"You have to ask yourself why 3D printing isn't already being used more ".

Prof. Jürgen Stampfl is teaching at the Vienna University of Technology (TU Wien) where most of the successful companies emerged from.

Mr. Stampfl, a dissertation was recently presented at your institute in which a 3D printable substitute for ivory was developed. The goal was to produce inlays for a historical chest of drawers. Is your work always this colourful?

Yes, actually it is. We get a lot of extraordinary requests and are now trying to filter out the most promising applications but special projects like this have to be funded first, and people usually underestimate that. Printing ivory was a remarkable, creative and also costly project we realized together with the Archdiocese of Vienna. The material not only looks beautiful but is also very special concerning haptics. It is likely that now a company will arise from this project.

It would not be the first time. Your Institute for Materials Science and Technology at the Vienna University of Technology has produced six printer manufacturers in recent years. What are you currently researching?

Our latest research field is Design for Disassembly. To explain quickly, it's about things that decompose on command to make recycling of complex assemblies easier.

About "Design for Disassembly"

What is the context with 3D printing and Design for Disassembly?

That's what we're trying to figure out right now. The basic sustainability idea is to assemble things in such a way that disassembly can be done without much effort. We already know „Debonding on Demand“ from the dentistry, where, for example, adhesives can be dissolved again by a change in temperature. We want to transfer such functions to other industrial sectors, but we are still at the very beginning.

In terms of design, the possibilities of 3D printing will certainly play a major role, including offering a software capable of producing complex geometries and multi-material structures.

The precise application still seems to be a bit visionary...

In fact, we are at the very beginning of the development process of the application. Our main field, at the moment, is definitely biomedicine, especially in dental technology. In the dental field, regulatory requirements are high but not as strict as in other medical fields, so things developed rapidly here. You can get a dental prosthesis more easily approved than a new organ. In the longer term, of course, tissue fabrication and eventually 3D printed organs are our big prospect.

From first steps in additive manufacturing to developing materials and technologies in 3D printing

Can you remember when you first got involved with additive manufacturing?

As a doctoral student at the Montanuni in Leoben, I had to analyse fractured surfaces. At the time, this was done with a Zeiss Stereo Comparator that felt like it came from the Second World War. That was tedious and I thought I would never be able to cope with it. We then started developing a software for automated evaluation of stereo images, together with a team at TU Graz. That's when we got into the 3D topic. Later, I applied at Stanford University in the USA as a postdoc in the field of 3D printing of ceramics. All that was about 25 years ago, and since then I work on this subject.

When you talk about sustainability, as with the idea of Design for Disassembly, you can't avoid the question of the resin itself. Liquid polymers are actually an unpleasant material over their entire life cycle. They are toxic at the beginning and hardly recyclable at the end. Do you see a change about that?

For recycling of polymers, we have three major routes: Chemical and mechanical recycling, and additionally incineration. Basically, the resins would be very good for chemical recycling because you have a lot of latitude in material design.

Toxicity, by the way, was also the reason we came up with hot lithography for Cubicure. If you want to process resin at room temperature, it has to be chemically very reactive and is toxic. But if you design it so that it can only be processed hot, you largely solve this problem.

And that was the whole starting idea for hot lithography?

We always had to deal with very viscous materials that do not work in conventional stereolithography. There was then the quite simple approach of heating up the material. The idea is obviously simple, this could have been done 30 years earlier. But nobody did it anyway, because they obviously didn't see the material science aspect of this approach. And because the idea is so simple, other groups tend to ignore the fact that we started with it.

Future applications in 3D printing

We keep hearing that manufacturers make more money with the resin than with the printers. Many seem to be dreaming of the Nespresso model. Is that the future?

It certainly depends on the application - in the hobbyist sector, perhaps, but I don't think the really big customers want to have this model imposed on them.

Right now, the biggest markets for polymer 3D printing seem to be shoe soles, dentistry and connectors. Where do you see the next big volume applications?

I think in electronics, where traditional manufacturing technology is reaching its limits as parts get smaller and smaller. This could turn out to be very interesting. Especially with small parts, AM can already now provide the throughput of injection moulding, considering the large build areas available today. In fact, you have to ask yourself why 3D printing isn't already being used more, because designers also have a much more convenient way of working. Just think of injection moulding - they design something and then perhaps realize months later that they were wrong and that the parts cannot be produced at all. Designers, in my opinion, haven't fully understood how 3D printing can make their lives easier.

In polymer 3D printing, it's often a matter of deciding between laser, DLP or even LCD. Which technology will win the race?

It's hard to say, both the laser and DLP (Digital Light Processing) printing sides are still making a lot of progress. I think there will be an even race there for a long time. LCD is out of the race in my opinion, there is just too much dark field intensity here in comparison to DLP and laser.

The market seems to be divided into two segments: on the one hand, extremely low-cost devices for the end consumer and high-end devices for industrial applications. Which segment is more innovative?

Certainly from industrial applications, but innovation also comes to some extent from the hobbyist scene, where good results can be achieved even with small devices, and in some areas is already further along than the professionals. 3D printing, in my view, is the ideal technology to attract young people, and make them interested in pursuing a career in digital and mechanical engineering.

Innovations and Companies made in Austria

Six successful 3D printer manufacturers have emerged from your institute - Lithoz, Cubicure, UpNano, Incus, Way2P and Genera - plus a large number of other companies, as you can see on the Additive Manufacturing Austria website https://www.am-austria.com/.
Why is it that Austria has obviously done many things right with this technology - apart from the lack of venture capital?

When one starts, everyone wants to play. The companies are actually all doing well, and a key aspect of this is the management talent of our alumni. Although I must admit, that they certainly didn't learn management from me (laughs).

A good advice from Prof. Stampfl for building a successful startup

What does it take to create something like that?

Unfortunately, I don't know a secret formula for that. I think management is crucial. The danger with scientists is always that one idea follows the next and the focus on implementation is lacking. You have to stick to it and not be too erratic. That seems to have worked quite well. And it has to be said that the companies all made sales and profits right from the start. It's very helpful if you have customer contacts right from the start instead of spending five years for development, risking that customers finally do not accept your product.

Finally, what research result has impressed you most recently as a scientist?

Well, the rapid development of the Covid vaccines was a sensational thing. The mRNA vaccines were a gigantic scientific achievement, and also a bit of a European success story.