March 7, 2021
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Directed Energy Deposition (DED): A Complete Guide

Directed Energy Deposition (DED) — sometimes just Direct Energy Deposition — is a metal 3D printing technology offering key advantages in larger metal part creation. Similar to other metal 3D printing methods, DED builds parts by sintering metal in layers to form a three-dimensional structure.

Part 1: Introduction to Directed Energy Deposition

DED uses a slightly different technique to Powder Bed Fusion methods such as Direct Metal Laser Sintering (DMLS) or Electron Beam Melting (EBM). With Powder Bed Fusion, powdered metal is deposited on the baseplate and then sintered from above by the laser. However, with DED the metal is deposited at the same time it is melted.

DED uses a feedstock of metal powder or wire, which is fed through the metal 3D printer’s extruder, melted by the focused heat source — either laser, electron beam, or plasma — and then deposited. After each layer of metal is deposited, the baseplate lowers to allow the next to be constructed.

The Directed Energy Deposition process

DED is compatible with a versatile set of metals including aluminum, copper, titanium, various types of steel including tool and stainless, as well as many alloys. This material versatility means that DED has a range of applications and can produce products in numerous industries.

Cladding

While DED methods can be used to construct products from scratch, one very popular area of use is coating or cladding other items in metal, or for repairing damaged metal products.

DED has carved a very useful niche in the additive manufacturing industry for large metal parts. Whereas other technologies like DMLS and EBM are limited in the size of parts they can build, DED can print far larger parts.

DED 3D printers can produce several-feet-long parts, and as metal is deposited and heated simultaneously, also prints parts faster.

Part 2: Market Leaders in Directed Energy Deposition

Much like DMLS, Direct Energy Deposition encompasses a range of different methods and technologies. Many companies have developed their own variations, with different advantages and disadvantages.

Optomec — Laser Engineered Net Shaping (LENS)

Founded in the USA in 1979, Optomec have grown into an industry leader in additive manufacturing, and have worked closely with Boeing, General Electric, NASA and the United States Military to develop new designs and produce them using 3D printing technology.

They developed Laser Engineered Net Shaping, a variation on DED where powdered metal is heated by a high-powered laser in a sealed chamber to keep the part clean and pure. Once all layers are constructed, the product is heat treated, machined and finished.

Using LENS, Optimec can produce parts using titanium, stainless steel, nickel, copper, cobalt, aluminum and Inconel, showing the breadth and versatility that the technology offers and the widespread applications of DED.

Directed Energy Deposition at Optomec

Sciaky — Electron Beam Additive Manufacturing (EBAM)

Sciaky are one of the most tenured organizations in the industry, with their lineage going back as far as 1939. They are inventors of the technique EBAM, or Electron Beam Additive Manufacturing, which promises faster production, less waste metal and reduced machining time.

EBAM uses metal wire, similar to a filament, which is melted using a high-power electron beam. The increased intensity of this laser type helps to reduce production time, with Sciaky claiming they are able to produce between 7 and 25 pounds of metal per hour.

Furthermore, EBAM can combine two metals together to create custom alloys. This is extremely useful in sectors such as construction, where location affects the weather. Being able to tailor your metals to the specific location could improve longevity and reduce repair costs.

Siemens — Wire Arc Additive Manufacturing (WAAM)

Siemens are a German manufacturing and software giant working in some of the largest and most important sectors in society including energy, construction, and healthcare.

For years, they have been a pioneer of additive manufacturing, and have made great progress in 3D printed steel through their Wire Arc Additive Manufacturing method.

Wire Arc uses a laser to melt a metal wire as it is fed through the extruder, which is then deposited onto the baseplate. Using wire vastly increases the production speed, as metal is being melted in a single place, rather than over a wide surface as with Powder Bed Fusion. Each machine is able to print 3 to 4 kilograms per hour.

This method is an important first step in pushing metal 3D printing forwards towards an industrial scale. With Wire Arc significantly faster than EBM or DMLS, large scale projects, both in size and quantity, are where DED shines.

Wire Arc DED at Siemens

Norsk Titanium — Rapid Plasma Deposition (RPD)

As the name might suggest, Norsk Titanium were founded in Norway in 2004, and their Rapid Plasma Deposition technique has earned them notoriety in the aviation industry.

RPD works by precisely melting titanium wire in an inert, argon gas environment, similar to Siemens’ method. They focus on maintaining superior metal quality throughout the process, which retains better properties, a consistent structure, and reduces the risk of striation or poor bonding.

Norsk Titanium claim their technology reduces metal waste by between 50-70%, making them a favorite in the industry, with Boeing beginning to implement Norsk Titanium’s 3D printed brackets in 2015.

  • Read our feature story on Titanium 3D printing here.

