Fabrication of the Fresnel lens with liquid silicone rubber using rapid injection mold

Liquid silicone rubber (LSR) parts are used in aerospace application due to their stable properties. In order to compress time to market for a new product, it is necessary to develop an injection mold for LSR injection mold swiftly and effectively. Rapid tooling (RT) technology can reduce time to market compared to the conventional machining methods. The aluminum-filled epoxy resin mold is capable of replacing the conventional steel mold for small batch production using injection molding. In this study, an injection mold with heating element was developed using RT technology for LSR injection molding. It was found that the replication rate for the average microgroove depth and width of the Al-filled epoxy resin mold is about 90.5% and 98.9%, respectively. The transcription rate for the average microgroove depth and width of the LSR molded parts is about 91.5% and 99.2%, respectively. The variations in dimension of microgroove depth and width of the LSR molded parts can be controlled within ± 1 μm. The average surface roughness of the Al-filled epoxy resin mold was only increased by about 12.5 nm after 200 test runs of LSR injection molding.