Due to technical challenges, copper was previously not very suitable for 3D printing. The development of a new process could change that now.

From the original coin and ornaments to the electronics manufacturing today, copper remains a popular material as it not only has a long life and a non-corrosive texture. It is also one of the best power conductors, making it the centerpiece of most electrical wiring in buildings and windings in electric motors. Less well known are the antimicrobial properties that protect against insects and viruses, which also qualifies copper for medical use.

Despite the variety of applications described above, copper has not been successful in an increasingly important field: 3D printing. This is due to the procedure of the usual 3D printing process by laser welding. In this process, metal powder is melted together under computer-controlled guidance.

New technologies needed for copper
For copper, however, this process is difficult. The high reflectivity when impinging on conventional infrared fiber laser prevents the absorption of energy and thereby the melting process. In addition, the thermal conductivity of copper dissipates the heat from the last molten bath and thus reduces the effectiveness of the process. Although there are already methods that can process copper, but these are still very expensive and therefore not widely used. These include electron beam melting or green laser beam melting developed by the Fraunhofer Institute.

ltrasonic separation of particles
One method that does not rely on thermal welding for the additive fabrication of copper parts is the Supersonic 3D Deposition (SP3D) technology of Spee3d of Australia. The printing process is carried out here by a rocket nozzle, which accelerates the particles to the triple supersonic speed and attaches to a carrier material that hangs on a six-axis robot arm. The kinetic energy of the particles causes the metals to fuse into a very dense object. Its metallurgical properties are approximately 80-95% of the solid material. The application of the 25-35 micron metal particles is done in approximately layered deposition in the order the printing program deems ideal. The speed is 20 -100 g / min.

Design features
Design restrictions apply to the wall thicknesses, which must have a minimum thickness of 6 mm. In addition, thin holes and cavities are difficult to implement by the printer, which is why machine post-processing is often cheaper and faster to implement. Like other additive processes, SP3D also allows slopes of up to 45 ° without the use of support material.

The CAD data transfer (STL or Step) takes place by reading into the print program and the subsequent conversion to the printing process. Incidentally, the program simulates the element to be printed so that you can see with almost 100% accuracy how the finished piece looks at the end.

The application possibilities are manifold, as copper can be easily combined with aluminum and other materials. This makes it suitable for a wide range of uses such as the automotive sector, where it can be used from engine parts to high-performance heat sinks for electric and autonomous vehicles. (Qui)

Article by: Dorothee Quitter