Gravity Die Casting
Casting is a method or process used to shape materials into useful products. It is one of the oldest methods which was used around 4000 B.C. to make tools and ornaments. Casting is a process in which molten metal is poured into the mould cavity and allowed to solidify, after solidification the metal takes the desired shape of the cavity. Through this process, we can cast a variety of products with intricate shapes in a single piece as well as sizes from very small to large and with shapes having internal cavities. Engine blocks, pistons, cylinder heads, transmission housings, ornaments etc. are typical examples of Casting.
Permanent moulds are designed such that mould can be reused again and can be removed easily. The moulds are made up of metals as they are good conductors of heat as compared to expandable moulds, they also maintain high strength at high temperature. It is also called as Gravity Die Casting. In the gravity die casting process gravitational force is used to pour the molten material into the Die.
Gravity Die casting is a repeatable casting process normally used for nonferrous alloy typically copper, aluminium and zinc.
The three important stages in Gravity die casting are:
Stage 1: The mould or Die is heated and coated with a die coating material. The function of die coating material is to act as a non-sticky medium between Die and product after solidification. Its secondary function is to cool the mould face after the previous product is removed from the Die.
Stage 2: Molten material is poured into the cavity by using steel ladles such that it fills all the cavities of the section. The design of the gating system is done in such a way that it avoids the formation of turbulence and other casting defects.
Stage 3: After the solidification of product the die is opened manually or by any mechanical means.