Pressure casting is the types of permanent mold casting processes in which air pressure is used to move the molten metal into the mold. Unlike other casting processes in which metal flow from top to bottom in pressure casting molten metal moves from bottom to the top.
Parts of pressure casting machine
- Air tight camber
- Inlet valve
- Container for molten metal
- Refractory tube
- Mold moving mechanism
Steps involves in pressure casting
Step 1Two parts of the mold are prepared and machined with extreme accurately, so they can open and close precisely for removal of metal parts. Unlike other molds, mold of pressure casting have the gating system which support the flow of metal from bottom to the top. Mold is then placed over the air tight sealed chamber having the molten metal in it
Step 2After that air is introduce into the chamber through the air inlet valve. After some time chamber is completely filled with air and after that when more air is introduce into the chamber it will create pressure on the molten metal.
Step 3Air pressure on the molten metal will force it to move up into the mold through the refractory tube. Air pressure will be maintained until the molten metal in the mold solidifies.
Step 4After the metal solidifies pressure is removed and mold is open to remove the cast part
Advantages of pressure casting
- Good mechanical properties
- Good dimensional accuracy
- Good surface finish
- Good for mass production
- Less oxidation effect
Disadvantages of pressure casting
- High set up cost
- Not suitable for small production
- Geometry of the part is limited