Selective Laser Sintering is also called powder bed fusion and SLS. The SLS process sees a bed of polymer powder selectively sintered by a laser. A new layer is applied and this is then also hardened with unsintered powder acting as a support. Dominated by EOS Gmbh, SLS is probably the most high volume, high throughput 3D printing technology for high volume manufacturing of relatively small polymer parts in the medical field. Print speeds and time to part are rather long but if you want to print ten thousand of something in a predictable way every day then SLS is a very good bet. Mainly working in PA 12 (polyamide, nylon), highly productive SLS systems have conquered markets such as surgical guides and are widely used in prototyping. SLS is a great technology since it produces parts with good mechanical qualities and high levels of detail. SLS is also a cost effective technology since part post processing is predictable and the process is relatively high volume. SLS is the easiest technology to do costings in and is predictable as well in a production scenario.

SLS: zeit for Gründlichkeit? 

SLS is not perfect, however. FDM gets you parts faster while SLA parts are smoother. The porous surface texture of SLS is annoying, often limiting its areas of application. The systems use powder and this means increased care has to be taken with handling. Some SLS powders may prove long term respiratory risks or may even penetrate blood brain barriers. Lasers are much more dangerous than the heating systems on FDM printers.  Also fire is a real risk with SLS but is difficult to achieve with FDM. High powered lasers and inert gas systems mean that it is a high cost, high complexity technology to set up. Once you’ve done that and mastered it, however, it is probably the most versatile 3D printing technology for end use parts and a highly productive one at that.

A current SLS machine is about the size of a Coke machine. It costs about $150,000 and maybe twice as much if you get all the cool stuff needed to recycle powder and clean parts. It’s meant for production environments with HVAC and the like. Below you can see what an industrial SLS setup would look like. 

The EOS setup above is integrated into existing ERP software, connected to PLM and has monitoring throughout the system. Powder handing, cooling, unpacking and sieving, and post processing are important steps that have to be managed in addition to the printing itself. This kind of setup is meant for manufacturing or service bureaus. With it EOS and SLS competitor 3D Systems wish to penetrate markets for manufacturing medical devices, car parts as well as prototypes. What if there was another way, though?

The Innovator’s Dilemma

Blueprinter led the way in coming up with a cheaper alternative to SLS. Elegantly engineering themselves around existing SLS patents, the company came up with a low cost machine. Initially standalone, the Blueprinter M3 cost $13,000, a factor ten times cheaper than existing machines. Output was not as good and missed a lot of detail. But this was the classic Innovator’s Dilemma, right? An original innovative company develops a technology. A few years later this technology gets copied by newer entrants. These newer entrants develop a less expensive alternative. Initially not seen as a threat because it is not as good, the newer entrants do have cost advantages however. The newer products become popular in low value applications. By harnessing low cost and volume the newer entrants grow and then become increasingly more sophisticated. Eventually the newer entrants outperform the innovative companies and surpass them. The Innovator’s Dilemma is not only one of the most popular management books, it is in and of itself so established that it is almost seen as a truism. In 3D printing the ideas behind the Innovator’s Dilemma are so well established that they are almost becoming a self fulfilling prophecy.

The Killing Fields 

New entrants automatically assume that they will move up in value over time. No one in our industry wants to be in a “race to the bottom.” Every early innovator is taking a worried look over their shoulder for new entrants. If everyone in a market believes in the Innovator’s Dilemma Thesis then everyone will act accordingly. If everyone acts accordingly then we actually have a big chance that this will become a self fulfilling prophecy. At the same time what we see now is also a logical consequence of this. Established companies such as EOS, 3D Systems and Stratasys are redoubling their efforts to engage with high value manufacturing applications in medical and aerospace. These companies are seeing the most difficult high tolerance applications in 3D printing. Their hope? To find regulatory and technological barriers to insulate them from hyper Darwinian competition. Third generation 3D printing companies such as Ultimaker are also following this trend by becoming more reliable and aiming for manufacturing and the enterprise. Indeed the Ultimaker 3 is $1,000 more expensive than the Ultimaker 2. Going up in 3D printing is not a problem – if you perform. Meanwhile it seems like the exploding lineup of $1,000 to $15,000 3D printers will be where we will see the heftiest competition. Overcrowded and without any defining features of merits, most market entrants in this area are doomed. This price point will be the killing fields of 3D printing. At the bottom end of the market XYZprinting and Printrbot seem to be strong contenders while new alphabet soup $150 to $600 China 3D printers emerge daily.

Blueprinter 

Come to think of it, the Blueprinter did always look a bit like a coffin. And not in a good Dieter Rams kind of way.

