Building the Future with Additive Manufacturing

In the early 1980s, a quiet revolution began in the world of manufacturing. It started with a simple idea — building objects layer by layer rather than carving them out of solid blocks. The first success? A humble plastic cup was created using a process called stereolithography. This marked the birth of what would become known as additive manufacturing (AM). 

At first, AM was a niche technology, mainly used for prototyping with plastics. But as the years passed, innovation surged. Engineers and scientists pushed the boundaries, expanding the range of materials far beyond plastic. Metals, ceramics, composites, and even biomaterials for medical implants joined the AM family, transforming the technology from a curiosity into a cornerstone of modern manufacturing.

Among the most transformative developments was metal additive manufacturing, often referred to as metal 3D printing. This field branched into several primary categories, each with its own unique processes, strengths, and challenges.

Directed Energy Deposition

Directed energy deposition (DED) has earned a reputation for versatility and scale in AM. It’s particularly prized in industries where large, high-value parts are the norm and downtime is costly. Whether it’s fabricating a brand-new turbine blade (Fig. 1) or restoring a damaged aerospace component, AM delivers.

Among the many flavors of DED, two stand out: laser-directed energy deposition and arc-based DED. The latter, often powered by an electric arc, is gaining traction for its efficiency and adaptability. One of the most widely used arc-based techniques is gas metal arc welding (GMAW). Known for its high deposition rates and compatibility with a wide range of materials, GMAW is a workhorse in the DED category, as existing robots and power sources at a facility can be repurposed for additive manufacturing.

But as with all things in engineering, there’s a trade-off. More doesn’t always mean better. While higher deposition rates can speed production, they also introduce more heat input. That excess heat input can cause the weld deposit to spread out rather than build up, compromising the final product’s precision and causing longer build times.

This challenge has sparked a wave of innovation. Manufacturers are racing to refine their techniques, seeking the sweet spot where maximum deposition meets minimal heat input. Some ways manufacturers are optimizing these efforts include developing advanced controlled short circuit processes, introducing multiple electrodes, combining a reciprocating wire process with alternating current, and enabling a constant wire deposition combined with a laser. All these techniques have a place in AM, and there are several factors to consider when evaluating which process is most suited to your needs.

When selecting a DED process, factor in the desired structure shape, material type, and component size. GMAW processes excel in AM when building larger components and where versatility is needed with a wide variety of materials. Laser-directed energy excels in precision and resolution, allowing for more-intricate details compared to a GMAW process. Postprocessing is another factor to consider, as all DED processes often require postprocessing steps, like machining, to achieve the required dimensions for the build — Fig. 2.

Powder Bed Fusion

One technology that stands out for its ability to turn powdered metal into intricate and complex parts is powder bed fusion (PBF) — Fig. 3. This technique uses a laser or electron beam to selectively melt and fuse layers of metal powder, building complex 3D shapes. The result? Components with geometries so intricate, they’d be nearly impossible to produce using traditional manufacturing methods. But like all powerful tools, PBF comes with trade-offs.

Compared to other additive manufacturing techniques, PBF can be relatively slow, making it less ideal for high-volume production runs. It’s a master of detail, not speed.

Safety must also be considered. The same fine metal powders that make PBF so precise also pose health risks. Inhalation of these particles can be hazardous, and some powders are toxic upon skin contact or may cause allergic reactions. Dust clouds formed from mishandling powders can be combustible, causing flash fires or explosions. That’s why strict safety protocols are non-negotiable. Proper personal protective equipment, appropriate ventilation and filtration systems, and careful material handling are essential to keeping the workplace safe.

What Else is Out There?

There are two additional major categories in AM: binder jetting and sheet lamination.

Binder jetting uses a liquid binding agent with a powder bed to create the component. Because binder jetting doesn’t use heat to fuse the powder, it can be used with metals, ceramics, and composites to create one-of-a-kind objects. Binder jetting is often used for rapid prototyping and producing large sand-casting molds.

Sheet lamination creates a 3D object by layering individual sheets of material then creating the final shape through postprocessing methods like machining or laser cutting. Each layer can be joined through different methods, such as using an adhesive to laminate the sheets together or through bonding with an ultrasonic process. Sheet lamination is used across multiple industries, including aerospace, automotive, and sports, as well as in applications such as electrical insulation and decoration.

From creating plastic cups to complex metal implants and aerospace components, additive manufacturing is a testament to human ingenuity. As technology matures, one thing is clear: AM isn’t just building parts; it’s building the future.

SHAUN RELYEA (relyea.shaun@fronius.com) is leader of systems and application support for Fronius USA, Portage, Ind.