Wacker Chemie Develops Method for Printing Silicone

Munich, Germany-based Wacker Chemie has been developing chemicals for more than a century, specializing in rubber silicones, plastics, and more.  While these products have mostly been implemented in traditional manufacturing processes, like injection molding, in their Q2 report for this year, the chemical giant announced that it had developed a method for 3-D printing silicone.

There are companies whose pneumatic pump-based extrusion systems are capable of 3-D printing silicone type materials, such as Hyrel 3D and Structur3D. Picsima also plans to release its own silicone 3-D printing system, but the details about its mechanics are still under wraps. Other than that, silicone 3-D printing has been somewhat limited; Wacker Chemie is the first large company that has entered the space with a substantial machine devoted to manufacturing rubbers.

According to the company, the firm’s silicone division, Wacker Silicones, worked alongside Enders Ingenieure GmbH to develop a ultraviolet (UV) printing process that deposits transparent silicone in drop form before curing it with UV light, “crosslinking the molecules into an elastomeric material.” The machine then deposits the next layer of droplets. The machine currently is not as fast as the company would like — capable of processing 100 grams of silicone per hour — but it can create details finer than 100 microns.

Company executives claim 3-D printing silicone has not been refined as much as Wacker Chemie’s new technology. “Until now, it had been impossible to print elastomers – i.e. rubbery materials. There were just no suitable processes available,” noted Dr. Bernd Pachaly, head of the company’s silicone division. “Injection molding is the established process for series production, and will remain so. But people who design prototypes or only want to make a few copies of a part can now very rapidly and flexibly modify such small series to meet changing demands. That is the unique advantage of the process.”

The material itself was developed by Dr. Ernst Selbertinger, who sought to achieve a material that would stay in place as it was deposited. “Think toothpaste – it flows under pressure as you squeeze it from the tube, but is firm when on the brush,” he said. While the rest of the recipe is secret, Selbertinger admits to using a platinum catalyst for allow the molecules to crosslink. In addition, the team had to create a custom software to power the machine.
Florian Ganz, CEO of enders explains, “

“A key step in the development work was to write a custom program,” Wacker Chemie CEO Florian Ganz said.

“It is the first really user-friendly software in this field,” Pachaly explained.

Wacker executives hope to use the silicone printing technology in the medical field to create custom implants for patients (live) during an operation. Potential devices include custom respirator masks and hearing aids, as well as personally-tailored nose pads. Because of silicone’s heat resistance, it might also be implemented to create baking molds.  And its transparency would lend it a number optical applications, including custom lenses.

“We have a lot of ideas, and we want to provide our customers with much more than just silicone for additive manufacturing.” Pachaly said. “It will no longer be enough to drop off drums of chemicals in front of the factory hall.”