So what does this mean for the SLS market itself? Will new SLS vendors move up in the space? We’re used to the 3D printing hype but we do forget when the dream does falter. Blueprinter was a credible device. While the part quality and surface quality wasn’t perfect, it did show a lot of promise. The Blueprinters themselves were introduced in 2010 and caused quite some buzz. The team was solid and the print quality improved remarkably over the years. The company was making inroads in the market and then…went bankrupt in 2015. Whereas it’s easy to create an FDM printer, creating an SLS printer is very costly and much much more difficult. So it will be much tougher going for low cost SLS competitors.

Open SLS 

Boom says the printer.

Open SLS is the result of a project at the Rice University Miller Lab by Ian Kinstlinger to essentially turn a Shopbot laser cutter into an open source SLS 3D printer. A shiver of dread went up my spine when I first heard this. I’m serious, the idea of people making FDM machines at home fills me with joy. I’m terrified, however, of the prospect of people making SLS machines at home. The increased risks to human health and the risks of explosions and fires really worry me. Open SLS did make an impact when launched but so far contributions and builds have been slow to get off the mark. The increased part costs and increased risk seem to have deterred many from doing this.

Norge Systems 

Norge first really freaked me out when I saw their machines; they were cheap and I worried that they’d blow up. Their Ice 1 and Ice 9 systems were on Kickstarter and in development for a number of years. The company however did not have enough money to complete the development by themselves. Norge was acquired by Prodways and their 3D printer was made more industrial and expensive (and less explody looking). While FDM printer companies can crawl along a bit with little revenue, SLS companies need significant resources to develop their machines. Even at $13,000 and $39,000 the Norge printers did not find enough buyers to move them towards maturity.

Sinterit

The Sinterit machine and tools.

Polish company Sinterit presented a complete package around their Lisa 3D printer including powder handling and recycling. This made their system seem much more well thought out and mature. The $13,000 price point was still very low, however, and a recent significant price drop means that the printer is now available for €4,990, which is insanely cheap. One thing that does speak in this company’s favor is that they’ve gotten a €1m investment from FIT AG. FIT is one of the world’s largest SLS machine operators and has a deep experience with SLS. FIT was the company that incubated and later sold Netfabb and also for years has been exploring developing Sintermask. Their SLS expertise should give Sinterit a lot of support.

Sharebot 

Sharebot is an innovative Italian company that makes a huge variety of 3D printers. The company also came out with the Sharebot Snowwhite with a 14 watt laser. The system is capable of printing TPU, PA, Alumide and other materials. One the one hand it does feel terrifyingly maker-ish but it does have a comforting industrial type kill switch. The Snowwhite is an interesting platform for researchers and other companies attempting to build on top of an inexpensive 3D printing platform.

Sintratec

Sintratec is a Swiss company that is offering a $5,000 kit SLS machine. The diode laser based system prints in PA powder and was launched in June. Sintratec doesn’t have much of a track record at the moment but the system itself seems promising.

Formlabs 

Formlabs is a well capitalized innovative company that has led the way in desktop stereolithography. Their well made Form 2 3D printers are easy to use with the software, materials and printer optimized to work together. Formlabs’ own ecosystem approach differs from most FDM 3D printer startups who focus just on the machine and leave the software and materials to others. Less open, this more controlled approach does give reliable results. The company now is undertaking a huge challenge and this is to take their engineering prowess and deploy it to enable desktop laser sintering. Their $13,000 Fuse 1 3D printer could really define desktop SLS just like their SLA machines have made desktop SLA. SLS is much harder than SLA to implement, however, so the team could still have a tough time making it happen.

Conclusion 

It seems that there is a lot going on with desktop SLS. The stories of Norge and Blueprinter do tell us however that implementing and commercializing desktop SLS is not easy. The technological and safety challenges are significantly more difficult than with SLA and FDM. This does imply that there may be more barriers to entry for companies after these. None of the desktop SLS companies have so far been able to prove that they’re here to stay or have found a viable market. Meanwhile the SLS industrial market continues to grow very quickly and may be set to double again next year. It seems that for now the industrial players have little to fear from desktop SLS. Most companies that are choosing SLS machines are buying quality and reliability; they care little about price. Part cost is important but the initial investment is not really, considering that they want a technology to always work. For the near term it would seem that these markets are very different indeed. SLS desktop machines may however cut off the path of desktop FDM companies wishing to make more industrial systems however. Desktop SLS will become very competitive and if they manage to make safe desktop SLS machines that don’t explode very often and where powder handling is easy, then this segment is sure to grow quickly.

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