Grayscale 4D Printing of Ferromagnetic Soft Materials

Area of Science:

• Materials Science
• Additive Manufacturing
• Robotics

Background:

• Ferromagnetic 4D printing enables shape changes using magnetic fields for soft robotics and biomedical devices.
• Current multi-material systems for high performance are complex and limit design flexibility.
• Achieving both high load-bearing capacity and large deformation is challenging.

Purpose of the Study:

• To introduce a streamlined ferromagnetic grayscale 4D printing strategy using a single-material system.
• To enable localized mechanical property programming through controlled light intensity.
• To overcome limitations of traditional multi-material approaches.

Main Methods:

• Combining digital light processing (DLP) grayscale 3D printing with ferromagnetic particles.
• Precisely controlling light intensity to program mechanical properties within a single material.
• Fabricating and analyzing grayscale cantilever beams under magnetic fields.

Main Results:

• Demonstrated high load-bearing capacity (up to 42.6 times its weight).
• Achieved significant bending angles (98.6% improvement at 200 mT) and rapid responsiveness (87% increase at 2 s).
• Successfully fabricated functional prototypes like a crawling robot and complex structures.

Conclusions:

• The grayscale 4D printing approach simplifies ferromagnetic 4D printing by eliminating multi-material complexity.
• This method allows for the creation of structures with coexisting soft and rigid domains.
• The technique expands the potential applications of advanced ferromagnetic materials.