Scientists at Tsinghua University have unveiled a groundbreaking advancement in digital light processing (DLP)-based 3D printing technology that promises to revolutionize the fabrication of multifunctional soft robots. Their novel technique allows for the one-step printing of composite magnetic structures consisting of multiple materials seamlessly integrated within a single manufacturing process. This new capability overcomes critical limitations inherent in traditional fabrication methods, offering unprecedented flexibility in material design and structural complexity for magnetically driven soft robotics.
The core innovation lies in an enhanced DLP 3D printing approach, enabling the sequential use of different resin tanks during a continuous printing workflow. This multi-material one-step printing concept allows researchers to produce composite structures with tailored magnetic properties by selectively switching between resins impregnated with different magnetic particles. Unlike conventional multi-step assembly or molding techniques, which require bonding separate components and often suffer from precision and scalability issues, this integrated process generates intricate, multi-functional magnetic architectures in a single pass.
Underlying this technology is a carefully optimized curing process where resins containing magnetic particles are solidified layer by layer under ultraviolet light. This controlled photopolymerization ensures the formation of homogeneous layers with consistent thickness, verified through scanning electron microscopy (SEM) imaging. Elemental mapping via energy dispersive spectroscopy (EDS) further confirms the uniform distribution and integration of magnetic constituents throughout the printed composite, demonstrating the method’s robustness in producing reliable, high-resolution magnetic structures.
Traditional methods for fabricating magnetic materials, including mold-assisted techniques and UV lithography, are inherently limited by the necessity of uniform material compositions and mold geometries. These restrictions prevent the creation of complex magnetic devices with precisely varied properties within the same object. The enhanced DLP process introduced by the Tsinghua team circumvents these obstacles, enabling gradients of magnetic particle concentrations and composite regions containing both hard magnetic materials and superparamagnetic particles within a single printed soft robot.
At the heart of the research is the development of a composite soft robot that combines hard magnetic materials with superparamagnetic counterparts, leveraging their distinct magnetic domains to achieve multifunctional actuation. This composite robot demonstrates remarkable abilities in ground mobility, obstacle negotiation, and object manipulation, skills that were systematically evaluated through mechanical and magnetic characterization tests. Moreover, the robot’s behavior in fluidic environments was examined, revealing efficient swimming capabilities mediated by the tailored magnetic properties engineered via the novel printing method.
An important technical challenge addressed by the researchers involved overcoming the poor adhesion between high-concentration magnetic resins and release films used during printing, as well as mitigating the sedimentation of magnetic particles which can degrade curing depth and structural integrity. Through meticulous optimization of resin formulations and printing parameters, the team minimized these issues, ensuring stable and reproducible printing outcomes essential for practical applications.
Beyond mechanical performance, the study also evaluated the thermal effects associated with superparamagnetic materials embedded in the soft robot. These materials exhibit unique heating behaviors under alternating magnetic fields, potentially enabling localized thermal responses useful for biomedical applications. The authors suggest that, once biocompatibility and safety verifications are thoroughly performed, this technology could be adapted to fabricate capsule robots capable of targeted drug delivery, navigating through biological tissues and releasing therapeutic agents precisely where needed.
The scientific paper detailing this breakthrough appears in the February 26, 2025 issue of Cyborg and Bionic Systems. The research was led by Jiadao Wang and co-authored by Zhaoxin Li, Ding Weng, Lei Chen, Yuan Ma, and Zili Wang, all affiliated with Tsinghua University’s State Key Laboratory of Tribology in Advanced Equipment and the Department of Mechanical Engineering. Their work received support from the National Natural Science Foundation of China under grant numbers 52275200 and 52205312.
This pioneering study not only advances the field of additive manufacturing but also enriches the toolbox available for the design and fabrication of next-generation magnetic soft robots. The ability to fabricate multifunctional magnetic composites with precise spatial control within a single printing step may herald a new era in soft robotics, enabling devices that are more adaptable, efficient, and capable of complex behaviors in both terrestrial and aquatic environments.
The team employed advanced simulation techniques, coupling multi-physics models to analyze the swimming dynamics of the soft robot in liquid mediums. These simulations, coupled with experimental validations, shed light on the intricate interactions between the mechanical structure, magnetic domains, and fluid forces, offering insights that will guide future design optimizations for enhanced locomotion and functionality.
This enhanced one-step multi-material DLP printing technique could also impact diverse disciplines beyond robotics, including bioengineering, medicine, and flexible electronics, where multifunctional composite materials are crucial. Its scalability and precision may accelerate the development of customized, miniaturized devices capable of combining magnetic actuation with other functional stimuli responsive behaviors.
The implications of this research are profound, marking a significant step toward realizing soft robots with tailored magnetic profiles that can perform complex tasks autonomously. From medical micro-robots capable of navigating intricate bodily pathways to adaptable robotic systems for environmental monitoring, the innovations stemming from this study are poised to influence the future of smart device fabrication profoundly.
Looking ahead, the researchers plan to expand the functionality of their soft robotic systems by integrating additional materials and exploring new actuation modalities. Emphasis will also be placed on enhancing biocompatibility and durability, critical parameters for transitioning these soft robots from laboratory prototypes into real-world applications, especially in biomedical contexts.
By addressing fundamental challenges associated with multi-material integration and magnetic particle management within resin matrices, this work lays the groundwork for an exciting frontier in digital manufacturing and soft robotics. It represents a successful confluence of materials science, mechanical engineering, and advanced manufacturing techniques marrying to push the boundaries of what 3D printing technologies can achieve.
Subject of Research: Advanced multi-material digital light processing (DLP) 3D printing for composite magnetic soft robots.
Article Title: Enhanced DLP-Based One-Step 3D Printing of Multifunctional Magnetic Soft Robot.
News Publication Date: February 26, 2025.
Web References: DOI: 10.34133/cbsystems.0215.
References: Li Z., Weng D., Chen L., Ma Y., Wang Z., Wang J. (2025). Enhanced DLP-Based One-Step 3D Printing of Multifunctional Magnetic Soft Robot. Cyborg and Bionic Systems.
Image Credits: Jiadao Wang, State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University.
Keywords: Applied sciences and engineering, Health and medicine, Life sciences.
Tags: 3D printing technologyadvanced photopolymerization methodscomposite magnetic structuresdigital light processing innovationmulti-material fabricationmultifunctional soft robotsone-step printing techniquerobotics material designscanning electron microscopy analysisseamless manufacturing processtailored magnetic propertiesTsinghua University research