Liquid Additive Manufacturing: A New Process for 3D Printing Silicone Seals and More

Seals play a vital role in many fields. Notably, seals are used to prevent or reduce the leakage or ingress of liquids, gases or solid substances such as dust. To be effective, they need to be plastic and elastically malleable, chemically resistant, resistant to temperature and aging, and wear-resistant. One material that is therefore a suitable material for seals is silicone rubber, an elastomer consisting of silicone, hydrogen, carbon and oxygen. In the injection molding process, silicone rubber is used in its liquid form, but this material could not be used for 3D printing. However, thanks to InnovativQ’s LiQ320 3D printer, which is based on the Liquid Additive Manufacturing process, this is no longer the case. With the LiQ320, it is possible for the first time to use liquid injection molding silicone for industrial 3D printing.

How does LiQ320’s Liquid Additive Manufacturing process work?

Liquid Additive Manufacturing is, as the name suggests, an additive manufacturing process for liquids and viscous materials, such as liquid silicone rubber. Like any AM process, it begins with the creation of a 3D model. For this, CAD data is converted for the programming software and the parameters are optimized. Afterwards, the final data is transferred to the LiQ320 3D printer. When the printing process starts, the LiQ320 begins volumetric material extrusion. The material consists of two components that are mixed in the printhead. Thanks to the printhead technology, precise metering and an ideal mixing ratio are possible, so that the structure buildup in the object can be controlled at the molecular level. Additionally, because of the Open Material Platform, the user is not tied to a specific manufacturer’s material.

The printhead technology enables precise metering and an ideal mixing ratio, so that the application direction and thus the crosslinking can be influenced at the molecular level. (photo credits: InnovatiQ)

Similar to the FDM process, the material is applied to the print bed layer by layer by the extruder. In contrast, the starting material is already in liquid form and does not have to be melted first. Additionally, each individual layer is cured during the printing process with the help of a high-temperature halogen lamp (approx. 2,000 watts), which thermally cross-links the material.