2:45pm - 3:00pm
Additive manufacturing of magnetic parts by laser powder bed fusion of iron oxide nanoadditivated polyamide powders
1Department of Materials Science and Additive Manufacturing, University of Wuppertal, 42119 Wuppertal, Germany; 2Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstrasse 7, 45141 Essen, Germany; 3Institute of Photonic Technologies (LPT), Friedrich-Alexander Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3-5, 91052 Erlangen, Germany; 4Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander Universität Erlangen-Nürnberg, Germany; 5Institute of Particle Technology (LFG), Friedrich-Alexander Universität Erlangen-Nürnberg, Cauerstr. 4, 91058 Erlangen, Germany
Laser powder bed fusion allows the processing of polymer powders with design freedom, achieving highly complex geometry required for medical and aerospace applications. The characteristics of the generated parts and processability depends on the initial polymer powder properties. A route to achieve a controlled modification of the polymer powders and adapt the properties of the final parts to the desired application is the nanoadditivation of the powders. The generation of superparamagnetic iron oxide nanoparticles by laser fragmentation and supporting on polyamide (PA12) is shown to transfer the magnetic response to the resulting nanoadditivated powder even when the nanoparticle loading is only 0.1 wt%. The characterization of the as built parts confirms that the saturation magnetization and structure of the iron oxide nanoparticles are not influenced by laser powder bed fusion processing, proving the successful transfer of the initial nanoparticle properties to the 3D-printed part.
3:00pm - 3:15pm
Polymer powders with enhanced absorption in the NIR for laser powder bed fusion with diode lasers
Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstrasse 7, 45141 Essen, Germany
Additive manufacturing techniques represent an ideal manufacturing process for series components, for example in the automotive industry when good mechanical properties and precision are needed. In that sense, Laser Powder Bed Fusion (LPBF) is a manufacturing technique already employed in several applications where polymer parts with complex geometries are required. However, since the employed polymer powders exhibit a low absorption in the visible and NIR wavelength range, the laser sources employed in polymer LPBF are limited.
To address this difficulty, the addition of near-infrared absorbing LaB6 nanoparticles is proposed and tested on the most employed polymer powder for LPBF, i.e. polyamide 12 (PA12). The nanoparticles are generated by laser ablation in liquid and homogeneously dispersed on the polymer surface by dielectrophoretic deposition. The resulting nanoadditivated polymer powder exhibits an absorption maximum at 800 nm, suitable for its processability by LPBF with NIR laser sources.
3:15pm - 3:30pm
Powder bed fusion of ultra-high molecular weight polyethylene using ultra-short laser pulses
1Institute of Applied Physics, Friedrich-Schiller University Jena; 2Institute for Technical and Macromolecular Chemistry, University of Hamburg; 3Fraunhofer Institute for Applied Optics and Precision Engineering, IOF Jena
Laser powder bed fusion (L-PBF) of ultra-high molecular weight polyethylene (UHMWPE) is a new approach to fabricate complex components for medical implants. CO2 laser radiation is the method of choice to selectively heat up the powder particles above the melting point. Although previous studies have shown the feasibility to fuse UHMWPE, the produced sprecimen lack of warping and material degradation. Moreover the achievable geometrical resolution is limited by the large spot size of several 100 µm.
In this paper, we demonstrate an alternative approach for L-PBF of UHMWPE by using 500 fs laser pulses at a wavelength of 1030 nm. The peak intensity of several 100 MW/cm2 allows for an efficient multi-photon absorption in the transparent polymer. Thus, it was possible to completely melt the powder with less degradation. Furthermore, the achieved tensile strength of 4 MPa is 60 % higher in comparison to produced samples using conventional CO2 L-PBF.
3:30pm - 3:45pm
Experimental investigations on lateral path overlay and the degree of mixing of additively manufactured soda-lime and borosilicate glass structures
Technische Universität Ilmenau, Production Technology Group, Germany
In this scientific paper, the influence of the lateral distance between the welding lines on the geometric dimensions and the degree of mixing of the additively manufactured glass structure is investigated. Initial experimental investigations have shown that the additive manufacturing of quartz, soda-lime and borosilicate glass is possible when material- and process-specific process parameters are taken into account. Using a CO2-laser, the silicate glasses and the rod-based additive material are melted. For this experimental investigation, the ratio between welding and feeding speed of the filler material, as well as the laser power, is kept constant. The fabricated structures are subjected to post heat treatment to relieve thermally induced stresses and are examined with photoelasticity. Geometrical dimensions, such as layer height, width and bond angle, as well as the degree of mixing are quantified after materialogprahy sample preparation. The knowledge is used to optimise near-net-shape additive manufacturing of glass components.
3:45pm - 4:00pm
Manufacturing of fused silica volume parts by means of laser glass deposition
1Laser Zentrum Hannover e.V., Germany; 2Institute for product development, Leibniz University Hannover, Germany
Additive manufacturing (AM) of polymers and metals is already established in the industry. Materials such as glass create significant challenges based on their material properties. Especially mechanical and thermal properties as well as the viscosity behavior are difficult to handle. So far, only few specialized glass AM processes exist and are established in research and development.
The Laser Glass Deposition (LGD) process offers the possibility to deposit glass fibers without using binder materials. For the application area of optical components, manufactured parts must fulfill high requirements for transparency, surface quality, material purity and homogeneity of the material. Investigations on the printing of individual single-layer quartz glass structures have already been carried out with the LGD process. Within this article the influence of laser power, axis speed and fiber feeding speed on the deposition characteristics is investigated shortly. Subsequently, a multilayer deposition is investigated to manufacture solids with an optical transparency.