The family of machines uses a powder-based technique as do some commercial metal printers. Here’s their description of the process:
The control system for the printer feeds power to a motor at a controlled speed, and powder is propelled into the high energy beam. Once fed, it is then melted and fused with substrate – the base material.
It seems this machine has two modes of operation, which is unique. It’s also unique that it can deliver two different metal powders during the same print, suggesting the possibility of creating varying alloys during prints.
Various metal powders can be used in the machines, including: “316 Stainless Steel, 420 Stainless Steel, Inconel 625, Inconel 718, Hastelloy C, Brass, Bronze and Mild Steel”. Evidently the team believes they will eventually print in ceramics and plastic powders as well. Aurora Labs has been able to successfully 3D print small rocket engines, proving the ability of their process.
The S1 is the “consumer-level” version, which includes two powder feeders and a relatively small build volume of 150 x 150 x 200mm. An “S2” model adds a third powder feeder, while the S2+ increases the build volume to 180 x 180 x 500mm. Each machine’s layer resolution is a very tight 0.050mm.