Before the machine age, every article had to be made by hand. The craftsmen could make only one thing at a time. They could not make exactly similar articles. Moreover this took a long time. The total production was small.
Once upon a time, there was a blacksmith who used to make rifles. He was a skilled worker. Once he was asked to manufacture about 10,000 rifles in a fixed time. He accepted the challenge and prepared a plan after studying the deal carefully. The due date for the supply of rifles drew near. No one noticed any change in the working of his workshop. One day, he went to his client with two big boxes full of rifle parts. In a short time the blacksmith assembled the parts and made about a dozen identical rifles. The client was surprised as all the rifles were of the same size and quality. Parts of any rifle could be easily replaced.
Actually, the blacksmith prepared the design and model of a rifle. He prepared the mould for each part. With the help of the mould, he got the various parts manufactured in different workshops. On assembling these parts, the rifles were ready. This method is called mass production. This method improved the quality and reduced the cost of a product. Now articles could be made in large numbers in a short time. The idea of mass production resulted in the development of big factories. Workers left their villages to settle near big factories. This brought about a great change in our life and occupations. It was called the industrial Revolution.