2.3 Types of casting
2.3.1 Permanent pattern
This type of casting uses a model, or pattern, of the final product to make an impression which forms the mould cavity. Each mould is destroyed after use but the same pattern is used over and over again. Sand casting is a typical example of a permanent pattern process, where a pattern is placed into a special casting sand to form the right shape of cavity. Permanent pattern processes are usually cheaper than other methods, especially for small quantity production or 'one-offs', and are suitable for a wide range of sizes of product.