Additive manufacturing—the industrial version of 3-D printing—is already used to make some niche items, such as medical implants, and to produce plastic prototypes for engineers and designers. But the decision to mass-produce a critical metal-alloy part to be used in thousands of jet engines is a significant milestone for the technology. And while 3-D printing for consumers and small entrepreneurs has received a great deal of publicity, it is in manufacturing where the technology could have its most significant commercial impact

via 3-D Printing Will Soon Become a Routine Manufacturing Tool | MIT Technology Review.