Precise, flexible and modular 6 dimensional additive manufacturing platform including individual in-situ analysis

• Applicants: Professor Dr. Rainer Börret; Professor Dr. Andreas Heinrich; Professor Dr. Harald Riegel
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Synthesis and Properties of Functional Materials
• Term: from 2017 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 326738811

• Final Report Year: 2025

Final Report Abstract

Additive manufacturing (3D printing) is a manufacturing process in which components are built up layer by layer from material, resulting in complex geometries without material loss. It takes place in three degrees of freedom (x, y, z): The material is positioned horizontally (x, y) and built up layer by layer in height (z). This technique enables the production of complex structures without special tools or molds and is particularly efficient for individual components and prototypes. Robot-based additive manufacturing extends this classic 3D printing by six or more degrees of freedom, allowing the print head to be moved flexibly. This enables the production of complex geometries without support structures, the manufcturing of existing components or even the combination of different materials. The optimized layer arrangement also improves the mechanical and optical properties of the components. The aim of this project was to develop a robot-based additive manufacturing platform. The core elements are two robots, with one robot carrying an inkjet print head (for the deposition of UV-curable materials) and a second robot carrying either an analysis unit (e.g. confocal sensor for layer thickness measurement) or a UV curing unit (UV DLP projection system). The decisive factor here is that additive manufacturing is to be carried out on existing 3D-shaped components. For this reason, the sample is fixed on a hexapod and can therefore also be moved with 6 degrees of freedom. For the printing process, the inkjet print head is positioned above the component with the help of the robot. During the printing process, however, the component is moved below the print head with the help of the hexapod in order to achieve higher printing accuracy. The liquid polymer is then cured using a laser system or a DLP system. In the case of the DLP system, there is the option of overlapping double exposure in order to achieve higher structural accuracy. Furthermore, analysis units can be integrated into the platform in a modular design. For example, an (infrared) camera system to visually monitor the components during production, a confocal measurement system to carry out layer thickness measurements, for example, or a laser system to check the optical properties of the components in-situ.

Publications

• 3D Printing of Optical Components. Springer Series in Optical Sciences, 2021. Springer International Publishing.
  Heinrich, Andreas (Ed.)
  
• “Directed Self-Assembly of Polystyrene Nanosphere Lithography Masks Using Additively Printed Templates”, 14th International Conference on Physics of Advanced Materials (2022)
  A. Wolff, Y. Bauckhage, A. Heinrich & J.K.N. Lindner
  
• Accuracy evaluation of a new 3D photogrammetric position measurement system for 6D Printing. Photonic Instrumentation Engineering X, 15. SPIE.
  Garcia-Barth, Luis; Bielke, Uwe & Börret, Rainer
  
• Evaluation of a 6-DOF inkjet printer for the production of microstructures on curved surfaces using UV curable resin. Eleventh European Seminar on Precision Optics Manufacturing, 8. SPIE.
  Reck, Christoph; Wilczek, Adam & Börret, Rainer