Plastic materials were the first to be 3D printed. But for many users, the ability to print in metal material is key. The use of metal materials in a 3D printer or additive machine has challenges, though. The primary one being that many metals are highly combustible, especially when using a heat source like a laser to melt the metal material sufficiently to adhere one layer to another, so safety is a concern.

But several companies have developed unique methods of heating metal material enough to cause layers to properly adhere. Most companies use a form of powder bed additive manufacturing. Several, though, have developed a safe way to extrude metal material. Here’s a quick look at who offers additive systems for metal.

3D Systems—began with Direct Metal Laser Sintering (DMLS), now known as Direct Metal Printing (DMP). This powder-bed technology uses a high precision laser to melt metal powder particles to build up horizontal metal layers one after the other.

AddUp—offers three types of metal additive manufacturing: powder bed fusion, directed energy deposition, and electron beam melting.

Admatec—uses Digital Light Processing (DLP) technology on a material that is a mix of a photosensitive resin and a metallic powder. The DLP source fuses this hybrid material in a manner that is similar to the company’s 3D ceramic printer.

Airwolf—primarily offers extrusion with plastic materials, but its Evo Additive Manufacturing Center can work with metal. The metal material is combined with a binder, which ensures safe handling.

Aurora Labs—offers machines that use the company’s Multi-layer Concurrent Printing technology. This technology combines powder bed fusion and direct energy deposition. Part of the benefit of this printing method is speed and minimal post processing.

BeAM—uses Directed Energy Deposition technology. Most DEP approaches are used to dispense a powdered metal material through a nozzle onto an existing object. The primary uses of this technology are to repair components, add features to existing parts, or build near net shape parts with minimal post processing. (BeAM is part of the AddUp Co.)

Desktop Metal—offers systems for both extrusion metal 3D printing and binder jetting technology. In the extrusion system, metal rods are bound with another material (carbon, for example) to make them safe to handle. In the binder jetting system, the printer spreads metal power across the build bed, then jets a binding agent in specific pattern. This process is repeated layer by layer. Once complete, the build box is removed and placed in a powder station for “depowdering.” The final step is sintering to remove the binder material and finish the part.

DMG Mori—primarily offers powder bed additive technology. Although there is laser deposition welding with metal powder deposited through a spray-type nozzle that complements the company’s subtractive machining operations.

EOS—was one of the pioneers in Direct Metal Laser Sintering additive manufacturing. The company’s products are powder-bed fusion systems.

ExOne—offers a number of metal 3D printing systems that use powder bed and binder jetting for metal.

GE Additive—GE bought the Arcam and Concept Laser companies and their technologies. Thus, the company offers Electron Beam Melting and Direct metal laser melting. Electron Beam is an additive manufacturing technique that uses a cathode ray as its heat source for powder bed fusion.

HP—offers the HP Metal Jet, which combines powder bed technology with jetting. Metal powder is spread in a layer on the powder bed build box, then a chemical agent is jetted onto the powder in a specific pattern. Evaporation of the agent begins the binding process, which is finished when a heat source solidifies the layer. Sintering is the final step, performed in a furnace.

Markforged—develops extrusion-based metal 3D printers. The metal material is combined with another material that makes it extrudable as well as safe to handle and melt.

Optomec—uses a type of directed energy deposition it calls LENS. The metal powder feedstock is delivered to the material deposition head by a proprietary powder-feed system that regulates mass flow. Deposition occurs layer by layer. When complete, the component is removed and can be heat-treated, Hot-Isostatic-Pressed, machined, or finished in any customary manner.

Renishaw—offers powder bed fusion machines. The additive manufacturing (AM) solutions enable the production of lattice structures, and part consolidation for lightweighting, complex internal galleries to optimize fluid flow, and design for AM (including topological optimization).

Sciaky—developed a deposition method it labels as Electron Beam Additive Manufacturing (EBAM). A laser melts powdered metal in a specific pattern to build objects.

SLM Solutions—offers powder bed fusion systems. Several machines use multiple lasers to smelt the powder material for multiple parts simultaneously.

Trumpf—offers laser metal fusion and laser metal deposition systems. These methods are similar to other powder bed fusion and directed energy deposition systems.

Vader Systems—was recently acquired by Xerox. Vader technology is liquid metal jetting, which the company patented as Magnet-o-Jet technology. The machine works with wire feedstock instead of powder. The wire is fed through a heating system and then propelled through ceramic nozzles as a liquid from a chamber encased in an electromagnetic field. The magnetic field controls the position of the liquid metal to enable precise placement. The material solidifies as it cools.

Velo3D—this company began first with software. Its 3D Flow software is said to accelerate 3D printing design and help engineers collaborate with their designs. Then the company created the Sapphire System for 3D printing. This machine is powder bed based using the company’s patented technology–Intelligent Fusion. Most parts need little to no supports.

XJet—offers NanoParticle Jetting technology. By depositing fine metal droplets suspended in a liquid, it safely creates metal objects one layer at a time.