Want to 3D-Print an Airplane? Look to Laser Metal Deposition

If you want a shining example of the benefits that can achieved with metal 3D printing look no further than the aerospace industry.

It's not hard to understand why so many industries haven’t adopted or have been slow to adopt additive manufacturing technologies. A broad lack of understating as to how to design for 3D printing, a lack of understanding as to how the design parameters are different across the various technologies, and a lot trial and error as to where in the workflow to apply additive processes has made for slow going in many sectors.

In addition many less experienced manufacturers make cost comparisons based solely on a "part-to-part" basis and conclude 3D printing isn’t for them. It is true that when compared to traditional manufacturing technologies such as CNC machining and its associated materials, 3D-printed parts may well indeed be more expensive (but not always; that calculus continues to evolve). But making the comparisons in this manner does not consider all of the other potential benefits such as more efficient supply chains, superior part performance due to more efficient designs, less parts in inventory, faster time to market (and therefore faster revenue generation) and less cost for customization. It is in these areas where aerospace really shines as an example of what benefits can be achieved with metal 3D printing.

Metal additive manufacturing is complicated and has the longest and most costly learning curve of all the 3D printing technologies. However, like the other technologies, 3D printing in metal offers huge benefits in two primary areas: the superior part performance that comes with optimized design that can only be achieved with 3D printed parts; and the cost reductions achieved simply by lowering the weight of a component.

A July 2017 article from The Economist on 3D printing's impact on manufacturing presents the benefits of cost reduction as a function of weight reduction very clearly. Speaking with The Economist, Marcus Pont, General Manager at Domin Fluid Power, noted that a weight decrease of 1 kilogram in an aircraft can result in a cost savings of $1,200 to $13,00.

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This is where the value of metal additive for aerospace becomes obvious, and all the more so through the application of laser metal deposition (LMD) technology. LMD (also known as “direct energy deposition” or DED) has enormous benefit in this area.

I recently interviewed Melanie Lang, co-founder of metal 3D printing technology company Formalloy, for the 3DTechTalks podcast, where she spoke about the advantages of this particular technology. LMD lacks some of the key benefits of the other metal additive technologies like DMLS, which is good for small prints requiring the fine features found in medical devices and knee replacements. However, since it is not a powder-bed system, the laser deposition technology makes it possible to use multiple materials in one print. Instead of the metal powder lying in the build chamber, the powder flows from a hopper and is hit with a laser at the point of application.

As Lang explained, this has the enormous advantage of being able change materials during a print or have multiple hoppers next to each other while the printer switches from one to the other automatically. This metal process works with a wide variety of materials including titanium-, nickel-, cobalt-, copper-, and iron-alloys, and many others.

Regardless of which additive technology you use (metals, resins, or thermoplastics), they all have their challenges. One of the big hurdles for metal 3D printing with aerospace applications is the powders are not designed specifically for aerospace. But today, new materials are being developed that are optimized and have better materials properties for these applications. Another issue that has been a consistent challenge is the lack of standards from one metal powders supplier to another. As Lang explained on 3DTechTalks, you can buy titanium metal powder from one supplier; then buy titanium powder from a different supplier and even though the material specs say they're the same the powders react differently. The industry still has to get to an international level of standards across all the technologies, whether its powders, resins, or thermoplastics.

Finally, an issue with metal additive manufacturing that is true regardless of the application is part variability. We all know that whether you have a CNC machine make 10 parts or 10,000, those parts are flawlessly identical. However, as with all the 3D printing technologies, that level of consistent precision has yet to be achieved with metal. Regardless of which metal additive technology you use, post-print processing is always required to get to the net shape or achieve a specific surface finish.

However, with the right applications (and aerospace is certainly a leading one) the limitations of metal additive are certainly outweighed by the not only the benefits to the production process but also the ripple effect that process makes possible across all the associated business functions.

Jack Heslin is the president and founder of 3DTechtalks. A 3D Printing consulting firm helping small to medium size manufacturers develop an additive manufacturing strategy. He is also the host of the 3DTechTalks podcast series and a speaker at industry trade shows. He can be reached at [email protected]