Previously, it was not possible to melt copper for complex 3D-printed parts using an infrared laser.
But now, the Fraunhofer Institute for Material and Beam Technology (IWS) in Dresden, germany, is now using a novel additive manufacturing system, which processes the metal almost defect-free using a shortwave, green-emitting laser.
This capability, says IWS, enables new production approaches which previously could not be realized with pure copper. Thus, complex components made of pure copper and copper alloys can be realized for aerospace and automotive industry and the efficiency of electric motors and heat exchangers can be increased.
Fraunhofer IWS can now design and create pure copper components with excellent electrical and thermal conductivity. These components enable, for example, more efficient electric motors and innovative heatsinks in power electronics.
Furthermore, applications in coil and inductor production are conceivable. Additively manufactured copper components are particularly suitable for compact devices with small installation space, high efficiency and high performance. 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.
The new laser beam melting system is unique in Saxony – there are only few comparable systems in Germany. Instead of infrared light with a wavelength of 1064 nm, the system utilizes a disk laser with high- energy green light with a wavelength of 515nm.
“Previous experiments have repeatedly shown that infrared laser beam sources of up to 500 watts are not efficient enough to completely melt copper,” commenetd Samira Gruber, who supervises the project as a research assistant at IWS.
Only 30 percent of the energy used reaches the copper material – the rest is reflected by the metal. The new green laser with a maximum of 500 watts offers a different solution: Here, the copper powder absorbs more than 70 percent of the energy used and melts completely, which in turn permits its application in additive manufacturing.
Since copper conducts heat and electricity very well, it constitutes a major improvement if this metal can also be processed in additive production systems. “Components made of pure copper and copper alloys play an important role in aerospace, electronics and automotive industries, for example, in electric drives or as heat exchangers,” said Elena Lopez, head of the additive manufacturing department at Fraunhofer IWS.
Many copper parts can already be machined, forged or cast today. However, the implementation of additive manufacturing processes opens up new options to produce highly complex geometries, which are simply not possible with conventional manufacturing.