Univ. Prof. Dr. Ing.

Bergs, Thomas

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Now showing 1 - 10 of 32
  • Publication
    Compensation of structure distortion in nonisothermalhot forming of laser structured thin glass
    ( 2024-06-12)
    Kohse, Martin orcid-logo
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    Meiners, Constantin
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    Plakhotnik, Denys
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    Vogel, Paul-Alexander
    ;
    Day, Robin
    ;
    Grunwald, Tim
    ;
    Bergs, Thomas
    The modern automotive industry employs various complex shaped glass components. Around 50% of these components are currently functionalized using environmentally and economically unfriendly etching or replication processes. We present a new approach of direct laser structuring on glass, which reduces costs and energy by up to 60% and avoids harmful chemicals, offering a more sustainable alternative to conventional processes.
  • Publication
    Precision Glass Molding of Fused Silica Optics
    ( 2024-05-28)
    Karimova, Albina
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    Vu, Anh Tuan orcid-logo
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    Grunwald, Tim
    ;
    Bergs, Thomas
    Fused silica glass products have exceptional properties that make them ideal for optical components in cutting-edge technologies. The traditional manufacturing process has limitations in scalability and cost. Glass molding offers a sustainable solution for series production of optical components. However, the transferability of glass molding to mass production is challenging due to high forming temperatures. This research focuses on enabling a high temperature molding process for fused silica optics through material screening, numerical simulation, and real experiments. The findings contribute to the development of a high temperature molding process for mass production.
  • Publication
    Surrogate Modeling for Multi-Objective Optimization in the High-Precision Production of LiDAR Glass Optics
    ( 2024-04-26)
    Vu, Anh Tuan orcid-logo
    ;
    Paria, Hamidreza
    ;
    Grunwald, Tim
    ;
    Bergs, Thomas
    This study addresses the ever-increasing demands on glass optics for LiDAR systems in autonomous vehicles, highlighting the pivotal role of the recently developed Nonisothermal Glass Molding (NGM) in enabling the mass production of complex and precise glass optics. While NGM promises a significant advancement in cost- and energy-efficient solutions, achieving the requisite shape and form accuracy for high-precision optics remains a persistent challenge. The research focuses on expediting the development phase, presenting a methodology that strategically utilizes a sparse dataset for determining optimized molding parameters with a minimized number of experimental trials. Importantly, our method highlights the exceptional ability of a robust surrogate model to precisely predict the accuracy outputs of glass optics, strongly influenced by numerous input molding parameters of the NGM process. This significance emphasizes the surrogate model, which emerges as a promising alternative to inefficient traditional methods, such as time-consuming experiments or computation-intensive simulations, particularly in the realm of high-precision production for LiDAR glass optics. In contributing to optics manufacturing advancements, this study also aligns with contemporary trends in digitalization and Industry 4.0 within modern optics production, thereby fostering innovation in the automotive industry.
  • Publication
    Surrogate modeling for multi-objective optimization in the high-precision production of LiDAR glass optics
    ( 2024-04-24)
    Vu, Anh Tuan orcid-logo
    ;
    Paria, Hamidreza
    ;
    Grunwald, Tim
    ;
    Bergs, Thomas
    This study addresses the ever-increasing demands on glass optics for LiDAR systems in autonomous vehicles, highlighting the pivotal role of the recently developed Nonisothermal Glass Molding (NGM) in enabling the mass production of complex and precise glass optics. While NGM promises a significant advancement in cost- and energy-efficient solutions, achieving the requisite shape and form accuracy for high-precision optics remains a persistent challenge. The research focuses on expediting the development phase, presenting a methodology that strategically utilizes a sparse dataset for determining optimized molding parameters with a minimized number of experimental trials. Importantly, our method highlights the exceptional ability of a robust surrogate model to precisely predict the accuracy outputs of glass optics, strongly influenced by numerous input molding parameters of the NGM process. This significance emphasizes the surrogate model, which emerges as a promising alternative to inefficient traditional methods, such as time-consuming experiments or computation-intensive simulations, particularly in the realm of high-precision production for LiDAR glass optics. In contributing to optics manufacturing advancements, this study also aligns with contemporary trends in digitalization and Industry 4.0 within modern optics production, thereby fostering innovation in the automotive industry.
  • Publication
    Precision glass molding process enhancing the expanding of chip-on-tip endoscopes
    ( 2023-06-07)
    Jiang, Cheng orcid-logo
    ;
    Friedrichs, Marcel
    ;
    Grunwald, Tim
    ;
    Bergs, Thomas
    A new endoscope structure called chip-on-tip is designed to reach both miniaturization and affordability beyond the conventional rigid endoscope. Hence, the precision glass molding process as a replicative manufacturing method can be integrated into the endoscopes production chain and deliver the optics with not only high quality but also reasonable cost under large production volume.
