SHENZHEN, China — Inside one of the world’s largest electronics factories, Yuan Yandong, 24, sits on a stool six nights a week, 12 hours a night barring meal and bathroom breaks, and assembles computer hard drives for an American company called EMC.

Until a few months ago, he lived in northern China, where he grew up on a farm and worked at a local hotel after finishing middle school. But this year, he traveled 36 hours by train to Guangdong Province in the southeast to find work in Shenzhen. All he took for his journey south on the hard train seat was a sack of clothes, toothpaste, shampoo and his mobile phone.

“Friends in my hometown said wages at Foxconn were good,” he said. “So I figured I could earn more here.”

A series of puzzling suicides at Foxconn and labor strikes at Honda auto parts factories in southern China have put the spotlight on what work is like inside the country’s booming factories. Analysts say rising wage pressure and demands for better conditions are threatening China’s competitive advantage and raising questions about whether its manufacturing model can continue to churn out much of the world’s toys, textiles and electronics at rock-bottom prices. To do so, China will need legions of young migrants like Mr. Yuan to continue to make the journey from villages in the interior to the manufacturing hubs along the coast.

And what is life like for a cog in China’s labor-intensive factory model? Mr. Yuan, with the approval of his supervisor, described it for The New York Times last week before and after his Thursday shift.

7:30 p.m. | | The Shift Begins

Mr. Yuan (pronounced yu-wen) wakes at 6:10 p.m. at his small apartment, a 20-minute walk from Foxconn’s campus. He arrives at the factory at 6:50 for a quick free meal at the canteen, then starts work at 7:30.

His task is to help complete 1,600 hard drives — his workshop’s daily quota — and to make sure every one is perfect. Seated in the middle of the assembly line in his black Foxconn sports shirt, cotton slacks and company-mandated white plastic slippers, he waits for the conveyor belt to deliver a partly assembled rectangular hard drive to his station. He places two plastic chips inside the drive’s casing, inserts a device that redirects light in the drive and then fastens four screws with an electric screwdriver before sending the drive down the line. He has exactly one minute to complete the multistep task.

Working at a company known for its precision manufacturing and military-style regimentation is not easy. Mr. Yuan can take his cellphone to work, as long as it doesn’t have a camera, but no MP3 players are allowed. He can chat with other line workers, but on the line there are no wasted movements; they have been analyzed and tested with a stopwatch, he said.

“If you do the same thing all day long you can become numb,” he said. “But I’ve gotten used to doing this type of work.”

10:30 | | Dinner Break

Time for a subsidized meal at the canteen. This night, he had rice and scrambled egg with tomato and eggplant, well within the 65-cent allowance for the meal. Then he went for a short walk.

11:30 | | Back on the Line

Foxconn, owned by Taiwan’s Hon Hai Group, is one of the world’s biggest contract manufacturers — building and assembling for leading brands like Apple, Dell and Hewlett-Packard.

Luo Jar Der, a sociology professor at Tsinghua University in Beijing and an authority on China’s manufacturing model, says contractor manufacturers like Foxconn have borrowed techniques from the United States and Japan.

“Foxconn has a team of 500 people who analyze each action a worker makes,” Professor Luo said. “They want to find the most efficient actions of a worker.”

Professor Luo says that the pressure can be intense and that workers are treated like machines at some factories. This is the marvel of China’s low-cost manufacturing boom. Factories are known to replace workers with machines that automate a process, but here in China factories often reverse the trend and replace costly machines with workers like Mr. Yuan — slower but sometimes preferable because there is no large upfront capital investment.

Mr. Yuan does not complain. This is his job, he says, and for now he’s comfortable doing it.

5:30 a.m. | | Overtime

After a second meal break at 4:30, Mr. Yuan begins his overtime shift. Oddly, he says he is not aware of a law that limits overtime work to 36 hours a month (a law that many factories in southern China ignore). He often works more than twice that. When big orders come in, for instance, he says he can be told to work longer. And if his team members don’t meet the daily quota, they are asked to keep working.

Mr. Yuan earns about 75 cents an hour. With overtime premiums, he takes home $235 a month. His rent is about $44 a month, plus $7 for water and electricity, and there are quite a few other expenses, but he said he manages to save about 40 percent.

Foxconn, forbidden city from sportsouyang on Vimeo.

8 a.m. | | Home to Sleep, to Dream

Mr. Yuan returns to the apartment he shares with his girlfriend, who works at a smaller factory. He often reads a management book or watches TV. Post-shift on Thursday, “I felt O.K.,” he said, “not as tired as when I first got to Shenzhen because I’ve gotten used to the night shift.”

How long can China be the world’s workshop? It has distinct advantages even though costs are rising. Few countries can match the manpower, supply chain or will to work, experts say. But factories like Foxconn have a high rate of turnover. A new generation may be tiring of the monotony. Mr. Yuan, for example, says he is not content to be a factory worker for long. After two years he’d like to use his savings to open a hotel management company. That might be more possible after the 33 percent raise Foxconn recently gave all its workers kicks in.

Bao Beibei contributed research.