Why 3D Printing Aircraft is now Possible

After a metal additive manufacturing breakthrough, researchers have found a way to 3D print and weld high-strength aluminum alloys.

The additive manufacturing market is evolving rapidly with many players helping to democratize the technology and develop its market.

One of the main technical constraints of additive manufacturing was that 3D printers generally had to limit themselves to using plastic materials.

That was until companies like Norsk Titanium AS used plasma displacement systems to create reliable titanium parts that Boeing has used in its commercial airliners.

Materials dedicated to additive manufacturing are diversifying further, now using plastics, ceramics, and metals, to create more specialized and useful products.

Metal Additive Manufacturing

Many industries, such as aerospace, military, automotive, and medical are all looking for ways to cut down on costs and improve efficiency. For example, with lighter parts, aerospace could save billions of dollars cutting the excess fuel budget of the heavier craft. What’s more, materials aren’t wasted in additive manufacturing.

With additive manufacturing, because materials are added layer by layer, only what is needed is used. This is much more efficient than starting with a huge amount of material and cutting away what you don’t need.

For all these industries, metals are certainly the material that promises the most for additive manufacturing.

According to a report by research firm MarketsandMarkets, the materials market, which was valued at $530 Million USD in 2016, is projected to reach over $1.4 billion USD by 2021. The report also predicts that, compared to plastics and ceramics, metals will take the biggest market share.

And among metals, aluminum, in the form of different alloys (alloying metals, such as zinc, silicon and magnesium, improve the physical and mechanical properties of aluminum), offers an excellent compromise between lightness and solidity.

Versatile, strong, and ultra-light, aluminum alloys are also resistant to corrosion. Although less resistant to fatigue and high temperatures, aluminum enables manufacturing topologically optimized parts that with shapes that are impossible to achieve with traditional foundry techniques.

New Technique to 3D Print and Weld Aluminum Alloys

Currently, manufacturers can 3D print only single-material parts, which prevent them from tapping into alloys and composite materials with all their properties and potential applications.

Because they are made up of different metals, alloys come with different mechanical properties which pose challenges for the process of applying layers and melting them.

HRL Laboratories, LLC  (Hughes Research Laboratories), once the research lab of Hughes Aircraft, is now owned by Boeing. HRL launched the Center for Additive Materials (CAM), dedicated to expanding the materials available to additive manufacturing.

An HRL research team, co-led by Hunter Martin and Brennan Yahata from HRL’s Sensors and Materials Laboratory, has tackled the issue of composite 3D printing.

The team came up with a new technique to 3D print high-strength aluminum alloys, such as AI7075 (with zinc as one of the aluminum alloy’s metals) and AI6061 (made of magnesium and silicon).

The technique, said researchers, could be extended to use other high-strength alloys (based on steel and nickel) that until now remained inaccessible additive manufacturing processes.

The technique solves an old problem, as the printed parts no longer have to be riveted, and can be welded in their place. HRL’s “nanoparticle functionalization technique” also addresses the problem of hot cracking.

To make aluminum alloy powders “weldable” and retain the strength of the alloy, researchers enveloped them in special nanoparticles that serve as nucleation sites, preventing cracking.

Although hailed as a “breakthrough in metallurgy” by its developers, and it is, an approach similar to this method was already used by craftsmen during the high Middle Ages to make super strong swords.

How long before we are 3D printing entire vehicles?