With 3D inkjet printing systems, engineers can fabricate hybrid structures that have soft and rigid components, like robotic grippers that are strong enough to grasp heavy objects but soft enough to interact safely with humans.
These systems utilize thousands of nozzles to deposit tiny droplets of resin, which are smoothed with a scraper or roller and cured with UV light.
A new 3D inkjet printing system has been developed by researchers from MIT, the MIT spinout Inkbit, and ETH Zurich. By utilizing a contactless system with computer vision, this printer works with materials that cure more slowly than traditional materials. The automatic system allows adjustments without stopping or slowing the printing process and is about 660 times faster than comparable 3D inkjet printing systems.
The researchers used this printer to create complex, robotic devices that combine soft and rigid materials. The key insight was to develop a machine vision system and active feedback loop, allowing for a printer with a set of eyes and a brain, where the eyes observe what is being printed, and then direct it as to what should be printed next.
A technique known as vision-controlled jetting uses four high-frame-rate cameras and two lasers that rapidly and continuously scan the print surface, rapidly and continuously scanning the print surface. The computer vision system converts the image into a high-resolution depth map, which is a computation that takes less than a second to perform. It compares the depth map to the CAD (computer-aided design) model of the part being fabricated, and adjusts the amount of resin being deposited to keep the object on target with the final structure.
The researchers used the system to print with thiol-based materials, which are slower-curing than the traditional acrylic materials used in 3D printing. However, thiol-based materials are more elastic and harder to break, as well as being more stable over a wider range of temperatures and more resistant to sunlight.
The researchers were able to fabricate several complex devices using the system, such as a functional, tendon-driven robotic hand with sensor pads and a six-legged walking robot. The team also created a heart-like pump with artificial heart valves and metamaterials with non-linear material properties.
The future of AI in 3D printing looks promising as the researchers plan to use the system to print with hydrogels, silicon materials, epoxies, and special types of durable polymers. They also aim to explore new application areas, such as printing customizable medical devices, semiconductor polishing pads, and even more complex robots.