3-D Printing with Silicones
Wacker Chemie AG, the Munich-based chemical group, has developed a method that also allows silicone articles to be produced by 3-D printing.
3-D printing is used by companies, product developers and designers to manufacture spare parts, prototypes and much more. But the range of materials is limited. So far, it has only been possible to print plastics and metals. Wacker has developed a method to print also with silicones. A robot deposits tiny droplets from a nozzle side by side, to build up the article layer by layer. Then the silicone is vulcanized with UV light.
It all takes place in a glass case containing the workspace and a robot. The machine is equipped with a nozzle, which rapidly deposits one droplet of silicone at a time on a base surface. The robot regularly pauses and a UV beam scans over the tiny drops, which have merged into a fine line. The silicone then vulcanizes in less than a second in the UV light, crosslinking the molecules into an elastomeric material. The robot then applies the next layer of silicone droplets.
The homogeneous objects that are produced have virtually smooth surfaces. The material is biocompatible, heat resistant and transparent – opening up new industrial applications in automotive manufacturing, medical technology, household appliances, and optics. Since the structures generated by the robot are extremely fine, the precision is impressive. The silicone strip is about 0.6 mm wide, and only half as thick. That makes it possible to produce extremely precise contours and results in a surface that is almost smooth and is pleasant to the touch.
“Until now, it had been impossible to print elastomers – i.e. rubbery materials. There were just no suitable processes available,” explains Dr. Bernd Pachaly, head of silicones research at Wacker Silicones. Silicone parts could only be produced by expensive injectionmolding processes. Because of the costs for custom-making the molds, the process is only worthwhile for large production runs – not for small series. With the new technology, silicone joins the ranks of materials such as thermoplastics, metals and ceramics.
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