Laser Additive Manufacturing

Laser deposition welding is an industrially established process with a focus on component coating or repair and is one of the additive manufacturing technologies in the metal sector. Here, a melt pool is locally created on the workpiece using a laserbeam, into which an additional material in the form of a wire or powder is introduced. The resulting weld tracks line up in a row in order to form a layer.
In addition to repair and coating processes, 3D structures can also be generated with a high building rate. Very high temperatures can be reached with the help of the laser, so that metals such as titanium and tungsten can be melted and processed into complex structures. By combining supplied elemental metals (in-situ alloying), new alloy compositions and gradients can be achived in the process, such as high entropy alloys (HEA) of refractory elements.

• H. Dobbelstein, E. P. George, E. L. Gurevich, A. Kostka, A. Ostendorf, und G. Laplanche, „Laser metal deposition of refractory high-entropy alloys for high-throughput synthesis and structure-property characterization“, International journal of extreme manufacturing, Bd. 3, Nr. 1, Art. Nr. 015201, Dez. 2020, doi: 10.1088/2631-7990/abcca8
• D. Dillkötter, M. Thiele, J. Stoppok, H. Dobbelstein, C. Esen, und M. Mönnigmann, „Model-based pyrometer alignment method for additive manufacturing by laser metal deposition“, in 11th CIRP Conference on Intelligent Computation in Manufacturing Engineering, Neapel, Sep. 2020, Bd. 67, S. 436–440. doi: 10.1016/j.procir.2020.09.160

Magnus Thiele, M.Sc., Room ID 05/631, Tel. +49 (0)234 / 32 25698, E-Mail: magnus.thiele@ruhr-uni-bochum.de

Prof. Dr.-Ing. Cemal Esen, Room ID 05/643, Tel. +49 (0)234 / 32 25697, E-Mail: cemal.esen@ruhr-uni-bochum.de

Selective laser melting is a layer-based building process in a powder bed. The 30-100 µm powder layer is first jagged on a build platform and the contour of the component is then exposed by laser. After completion of one layer the platform is lowered an a new powder layer is applied on top. This process is repeated sequentially until the final part is produced. Using this tool-free method, it is possible to produce free-form surfaces of any complexity on components, with a high degree of customisation.
This enables e.g. the production of triple period minimal surface (TPMS) structures. The components consisting of TPMS single cells are examined with regard to their surface and mechanical properties.

• A. Röttger u. a., „Microstructure and mechanical properties of 316L austenitic stainless steel processed by different SLM devices“, The international journal of advanced manufacturing technology, Bd. 108, Nr. 3, S. 769–783, Juli 2020, doi: 10.1007/s00170-020-05371-1
• C. Hardes, F. Pöhl, A. Röttger, M. Thiele, W. Theisen, und C. Esen, „Cavitation erosion resistance of 316L austenitic steel processed by selective laser melting (SLM)“, Additive manufacturing, Bd. 29, S. 100786, Juli 2019, doi: 10.1016/j.addma.2019.100786

Magnus Thiele, M.Sc., Room ID 05/631, Tel. +49 (0)234 / 32 25698, E-Mail: magnus.thiele@ruhr-uni-bochum.de

Prof. Dr.-Ing. Cemal Esen, Room ID 05/643, Tel. +49 (0)234 / 32 25697, E-Mail: cemal.esen@ruhr-uni-bochum.de

Polymers are among the most widely used materials in our modern lives. In order to support the sustainable use of this type of material, LAT is researching new polymers powders for additive manufacturing. A Laser Polymer Deposition procces has been developed, which enables the handling and production of components from state-of-the-art polymer powders.

• M. Thiele, Y. Kutlu, H. Dobbelstein, M. Petermann, C. Esen, und A. Ostendorf, „Direct generation of 3D structures by laser polymer deposition“, Journal of laser applications, Bd. 33, Nr. 2, Art. Nr. 022002, März 2021, doi: 10.2351/7.0000166.
• Y. L. Wencke, Y. Kutlu, M. Seefeldt, C. Esen, A. Ostendorf, und G. A. Luinstra, „Additive manufacturing of PA12 carbon nanotube composites with a novel laser polymer deposition process“, Journal of applied polymer science, Bd. 138, Nr. 19, Art. Nr. 50395, Dez. 2020, doi: 10.1002/app.50395.
• Y. Kutlu, Y. L. Wencke, G. A. Luinstra, C. Esen, und A. Ostendorf, „Directed Energy Deposition of PA12 carbon nanotube composite powder using a fiber laser“, in 11th CIRP Conference on Photonic Technologies [LANE 2020], 2020, Bd. 94, S. 128–133. doi: 10.1016/j.procir.2020.09.025.

Yunus Kutlu, M.Sc., Raum ID 05/637, Tel. 0234 / 32 23306, E-Mail: christian.guenther@ruhr-uni-bochum.de

Prof. Dr.-Ing. Cemal Esen, Raum ID 05/643, Tel. 0234 / 32 25697, E-Mail: cemal.esen@ruhr-uni-bochum.de

Two-photon polymerization (2PP) is an emerging Additive Manufacturing technique to process photosensitive materials with highest precision. The laser-based approach enables the fabrication of arbitrarily complex 3D microstructures with ultra-high resolution without using exposure masks or harsh chemicals. The extraordinary characteristics of 2PP offer new opportunities to develop novel applications for various fields. At LAT, 2PP is used to study microfluidics, microoptics, photonics, and biomimetics. In addition, LAT currently develops a compact and cost-effective 2PP system in a project funded by the German Federal Ministry of Education and Research (BMBF).

• G. Zyla u. a., „Structural colors with angle-insensitive optical properties generated by Morpho-inspired 2PP structures“, Applied physics A, Bd. 126, Nr. 9, Art. Nr. 740, Aug. 2020, doi: 10.1007/s00339-020-03931-6.
• G. Zyla u. a., „Two-photon polymerization with diode lasers emitting ultrashort pulses with high repetition rate“, Optics letters, Bd. 45, Nr. 17, S. 4827–4830, Aug. 2020, doi: 10.1364/ol.401738.
• G. Zyla u. a., „Generation of bioinspired structural colors via two-photon polymerization“, Scientific reports, Bd. 7, Nr. 1, Art. Nr. 17622, Dez. 2017, doi: 10.1038/s41598-017-17914-w.

Felix Behlau, M.Sc., Room ID 05/625, Tel. +49 (0)234 / 32 23593, E-Mail: felix.behlau@ruhr-uni-bochum.de

Prof. Dr.-Ing. Cemal Esen, Room ID 05/643, Tel. +49 (0)234 / 32 25697, E-Mail: cemal.esen@ruhr-uni-bochum.de