This article is fully available at the following address

A startup will soon launch game changing 3-D printers that can fabricate metal parts cheaply and quickly enough to make the technology practical for widespread use in product design and manufacturing.

The company, Desktop Metal, has raised nearly $100 million from leading venture capital firms and the venture units of such companies as General Electric, BMW, and Alphabet. The founders include four prominent MIT professors, including the head of the school’s department of materials science and Emanuel Sachs, who filed one of the original patents on 3-D printing in 1989.

Though it is possible to 3-D-print metals, doing so is difficult and pricey. Advanced manufacturing companies such as GE are using very expensive machines with specialized high-power lasers to make a few high-value parts. But printing metals is limited to companies with millions to spend on the equipment, facilities to power the lasers, and highly trained technicians to run it all.

Desktop Metal will have the tough task of converting manufacturers away from production methods that are at the heart of their businesses. But the very existence of this large, established market is what makes the prospect so intriguing. Making metal parts, says Fulop, “is a trillion-dollar industry.” And even if 3-D printing wins only a small portion of it, he adds, it could still represent a multibillion-dollar opportunity.

To make a 3-D printer fast enough to be used in manufacturing metal objects, Desktop Metal turned to a technology that dates back to the late 1980s. That’s when a team of MIT engineers led by company cofounder Sachs filed a patent for “three-dimensional printing techniques.” It described a process of putting down a thin layer of metal powder and then using ink-jet printing to deposit a liquid that selectively binds the powder together. The process, which is repeated for hundreds or thousands of layers to define a metal part, can make ones with nearly unlimited geometric complexity. In the most common application of the technology, the binder acts like a glue. However, it can also be used to locally deposit different materials in different locations.

The MIT researchers knew their printing method could be used to make metal and ceramic parts, says Sachs. But they also knew it was too slow to be practical, and the metal powders required for the process were far too expensive at the time.

The founders of Desktop Metal decided that to make 3-D metal printing more widely accessible, they would need to sell two different types of machines: a relatively inexpensive “desktop” model suitable for designers and engineers fabricating prototypes, and one that is fast and large enough for manufacturers. Luckily, several innovations have finally made Sachs’s original invention practical for mass production, including the development of very high-speed ink-jet printing for depositing the binder. Successively printing about 1,500 layers, each 50 micrometers thick and deposited in a few seconds, the production-scale printer can build up a 500-cubic-inch part in an hour. That’s about 100 times faster than a laser-based 3-D printer can make metal parts.

For its prototyping machine, Desktop Metal adopted a method from plastic-based 3-D printing. But instead of a softened polymer, it uses metal powders mixed with a flowable polymer binder. The formulation is extruded, using the printed binder to clump the metal powder into the intended shapes.

Desktop Metal’s prototyping printer and sintering furnace will cost $120,000.