Braids are generally divided into 2D braids and 3D braids. Two-dimensional braids include flat braids and circular braids. Circular braids represent three-dimensional textiles, as they enclose a volume, but consist of a two-dimensional yarn architecture. Three-dimensional braids are defined by a three-dimensional yarn architecture. Historically, 3D braids were produced on row and column braiding machines with Cartesian or radial machine beds, by bobbin movements around inlay yarns. Three-dimensional rotary braiding machines allow a more flexible braiding process, as the bobbins are moved via individually controlled horn gears and switches. Both braiding machines at the Institut für Textiltechnik (ITA) of RWTH Aachen University, Germany, are based on the principal of 3D rotary machines. The fully digitized 3D braiding machine with an Industry 4.0 standard enables the near-net-shape production of three-dimensionally braided textile preforms for lightweight applications. The preforms can be specifically reinforced in all three spatial directions according to the application. Complex 3D structures can be produced in just one process step due to the high degree of design freedom. The 3D hexagonal braiding technology is used in the field of medical textiles. The special shape of the horn gears and their hexagonal arrangement provides the densest packing of the bobbins on the machine bed. In addition, the lace braiding mechanism allows two bobbins to occupy the position between two horn gears, maximizing the number of bobbins. One of the main applications is the near-net-shape production of tubular structures, such as complex stent structures. Three-dimensional braiding offers many advantages compared to 2D braiding, e.g., production of complex three-dimensional geometries in one process step, connection of braided layers, production of cross-section changes and ramifications, and local reinforcement of technical textiles without additional process steps. In the following review, the latest developments in 3D braiding, the machine development of 3D braiding machines, as well as software and simulation developments are presented. In addition, various applications in the fields of lightweight construction and medical textiles are introduced.

In the field of textile technology, this study centers on towpreg—an integral component utilized in production techniques like tape laying and filament winding. Here, fibers are pre‐coated with resin, typically epoxy but not exclusively. Notably, towpreg retains a partially cured state, maintaining tackiness throughout the processing stages. The ultimate quality of the product manufactured with this towpreg is highly dependent on this initial material. This research highlights the importance of considering various factors that impact product quality. While not exhaustive, a systematic analysis of diverse towpreg parameters, including tack, resin content, and width, is provided. The work encompasses findings, challenges, and insights derived from towpreg manufacturing, incorporating the investigation of various experimental methodologies. The study also evaluates methodologies for laminated coupon production with towpreg, assessing their applicability in characterizing filament‐wound components. Although the article seems like a review, the authors aim to give a clear and holistic picture in one work instead of spreading information across many articles.Highlights: Techniques for the quantification of towpreg tack are presented. Resin content distribution along towpreg length is presented. Towpreg width variation was investigated, seen to be one of the major causes for the gaps and voids in a filament wound composite. Coupon‐level characterization of towpreg through filament winding approach is presented. Other filament winding parameters influencing the quality of the manufactured composite are discussed.

Fiber composites with a three-dimensional braided reinforcement architecture have higher fiber volume content and Z-fiber content compared to a two-dimensional braided reinforcement architecture; as a result, the shear strength increases. Porous oxide fiber composites (OFCs) have the inherent weakness of a low interlaminar shear strength, which can be specifically increased by the use of a three-dimensional fiber reinforcement. In this work, the braiding process chain for processing highly brittle oxide ceramic fibers is modified; as a consequence, a bobbin, which protects the filament, is developed and quantitatively evaluated on a test rig with regard to tension and filament breakage. Subsequently, a braiding process is designed which takes into account fiber-protecting aspects, and a three-dimensional reinforced demonstrator is produced and tested. After impregnation with an Al₂O₃-ZrO₂ slurry, by either a prepreg process or a vacuum-assisted process, as well as subsequent sintering, the three-dimensional braid-reinforced OFC exhibits an interlaminar shear strength (ILSS) which is higher than that of two-dimensional braid- or fabric-reinforced samples by 64–95%. The influence of the manufacturing process on the relative macropore content is investigated and correlated with the mechanical properties.

A key element for the transition to sustainable energy lies in the transformation of the power plant fleet, which is dominated by fossil fuels, toward sustainable energy production from renewable energy sources. An increase in efficiency and reduction of exhaust gas emissions, especially the minimization of CO2 emissions, is possible through the use of new turbine materials, which can withstand higher temperature levels. Oxide ceramics are well known for their high stability in aggressive environments, low density, high melting point, high stiffness, and great creep resistance, but their brittleness has strongly limited their number of applications. Therefore, the implementation of fiber reinforcement using the three-dimensional (3D) braiding process shows great potential to increase the damage tolerance of ceramic matrix composites (CMC) and consequently the performance of thermal machines significantly. Currently, the impregnation of 3D braids for the reinforcement of ceramic composites poses a challenge due to the high packing density of the textiles. In order to enable a homogeneous impregnation of the fiber structures using highly viscous ceramic slurries, the CMC research group at RWTH Aachen University's Institute of Textile Technology (ITA) is investigating the combination of 3D braiding and pressure slip casting for an economical production of all-oxide CMCs. To increase the impregnation quality of dense textiles, this paper describes approaches to reduce the filter effect of braids. The results of an initial investigation into the functionalization of two-dimensional braided reinforcement structures by using support structures and flow aids are described. The effectiveness of the impregnation ability is assessed by evaluating the residual porosity of generated green compacts via μCT analysis.