Optical Liquid Silicone Rubber: A New Fixture in Molding

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Proto Labs offers many manufacturing processes and materials for prototype and production parts. But one process has a material that separates itself from the rest, optical liquid silicone rubber (OLSR). OLSR is an advanced material that has many properties that make it a preferred material choice over polycarbonate (PC) and acrylic (PMMA) for lighting and optical parts. Here are a few of the benefits that OLSR offers:

prototype lenses molded in liquid silicone rubber

Prototype lenses molded in liquid silicone rubber.

Light Transmission
Light transmission is lost as light passes through a material. PC, PMMA, and even glass will have light loss with glass retaining up to 95 percent, PMMA around 93 percent, and PC between 88 to 90 percent. When your product requires a clear PC or PMMA part, you can improve on light transmission using OLSR, which retains up to 94 percent light transmission.

How about the refractive index? OLSR has a low refractive index of 1.42 when compared to PC and PMMA, which are at 1.58 and 1.49 respectively.

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Still another advantage is the non-yellowing factor. Thermoplastics without additives are not UV resistant, which means the parts could yellow and degrade over long exposures to lights and sunlight. OLSR is non-yellowing so it’s great for outdoor fixtures exposed to harsh environments.

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