Researchers come together to review both 3D and 4D printing, as well as exploring its ongoing potential in ‘Recent 3D and 4D intelligent printing technologies: a comparative review and future perspective.’
While both technologies offer great opportunity for industrial users to make and maintain functional parts and prototypes, 3D and 4D printing are a source of fascination around the world due to the ability to innovate at will, cutting out the middleman, and making new objects with new materials that may not have been possible previously.
The brief overview of relevant 3D printing methods
In the 4D realm, we see the progress being made from materials that may be less flexible to those that are able to shift with their environment—and according to the user’s needs. The authors not only delve further into fundamentals and development (especially in the evolution from 3D to 4D) but also perform comparative analysis regarding both forms of digital fabrication.
From the inception of 3D printing in the 80’s via Chuck Hull to its emergence in the mainstream and now integration into many fields—from robotics to tissue engineering, electronics, and more—the authors follow 3D printing, pointing out correctly that it is currently ‘still in the active stage of industrial innovation.’ Designers and engineers are able to take advantage of a wide variety of benefits—even including applications like fashion and jewelry.
Schematic illustration of 1D, 2D, 3D, and 4D concepts
具有固体，液体和基于功率的图案的3D打印技术的总体示意图（a）FDM； （b）SLS； （c）SLA
General schematic overview of 3D printing technology with solid, liquid and power-based patterns (a) FDM; (b) SLS; (c) SLA
While advantages such as affordability, accessibility, and greater efficiency in production are being enjoyed by many, there are still challenges regarding materials in applications like soft robotics and aerospace. With the ability to shift form while under pressure from temperature or moisture, 4D printed smart materials avail the user of greater flexibility and versatility.
“Compared to 3D printing, 4D printing updates the concept of change in the printed configuration over time, which relies on environmental stimuli. Therefore, 4D printed structures should be fully preprogrammed using time-dependent deformations of products,” state the authors.
SWOT分析a）。 3D打印技术； b）。 4D打印技术。
SWOT analysis of a). 3D printing technology; b). 4D printing technology.
Smart materials and the ability to deform and then return to their natural shape mean that 4D printing is suitable for not only for robotics but also self-repairing of materials like hydrogels, piping, and other materials which may be related to reusability and recycling.
The illustration of shapeshifting by self-folding using water absorption materials: (a) 1D to 3D41; (b) 2D to 3D41
While one of the obstacles in 3D printing is the general need to fabricate items with only one material, 4D printing is beginning to emerge as a forerunner in applications like the medical and engineering fields.
3D printed models in the medical area (a) 3D printed heart; (b) 3D printed skull
3D printing is still becoming increasingly popular, however, for use in the military field, creating weaponry and allowing for better maintenance of parts. 3D printed models are improving treatment for patients and can be used as extremely helpful pre-planning devices for surgery. Various hardware has also been created for extrusion of food like chocolate and pancake batter.
As for 4D printing, the authors expect that it will be used to create more advanced smart materials that can transform environmentally as users require, offer ‘self-controllable functions,’ expand longevity in products, and promote greater complexity in structures.