Munich-based WACKER CHEMIE has been developing chemicals for over a hundred years, 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 3D printing silicone.
There are companies whose pneumatic pump-based extrusion systems are capable of 3D printing silicone type materials, such as Hyrel 3D and Structur3D. Picsima also plans to release their own silicone 3D printing system, but the details about how it works are still under wraps. Other than that, silicone 3D printing has been somewhat limited and this is the first big company that has entered into the fray with a substantial machine devoted to rubbers.
According to the company, the firm’s silicone division, WACKER SILICONES, worked alongside Enders Ingenieure GmbH to develop a 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. At the moment, the machine is not as fast as the company would like, hoping to make the system process 100 grams of silicone per hour, but it is capable of creating details finer than 100 microns.
The company claims that 3D printing silicone has not been refined to the extent that their new technology has, with the head of their silicone’s division, Dr. Bernd Pachaly, saying, “Until now, it had been impossible to print elastomers – i.e. rubbery materials. There were just no suitable processes available. Injection molding is the established process for series production, and will remain so.” Pachaly continues, “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 concoted by Dr. Ernst Selbertinger, who sought to achieve a material that would stay in place as it was deposited. Dr. Selbertinger describes his silicone formula by saying, “Think toothpaste – it flows under pressure as you squeeze it from the tube, but is firm when on the brush.” The exact recipe is a secret, but he does say that he uses a platinum catalyst for allow the molecules to crosslink. On top of that, 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.” Pachaly contributes, “It is the first really user-friendly software in this field.”
WACKER sees this technology being used 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.
Pachaly elaborates, “We have a lot of ideas, and we want to provide our customers with much more than just silicone for additive manufacturing.” He continues, “It will no longer be enough to drop off drums of chemicals in front of the factory hall.”