That's changing. Companies have an increasing number of printing techniques to choose from, such as electron-beam melting, which, like SLS, makes production-grade aerospace parts. They can also print with many materials, including titanium, ceramic, and resin. Arcam, a 3-D–printer manufacturer in Sweden, is working with select labs to develop new materials and substantially expand its portfolio. As a result, companies are now using 3-D printing to create working parts, not just prototypes.