On March 29, I attended the official opening event of the Xaar 3D Centre, located on the Nottingham Science Park, in Nottingham, UK. Having been on the receiving end of a few cryptic teasers in recent months about Xaar’s 3D printing activities, I was eager to understand more about the company, which is headquartered at a 6,000 square meter (65,000sqft) facility in Cambridge, UK, and its place in the additive manufacturing (AM) and 3D printing industry.
It has been common knowledge for some time that Xaar technology—specifically its advanced digital inkjet printheads—have been critical to the development of the high speed sintering (HSS) AM process. Xaar’s commitment to and belief in the potential of this process were magnified early in 2016 when Professor Neil Hopkinson (the original inventor of HSS technology) transitioned out of academia to head up Xaar’s new 3D division.
At the time, I categorized Xaar in a similar way to Hewlett Packard (HP), Canon and Ricoh, as a company largely focused on 2D inkjet printing technology broadening its horizons by extending the axis of print. Now, I realize that was rather short-sighted. For a start, Xaar is a much younger (founded 1990) and more agile tech-focused company compared with the other 2D to 3D converts, and its business model is very different too.
Xaar does indeed design and develop highly advanced industrial digital inkjet printheads—it’s not over the top to say they are world leading. But the company is not a hardware original equipment manufacturer (OEM). Rather, the printheads the company develops are produced to meet customer-driven requirements and sold to hardware OEMs. The most straightforward strand of Xaar’s 3D business model replicates its 2D business directly, namely to develop and sell advanced printheads for additive technology platforms, specifically print and cure and print and bind processes. According to Prof. Hopkinson, this looks set to be extremely lucrative.
The press release that I received to coincide with the opening of the new 3D Centre, however, focused on Xaar’s announcement that it would be delivering ‘comprehensive high HSS technology services globally’. The immediate assumption here is that Xaar will be running a parts service, which it will. Now this is significant news in itself and a deviation from Xaar’s business model to date. The new facility in Nottingham houses the original HSS platform (affectionately named 'Little Blue') which was running during the tour. It had its own room, as did the next gen version, which was much larger but not running yet. Based on some of the cost and time figures presented for HSS compared with other powder bed AM processes—as well as some injection molding applications—these machines are going to be kept very busy.
Prof. Hopkinson revealed how Xaar has proven the HSS high-volume capabilities with some of the company’s own components, produced with HSS in large batches. The component he demonstrated was a small, complex manifold for feeding ink through an ink supply system, and he said Xaar is producing tens of thousands of these components every year. The cost analysis compared with traditional manufacturing methods were extremely favorable.
However, this is not the only service associated with HSS on offer from the Xaar 3D division. Last year, following the unfortunate demise of BluePrinter, the Danish OEM of desktop heat sintering 3D printers (for commercial reasons, not the quality of the hardware), a pool of talent from that company was subsequently employed by Xaar’s 3D division. The team in Copenhagen has particular skills developing powder bed hardware, which, married up with the advanced technology offered by Xaar, is an attractive service offering. The objective, according to Prof. Hopkinson, is to work with hardware vendors to get new machines onto the market. In parallel, there will be serious materials development out of Nottingham.
Xaar’s 3D division is multi-faceted, well thought out, and likely to be just as well executed. Doug Edwards, the company’s chief executive officer, said it’s a long-term plan too: ‘The 3D sector is an important part of our 2020 strategy and, with this new 3D Centre, some exciting growth opportunities will be available to Xaar.’
The history of the HSS process is in the public domain, but it was very useful to get the full outline from Prof. Hopkinson last week. A graphic to that effect is up on the wall at the Xaar 3D Centre.
2003 was the year it all started for HSS, in the Research Group at Loughborough University.
Milestones of the tech are closely aligned with successful funding rounds, notably from the Engineering and Physical Sciences Research Council (EPSRC) (in 2003) and Innovate UK (in 2013), the latter of which initiated the FACTUM project. Indeed, many of the FACTUM partners were in attendance, from Unilever, Cobham, the University of Sheffield, BAE Systems as well as Xaar.
Prof. Hopkinson started the project as an academic partner with the University of Sheffield and finished it as an industrial partner here at Xaar. This was obviously an important transition for him: ‘That transition, of the technology and myself, to industry was really catalysed by the Innovate UK funded work we did, and it’s created the jobs that we have here now.’
Xaar’s involvement with HSS began as early as 2004. This followed on from Prof. Hopkinson’s research, which began with the premise that ‘if you take a laser sintering machine and make it much quicker and cheaper, it would be a good thing in terms of being able to make parts at high production volumes’. The idea is simple; although the research—and the reality—not so much. One of the first issues involved asking lots of companies if their printheads could work under the extreme temperature conditions required for the HSS process. After countless knock backs, Xaar was the first company to give it a try. By 2015, Xaar had its secret weapons in place for maximizing the commercial potential of HSS—a unique printhead and Prof. Hopkinson backed up by a skilled team in Denmark.
While the Xaar printhead is a key enabler of the HSS process, there are other key differentiators from the standard laser powder bed processes commercially available. With HSS, the inkjet printheads are utilized in combination with heat-absorbing ink and an infrared heat source to form an entire layer of a part in one pass over the powder bed. This is in contrast to a laser that very quickly traces out the shape of a part layer. So, for a given part being produced with HSS, its shape is printed using heat-absorbing ink onto the top layer of the powder bed. Once complete, an infrared lamp passes over the bed and melts the powder that has absorbed the ink. Repeat.
The machine works more slowly than a laser melting machine, but overall the entire layer—and thus part—is formed much more quickly. The other thing to note is that the process is uniform across the X and Y axes, which is why large volumes of small parts can be built cost-effectively.
HSS is a powder process though, and with that there is an inevitable requirement for post-processing. During the tour, Xaar did not shy away from this, and when I queried the time involved, specifically in relation to the gains from the process itself, it seems it is similar to other powder processes and can be automated for high volumes.
The Xaar tour was geared up to demonstrate the mechanical properties of parts produced with the HSS process, which were quoted as being ‘equal to or greater than Laser Sintering’, particularly for elastomer materials. I suspect, however, that superior process performance will always come down to application selection. The big story here is definitely the volumes and the fact that HSS is now commercially available as a service.
On the materials front, I was particularly interested to learn that the effect of the HSS process on the chemistry of the materials is different to laser-based powder bed AM processes.
As you run any powdered material through any process, it ages and the chemistry changes, but Prof. Hopkinson said: ‘The HSS process doesn’t mind if the chemistry changes.’ Thus, the HSS platforms can run virgin powder as easily as waste powder (which is now unusable) from laser sintering platforms and in some cases, older powder gives better parts. For regulated parts, traceability and powder history is still of vital importance, but for chemists and engineers that want to jump on this, please talk to the Xaar engineers.
Licenses for the HSS process have already been issued to a number of companies other than Xaar, including German OEM voxeljet. Further licensing options are available for OEMs from Loughborough University, which holds the original base patents for HSS.