According to a recent analyst forecast, the market for using copper material in 3D printing applications will grow 51% thanks to key technical developments in copper additive processes and materials.
While copper materials are being explored within each of the three primary metal AM print technology families, their chemistry presents challenges to processing using established or ‘conventional’ metal AM system configurations in most available technologies. These challenges include:
• Alterations to or adaptations of hardware architecture of existing printing systems
• Tailoring of material properties and powder characteristics of copper materials used
• Development of alternative metal additive printing technologies suited to copper printing
Several additive vendors, however, have developed unique ways of solving these challenges.
GE Additive Arcam uses Electron Beam Melting (EBM) to produce electrically pure copper in geometries not possible with traditional manufacturing. The novel geometries can help remove other process steps such as; soldering, joining or bending, especially where these steps might compromise conductivity and possibly the lifetime of the component.
Copper’s ability to absorb energy varies with the wavelength of the energy source. Pure copper absorbs 80% of the energy from an electron beam, compared to only 2% of the energy from a red laser beam. This gives EBM an advantage in terms of the ability to melt.
The vacuum environment in which EBM operates minimizes the oxygen pick-up in copper, allowing a high conductivity copper to be produced. Oxygen reduces the conductivity of copper while also embrittling the component.
The ability to produce complex geometries in pure copper without compromising the high electrical or thermal conductivity is suited to a range of sectors, including the automotive industry, or customers looking at applications for electrical connectors, induction coils, and heat exchangers.
The Markforged Metal X 3D printer can be used to manufacture complex copper parts with high electrical and thermal conductivity. Markforged uses a copper that is more than 99.8% pure. (The Metal X System also works with Markforged stainless steel, nickel superalloy, and tool steels and aluminum over copper options.)
The copper powder is combined with a plastic binder and extruded in a Fused Filament Fabrication (FFF) process like other materials offered by Markforged. Once a part is built, users wash the part to debind the wax, and then load the part in a furnace which thermally removes the remaining binder and then sinters the powder into the final fully metal part.
Applications include heat sinks, bus bars, custom welded shanks, and parts with complex internal cooling channels. One benefit of 3D printing this way is it can eliminate brazed or welded assemblies.
Optomec offers a pure copper additive manufacturing process using its LENS directed energy deposition (DED) systems. Pure copper is a challenge for DED systems because of its high reflectance. The infrared wavelengths on most standard, laser-based AM systems are not readily absorbed by copper, making it difficult to establish a melt pool as the laser energy is reflected back into the source, causing havoc. Optomec’s laser-based solution is virtually immune to any back reflection, so the laser can operate at full power on reflective surfaces without difficulty. Optomec engineers have developed process parameters to account for thermal conductivity differences, as well as big changes in absorption and have demonstrated efficient DED builds with pure copper.
Establishing a DED process for pure copper is particularly important for designers of heat exchangers in a variety of industrial applications in aerospace and chemical processing. The Optomec copper process is also applicable to alloys of copper such as bronze, brass and cupronickel.
Spee3D introduced its copper 3D printing system a couple of years ago. This additive manufacturing technology uses supersonic deposition. Material is shot through a jet engine nozzle at speeds to Mach 3, and deposited in geometric patterns layer by layer. Known as Supersonic 3D Deposition (SP3D), no heat is used to melt the metal powders. And parts can safely be handled immediately after the build. The sheer kinetic energy of the moving particles causes the powders to bind together to form a high-density part with normal metallurgical properties.
The technology suits the production of parts you would otherwise build using sand or die casting. Applications include automotive, mining, commercial, HVAC and industrial parts. The machine does not need to use inert gases as the process works with normal compressed air. Post processing consists of finish machining. The deposition rate is up to 100 g/min. The deposition spot size is 4 to 7 mm.
Stratasys offers Copper (C18150), a chromium zirconium copper (CuCr1Zr) alloy, which offers excellent thermal and electrical conductivity. The company implemented controlled heat treat processes to optimize mechanical and material properties.
Stratasys uses its direct metal laser sintering (DMLS) technology with copper. Designers developing parts to be made of copper should keep an eye on wall thicknesses and feature details. Conformal cooling and complex internal passages may require the use of support structures. With heat exchangers, thinner walls are better, but there are limits on wall thinness–roughly 1000 micrometers of 0.040 in. In some cases, parts will need post-processing, including machining to improve the finish. Heat treatments may be needed for densification.
You will also find a number of service providers able to offer 3D printing with copper materials.
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