We all might be aware of 3D Printing technology that has been existed for almost 30 years now. While the Additive Manufacturing industry is still discovering a new applications, materials and a 3D printers, another technology known as 4D Printing is arising. 4D printing is the process through which a 3D printed object will transform itself into another structure over the influence of an external energy input such as temperature, light or other environmental stimuli. Thus, a fourth dimension added is time which provides an ability to change its shape over time.
This technology is part of the project of MIT Self-assembly Lab and the main purpose of this project is to combine technology and design to invent self-assembly and programmable material technologies aiming at re-imagining construction, manufacturing, product assembly, and performance. A 4D printed object is printed similar to that of a 3D printed shape. But, the major difference is that 4D Printing technology uses programmable and advanced materials which performs a different functionality by adding hot water, light or heat.
Some of the major research areas of 4D printing involves Smart materials, Equipment design and mathematical modeling. Smart Material is one of the highly focused research areas in 4D printing, wherein the deformation mechanism of various materials is synthesized as per their responses to various external stimuli. Equipment Design deals with developing an advanced printer technology, which can print multiple materials congruently. On the other hand, Mathematical Modeling is essential for understanding the functional structures of 4D printed objects and capable of predicting the deformation (forward) and formation (backward) process of an object triggered by stimuli.
Materials for 4D printing are classified based upon their environment or external stimuli they react with. It includes the Thermo Responsive Materials which works on the mechanism of Shape Memory Effect (SME) and Photo/Electro/Magneto Responsive Materials which reacts with light, current, and magnetic fields and thereby increasing its volume and expanding the overall matrix. While, the Moisture responsive materials reacts when in contact with water or moisture and hydrogel is one of the smart materials that fall under this category as it reacts vigorously with water.
The most obvious advantage of 4D printing technology is computational folding which allows the larger objects to be printed as only one part. Since the 4D printed objects can change its shape, shrink and unfold. Another advantage of 4D printing technology is the usage of possible applied materials as it has a vast potential to revolutionize the world of materials. The idea of the pre-programmed intelligent object (created using smart materials) would seem to have several applications in various industries.
However, being a novel technology, most of the applications are currently in the research & development phase and major end-use applications of 4D printing technology are expected to arise from healthcare, automotive, aerospace, and consumer industries. Along with that, the potential of 4D printing is expected to impact other industries such as electronics, construction and industrial as well in the near future.
Despite being a promising technology, 4D printing needs to overcome several technological hurdles prior to being widely adopted. Some of the major challenges in the printing industry include lack of ability to provide support structures for complex objects, lack of multi-material printers, lack of low-cost printers and smart materials, slow print times, and the limited reliability of printed objects in the long run. Though there are certain advancements in printing technology, such as 5-axis printing equipment, which is expected to eliminate the problem of building support structures for complicated internal structures, other challenges still remain.
Furthermore, challenges such as slow and inaccurate actuation, lack of control over intermediary states of deformation, and limited material availability are other reasons for the delayed adoption of the 4D printing technology. However, considering the interest shown by manufacturers and the high-intensity level of research and development activities with respect to 4D printing, the technology could make an exponential jump at a faster pace than the predicted pace.