The Race to Mass-Produce Humanoid Robots Is On — Magnesium Alloy Is Already in the Joints

Every leap in civilization has been shaped by advances in materials and manufacturing. Today, as humanoid robots move from science fiction to reality, their future will depend not only on smarter algorithms, but also on more reliable manufacturing.

 

On July 8, at Booth N2-C10 of the Shanghai New International Expo Centre, magnesium-alloy robotic components exhibited by Bida New Energy, a subsidiary of Xinbo, including upper-arm outer shells, upper-arm inner shells, and elbow connecting links, attracted considerable attention from industry professionals.

 

At the same time, Tesla is pushing Optimus toward mass production, with a long-term target of one million units annually. This signals a clear shift: humanoid robots are moving from prototypes to industrial-scale manufacturing.

 

The competition is no longer only about smarter algorithms. It is also about who can build a reliable manufacturing system and turn prototypes into products at scale. This change is already reaching the upstream supply chain. At this year’s exhibition, more robotic arms, joint connectors, and precision housings appeared across the show floor, showing how aluminium and magnesium components are entering new applications.

 

Against this backdrop, Xinbo is extending its expertise in lightweight materials and precision manufacturing into the robotics sector.

 

 

1. Why Magnesium Alloy Could Be the Key to Lighter Humanoid Robots？

 

At this year’s exhibition, Builder showcased several robot joint components, including upper-arm inner and outer housings and elbow links.

 

The upper-arm housings and elbow links are made from AZ91D magnesium alloy. They are formed using a 350-ton semi-solid die-casting process, followed by CNC machining of key areas such as mounting surfaces and connection holes. Although the elbow link is relatively small, it requires a careful balance of structural strength, hole-position accuracy, and assembly fit, placing high demands on both forming and subsequent machining.

 

 

Why magnesium alloy?

 

Its density is about 63% that of aluminium alloy, while offering a tensile strength of 230–255 MPa, a yield strength of 155–170 MPa, and an elongation of 4%–7%. Magnesium alloy can reduce the weight of robot joint modules by around 20%–30% compared with aluminium alloy, while maintaining the strength required for frequent movement. This helps lower energy consumption and extend operating time.

 

 

2. From R&D to Finished Products: A Closed-Loop Manufacturing System

 

Turning material advantages into real products requires more than the material itself. It also depends on reliable forming, dimensional control, and scalable production.

 

Builder has established a rapid innovation system covering material development, process optimization, and product iteration, supported by platforms such as the Anhui Provincial Key Laboratory for Lightweight NEV Technologies and the Highly Integrated Die-Casting Technology Laboratory.

 

Its manufacturing capabilities span R&D and design, die casting, CNC precision machining, pretreatment and passivation, automated powder coating, and environmental treatment, enabling one-stop customized production from product development to final delivery.

 

Builder is currently developing 17 die-casting production lines, including 15 semi-solid die-casting lines, of which 9 are already in operation. Once fully completed, its semi-solid die-casting capacity will cover products ranging from small precision parts to medium- and large-sized structural components, providing broader manufacturing support across different applications.

 

 

3. From Automotive Expertise to the Robotics Frontier

 

Builder has already supplied components to multiple automotive OEMs and parts manufacturers in the new energy vehicle sector.

 

Developing automotive components requires the close integration of materials, structural design, tooling, forming, and machining. This long-term experience has become the foundation for Builder’s expansion into robotics.

 

The core requirements remain the same, whether the product is an automotive structural component or a robot part: reliable materials, precise processes, and scalable manufacturing.

 

Builder is now transforming its accumulated expertise in automotive lightweighting into new product development capabilities for the robotics industry.

 

 

4. When Humanoid Robots Scale Up, Manufacturing Takes the Lead

 

As Optimus moves toward a million-unit production target, the question for the supply chain is changing from “Do we have a solution?” to “Can we turn that solution into a real product?”

 

The race in humanoid robotics will not be decided by algorithms and models alone. Once mass production begins, tooling, equipment, processes, and every critical component must go through repeated validation—and ultimately prove themselves at scale.

 

The upper-arm housings, elbow links, and precision parts on display today may be only the beginning.

 

Is the component supply chain ready?

The answer is not in a slogan. It is in every step from prototype to product, and from trial production to mass manufacturing.

 

From July 8–10, visit Xinbo at Booth N2-C10, Shanghai New International Expo Centre to explore Builder’s robot components and lightweight manufacturing capabilities.

 

What role do you think lightweighting will play in humanoid robot components? Join the discussion.