Creating the Perfect Recipe – Why Chemistry Makes All the Difference at ACEO®

Florian Liesener tests mechanical properties in one of the labs (Photo: ACEO®; Wacker Chemie AG)

Chemistry is an essential part of 3D printing with silicones. As Materials Engineer, Dr. Florian Liesener develops silicones with manifold properties to meet the individual requirements of ACEO®‘s customers. In our interview we learn all about his passion for working with silicones and why his tasks are not so different from those of a gourmet chef.

Florian, can you tell us about your background in chemistry?

It all started with a coincidence: my chemistry teacher at school is the reason I work at ACEO® today. She was so inspiring and sparked my interest in the field, which made me sign up for chemistry at university. During my studies I focused on organic chemistry and spent six months in Cambridge for a research project. After my diploma I earned my doctorate degree in Berlin and Hannover in the field of the synthesis of biologically active materials. This way my starting point in medicinal chemistry.

How did you get from medicinal chemistry to working with silicones at ACEO®?

My career started in the pharmaceutical industry in Berlin with the synthesis of molecules for new pharmaceuticals. Your work can help to save lives, which is a great motivation to work in this field. But in the end, only a small fraction of what you do might go to market.

My current job at WACKER is the complete opposite of. When I joined the R&D department for silicone elastomers, my work suddenly had almost immediate market impact. That means all your research and testing eventually make a product come to life. Before joining the ACEO® team, I was responsible for the Product Line LSR/RTV, which was a perfect preparation for what I do today as Materials Engineer.

Can you give us some insights into how silicone elastomers are produced?

It all starts with quartz, which is transformed into silicon metal. The next step is the so-called Müller-Rochow synthesis, which turns the silicon metal into methylchlorosilanes which are then separated by distillation. One type of methylchlorosilanes , the dimethyldichlorosilane, is turned into oligomers when hydrolyzed with water. And these oligomers are the basis of all polydimethylsiloxanes (PDMS) – the main component of silicone elastomers. Only the fully cured product is referred to as silicone rubber, or as we say silicones.

As materials engineer, my task is to create silicone elastomers with the properties that meet the needs of our customers and fit our printing process. You could probably compare this part of my job with creating a recipe: advising on the perfect ingredients and the way of preparing the food in order achieve a culinary experience.

How long did it take you to develop silicones that could be 3D printed? What were the challenges or milestones in this process?

It took the R&D team no longer than two years from idea to market, which is very fast for such a complex process. ACEO® does not only provide a specific product or material but a true system solution. We developed a material with manifold properties, a software to translate the final part geometry into voxels and a printer that can handle the consistence of uncured silicone rubber.

One major milestone of this package has been the development of the printing material. We had to ensure that its flowing behavior, the so-called rheological profile, is perfectly controlled. Thus single droplets, the voxels, can be created at the nozzle and a smooth surfaces can be formed when building up the 3D sample. The perfect voxel doesn’t show any splashing effect or unevenness but forms a perfect dome. This rheological profile is important for both the silicone and the water-soluble support material that helps us build up complex 3D structures. The latter is rinsed off easily after the printing process revealing overhangs, channels, or holes.

With all these challenges that mastered before going to market, I am very proud that my colleagues who were doing the R&D work were recently awarded the “Alexander Wacker Innovation Award” for their pioneering work. 

Apart from material development, what else is on your task list?

You can compare what I do with product management: My task is to oversee the supply chain and quality management on the material side. One part is to create the material so it can be 3D printed. Once the 3D printed part leaves the printer, it needs to be checked. If needed, support material is removed and it undergoes a final post-curing process to meet the requirements and strict regulations of e.g. medical and food applications. Another exciting part of my job is that for material topics I am the technical contact person for our customers. Furthermore, it is a great honor that I can also share my knowledge with customers and the scientific community. It was only very recently that I held a speech during the Additive Manufacturing Symposium at the Technical University of Dresden.

What would you consider the most striking feature of ACEO®?

We are the first on the market with a drop-on-demand technology for 3D printing silicones. That means for the first time, a real elastomer can be 3D printed and ordered in our online shop. This technology enables product designers to think outside pre-existing technical boundaries and rigid material structures and thus paves the way for many innovations to come.

 

 

How is silicone manufactured? Watch WACKER’s video.

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