Manufacturing means changing raw materials into products using a range of processes. For example, in bread manufacturing, you start with the raw materials: flour, water, yeast, and fat. These materials are changed into a final product: a loaf of bread wrapped in plastic foil. They are changed into the product by a number of processes or actions: for example mixing, cutting, putting into tins, baking, cooling, taking out of tins, spraying, slicing, and wrapping.

In the past, these processes were mainly done manually (by hand), but now manufacturers want to keep costs low, avoid waste, and make high-quality products as quickly as possible. Increasingly these jobs are done by using computer-controlled automation. Food processing is an important area of automated technology. The bread- making factory in this unit has more in common with a car assembly plant or with steel-making than with a traditional bakery where bread was made by hand. (Assembly means fixing together parts which have already been produced.) The factory runs for 24 hours a day and very little is done by hand. The work force is small so costs are low. A lot of mass-produced food and drink comes from factories like this.

Every type of manufacturing has its own special processes. An illustrated list of some of the most common processes is provided in the Reading bank (pp.56—58) of the Student’s Book. In metal manufacturing, impact extrusion is a process by which a sheet of metal is pushed or drawn up into shape. Aluminium cans are made in this way. Bonding is joining materials using adhesives. Welding joins metals by heating them to melting point. Plating is applying a thin layer or coat of metal to another metal to improve its appearance or to protect it from corrosion.

In plastics manufacturing, injection moulding is a common way of making plastic items such as bottle tops, caps, and CD covers. The hopper is a container or reservoir which feeds pellets (small pieces) of plastic into the barrel of the machine. The ram is like a piston. It pushes the soft warm plastic along the barrel into the mould. The mould is usually water-cooled to allow the molten plastic to set quickly.

* Tip
a process is a sequence of actions which changes materials or assembles parts into a completed product.
a product is a completed, finished item which can be sold.
* Tip
extrusion (n) is related to the verb extrude, which means to push (or squeeze) a substance out of a container. When you squeeze a toothpaste tube, you extrude the toothpaste.
injection (n) is the opposite process, related to the verb inject, which means to push a substance into a container. Doctors and nurses inject medicines into a patient’s arm.

Processes
colour-printing, impact extrusion cutting, bending, moulding, welding, painting, assembly injection moulding