A Tesla humanoid robot team began factory audits in China's Yangtze River Delta last week, checking production lines at Tuopu Group, Sanhua Intelligent Controls and Joyson Electronics ahead of the planned volume launch of the third-generation Optimus, The Paper reported on Monday, citing a person familiar with the industry chain.

The audits cover quality and compliance of the relevant production lines, and several of the companies had already secured Optimus orders before the review began, the person said. "Before this round of audits, these companies had all already received orders for Tesla's humanoid robot, differing only in size."

The three companies mainly supply Tesla with core electromechanical components such as joint modules, actuators and precision structural parts. Production will start soon after they pass the audits, according to the report.

The audit scope extends beyond Ningbo in Zhejiang province, as previously rumored, to supply chain companies in Hangzhou, Shanghai and other parts of the Yangtze River Delta. Most are existing suppliers to Tesla's auto business, the person said.

21jingji reported on September 17, citing industry chain sources, that a Tesla team arrived in Ningbo on September 16 and began a new round of mass production audits for the Optimus robot on September 17, having already placed orders with supply chain companies.

The model set to enter mass production is Tesla's third-generation Optimus, its first designed for volume production. It features major upgrades to its dexterous hand mechanism and joint actuators, and will initially take on industrial tasks such as material handling and simple assembly line assistance in factories.

Tesla has converted its former Model S and Model X production line at the Fremont plant into a dedicated Optimus line with a planned annual capacity of 1 million units. The company is also preparing a second robot production line at its Texas Gigafactory, with a long-term designed annual capacity of 10 million units, expected to start production around summer next year.

CEO Elon Musk has called mass production of the humanoid robot "the hardest product to scale manufacturing that we've ever made at Tesla." On the January earnings call, he said Tesla's biggest competitors in humanoid robots will come from China.

This is the second major audit round for the Chinese supply chain. Tesla conducted a previous round from September 2025 to around February this year to prepare for the redesign and mass production of the third-generation model, according to 21jingji. That round applied automotive-grade standards, requiring fast cycle times and high yields, breaking down the per-unit cost, and requiring suppliers to have overseas manufacturing capabilities and tier-2 supplier management capabilities.

The reported order placements and audit timeline come from unnamed industry chain sources cited by Chinese media and have not been confirmed by Tesla or the named suppliers. The Fremont and Texas capacity figures are company statements of intent rather than demonstrated output, and the Texas line's summer start date remains a target rather than a confirmed schedule.

What to watch next: whether the named suppliers pass the current audits and begin Optimus component production, the ramp of the Fremont line toward its 1-million-unit annual capacity, and confirmation of the Texas Gigafactory line's production start around summer next year.