Fast fabrication of microfeatured plastic diffusers using IR-Assisted injection molding

Injection molding has been one of the most important polymer processing methods for the manufacturing of plastic parts. This article discusses an innovative and effective infrared assisted injection molding process, which enables the rapid fabrication of surface-relief plastic diffusers. A mold insert bearing microfeatures is fabricated using a tungsten carbide turning machine. An infrared radiation system, which consists of four 1,000 W halogen infrared lamps and a semi-spherical reflective cover, is employed to provide additional heating for the mold surface that bears microfeatures. Before each molding cycle, the infrared energy is converted into heat at the master mold/plastic plate interface to increase the cavity surface temperature and to facilitate the replication of the microfeatures. After molding, the properties of the fabricated diffusers are verified with an optical microscope, scanning electronic microscope, surface profiler, and hazemeter. The results suggest that with a minimal heating of five seconds, high-performance plastic diffusers may be successfully fabricated. The experimental results in this study suggest that the infrared assisted injection molding can provide an effective way to fabricate high-performance plastic diffusers with a high throughput.