Prints Charming

Prototyping used to be a very complicated matter before practical and inexpensive 3D printers came along. Now, for a few hundred dollars, one can simply design a 3D model of an object, then make it into a real, physical object right in their own home. Both hobbyists and professionals benefit from the ability to quickly iterate on designs, test functional prototypes, and bring creative ideas to life with these printers. The accessibility of 3D printing has democratized innovation, empowering individuals to become makers and problem-solvers without needing extensive resources or specialized skills.

But naturally, there are some pretty significant limitations to these technologies as well. Existing 3D printers can make some bits and pieces of a complex device, while other parts need to be produced in different ways before they are all assembled. This is because most 3D printers can only work with a single type of material, usually some type of plastic. Multi-material printers do exist — although they are much less common — but even these are quite limited. They tend to print with a few types of similar materials, like different colored plastics that perhaps have somewhat different qualities.

In order to take 3D printing to the next level, such that complex, functional objects can be prototyped with them in one step, new technological advancements are sorely needed. We are now closer to that goal, thanks to the work of a team led by researchers at the University of Missouri. They have created a multi-material 3D printer that incorporates a wide variety of techniques that enable it to create diverse and functional objects. These objects can include structural elements, sensors, and other electronic components, all in a single pass — no assembly required.

This innovative printer combines multiple techniques into a single integrated system. First, it is capable of multi-axis fused filament fabrication, which is the technology used by most 3D printers today. This allows for creating structural components, typically made of a plastic material. The printer also has a direct ink writing nozzle from which it can lay down materials like silver, nickel, or copper oxides to create traces, sensors, and other electrically functional structures. Furthermore, the printer is capable of freeform laser induction. Using this technique, other printed materials can be transformed. For example, plastics can be converted into laser-induced graphene, which has high levels of thermal stability, mechanical strength, and electrical conductivity, and it can be used in sensors or even for energy storage applications.

Using this printer, functional components can be embedded deep within an object, or can be placed on its surface. These components include crossbar circuits, strain sensors, springs, UV sensors, haptic manipulators, capacitive sensors, and rotational encoders just to name a few possibilities. Notably, all of these components can be integrated into a complete device in a single pass, with no post-printing assembly steps.

The researchers envision their printer being used to create tightly integrated devices, like a natural-looking rock, for example, that senses environmental conditions. They also see future applications in wearable devices, where small systems that are custom-designed for each individual can monitor vital signs and other physiological parameters.