3D Printing at the Speed of Light

3D printing, which dispenses with expensive industrial molds, has proved to be a real revolution for home users. Are your glasses broken? Just print new temples. Do you need a prosthesis? Just download the blueprints and make it. Despite its versatility, however, this technology has not made a large impact on an industrial scale. Besides fields such as the printing of construction modules or even full-size homes, manufacturers have not embraced it for industrial production. Anyone acquainted with 3D printers will know the reason—they tend to be quite slow. In order to achieve the final product, layers, and layers of material need to be piled up successively. It is known as additive printing and it takes time. Nevertheless, there are some options to speed up the process. The most radical approach does away with the usual extruder and replaces it with a light beam. This new 3D printing system developed by researchers at the University of Michigan (USA) is a hundred times faster than other technologies used so far.   

Their technology projects two light beams on a resin tank, with the latter solidifying instantly through a polymerization process. The resin flows under the printed object and is gradually solidified by the light source. Instead of having layers, the object is printed in a single piece, which makes it far more robust and durable than its additive manufacturing counterparts. Thus, the research team has announced it as one of the first real 3D printers in the world.

The challenges of printing with light

One of the main problems posed by printing with light is that the resin at the bottom of the tank tends to solidify, which means that the object can get stuck to the surface. This was previously addressed by adding oxygen to the bottom layer, an element that keeps the resin in a fluid state. The resin layer exposed to the oxygen is extremely thin, which only allowed the use of highly fluid resins that could fill the space fast enough. But the 3D printed objects manufactured with this type of resins are much more fragile.  

The new solution resorts to a second light beam, which prevents the solidification process. I.e., two different wavelengths are used: one plays a photoactivation role, while the other is photoinhibition. With this new technology, the liquid layer in contact with the window can be several millimeters thick, allowing the resin to flow much faster.

Nevertheless, this innovative technology developed by the University of Michigan is not commercially available yet. What can already be found are the Digital Light Synthesis systems developed by Carbon 3D, one of the first manufacturers in this type of 3D printing. Their approach uses oxygen to keep the resin flowing. Then, once the object is printed, they apply a thermal curing or hardening treatment to achieve the required rigidness.

Source: University of Michigan