Inside the Ongoing Industrialization of Metal Additive Manufacturing
Ian Wright posted on December 13, 2018 |
EOS direct metal laser sintering for additive manufacturing. (Image courtesy of EOS.)
EOS direct metal laser sintering for additive manufacturing. (Image courtesy of EOS.)

How do we decide when a technology has gone from emerging to mainstream?

If we use NASA’s Technology Readiness Levels, the standard is quite high: it’s a matter of transitioning from observing the basic principles that underpin the technology to getting it “flight proven” through successful mission operations. Alternatively, we can frame the question in terms of adoption: smartphones have been around since the ‘90s, though they only started to see widespread use with the first iPhone in 2007.

There are innumerable other ways to delineate between up-and-coming and established tech, but by almost any standard, 3D printing is fast approaching the mainstream. The push toward designing for additive manufacturability is early evidence of this. However, additive manufacturing (AM), as it’s more commonly known in industrial contexts, still tends to be contrasted with “traditional” or “conventional” (i.e. subtractive) manufacturing techniques. Nevertheless, the gap between them is shrinking.

This is particularly evident in the case of metal AM.

Metal Additive Manufacturing – Then & Now

Let’s go back to the Dawn of Time for metal 3D printing: the 1990s. Dr. Ankit Saharan, Manager for R&D and Applications Development at EOS, explained how different things were in the beginning. “EOS started in metal additive manufacturing back in ’94,” he said. “At that point, we were dealing with CO2 lasers, which obviously aren’t as powerful as the fiber lasers we use today. There were no powder producers making powders especially for additive, so we were basically using the powder that other industries didn’t use.”

The combination of lower-power lasers and lack of AM-specific metal powders resulted in one of the most common misconceptions about metal 3D printing today. According to Saharan, the term Direct Metal Laser Sintering (DMLS) should really be Direct Metal Laser Melting, or maybe Direct Metal Laser Schmelzen (the German word for ‘melting’) for consistency’s sake. “We were initially using a sintering process—partially melting the powder and forming a liquid face around the solid particles—and trying to make a whole complex shape in 3D,” he explained.

“With the EOS M 270, EOS M 280, EOS M 290 and the EOS M 400, the fiber laser became available and allowed us to deliver power in a more efficient way,” Saharan continued. “That’s when we moved away from sintering into fully melting the powder. However, the DMLS term has stuck for legacy reasons, which has led to the misconception that it’s still sintering.”

The Digital Factory of the Future. (Image courtesy of EOS.)
The Digital Factory of the Future. (Image courtesy of EOS.)

As any materials engineer knows, the difference between melting and sintering is no mere semantic quibble—the implications in terms of voids, porosity and the overall need for post-processing operations are significant. For example, Saharan made the following bold claim about the latest generation of EOS machines.

“I will put my money down on us being able to surpass casting properties any day,” he said. We hold forging and wrought as our gold standard. In some cases, we even beat wrought properties, as well.”

As he described it, Saharan’s confidence in the EOS process comes from the sometimes excessive scrutiny metal additive manufacturing receives as a result of still being perceived as an up-and-coming technology. If parts made with casting were held to the same standard as those made with additive (i.e., expecting absolutely minimal voids or porosity), Saharan believes many would fail to meet it. This is the perception problem faced by metal AM today: as a relatively new technology—especially one with so much hype—many manufacturers simultaneously hold high expectations and lingering doubts about what metal AM can really do.

However, as Saharan explained, the capabilities of metal AM should not be underestimated. “The microstructure that we get from additive is truly unique: it’s different from forging or casting,” he said. “If we’re talking about the direction of the grain structure and whether you can make it equiaxial or isotropic, that’s definitely possible.”

Industrializing Metal 3D Printing

One way to see metal 3D printing’s transition from prototyping to production is via its proliferation across different industries. It’s well known that the aerospace and medical device industries have led the adoption of metal AM, and for good reason. Both industries largely deal with components that are complex, expensive and produced in relatively low volumes—perfect for 3D printing.

