Wayland Additive offers new way for metal PBF AM

A view of the NeuBeam® process. (Courtesy: Wayland Additive)

Wayland Additive has been working on the development of an entirely new powder bed fusion (PBF) process for metal AM that minimizes the existing limitations current users have to work around. When considering the existing two PBF technologies — laser PBF and traditional eBeam PBF — NeuBeam offers a new way, a third way.

PBF is arguably the most widely adopted AM process for structural production applications. To date there has been a clear two-way choice with PBF — users having the option to use laser-based PBF systems or eBeam PBF technology.

One trade-off between the two technologies comes down to precision versus speed. While laser PBF has traditionally held the advantage in terms of fidelity and surface finish (due to the precise nature of the laser(s)), eBeam PBF gains significant advantage in terms of speed and productivity as a result of the more efficient way that electrons transmit energy to the powder bed, and through-thickness heating of the entire layer. In addition, eBeam can process multiple meltpools simultaneously, further contributing to increased productivity.

Will Richardson, co-founder and CEO at Wayland Additive, said, “It is no secret that existing laser and eBeam PBF systems come with limitations, some of them prohibitive. With laser PBF, the internal residual stresses that the process generates requires extensive structural supports to prevent the parts distorting or cracking during the print process. Sometimes these supports require as much material to manufacture as the parts themselves. Removing them post-build typically requires the use of wire EDM and machining operations, which are expensive and time-consuming. The parts typically also require stress-relieving in a furnace post-build – another operation, more cost, and another piece of equipment to maintain and run.”

Peter Hansford, business development director at Wayland, said, “The traditional eBeam PBF process faces its own challenges and constraints, most notably the instability of the process caused by charge accumulation within the build chamber. This can result in powder scattering or a so-called ‘smoke event’ that distorts the current layer of the build and therefore compromises the entire build. To avoid this, the process has to be operated in a very specific way, and has a steep learning curve. Particularly, it is critical to maintain the temperature of the powder bed between strict limits, which is required to cause the powder bed to sinter so that it isn’t disturbed by powder charging. This unreliability means that eBeam PBF has typically been considered less favorable than laser-based PBF.

“These compromises severely limit the materials that can be used with eBeam PBF, as well as the geometrical forms that can be produced and ultimately the applications that it can be used for successfully.”

The end part – an impeller – directly off the NeuBeam® system with no post-processing.
(Courtesy: Wayland Additive)

This is why Wayland Additive developed NeuBeam®, providing an entirely new PBF process that is ground-breaking and offers the best of both laser and eBeam PBF.

The NeuBeam process is an eBeam PBF process that neutralizes the charge accumulation generated by the electron beam.

“This offers greater flexibility than laser PBF while overcoming the stability issues of eBeam PBF. What is more, both of these things mean that the NeuBeam process enables metallurgical requirements to be tailored to application requirements rather to maintain the print process within the narrow bounds permitted by the process. These process capabilities, along with the greatly improved ease of process development, also opens up the use of a much wider range of metal materials,” Richardson said.

Despite a couple of commonalities between EBM and NeuBeam — namely that they are both PBF processes and they use an electron beam as the heat source to melt the metal powder — it is important to understand that EBM and NeuBeam are fundamentally different. Richardson said, “Unlike the traditional eBeam PBF process, the charging issues that make EBM so unstable have been fully neutralized with NeuBeam using core physics principles developed in the demanding semi-conductor industry. Moreover, NeuBeam is a hot part process rather than a hot bed process. This efficiently creates parts that are free of residual stresses because the high temperatures are only applied to the part and not the bed, ensuring free-flowing powder post-build (no sinter cake) and stress-free parts with reduced energy consumption.”

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