Where traditional manufacturing still holds a candle to AM is the possibility to produce multi-material parts through techniques such as over-molding, welding, or simple joining. The use of more than one material allows optimizing the functionality of devices.
1) Powder bed based multi-metal 3D printers are commercially available
The feasibility of multi-metal AM parts produced by laser powder bed fusion (L-PBF) has been demonstrated over a decade ago in academia. Ever since different groups have been working relentlessly on developing both the science between multi-metal processing and methods to generate the powder bed with multiple materials needed in this approach. The reputable German research center Fraunhofer IGCV has made it one of its core competencies by working on various multi-metal-related projects in the last decade.
These efforts did not limit themselves to academia. In 2020 the first functional multi-metal part was showcased by Aerosint and Aconity3D. These 2 companies worked together to incorporate Aerosint’s proprietary selective powder deposition recoater into the Aconity3D MIDI+ LPBF printer. This machine equipped with Aerosint’s recoater is commercially available today.
Recently SLM solutions have also announced a multi-metal module for their popular SLM 280 and 125 platforms. There is, however, very little information on the technical approach SLM implemented to print multi-material.
2) Commercial powders can be used in multi-metal AM
One of the largest roadblocks towards the adoption of new technology is the need to use proprietary consumables. This not only drives up cost but also makes the early adopters dependant on the technology providers.
However, powder-based metal AM has always been relatively open as it is nearly impossible to control the powder used in machines.
The selective powder deposition technology from Aerosint has been developed to work with commercially available powder.
3) Multi-metal is not limited to Laser Powder Bed Fusion
Binder jetting is the new challenger in the metal AM world. This technology is based on generating parts by selectively gluing powder together into predetermined shapes, and converting these “green parts” into functional structures using traditional powder metallurgy (PM) sintering technologies. Because of this approach the binder jetting technology has the potential of using the complete material range as developed over more than a century in PM.
Some multi-material approaches, like the one developed by Aerosint, can be used in combination to any powder bed process. This means the approach can in theory be directly applied to binder jetting as well although it has not been demonstrated yet by Aerosint.
4) The Powder Metallurgy based sintering approach is already proven
In order to investigate whether sintering would be a feasible approach to combine multiple metals, Aerosint has worked with leading Research institutes to validate the dual metal sintering principle. In 2020 Aerosint published their first results from this effort at EuroPm2020.
As we speak several academic groups are investigating the sintering mechanisms and working towards the validation of different material combinations. These don’t limit themselves to multi-metal combinations but also include metal-ceramic composites.
5) Applications are only limited by your imagination
The range of applications for multi-material 3D printing is very wide. In the end, most of the objects we use every day are made of more than one material. Having the possibility to put the functionalities in your parts exactly where you need them could be game-changing!
The materials experts at Aerosint have shared several ideas as to how the multi-material AM technology could be used. These range from simple applications, such as optimizing the thermal behavior or corrosion resistance of parts, to more out-of-the-box concepts such as near net shape HIP and soluble supports in metal AM.