  • Publication
    Precision glass molding process enhancing the expanding of chip on tip endoscopes
    ( 2023-06-07)
    Jiang, Cheng orcid-logo
    ;
    Friedrichs, Marcel
    ;
    Grunwald, Tim
    ;
    Bergs, Thomas
    A new endoscope structure called chip-on-tip is designed to reach both miniaturization and affordability beyond the conventional rigid endoscope. Hence, the precision glass molding process as a replicative manufacturing method can be integrated into the endoscopes production chain and deliver the optics with not only high quality but also reasonable cost under large production volume.
  • Publication
    Prozessoptimierung beim Glaswafer-Trennschleifen
    ( 2023)
    Jahnel, Kirk
    ;
    Wilhelm, Dennis Patrick
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    Hähnel, Sebastian
    ;
    Grunwald, Tim
    ;
    Bergs, Thomas
    ;
    Maier, Waldemar
    Fast-Axis-Kollimatoren (FAC) sind essenzielle optische Elemente für Diodenlasersysteme. Beim aktuellen Prozess des Trennschleifens mit nachgelagerter Reinigung von FAC-Optiken aus gepressten antireflexionsbeschichteten Glaswafern entstehen vermehrt Beschädigungen, die eine Verwendung der Optiken limitiert. Die Verwendung von Schneidfolie zur Substratfixierung beim Trennschleifen der FAC-Optiken ermöglicht ein defektfreies Schneiden und Lösen ohne Reinigung von der Folie und gleichzeitig können Kosten und Fertigungszeit eingespart werden.
  • Publication
    Surface Grinding of Borosilicate Crown Glass Optics via a Robotic Approach Based on Superposed Trajectories
    ( 2023)
    Tamassia, Eugenio
    ;
    Pini, Fabio
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    Grunwald, Tim
    ;
    Bergs, Thomas
    ;
    Leali, Francesco
    The production of large-sized optical components with complex shapes requires several phases, including surface finishing. Currently, mainly skilled workers can correctly perform this operation, divided into the successive steps of grinding and polishing, leading to long production times, poor reproducibility of results, and exposure to human error. For this reason, the industry is trying to move towards automation involving, for example, high-precision machine tools and machining centers. However, these solutions require high investment costs and long setup times. Using robotic cells helps to reduce these expenses, manufacture larger components, and increase the flexibility in the production chain. In this research, we present an unconventional approach to the robot-assisted grinding of optical samples made of borosilicate crown glass. The samples were guided by a six-degree-of-freedom industrial robot on a rotating grinding disc while imposing to them different trajectories with complex geometry. We avoided regular grinding patterns, which are easily recognizable by human eyes and affect the quality assessment, by superposing multiple relative movements between the machined surface and the abrasive grains. The ground surfaces of the samples were characterized based on average roughness values, profile error data, and surface topography images. Finally, we selected the best robotic grinding procedure matching the trajectory and strategy with optimal surface quality, processing time, and productivity. The suggested methodology not only shortens the manufacturing sequence by eliminating manual methods but also provides components with optical properties within the required specifications for subsequent polishing steps.
  • Publication
    Investigation of Surface Integrity Induced by Ultra-Precision Grinding and Scratching of Glassy Carbon
    ( 2023)
    Jahnel, Kirk
    ;
    Michels, Robert
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    Wilhelm, Dennis Patrick
    ;
    Grunwald, Tim
    ;
    Bergs, Thomas
    Glassy carbon provides material characteristics that make it a promising candidate for use as a mould material in precision glass moulding. However, to effectively utilize glassy carbon, a thorough investigation into the machining of high-precision optical surfaces is necessary, which has not been thoroughly investigated. This research analyses the process of material removal and its resulting surface integrity through the use of nano-scratching and ultra-precision grinding. The nano-scratching process begins with ductile plastic deformation, then progresses with funnel-shaped breakouts in the contact zone, and finally concludes with brittle conchoidal breakouts when the cutting depth is increased. The influence of process factors and tool-related parameters resulting from grinding has discernible impacts on the ultimate surface roughness and topography. Enhancing the cutting speed during cross-axis kinematic grinding results in improved surface roughness. Increasing the size of diamond grains and feed rates leads to an increase in surface roughness. An achievable surface roughness of Ra < 5 nm together with ductile-regime grinding behaviour meet optical standards, which makes ultra-precision grinding a suitable process for optical surface generation.
  • Publication
    Variationskraftgeregeltes 5-Achs-Schleifen
    ( 2023)
    Hähnel, Sebastian
    ;
    Jahnel, Kirk
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    Grunwald, Tim
    ;
    Bergs, Thomas
    Eine variierende Anpresskrafteinstellung im Werkzeugeingriff des Schleifstiftes entlang stark gekrümmter Werkzeugkonturen ermöglicht eine konstante Schleifprofiltiefe. Dies verhindert unerwünschte Bauteilformabweichungen und erlaubt eine automatisierte Nachbearbeitung komplex geformter Konturen in einer Aufspannung. So wird ein durch einen Werkzeugwechsel unterbrochener Schnitt vermieden. Insbesondere Übergänge von ebenen auf stark gekrümmte, konvexe Flächen und kleine Radien in Kantenbereichen lassen sich mit diesem Verfahren automatisiert nachbearbeiten.