Metal 3D Printing: What is Direct Energy Deposition?

Direct Energy Deposition (DED) refers to several similar metal 3D printing technologies that produce components by melting and fusing material. While it can be used for manufacturing new parts, DED is typically also used for repairing and rebuilding damaged components. As one of the most important 3D metal printing technologies, DED is already being used in key industries such as aerospace, oil and gas, and maritime industries. In today's tutorial, we will examine the DED process, its advantages and limitations, as well as existing use cases.

Direct Energy Deposition (DED) is often referred to by various names, including 3D laser cladding and Directed Light Fabrication. Furthermore, certain proprietary technologies modeled after DED are sometimes used synonymously: Electron Beam Additive Manufacturing (Sciaky), Laser Engineered Net Shaping (Optomec), Rapid Plasma Deposition (Norsk Titanium), or Wire Arc Additive Manufacturing. Although each process works somewhat differently, the principle behind it is the same. In the DED process, the starting material, which is available in either metal powder or wire form, is pushed through a feed nozzle, where it is melted by a focused heat source (most commonly a laser, but could also be an electron beam or arc) and added successively to the build platform. Both the heat source and the feed nozzle are mounted on a gantry system or robot arm. The process typically takes place in a hermetically sealed chamber filled with inert gas to better control material properties and protect the material from unwanted oxidation.

Notably, the materials used in DED are significantly cheaper than the metal powders used in powder bed machines.

DED technology has been in use for several years now and offers a number of advantages:

Ideal for the repair of components: The ability to control the grain structure of a part makes DED a good solution for the repair of functional metal parts.

Larger 3D-printed parts: In contrast to powder metal AM processes, which typically produce smaller, high-resolution components, some proprietary DED processes can manufacture larger metal parts - for example, EBAM technology (Electron Beam Additive Manufacturing) developed by Sciaky is said to be capable of producing parts larger than 6 meters in length.

High deposition speed: DED machines typically have high material deposition rates. For example, some DED processes can achieve a speed of up to 11 kg of metal per hour.

Less material waste: In SLM and DMLS processes, powder is distributed on the build platform and then selectively fused together, which often leaves a lot of unfused powder that must be reused. With DED processes, only the required amount of material is processed. Since there is no waste powder to recycle, this results in efficient material consumption and cost savings.

Multi-material capabilities: With DED, powders or wires can be modified or mixed during the build process to produce custom alloys. The technology can also be used to create a gradient between two different materials within the same build job, thereby achieving superior material properties for a part. High-quality metal parts: DED produces high-density parts with mechanical properties that are as good as or better than those of comparable cast or wrought materials. Parts manufactured with DED can also assume near-net-shape forms, which means they require minimal post-processing. Hybrid manufacturing capabilities: DED is one of the few metal 3D printing technologies that can be integrated into machining centers to create a hybrid manufacturing solution. By mounting a deposition nozzle on a multi-axis machining system, highly complex metal parts can be produced faster and more flexibly.

The limitations of DED include:

Low Resolution: Parts manufactured with Direct Energy Deposition have low resolution and poor surface finish, which requires post-processing that adds time and cost to the overall process.

No support structures: DED is not suitable for creating support structures, which limits the manufacturing of parts with certain geometries, such as overhangs.

Costs: The costs for DED systems are normally very high and exceed 500,000 US dollars.

In the following table, we have summarized the most important companies that have developed proprietary technologies based on the DED process, together with the available machines and their build volumes.

DED has been successfully deployed in various industries, including aerospace, oil & gas, defense, marine, and architecture. Aircraft manufacturers are increasingly using this technology to produce components for satellites and military aircraft. Lockheed Martin Space, for example, recently qualified Sciaky's EBAM process for the construction of titanium fuel domes for satellites. By implementing the technology, the company was able to reduce production time for the component by 87% and shorten lead time from two years to three months. DED is also being considered for structural parts for commercial aircraft. An example is aircraft titanium parts for Boeing's 787 Dreamliner, recently approved by the FAA and manufactured by Norsk Titanium. The Norwegian company utilized its proprietary Rapid Plasma Deposition technology, a form of DED technology, which resulted in a significant improvement in the buy-to-fly ratio compared to conventional manufacturing methods. Now that titanium parts are going into series production, Boeing expects to reduce production costs per aircraft by 2 to 3 million US dollars. In addition to manufacturing metal parts, DED technology is well-suited for repairing damaged components. Thanks to the strong metallurgical bond and fine, uniform microstructure that DED can produce, components such as turbine blades and injection molding tool inserts can be refurbished. By repairing worn parts, molds, or dies, DED enables significant reduction of downtime and costs associated with part replacement, while extending the service life of the component. Furthermore, DED can be used to modify parts. For example, the wear and corrosion resistance of a component can be improved by using the technology to build up a wear-resistant hard-facing layer.

Direct Energy Deposition offers numerous advantages for industries in which high-quality equipment and customized metal parts, particularly those with larger dimensions, must be manufactured or efficiently repaired. Looking ahead, we expect the application possibilities for the technology to expand, particularly due to the exciting trend of hybrid manufacturing. Through integration with conventional manufacturing technologies, DED could make advances in industries seeking innovative and cost-effective production options.