Optical lenses are found in countless products – from cell phone cameras to room and automotive lighting, endoscopes and display technologies. The function and design of optical products are constantly being developed to meet market requirements. Since product design is subject to ever shorter development cycles, it is necessary to design new process technologies for optical plastic production. When plastic optics are developed, several designs with different shape and position tolerances often have to be tested, each of which requires the construction of a complete injection mold. As soon as an optical system consists of five or more lenses, it becomes clear how much manufacturing effort is involved in the production of injection molds alone. Interchangeable tools offer a clear alternative; here, only the optical mold insert has to be replaced and not the complete tool. Researchers at Fraunhofer IPT are developing such a quick-change tool together with partners from industry and research in the "FINTOOP" project.
Conventional interchangeable tools meet the requirements for geometries with coarser tolerances. Up to now, these tools have not been able to reproduce the high accuracies required by high-performance micro-optics. In the "FINTOOP" project, the project consortium is optimizing the centering technology used to align the optically relevant surfaces of the mold insert and the master tool more precisely than before. With this technology, precision parts with tolerances of just a few micrometers can be manufactured. In order to determine the optimum centering parameters, the researchers are testing and validating the accuracy, service life and flexibility of various centering concepts. The consortium is designing a demonstrator tool for the centering design with the best results.
The new quick-change concept enables optics developers to save time and money by shortening machine set-up times. This means that optical multi-lens systems, such as lenses – usually only produced in small quantities – can be manufactured more cost-effectively than before. Another aim of the project consortium is to make the master mold system so flexible that not only prototypes or small batches can be produced: If a large part of the machinery can be equipped with the master mold, different products can also be manufactured simply by exchanging the shaping inserts. The interchangeable inserts can be exchanged directly on the injection molding machine without the need for a crane system to lift the entire mold out of the machine. At the end of the development process, the result is a high-precision mold that can be retooled directly in the machine in less than 30 minutes.
Project coordination: South Westphalia University of Applied Sciences
Project partner:
The "FINTOOP" research project is funded by the Federal Ministry for Economic Affairs and Climate Protection (BMWK) as part of the Central Innovation Programme for small and medium-sized enterprises (SMEs).
Funding reference: 16KN100539