The Fraunhofer Institute for Material and Beam Technology IWS in Dresden, Germany, has designed a green laser with wavelength much shorter than the typical infrared laser to melt copper powder during additive manufacturing. It enables new production approaches that previously could not be achieved with pure copper.
“Previous experiments repeatedly showed that infrared (ʎ = 1064 nm) laser beam sources of up to 500 watts are not efficient enough to completely melt copper,” explains Samira Gruber, who supervises the project as a research assistant at Fraunhofer IWS. Only 30 percent of the energy used reaches the copper material – the rest is reflected. With the green laser (ʎ= 515 nm) at a maximum of 500 watts, the copper powder absorbs more than 70 percent of the energy, and melts completely, which in turn permits its application in additive manufacturing.
“Additively manufactured copper parts are superior to many aluminum solutions due to a higher volume-specific conductivity,” says Elena Lopez, head of the additive manufacturing department at Fraunhofer IWS. “This is particularly interesting wherever small designs and high performance are required
Complex components made of pure copper and copper alloys can now be built via AM for aerospace and automotive industries, and the efficiency of electric motors and heat exchangers can be increased. For example, more efficient and compact heat sinks for future power electronics can be manufactured, as well as particular individual coils for electrical drives in satellites, cooling systems in space propulsion systems, and many other parts.
https://www.iws.fraunhofer.de/en/pressandmedia/press_releases/2020/presseinformation_2020-07.html
