“Pure copper is a big challenge for DED systems because of its high reflectance,” said Tom Cobbs, product manager for Optomec LENS systems. “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 all kinds of havoc. Our laser-based solution is virtually immune to any back reflection, so the laser can operate at full power on reflective surfaces without any 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 industries such as aerospace and chemical processing. The Optomec copper process is also applicable to alloys of copper such as bronze, brass and cupronickel.
“We see this as a major milestone for LENS and DED additive manufacturing — because working with copper is essential for many of our customers. Copper is so critical because it enables the addition of high thermally-conductive features like cooling fins, the addition of soft metal sealing surfaces and high electrically-conductive surfaces for power transmission.” Cobbs concluded.