In October 2026, Xinjian Transmission, in its reply to the Shenzhen Stock Exchange's inquiry regarding its ChiNext IPO, put into writing a judgment that had previously circulated only in narrow supply chain circles: Tesla's Optimus V3 hardware design is essentially frozen, and the program is about to enter the mass production cycle. Core components including planetary roller screws, harmonic reducers, and six-axis force sensors have moved from the sample validation stage to batch delivery.
The weight of this statement lies not in the word "mass production," but in the qualitative shift it implies for upstream machining capability. In the sampling stage, the question is "can you make it." In the batch delivery stage, the question is "is every single unit the same." For planetary roller screws and micro gears, that difference is almost everything.
The former Model S/Model X line at the Fremont factory is being converted into the Optimus V3 mass production line, with a long-term capacity target of 1 million units per year. The Texas Gigafactory is planned to break ground in 2027, with a long-term target in the tens of millions. V3 is scheduled to start mass production before the end of 2026, and a small number of robots are already running inside the Fremont factory for AI training and data collection.
The supply landscape for planetary roller screws is also narrowing. Xinjian Transmission stated in its inquiry reply that for humanoid robot linear joint actuators in heavy-load scenarios, planetary roller screws will not see a practically viable alternative for a considerable period. This means there is no "route-switching" suspense for heavy-load joint transmission. Suppliers face the same drawing, under continuously amplified batch consistency pressure.
The dexterous hand transmission architecture is more complex. The V3 hand increases degrees of freedom to 22 and adopts a compound transmission scheme of "planetary gearbox + micro ball screw + tendon". The micro ball screws and micro gears in this structure handle precise finger actuation at a smaller scale and with tighter fit relationships, demanding machining precision no lower than heavy-load screws, but with far narrower tolerance for error.
The core difficulty of planetary roller screws is not making a qualified sample. Thread profile geometry, the fit clearance between rollers and screw, and deformation control after heat treatment can all be resolved in single-piece trial production through hand-fitting and sorting. In batch delivery, the same precision must be output stably by the process itself, without sorting and without hand-fitting.
At the machining level, thread grinding of the screw requires control of profile angle error and cumulative pitch error. Crowning of the rollers directly affects contact stress and service life. The fit clearance between the nut's internal thread and the screw must remain within the design window after heat treatment distortion. The difficulty is not the precision ceiling of a single machine, but whether error accumulation across a multi-process sequence remains controllable. One qualified screw does not mean the hundredth will be. Batch consistency depends on locked process parameters, tool wear management, and a closed loop of in-process inspection, not final inspection sorting.
Tesla's supplier audit standard states this directly. TS-00005 contains 112 core clauses, and its "zero-defect mass production" requirement does not use AQL sampling; it requires 100% inspection. Full inspection means every screw's thread parameters, fit clearance, and surface integrity must leave a traceable data record. The process window must be narrow enough that batch quality is not a gamble settled by sampling.
The size of dexterous hand micro gears has entered a range where traditional cutting becomes economically unfavorable. Small module, low tooth count, irregular structure — piece-by-piece CNC milling not only struggles to match the production takt, but tool wear in micro-module tooth slots rapidly degrades consistency.
Metal injection molding (MIM) offers adaptability rooted in the process itself. MIM can hold tolerances in the ±0.2% range with material utilization above 95%, and is suited to small, complex, high-volume metal parts. Dexterous hand micro gears, connectors, and joint structural parts fall squarely within MIM's advantage zone. Industry research explicitly notes that MIM can be applied to micro gears and connectors for dexterous hands, addressing manufacturing pain points at the mass production stage.
But MIM is not "open the mold and ship." The tooth profile accuracy of micro gears depends on mold cavity machining precision and injection process stability. Sintering shrinkage compensation must be designed into the mold from the start. Dimensional drift during debinding and sintering must be controlled by narrowing the process window. For gear trains with dense fit relationships, a single qualified gear is only the starting point. Whether the mesh clearance and backlash of the entire gear set remain stable across the batch is what customers will actually scrutinize during audits.
The special context of this audit round is Musk's explicit statement that Gen3 will "not use the existing supply chain" and will be redesigned from first principles. Fixed-point qualifications obtained in the previous round may be reset to zero. Every supplier must prove itself again.
Several TS-00005 clauses point directly at the underlying capabilities of precision machining enterprises. "Full-chain traceability" requires every link from raw material to finished product to be verifiable, with tier-2 suppliers brought under control. For MIM gear suppliers, this means powder batches, binder ratios, injection parameters, sintering curves, and mold maintenance records must form an associable data chain. "Cost breakdown" requires per-unit cost to be itemized and reconciled toward a USD 20,000 total selling price target, with every machining step's cost laid open for scrutiny.
Together, these requirements filter out not factories that "cannot make a sample," but factories that "can make a sample but cannot hold consistency in batch, and cannot explain traceability." For precision machining enterprises that have already run full-process quality control in medical devices and military sectors, this logic is familiar. The difference is only in product category and production takt.
The process capabilities that Shenzhen Yujiaxin Technology Co., Ltd. has accumulated in custom precision metal parts manufacturing map directly onto the batch delivery requirements for planetary roller screws and micro gears.
In micro gears and dexterous hand transmission components, Yujiaxin's MIM metal injection molding process covers one-piece forming of micro gears, irregular connectors, and joint structural parts, complemented by precision CNC machining for finishing mating surfaces and critical dimensions. Precision gear forming covers micro tooth profile machining at the reducer end. This combination of "MIM near-net forming + CNC finishing + gear forming" is not a stack of isolated processes, but a selection of the most suitable machining path for each component's balance of precision, cost, and production takt.
On the quality system side, Yujiaxin has passed GJB9001C-2017 military certification, with quality management covering the full process of complex structural hardware machining. The military system's requirements for batch consistency, process records, and traceability chains share the same underlying logic as Tesla's TS-00005 zero-defect full inspection and full-chain traceability. For a precision machining enterprise that needs to prove "every unit in batch delivery is traceable" to customers, this system capability carries more weight than a single machine's precision specification.
Planetary roller screw machining is a direction requiring sustained investment for Yujiaxin, as thread grinding and heat treatment distortion control involve dedicated process accumulation. But in micro gears, dexterous hand transmission components, and joint structural parts, the existing MIM, CNC, and gear forming capabilities already provide a process foundation for entering the supply chain. The key is organizing these capabilities into a form that can be verified during customer audits: batch consistency data, process traceability records, and proof of process window stability. For more precision hardware component machining scenarios, refer to Yujiaxin's custom precision hardware services.
The freezing of Optimus V3 hardware and the start of batch delivery have pushed competition in humanoid robot precision components from "sampling capability" to "batch consistency capability." Heavy-load planetary roller screws and dexterous hand micro gears — one tests error control across multi-process sequences, the other tests forming consistency and fit stability of micro parts. Suppliers that can deliver reliably in these two categories rely not on the precision ceiling of a single machine, but on the system capability formed by process windows, inspection loops, and traceability systems. Shenzhen Yujiaxin Technology Co., Ltd. is ready to work with global partners to address the supply chain needs of this phase, providing verifiable build-to-print custom machining support for micro transmission components and joint structural parts through its multi-process capabilities in MIM, precision CNC, and gear forming.
Learn more about custom precision metal parts manufacturing services: https://www.szyujiaxin.com/en/
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