Desktop Metal attracted attention earlier this year with its innovations in metal 3D printing. Observers also took notice of its venture capital funding of $212 million and valuation of over $1 billion, an estimate from data and technology provider PitchBook (Seattle).
There are other interesting aspects to the company and its technology, though. For one, although both of Desktop’s (Burlington, MA) models print metals, they work differently. Another is that the firm had hoped to use an off-the-shelf debinder for its prototyping system, but had to develop its own. And, remarkably, its co-founders’ original plans didn’t include a printer for mass production.
It was only after the company’s beta testers for its prototyping Studio System asked for a printer to mass produce parts that Desktop’s CEO Ric Fulop and his fellow co-founders, materials science, robotics, metallurgy and software veterans, decided to develop one. Still in development, it’s known as the Production System, said Larry Lyons, head of product.
The Production package relies on the existing supply chain of powders used in metal injection molding to churn out parts. It also relies on an existing technology, binder jetting, to print parts. Not coincidentally, binder jetting was invented by Desktop co-founder Ely Sachs, who applied to patent it in 1989.
The Production printer is similar to direct metal laser sintering printers in that layers are formed on a bed of powder that’s repeatedly replenished as each new layer is created. Instead of using laser sintering to solidify the metal, though, Desktop’s machine sprays a layer of liquid binder on the powder bed to achieve a resolution of <50 µm. Once the “green” or “brown” parts, as they’re known in MIM, are removed from the powder, they’re ready to go directly into the furnace for sintering.
Design and engineering work on the Production printer began in earnest in December 2016, and the first machines are expected to be shipped in late 2018 at the earliest.
While the Production printer is compatible with already-available powder, users of the Studio machine have to buy Desktop’s feedstock, which is similar to the feedstock used in metal injection molding. The company’s powder comes encapsulated in a proprietary polymeric binder with a claylike consistency that’s formed into rods that dispense automatically from a cartridge. The cartridge works similar to a restaurant’s straw dispenser.
In a process similar to fused deposition modeling, the rods are heated and extruded through the printer’s 400 µm tip to 200°C for layered deposition: A second tip deposits support interface material that turns to dust in the furnace, allowing for the supports to be removed by hand.
Those who want a smoother surface finish can work on the outside of the resulting green ware without special protection from metal because it’s encapsulated.
“The advantage is there’s a lot of companies who are familiar with FDM for printing on the plastics side,” Lyons said. “This printer is going to come very easy for them because they already have a lot of experience with plastic.”
While seven materials were available at launch, many more are planned since more than 200 MIM alloys are compatible with the Studio System.
Lyons said his company had hoped to partner with a debinder unit manufacturer, but no office-friendly units were available. Also, because commercially available debinder fluids are so noxious, Desktop had to develop one that’s safe to use in an office environment. It’s compliant with Prop 65, aka California’s 1986 Safe Drinking Water and Toxic Enforcement Act.
If successful, Desktop will have another interesting aspect to its profile: It will have broken 3D printing out of its current niche in high-end aerospace and medical manufacturing and brought it to a much broader market that the co-founders feel is ripe for disruption.