Is That a 3D Printer in Your Pocket?

With the rise of 3D printing technologies, we have been given an unprecedented ability to manufacture objects of any sort right in our own homes. This democratization of means of production has enabled individuals to create custom items ranging from simple household tools to complex mechanical components on demand. But 3D printers are far from portable, so if you need a part to repair your bicycle while you are out for a ride, for example, you will need to wait until you get back home.

But what if you could fit a 3D printer in your pocket for these situations? This may sound impossible, but such innovations are by no means unheard of. Just a few decades ago, the thought of everyone having a powerful computer in their pocket seemed fantastic, but look where we are now. 3D printing is advancing similarly. While the work is still in the early stages, researchers at MIT and the University of Texas at Austin have developed a 3D printer on a chip. This device, about the size of a quarter, can produce three-dimensional objects on demand — although at this stage they are still very small and simple objects.

You may be wondering how the team fit all of the stepper motors required to make a 3D printer into a tiny chip. Traditional motors would certainly be a deal-breaker for a device this size, but the researchers’ printer operates on completely different principles and has no moving parts whatsoever. Instead, the printer-on-a-chip steers beams of light to guide the printing process.

Inside the chip, there is an array of tiny optical antennas that direct the beam of light. The trick is to alter the time at which the optical signal reaches different antennas. By spending up or slowing down this signal at various points within the chip, the beam of light can be controlled with precision. And crucially, this capability can be achieved on a tiny scale and with no moving parts.

The light beams are directed into a reservoir of a resin that rapidly hardens in the presence of certain wavelengths of light. As such, when the light strikes the resin, a solid object is produced. Careful control of the light beams can be leveraged to create custom, if not tiny, parts requested by the user.

At present, the printer is not fully self-contained — it relies on an external laser to feed into the optical antennas. Furthermore, the prints that were produced are very simple, ranging from a straight line to a few two-dimensional letters (spelling out “MIT,” naturally). So as it presently stands, you will not be able to pull a 3D printer out of your pocket to replace a broken part on your bicycle just yet.

Toward that goal, the researchers are working to improve their design. One idea they are presently exploring is the use of holograms to enable the production of complex, volumetric three-dimensional shapes in a single step.