While large 3D-printed objects such as cars or buildings may get a lot of attention, the technology is also used to produce tiny, multi-faceted objects. The latter could soon be whipped up faster and in more detail than ever before, thanks to a new printing system.
If you're 3D-printing an object that's just a few millimeters long – and which includes features that are a fraction of a millimeter in size – then the usual approach of extruding molten plastic out of a nozzle just won't work. Instead, a laser is sometimes used to selectively harden a light-sensitive liquid polymer known as a photoresist. The laser beam focuses on specific areas of that material, one after the other, building up a three-dimensional structure in the process.
According to scientists at Germany's Karlsruhe Institute of Technology, this process usually allows for a maximum printing speed of several hundred thousand voxels per second – a voxel is a single data point within a 3D grid, and is the equivalent of a pixel in a two-dimensional image. And although that may sound pretty fast, it's actually only about one one-hundredth the speed at which inkjet printers produce 2D graphics.
Working with colleagues from Australia's Queensland University of Technology, the Karlsruhe researchers devised a new system, in which the usual one laser beam is optically split into nine partial beams. All of those "sub-beams" move independently, but also simultaneously, with each one focussing on a different area of the photoresist.
As a result, a 3D printing speed of approximately 10 million voxels per second is possible.
In a demonstration of the system, the team printed a rectangular cube that's 60 cubic millimeters in size, but that also has a lattice-like inner structure consisting of features on the micrometer scale (a micrometer is one one-thousandth of a millimeter). All told, it contains over 300 billion voxels, which is reportedly a new world record.
Once developed further, it is hoped that the technology could find use in fields such as optics and photonics, material sciences, bioengineering, and safety engineering. The research is described in a paper that was published last month in the journal Advanced Functional Materials.
