Applications

Cast parts are used in a variety of applications including:

• Lightweight components for vehicles, aircraft, ships and spacecraft.
• General engineering components where light weight and corrosion resistance are required.
• Architectural fittings where light weight and good appearance are important.
• High-tech products for office and home.

Casting falls into two main categories: Sand Casting and Die Casting.

Sand Casting

This technique is usually used for high production volume processes. Sand moulds are created using various materials, the sand must be bonded together using either synthetic compounds or clay and water and moulds must be rebuilt after each casting.

The design of moulds is a very complicated process, however, in general, they are filled simply by gravity without the need for any pressure differentials or mechanical action.

Die Casting

Die casting moulds are generally permanent and made of either cast iron or steel. There are three main modes of die casting: high pressure, low pressure and gravity die casting.

High pressure die casting is the most commonly used process, in which molten aluminium is injected at high pressure into a metal mould by a hydraulically powered piston. The machinery needed for the process can be very costly and this high pressure die casting is only economic when used for high volume production.

Low pressure die casting uses a die which is filled from a pressurised crucible underneath. The process is particularly suited to the production of rotationally symmetrical products such as automobile wheels.

Gravity die casting is suitable for mass production and for fully mechanised casting.