3D printing has been around for decades with the first hobbyist printers hitting the market around 2010. While the projections of 3D printing taking over the printing market, small run manufacturing has embraced this technology.
Auto companies are using 3D Laser Beam Melting (or Selective Laser Sintering) to produce high value, highly durable and functional, small run parts for ‘hand built’ automobiles. This additive manufacturing process can build extremely complex parts that could never be machined using traditional processes.
Basically, a laser is shot a load of powder, build material. The laser selectively fuses this powder, layer by layer, until the part is built. With each pass, the part is lowered and new powder is exposed to the laser beam. This is an expensive process and is designed for building one-off and very complex parts. As these are often unique parts, hand finishing rather than mass finishing is typically employed.
Autoweek.com explains this well in an article they published here.