Laser 2015: forum reviews progress of laser 3D printing

23 Jun 2015

Whether selective laser melting or laser metal deposition, the technique is rapidly finding new applications and markets.

This morning’s Industrial Laser Application Forum in Hall A3 reviewed some of the latest developments in metal laser additive manufacturing, which has become such a significant industrial process that this year’s show features a dedicated display area in the same hall (booth 541).

The session featured six presentations looking at different aspects of practice, research and commercialization of metal laser printing. These included optimizing techniques for working some of the hardest “super-alloys” available such as Inconel and various forms of stainless steel.

Warming up the full house was Dr Mark Richmond, of SPI Lasers, UK, a subsidiary of the Trumpf Group.

Dr Richmond said that additive manufacturing is a sweet spot application for high-brightness medium power fiber lasers operating in the 1070nm wavelength region. “Their near-Gaussian beam quality, operational dynamic range, long-term power stability and cost-effectiveness suit fiber lasers to this purpose,” he said

Dr Richmond noted that back reflection has been identified as a problem in this type of application of fiber lasers but that SPI Lasers had developed its Luminator fiber and a low-cost integrated management system to overcome the problem. In fact, he said, controlled back reflection could actually be a benefit “as it could be used to monitor the degree of laser processing, detect the breakthrough point and establish focus.”

Dr Wilhelm Meiners, Group Leader at the Fraunhofer Institute for Laser Technology (ILT) then gave a presentation on the principles and applications of laser additive manufacturing, differentiating the two main types: selective laser melting (SLM) and laser metal deposition (LMD).

“The main features of SLM are that its materials of applications are relatively limited and industry has less experience of it. Using SLM, the development of part complexity is almost unlimited with detail as fine as 0.1mm being possible. On the other hand it needs a flat base to build up the part.”

“In contrast, LMD works with a wide variety of materials, it is limited to less fine, 0.3mm features, but because the metal powder is delivered by jet it can build up 3D curved surfaces if required.”

Dr Meiners described a new process under development at the Fraunhofer ILT, based on “multi-spot processing”. “The main advantages of this approach is that the machine we are developing uses diode lasers, there is easy upscaling in both productivity, with more spots, and possible build size, with larger machine axes, and better control of the workpiece using shielding gas flows.”

Dr Dieter Schwarze, Scientific Coordinator at SLM Solutions spoke about the material properties of nickel-based super alloys with quasi-single crystalline structures produced by selective laser melting.

He commented, "SLM’s range of selective laser melting machines can process a wide range of harder metal alloys including titanium, aluminum, cobalt-chrome, various stainless steels and Inconel.”

Dr Schwarze gave a detailed example of the production of an aircraft turbine blade using his company’s SLM 280 system, commenting, “the unique double beam technology afforded by SLM Technologies tools is suited to creating microstructures in the metal build-up that can be very advantageous in high temperature applications.”

Harald Schmid, of FIT AG, also gave a presentation on the various benefits of additive design and manufacturing, describing the 3MF Consortium, which is working towards the establishment of global standards for additive manufacturing.

”The key messages we are trying to promote are that: ADM is already implemented in many value-added areas; effective delivery of ADM requires a lot of experience (which FIT has, including 20 years of experience with the production of prototypes; and my company FIT can now offer a range of comprehensive solutions from workshop to mass-production.”

Finally, Dr Thomas Ebert MD, IQ Evolution, spoke about the special requirements needed for making metal cooling microstructures using SLM. He was especially interested in the effect that different shapes of metal particle have on the quality and resilience of the resulting products.

"Outcomes can depend on whether you start with spherical metal particles or flakes,” he told the audience. “By modifying the design of the powder itself we have been able to significantly improve the quality of the final metal product.”

About the Author

Matthew Peach is a contributing editor to optics.org.