“That’s still the case today,” Saharan noted, “but we’re getting more and more applications from the oil & gas, tooling and automotive industries. They’re new to additive manufacturing, but are very promising when you look at what AM can do to change their production of high-value tooling and even replacement parts.”

A look at EOSPRINT 2 for optimizing CAD data. (Image courtesy of EOS.)
A look at EOSPRINT 2 for optimizing CAD data. (Image courtesy of EOS.)

Production volume has been a major hurdle for AM adoption in these industries, but engineers are finding new and better ways to design and orient parts to take advantage of 3D printing’s capabilities. As an example, Saharan noted Betatype, a manufacturer in the UK that used metal AM to produce heatsinks for automotive LEDs. “They were doing 384 parts, vertically stacked in EOS M280 machines,” he said. “That dropped the price tenfold.”

The move toward standardization and parameter development is also indicative of the industrialization of metal AM. For example, Saharan noted that the parameters EOS has developed for its machines are suitable for roughly 95 percent of applications.

“But there’s still that 5 percent of applications where the user needs to change something more drastically,” he added. “In those cases, we give them the flexibility to change the machine parameters according to their application.”

Challenges for Metal Additive Industrialization

Shifting the mindsets of engineers to think additively is one of the principal challenges for the industrialization of metal AM. That’s because most parts made with additive manufacturing were originally designed for traditional, subtractive processes. As a result, these legacy parts often fail to take advantage of the design freedom that comes with 3D printing. Saharan offered another example:

“There’s a company called Launcher which makes rocket engines. When they first looked at making their components conventionally, they concluded that it would take a lot of time and resources to do product development, an especially tough call for a start-up. But once they learned about the capabilities of additive, they decided to forget about doing things the way they were in the past and instead looked at completely redesigning the regenerative cooling concept. Now they’re pushing beyond that and looking at whether they can make the parts from copper alloys to make them more efficient.”

Of course, there are other challenges for the industrialization of metal AM. The availability—and hence the cost—of qualified metal powders is still an issue, though one that’s rapidly improving. Moreover, when it comes to highly regulated industries, such as aerospace and medical, Saharan pointed to qualification as a much bigger contributor to part cost than material.

“We actually ran a study where we looked at what would happen if you dropped the price of powder by half,” he said, “and found it would only make a marginal difference on the final cost of the part. Of course, this is relative to the criticality criteria and volumes associated.”

In any case, there’s a reason that aerospace and medical device manufacturers have been leading the charge on metal AM adoption. “You can definitely recoup some of your cost by increasing the buy-to-fly ratio, but you can also do it through fuel savings over the lifetime of an aircraft,” Saharan explained. “In some cases, incorporating additive components can equate to as much as a few million dollars per year in fuel cost savings.” For the right application, the benefits of additive manufacturing can be enough to justify dealing with even the steepest regulatory hurdles.

Is Metal AM Going Mainstream?

Assuming the answer to this question is “Yes,” the obvious follow-up is to ask is whether metal additive manufacturing will replace machining. On this point, Saharan’s reply was unambiguous: “No, absolutely not. That’s never been the intention of the additive manufacturing industry. Additive manufacturing complements machining, and vice versa. In most cases where additive will take you 90-95 percent of the way, you may still need machining or other conventional manufacturing processes to finish the part depending on the application.”

An injector head baseplate.  Redesigning with additive manufacturing reduced the number of components from 248 to 1. (Image courtesy of EOS.)
An injector head baseplate. Redesigning with additive manufacturing reduced the number of components from 248 to 1. (Image courtesy of EOS.)

The real question, then, is not whether metal AM is going mainstream, but rather how quickly. “If you think in terms of a Gaussian curve on technology adoption by Simon Sinek,” Saharan said. “The first 2-3 percent are the early adopters: the people who want to be the first ones to figure out the technology. The next 7-9 percent are like the people who wait in line all night for the new iPhone. After that, adoption explodes because the majority of people are always sceptical of something new; they want to see what it is and what it can do before they invest their money. I think we’re right at the cusp of that explosive path.”

If you want to learn more about industrializing metal AM in your business, you can contact Dr. Ankit Saharan directly.


EOS has sponsored this post.  All opinions are mine.  --Ian Wright

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