A new research paper delivers a comprehensive look at possible applications of 4D printing.
4D printing may at first sound fanciful, but in fact, it’s a well-understood variation of 3D printing. It’s also easy to understand: 4D printing occurs when the geometry of a 3D printed object can change after it’s made.
A simple example might be a folded object, where a large geometry is “compressed” through a folded design that fits into the 3D printer’s build chamber.
However, the more interesting case is dynamic geometry change after receiving a trigger. It’s possible to produce objects with more than one material and then stimulate the object with external energy. That energy could be light, heat, electricity, etc., but whatever it is, the two materials react differently.
A typical case would be applying heat to a bi-material object, where one material expands more rapidly than the other. This causes the object to spontaneously generate a curved shape.
This property could be used, for example, in a clamp or robotic end effector. However, the number of possible applications is infinite.
The problem is that this field is still quite new, and designers are mostly unfamiliar with the concept of 4D printing. The new research paper polled no less than 44 researchers in this field to identify a roadmap of how 4D printing may evolve in the future.
The researchers discuss many cutting-edge aspects of 4D printing, including:
Core 4D Printing Technologies
- Shape-Memory Materials: Materials that change shape in response to stimuli
- Smart Materials: Materials with adaptive properties that respond to external changes
- Functionally Graded Materials (FGMs): Materials with gradual transitions in composition or structure
- Biofabrication & Bioprinting: Use of 4D printing for medical applications
Material-Specific Approaches
- Shape-Memory Polymers (SMPs): Polymers that return to a pre-set shape when triggered
- Liquid Metal 4D Printing: Use of gallium-based liquid metals for dynamic conductive components
- NiTi-Based Shape Memory Alloys (SMAs): Nickel-Titanium materials with reversible phase transformations
- Composite 4D Printing: Printing fiber-reinforced or functionally graded composites
Fabrication Methods
- Powder Bed Fusion (PBF): Common in metal 4D printing
- Direct Ink Writing (DIW): Used for soft materials and responsive inks
- Two-Photon Laser Printing (2PLP): Enables high-resolution 4D printing at nano and micro scales
- Direct Energy Deposition (DED): Applied in metal additive manufacturing
- Multi-Material Printing: Combining passive and active materials in a single print
A conclusion in the paper sums up the current state of 4D printing:
”4D printing is an emerging manufacturing technology. Although there are many different printing methods, printable smart materials, and driving methods, 4D printing still faces many challenges in practical engineering applications. We need breakthroughs in new printing technologies, new smart materials, and new structural design and modeling software to promote 4D printing in soft robotics, biomedicine, aerospace, and intelligent electronic equipment, such as practical applications.”
With new materials continually coming online, it’s likely 4D printing will gradually increase in capability, making even more applications possible.
Via IOP Science
