An assembly line is a manufacturing process (most of the time called a progressive assembly) in which parts (usually interchangeable parts) are added as the semi-finished assembly moves from work station to work station where the parts are added in sequence until the final assembly is produced.
Before the Industrial Revolution, most manufactured products were made individually by hand.
Division of labor was practiced in China where state run monopolies mass-produced metal agricultural implements, china and armor and weapons centuries before it appeared in Europe on the eve of the Industrial Revolution.
Sociological work has explored the social alienation and boredom that many workers feel because of the repetition of doing the same specialized task all day long.
Over the last two decades, China's social structure has undergone significant changes. This is fueled by the rapid economic growth as manufacturers flock to China for its cheap and large labor force.
Some 260 million Chinese farmers have left their villages and to work in cities as factory workers
Despite their contribution to China's economic miracle, the social status of these migrant workers remains low.
The hukou system -- or household registration system that divides the population into two distinct categories of the urban and the rural -- makes things harder for the migrants, who don't enjoy the same access to healthcare and education as other city residents. They are often discriminated against in terms of salary and treatment.
Research done on factory migrant workers suggested that 58.5% of those surveyed suffered from depression, 17% from anxiety and 4.6% had considered the idea of suicide.
The majority of those surveyed, half of whom were under 30, bore a heavy financial and emotional burden as they left behind aging parents or young children.
Migrant workers felt guilty for being unable to care for parents or young children, at the same time, felt pressure to provide for their families.
A similar research was done five years ago on the mental health of sex workers in the Guangdong region, most worked at factories before turning to prostitution.
In 2010, the issue mental health of Chinese migrant workers made international headlines after a spate of worker suicides at Foxconn, a large electronic manufacturer that assembles many Apple products.
A study of Foxconn migrant workers revealed that loneliness and a sense of isolation were the most likely reasons that drove the workers to jump off factory and dormitory roofs.