Engel has introduced new injection molding technology specifically aimed at the production of optical components, offering machines with plasticizing unit components optimized for running transparent polymers and an overmolding process to create thick lenses. Called optimelt, the process starts with the production of a pre-molded part that is recoated with additional layers (usually of the same material) in one or more subsequent stages.
Engel pursued the technology at a time when it says more and more high quality optical components are switching from glass to polymers, propelled by greater cost efficiencies and more flexibility in product design. "The challenge now is to strike the right balance between superior optical quality and high cost effectiveness," Engel noted in a release.
Utilizing injection molded plastics does pose its own challenges, however, including microstructures on the surface of light-guide elements that must be precisely molded across the entire flow path, and the need to minimize residual stress in molded parts, especially where a subsequent coating will be applied. Finally, the optically effective surfaces on lenses with large differences in thickness must be accurately contoured....