7 FRONTIERS

Additive manufacturing is farthest along in its evolution in polymer scenarios, as the tens of millions of SLA-printed hearing aids attest. Work in metal is slightly behind, because the technology is newer, although the importance of aerospace and defense applications is pushing the frontier rapidly forward. While there remains much to learn about metal and plastic, new materials are being explored in labs and startups. Each of these—mammalian tissue, building construction, food, clothing, micromachines, and electronic circuits—represents a set of solutions to a grand-challenge-scale problem. In conjunction with mainstream uses of additive manufacturing, in turn, the many new applications challenge existing methods for education, production processes, and capital allocation.