@article{AbbasHedwigBalcetal.2023,
  author    = {Abbas, Karim and Hedwig, Lukas and Balc, Nicolae and Bremen, Sebastian},
  title     = {Advanced FFF of PEEK: Infill strategies and material characteristics for rapid tooling},
  series = {Polymers},
  volume    = {2023},
  journal   = {Polymers},
  number    = {15},
  publisher = {MDPI},
  address   = {Basel},
  doi       = {10.3390/polym15214293},
  pages     = {Artikel 4293},
  year      = {2023},
  abstract  = {Traditional vulcanization mold manufacturing is complex, costly, and under pressure due to shorter product lifecycles and diverse variations. Additive manufacturing using Fused Filament Fabrication and high-performance polymers like PEEK offer a promising future in this industry. This study assesses the compressive strength of various infill structures (honeycomb, grid, triangle, cubic, and gyroid) when considering two distinct build directions (Z, XY) to enhance PEEK's economic and resource efficiency in rapid tooling. A comparison with PETG samples shows the behavior of the infill strategies. Additionally, a proof of concept illustrates the application of a PEEK mold in vulcanization. A peak compressive strength of 135.6 MPa was attained in specimens that were 100\% solid and subjected to thermal post-treatment. This corresponds to a 20\% strength improvement in the Z direction. In terms of time and mechanical properties, the anisotropic grid and isotropic cubic infill have emerged for use in rapid tooling. Furthermore, the study highlights that reducing the layer thickness from 0.15 mm to 0.1 mm can result in a 15\% strength increase. The study unveils the successful utilization of a room-temperature FFF-printed PEEK mold in vulcanization injection molding. The parameters and infill strategies identified in this research enable the resource-efficient FFF printing of PEEK without compromising its strength properties. Using PEEK in rapid tooling allows a cost reduction of up to 70\% in tool production.},
  language  = {en}
}
@article{EichlerBalcBremenetal.2024,
  author    = {Eichler, Fabian and Balc, Nicolae and Bremen, Sebastian and Nink, Philipp},
  title     = {Investigation of laser powder bed fusion parameters with respect to their influence on the thermal conductivity of 316L samples},
  series = {Journal of Manufacturing and Materials Processing},
  volume    = {8},
  journal   = {Journal of Manufacturing and Materials Processing},
  number    = {4},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2504-4494},
  doi       = {10.3390/jmmp8040166},
  pages     = {12 Seiten},
  year      = {2024},
  abstract  = {The thermal conductivity of components manufactured using Laser Powder Bed Fusion (LPBF), also called Selective Laser Melting (SLM), plays an important role in their processing. Not only does a reduced thermal conductivity cause residual stresses during the process, but it also makes subsequent processes such as the welding of LPBF components more difficult. This article uses 316L stainless steel samples to investigate whether and to what extent the thermal conductivity of specimens can be influenced by different LPBF parameters. To this end, samples are set up using different parameters, orientations, and powder conditions and measured by a heat flow meter using stationary analysis. The heat flow meter set-up used in this study achieves good reproducibility and high measurement accuracy, so that comparative measurements between the various LPBF influencing factors to be tested are possible. In summary, the series of measurements show that the residual porosity of the components has the greatest influence on conductivity. The degradation of the powder due to increased recycling also appears to be detectable. The build-up direction shows no detectable effect in the measurement series.},
  language  = {en}
}