Belgium based Aerosint invented a unique selective powder dispensing technology which enable multi-powder SLS 3D printing for more cost effective and multi-material parts. If it reaches commercialization it could result in extreme cost efficiency for higher-end, more expensive polymers, among other benefits.
The project was initiated by the Start-up studio MAKEIT in 2015. The original idea required multiple iterations and deep technical validation which took 21 months. Confident about the technical feasibility of the innovation, Aerosint was founded and a first patent was filed. In 2017, the team managed to secure funding from the Walloon Government (DGO6) and from private investors Meusinvest and the Innovation Fund. This funding was used to create a first prototype of the dispensing technology and further integrate it into an industrial polymer 3D printer for value demonstration.
Aerosint has now planned development through to the end of 2018, while providing regular updates on the timeline through its Medium blogging account.
Aerosint, has taken a fundamentally different approach to multi-material powder deposition. Instead of a complex array of actuated nozzles, the Belgian team developed a patented technology that selectively deposits powder material from a rotating drum that passes over a build area.
One drum deposits one material, so at least two drums are used to achieve multi-powder deposition. The patterning drums selectively deposit fine powder voxels line by line. The result is a powder layer composed of more than one powder ready for sintering. The dispenser makes it possible to distinguish object and support powder. By using an inert support powder (like alumina) you can eliminate powder degradation that inevitably occurs when using the same polymer as object and support powders.
As no degradation of the support powder has occurred, all of it can be reused in the next print job reducing powder consumption cost by 30% up to 85% compared to traditional laser sintering. This is particularly important for high-temperature polymers like PEEK, that are extremely expensive. Powder degradation is preventing the wider adoption of this high-performance polymer in industrial applications.
The technique is inherently line-by-line, and can pattern at rates of up to 200 mm/s. This speed is comparable to today’s SLS recoater travel speeds and over 10x faster than the upper limit of a theoretical pipette array (extrapolating from the highest reported deposition speeds for a single pipette, as described in the Medium post).
Furthermore, the Aerosint process is designed to be less sensitive to the powder characteristics than a pipette-based technique, in which powder mass flow rates must be empirically determined for each material to be used. The goal is to make the process as material-agnostic as possible, so that a broad range of polymers, ceramics, and metals with less-than-optimal powder size distribution and flowability characteristics can be used with ease.
Multi-powder SLS 3D Printers of Tomorrow
According to Aerosint, the maturation of multi-powder deposition techniques, whether pipette-based, drum-based, or otherwise, will open up a sea of opportunities for manufacturers. In addition to the benefits of powder waste reduction, material cost savings, and reduction of post-processing time, Aerosint points to several areas of opportunity on an industrial scale using a multi-powder approach:
- Waste-free printing of high performance and exotic polymer materials such as PEEK for medical, aerospace, and automotive applications
- Multi-polymer parts for graded mechanical properties, tailorable surface properties
- Direct printing of conductive metal paths within polymer parts for flexible electronics such as ‘smart’ shoe soles, fitness trackers, etc.
- Multi-metal printing for combining the properties of rare and fragile metals with those of cheap and strong metals
- Metal-ceramic co-printing for combining heat resistance and hardness of ceramic materials with the elasticity and strength of metals.
The addition of multi-powder deposition capability to existing powder bed fusion techniques promises cost efficiency and processing capability outside the realm of possibility for SLS today. The AM system manufacturer that embraces the challenging technical approach of multi-powder deposition will grasp a majority share of a new market.