Research on the Composite DIW 3D Printing of Magnetic and Non-Magnetic Materials for Deformable Smart Structures

Integrating the “programmable” characteristics of smart materials with 3D printing technology enables the integration of structural design and manufacturing, showing broad application prospects in flexible electronics, aerospace, biomedicine, and other fields. Magnetically controlled smart fluids are characterized by flexible solid–liquid conversion, high driving efficiency, and high safety. By harnessing the distinctive characteristics of this material, manufacturing and actuation approaches for intelligent structures can be further diversified. Inspired by the sol–gel transformation mechanism of protoplasm, this paper proposes a composite 3D printing method for magnetic and non-magnetic materials. A magnetically controllable binary suspension system with strong thixotropic properties was constructed, and its microscopic self-assembly structure was characterized. The yield behavior, linear viscoelastic properties, and thixotropic recovery performance of the magnetic thixotropic fluid (MTF) were investigated through steady and dynamic rheological measurements, and the optimal rheological parameters for printing were determined. A 3D printing platform with coordinated control of a magnetic field and a motion system was built to further study and optimize the printing process. The supporting characteristics of the MTF on a silicone film and the deformation of the printed composite structure under a gradient magnetic field were studied. The composite 3D printing and its application in soft robotics may provide new insights for space exploration, biomedicine, military reconnaissance, and many other fields.