Media for Dimensional Stabilization of Rubber Compounds during Additive Manufacturing and Vulcanization

Abstract

The current article proposes a concept for the additive manufacturing of rubber components using extrusion-based 3D printing, in which an additional medium is added to ensure the maintenance of shape within the elastomeric structure during the additive manufacturing process and in the subsequent vulcanization process. Specific requirements for the dimensional stabilization of the media were defined and suitable media were derived. Silicone rubber, molding sand, and plaster were examined in experimental vulcanization tests for their suitability as possible media with regard to shape retention. Selected rubber geometries made of NBR were embedded in these media to undergo the vulcanization process. The results show a significant influence of the media on the heating times. All media were able to ensure that the rubber geometries maintained their shape during vulcanization. Nevertheless, some side effects were found. The silicone rubber did not cure properly around the rubber sample. Therefore, it was difficult to remove it from the rubber after vulcanization. The molding sand caused an increased surface roughness on the rubber. Plaster changed the glossy surfaces at the beginning to a matte one after vulcanization and residuals were difficult to remove. However, all media can serve as stabilization media with specific changes.

From Formulation to Application: Effects of Plasticizer on the Printability of Fluoro Elastomer Compounds and Additive Manufacturing of Specialized Seals

“…To prevent the post-print deformation of the printed adapter seal and eliminate the pinholes, thermoplastic support structures and a larger nozzle matching the crosssectional diameter of the seal were employed. Drossel et al [40] previously reported the use of silicone rubber, molding sand, and plaster as media for dimensional stabilization of 3D-printed parts from rubber compounds. However, in their work, the printed rubber geometry is fully embedded in the media.…”

Tailoring the Curing Kinetics of NBR-Based Rubber Compounds for Additive Manufacturing of Rod Seals

“…For a long time, additive manufacturing of materials with elastomeric properties was limited to silicone rubbers and block copolymers with rubber-elastic properties, also known as thermoplastic elastomers (TPEs) [1,2]. More recently, our preliminary work [3][4][5][6] and the research results of Drossel et al [7,8] have shown that carbon black-filled rubber-based elastomers can also be processed additively, which makes this technology interesting for the production of prototypes, spare parts, and highly individualized products [9]. In addition to the high viscosity of rubber compounds (especially during processing) compared to that of thermoplastic materials, the two-step production process makes the additive manufacturing of rubber components particularly challenging.…”

Additive Technologies in the Production of Vehicle Rubber with Sensory Properties

“…The enclosing material also serves to stabilize the shape during the vulcanization process. As additional material for dimensional stabilization of the rubber shape there are investigations with thermoplastic material [3,4] as well as molding sand, silicone rubber and plaster [5]. However, the above approaches are still subject of research and are not mature processes.…”