Part 3: Applications of Directed Energy Deposition

Construction

3D printing is beginning to be implemented in new building projects around the world, and metal 3D printing is a large part of it. Engineers are pursuing additive manufacturing as a cost-saving method of producing their materials.

Steel, aluminum and Inconel are often used for constructing the framework of building projects, and construction companies, much like other industries, are able to reduce material waste and improve strength by using Direct Energy Deposition methods. DED’s increased speed and cost savings make construction 3D printing more effective and efficient.

Aviation

As discussed, the aviation industry is one of the biggest industries researching new additive manufacturing methods, and Directed Energy Deposition specifically. Aircraft companies recognize the benefit of reduced waste material and reducing weight of plane parts, potentially saving millions of dollars in fuel costs per year.

DED can be used to manufacture everything from small brackets and fixtures, to the skeleton and exterior panels of the aircraft. DED’s versatility allows it to print a range of different materials used in aircraft production.

Directed Energy Deposition in aviation

Military

The military is always in search of innovative, cost-effective manufacturing methods that deliver on important specifications and consistent quality. All military equipment must be able to reliably function in life-or-death scenarios in harsh conditions.

Additive manufacturing is being explored in the production of firearms, body armor, armored vehicles, missiles and helmets. DED is able to produce large components for these items in one piece, making them less likely to break and less susceptible to wear and tear. Additionally, DED is useful for metal repairs, meaning any damaged items could be fixed in the field.

While we are yet to reach mass production capacity, the US military has already begun dabbling in investment into additive manufacturing, with DED being among the most useful technologies available in this field.

Part 4: Advantages and Disadvantages of Directed Energy Deposition

Advantages

Larger Parts

Directed Energy Deposition printers have larger build capacities that their Powder Bed Fusion counterparts, making the technology capable of creating much larger products that DMLS or EBM.

By melting and depositing the metal simultaneously, rather than rolling powdered metal over the baseplate, larger structures can be constructed with accuracy, similar to plastic 3D printing methods. This development is the first step to truly large-scale metal 3D printed products such as planes or cars.

Stronger Parts Quicker

DED produces dense 3D printed metal parts with consistent densities throughout. Sciaky 3D printers even allow clients to create custom alloys, mixing different metals in the feed pool in custom quantities to facilitate greater strength.

Despite this, especially when using wire feedstock, DED’s production speed is far greater than with other metal 3D printing methods. Optomec published a study showing DED printed an identical part 10 times quicker and at 5 times lower cost than Power Bed Fusion. This shows DED to be a much more cost-efficient method, making it more attractive for commercial expansion.

Low Material Wastage

Part of the reason why DED is so much cheaper than Powder Bed methods is that there is a lot less material wastage than other 3D printing methods, let alone traditional metal manufacturing.

When Boeing found success with their 3D printed titanium brackets, they estimated that 3D printing an entire aircraft would cost around $3 million less than doing so using traditional methods. This can also be seen in Norsk Titanium’s promise of a 50-75% reduction in the buy-to-fly ratio. This improves efficiency, and ultimately saves time and money.

Advantages and disadvantages of Directed Energy Deposition

Disadvantages

Expensive

Due to the increased complexity of the production process, and the size of the printers, Directed Energy Deposition 3D printers are a lot more expensive than Powder Bed Fusion printers.

For small R&D systems, like those at Optomec, a printer will cost around $200,000, but larger industrial 3D printers, like those at Sciaky, can costs as much as $2 million. Compared to DMLS printers, where an equivalent machine could cost far less, it very difficult to start up in the industry without significant financial backing.

Lower Build Resolution and Inconsistent Finishes

Directed Energy Deposition printers cannot produce parts with complex designs or many intricate parts. Powder bed Fusion is far more effective for these small and medium-sized components.

On top of this, DED cannot match the finish of DMLS printers. Parts often require heat treatment and machining to make them harder and denser, and give them an attractive aesthetic which requires extra time and equipment.

Part 5: Where Does Directed Energy Deposition Go from Here?

DED’s various benefits over other types of metal 3D printing technologies have opened up the possibilities for further development. Where Powder Bed Fusion technologies are limited in what they are able to achieve in scale, DED has no such restrictions. And much like with many types of 3D printing, DED’s future could lie beyond the stars.

In September 2020, NASA announced that they would be exploring additive manufacturing, and specifically DED, in the construction of new rocket engines. Their hope is to be able to reduce production time and costs for large, complex parts like nozzles and combustion chambers.

Directed Energy Deposition at NASA

The ability to produce intricate and important parts quicker and cheaper is a major hurdle overcome that means launches can be done more frequently, and increases the rate of progress.

With the newly formed Space Force agency of the United States government, who will be working closely with NASA, it is expected that DED manufacturing will play a key role in the research and development that is inevitably right around the corner.