United Sciences, an Atlanta company that develops 3D scanning technology, is using four MakerBot Replicator Minis to create molds for custom silicone headphones. When made on several 3D printers at once, the mold takes 20 minutes, and assembly takes another 30 — an improvement over the four-hour process on an industrial 3D printer. “It really brings it to the point where you can bring this to a store,” says co-founder Karol Hatzilias.