Humans have figured out lots of ways to shape metal — casting it with a mold, stamping it, drilling holes and milling surfaces in a machine shop, even zapping it with a laser. Well, now you can add a new method: 3D printing.
A number of companies offer metal 3D printing, which creates products and components layer by layer with a computer-controlled system tracing its lineage to ordinary inkjet printers. But on Monday, printing giant HP announced it’s entered the market with the ambition to dramatically lower prices with a $400,000 product called the Metal Jet.
“We’re really going to enable mass production for mainstream metals, in particular steels,” said Tim Weber, head of 3D metal printing for HP.
HP has signed deals with experienced metal manufacturing partners and with customers including Volkswagen and Johnson & Johnson Medical Devices. So don’t be surprised if your next car’s gears or suspension links are built partly from this new method of digital fabrication.
Consulting firm McKinsey sees a bright future for the technology. “3D printing is a very small part of the metals industry, but it is growing rapidly and this market is expected to be worth as much as $10 billion by 2030 to 2035,” it said in a 2017 report. “We expect the current low-scale experiments to shift to broader industrial adoption within the next five to 10 years.”
Why use 3D metal printing?
3D printing, also called additive manufacturing, lets you build parts that are expensive or impossible to make with conventional manufacturing methods. For example, you can make a part lighter with an interior lattice that’s strong but mostly hollow.
Although 3D printing is increasingly common today, it’s not the first approach you’d use for manufacturing mainstream products. It’s often used to fabricate prototypes, and even though you can make 3D-printed plastic guns, 3D-printed metal products and components are a relative rarity.
Science fiction authors are excited by the possibilities of 3D printing. Emma Newman’s Planetfall, Kim Stanley Robinson’s Aurora and Neal Stephenson’s The Diamond Age show off machines that can produce everything from spacecraft parts to internal organs. We’re nowhere near that future, but 3D metal printing is a step in that direction, and there’s more coming.
For example, 3D printing could let you precisely engineer products using multiple materials, for example using very durable metal on a gear tooth but something more flexible in the gear interior to make it quieter. “We’ve already done things like that in the lab,” Weber said.
3D printing also can be faster, reduce metal waste, combine multiple components that otherwise would have to be assembled later, and enable “mass customization” — large-scale production of fine-tuned parts.
How HP’s 3D metal printing works
HP’s Metal Jet today doesn’t produce a finished product, though.
It starts with a thin layer of powdered metal laid down on a bed. Then a print head traverses the layer, squirting tiny drops of a binding agent — glue, essentially — where solid metal is needed. When one layer is done, a new layer of powder is laid down followed by another pass for the binding agent. It takes about four or five hours to create a product or group of products using the printer’s full volume of 430x320x200 millimeters, which is about 17x13x8 inches.
The printer works at very high resolution. Its smallest metal element — a voxel — measures just 20x20x50 microns, or millionths of a meter. For comparison, human hairs range from about 17 to 181 microns in diameter.
When it’s done printing, the parts are taken out and the unused powder is separated for reuse. The parts then undergo a heating operation called sintering that fuses the powder into a solid block. Sintering technology is decades old but complex, which is why HP has signed partnerships for this stage with two manufacturing experts, Parmatech and GKN Powder Metallurgy.
You’re still not done, though. Sintering reduces the size of the part by about 15 percent, Weber said, and secondary processing puts on the finishing touches.
Why is this any better than 3D printing from rivals like Markforged, Xometry or 3D Systems? Weber promises faster print times since HP’s PageWide technology moves band of print heads across the entire bed in one swipe per layer instead of sending one print head traversing back and forth time after time. And HP promises lower costs because it develops and manufactures its own parts, most notably the print heads that must reliably squirt the binding agent.
“We have 30-plus years of figuring out how to jet crazy stuff,” Weber said.