Mr. Ludwig Pongratz Profile

Ludwig Pongratz

at Fraunhofer Institute for Laser Technology ILT

SPIE Involvement:

Author

Publications (3)

Proceedings Article | 12 March 2024 Presentation + Paper

Efficiency enhancement of Li-ion battery electrode structuring by pulse burst processing: results of an automated study

Matthias Trenn, Tobias Keller, Karsten Voigt, Anton Werwein, Karsten Lange, Christian Heubner, Ludwig Pongratz

Proceedings Volume 12873, 128730I (2024) https://doi.org/10.1117/12.3000904

KEYWORDS: Electrodes, Ablation, Graphite, Laser ablation, Lithium, Batteries, Anodes, Laser processing, Scanning electron microscopy, Ultrafast phenomena

Read Abstract +

Proceedings Article | 5 March 2021 Presentation + Paper

Automated spatial period variation for direct laser interference patterning

L. Pongratz, K. Vannahme

Proceedings Volume 11674, 116740P (2021) https://doi.org/10.1117/12.2579507

KEYWORDS: Optical lithography, Laser processing, Laser applications, Ultrafast phenomena, Picosecond phenomena, Optical components, Multiphoton lithography, Laser systems engineering, Atomic force microscope

Read Abstract +

Proceedings Article | 16 March 2015 Paper

Advantages and drawbacks of Thiol-ene based resins for 3D-printing

Holger Leonards, Sascha Engelhardt, Andreas Hoffmann, Ludwig Pongratz, Sascha Schriever, Jana Bläsius, Martin Wehner, Arnold Gillner

Proceedings Volume 9353, 93530F (2015) https://doi.org/10.1117/12.2081169

KEYWORDS: Polymers, Stereolithography, Digital Light Processing, Raman spectroscopy, Printing, Additive manufacturing, Two photon polymerization, Epoxies, Chemistry, 3D printing

Read Abstract +

The technology of 3D printing is conquering the world and awakens the interest of many users in the most varying of applications. New formulation approaches for photo-sensitive thiol-ene resins in combination with various printing technologies, like stereolithography (SLA), projection based printing/digital light processing (DLP) or two-photon polymerization (TPP) are presented. Thiol-ene polymerizations are known for its fast and quantitative reaction and to form highly homogeneous polymer networks. As the resins are locally and temporally photo-curable the polymerization type is very promising for 3D-printing. By using suitable wavelengths, photoinitiator-free fabrication is feasible for single- and two photon induced polymerization. In this paper divinyl ethers of polyethylene glycols in combination with star-shaped tetrathiols were used to design a simple test-system for photo-curable thiol-ene resins. In order to control and improve curing depth and lateral resolution in 3D-polymerization processes, either additives in chemical formulation or process parameters can be changed. The achieved curing depth and resolution limits depend on the applied fabrication method. While two-/multiphoton induced lithography offers the possibility of micron- to sub-micron resolution it lacks in built-up speed. Hence single-photon polymerization is a fast alternative with optimization potential in sub-10-micron resolution. Absorber- and initiator free compositions were developed in order to avoid aging, yellowing and toxicity of resulting products. They can be cured with UV-laser radiation below 300 nm. The development at Fraunhofer ILT is focusing on new applications in the field of medical products and implants, technical products with respect to mechanical properties or optical properties of 3D-printed objects. Recent process results with model system (polyethylene glycol divinylether/ Pentaerithrytol tetrakis (3-mercaptopropionat), Raman measurements of polymer conversion and surface modifications using bifunctional crosslinkers are presented with advantages, drawbacks and a general outlook.

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years