the ejector die.

6.since these materials would regularly pose problem when melted in a casting machine.

7. The cold chamber process is most ideal for metal alloys that have higher melting points .