From Soft to Rigid: How Polymer 3D Printing Empowers the Mass Production of “Humanoid Robots”?

On July 3, the 2nd Humanoid Robot Industry Chain Forum successfully concluded in Shenzhen.

At the forum, Shi Daokun, General Manager of Zhongke Sanwei (brand “iSUN3D”), delivered a keynote speech titled “From Soft to Rigid, From Verification to Application: Polymer 3D Printing Solutions Empower the Continuous Development of the Robot Industry”.

I. Why 3D Printing Has Become a “Mandatory Option”

The humanoid robot industry continues to boom. The combination of polymer materials and 3D printing technology not only improves the efficiency from design to production, but also directly endows robots with key characteristics such as being “lightweight, high-performance, intelligent, and humanized”.

Specifically, the application of polymer 3D printing has the following four major advantages:

Comprehensive materials: Meeting comprehensive needs from rigid skeletons to flexible skin.

High structural freedom: Easily realizing complex bionic structures.

Fast iteration speed: No need for mold opening, modifying and verifying at any time.

Cost reduction: Significantly reducing the costs of trial and error and early mass production.

II. Application Exploration of 3D Printing in the Field of Humanoid Robots

At present, mainstream polymer 3D printing technologies, such as FDM, light-curing, and SLS, have been widely applied in the research, development, and production of humanoid robots.

1.FDM Technology — Economical and Efficient

Advantages and characteristics: Low threshold for equipment and materials, huge comprehensive cost advantages, rich and complete material categories. Conventional PLA and ABS materials, TPU and PEBA series flexible materials, PA, PA-CF, flame retardant, anti-static and other engineering materials, as well as PEEK and other special materials can all be applied to robot manufacturing.

Main applications: Robot coverings, load-bearing structural parts, gearboxes, and artificial muscles.

2.Light-curing Technology — High Precision and High Performance

Advantages and characteristics: Possessing excellent molding precision and outstanding surface quality; rich resin material systems with large space for modification and regulation.

Main applications: Soft actuators, high-precision end-effectors, bionic skin, and musculoskeletal systems.

Elastic Resin + Bionic Lattice Design

Combining elastic resin and bionic lattice design, light-curing technology can integrally print complex components that combine softness and hardness. For example, in the manufacturing of bionic hands and feet, it can not only print the built-in high-precision porous skeleton, but also achieve gradient stiffness through the external lattice structure, giving the machinery both high bearing capacity and a human-like soft touch.

Palm area: To meet the skin-feel characteristics, finer lattices are set to increase softness; and partitioned lattices are established according to the design idea of palm pads to meet the needs of scenarios such as “lifting, pushing, pressing, and squeezing”.

Inner arm fossa: It is mainly under pressure at normal times and needs frequent folding and squeezing. Therefore, the X lattice with lower strength can be selected to increase arm flexibility and simultaneously increase the extensibility of the deformation of the upper arm and forearm.

Upper arm and forearm areas: The upper arm and forearm bear most of the force when raising the hand, lifting objects, supporting, etc., requiring higher strength. An extremely high-strength lattice design is adopted to provide high elasticity and high tensile resistance.

3.SLS Technology — Support-free, Lightweight, and High Strength

Advantages and characteristics: Relying on the powder bed to provide self-support, fitting the integral molding of complex spatial structures; adopting industrial-grade powders, such as nylon PA12 and PEBA, with excellent mechanical properties and wear resistance.

Main applications: Precision transmission structures, complex joint components, and ball joints.

III. From Soft to Rigid — eSUN 3D Printing Material Full-Matrix Solutions

To meet the demand gap for high-performance complex materials in the robot industry, eSUN, relying on its powerful polymer material research and development platform, has created a one-stop solution of “materials + equipment + processes + design + manufacturing services”.

1.Light-curing Resin Solutions: Breaking Traditions, Combining Strength and Toughness

The hardness range of eSUN light-curing resin products covers the interval from 55A to 85D, and the categories include flexible and elastic, water-washable, general rigid, high-hardness, and high-toughness, etc.

High-hardness and high-toughness resin: Breaking the bottleneck that traditional resins cannot take both strength and toughness into account, it can be tapped and is impact-resistant, and has been used on a large scale in industrial manufacturing.

FlexOne series single-component elastic resin: No mixing required, ready to use upon opening, and not limited by the pot life. Among them, FlexOne 55A elastic resin has an extremely high elongation at break, high resilience, and excellent bending resistance. Meanwhile, it has passed skin sensitization and skin irritation tests, perfectly matching application scenarios such as humanoid robot muscles and joints.

2.FDM 3D Printing Solutions: From Ultra-Flexible to Special Engineering

eSUN provides a full series of FDM filaments covering general, reinforced, ultra-tough, lightweight, anti-static, flame retardant, etc.:

High-performance engineering filaments: Such as carbon fiber reinforced PA/ABS/PLA, industrial-grade PEEK, etc., possessing characteristics such as high strength, high rigidity, high-temperature resistance, and impact resistance, perfectly applicable to robot bionic arms, transmission gears, load-bearing skeletons, etc.

Flexible filaments (PEBA, TPU, etc.): Meeting the needs of robot soft actuators.

*eSUN FDM materials have been successfully applied in the design and application of domestic and foreign competition robots, lunar rovers, and robotic dogs.

3.Full-Process Services: iSUN3D Flexible and Elastic Manufacturing Solutions

Ultra-large format high-speed light-curing equipment: Providing a 576324mm ultra-large format DLP printer with a maximum printing height of up to 650mm, which can complete the integral printing of a robot torso in just 10 hours!

Lattice Design Platform:

1.A variety of lattices are optional and adjustable, making designs richer;

2.Automated filling, quickly analyzing the model structure, and generating lattice files with one click;

3.Structural stress/distribution analysis, which can realize discontinuous connecting line/surface filling and rapid defect repair;

4.Appearance data import, with rapid filling of targeted lattices in different stress areas.

From soft to rigid, eSUN is committed to promoting the industrial application and development of 3D printing technology through material research and development innovation. We look forward to conducting in-depth cooperation with industry enterprises, equipment and software providers, as well as universities and research institutes to jointly build a 3D printing application ecology for humanoid robots and promote the rapid and healthy development of the industry.