For Zhu, and millions of other younger Chinese, the low pay, long hours of drudgery and the risk of injuries are no longer sacrifices worth making.
Factory bosses say they would produce more, and faster, with younger blood replacing their ageing workforce.
But offering the higher wages and better working conditions that younger Chinese want would risk eroding their competitive advantage.
China's Ministry of Education forecasts a shortage of nearly 30 million manufacturing workers by 2025, larger than Australia's population.
He runs a factory in Shenzhen with around 50 workers who make magnetically shielded rooms used by hospitals for MRI screenings and other procedures.
Rather than settling for jobs below their education level, a record 4.6 million Chinese applied for postgraduate studies this year.
After that he worked in another factory, moulding tin boxes for mooncakes, a traditional Chinese bakery product. »
