Electromagnetic embossing of optical microstructures

• Applicants: Professor Dr.-Ing. Ekkard Brinksmeier; Professor Dr.-Ing. Bernd Kuhfuß
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2018 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 395821503

Electromagnetic embossing is a promising high speed process for the mass reproduction of functional and optical microstructures. For embossing of foils it offers different advantages such as a contactless working volume force and the omission of lubricants like rolling oil. Especially for embossing of microstructures the increased plasticity is beneficial due to an increased replication precision. As the influence of process mechanisms and interactions of physical effects on the material behavior is still partially unknown, a process control of the electromagnetic embossing of optical microstructures is currently not possible. This joint research project of the institutes bime and LFM will therefore focus on the replication of large-area functional and optical microstructures via electromagnetic embossing, with the aim of obtaining a substantiated knowledge of the underlying process mechanics. In this context, the material flow with respect to the process parameters is experimentally investigated and a set of parameter dependent flow curves is determined. A simulation model is set up to visualize the physical effects that influence the material flow and to correlate the flow curves to main mechanisms and its interactions. Furthermore, the occurrence of both electro-magnetic and mechanical loads requires a customized embossing tool. Thus, different manufacturing strategies comprising selected base materials and coatings will be developed and investigated. The influence of varying loads on the embossing quality of different structure types and surfaces will be determined experimentally. This includes the behavior of the microstructures under high impact load. Besides the achievable surface quality, the contour deviations of the tools and the embossed microstructures will be analyzed. A strategy for the tool design will be the outcome of these findings. Based on the overall achievements an application-oriented model and a method for a systematical process layout will be set up and verified against exemplary embossing experiments.

• DFG Programme: Research Grants