USE AND PRODUCTION OF NON-CRIMP FABRICS FROM RCF-SLIVERS
Topic(s) : Special Sessions
Co-authors :
Rebecca EMMERICH (GERMANY), Christoph KLEMM (GERMANY), Felix TEICHMANN (GERMANY), Philipp HUBER (GERMANY), Carsten UTHEMANN (GERMANY), Adli DIMASSI (GERMANY)Abstract :
The demand of Carbon Fibre Reinforced Parts (CFRP) has been rising since more than 10 years to about 110.000 t worldwide [SS23]. At the same time, the amount of carbon fibre waste is increasing. Environmental, legislative and economic aspects are drivers for an efficient recycling of carbon fibres. [JEC21]. Thus, methods to handle recycled carbon fibres (rCF) efficiently.
Depending on the method of recycling, length, quality and surface properties of the fibres differ. Short fibres in different length distributions are available to be processed to various textile products, such as nonwovens, woven fabrics and non-crimp fabrics produced from rCF-slivers or -yarns. In the industry mostly, nonwovens with low degrees of orientation and products from rCF-yarns with high percentages of non-carbon content are used. These textile products are mainly used in non-structural applications, even though the available properties of the single fibres can reach up to 90 % of the virgin material properties of the single filaments [KKG+21]. For proper recycling instead of downcycling, these high residual properties could be utilised specifically for (semi-)structural applications.
To transfer the single fibre properties into part properties, other factors such as fibre orientation in the textile is one crucial factor. Fibre orientation can be achieved using different methods. In the given study, fibre orientation is achieved using a carding machine, followed by a funnel system and a thermal fixation. The produced slivers are processed on a warp knitting machine. The machine setup is constituted for processing fibre rovings with an even width and low thickness. In a first step a manual lay down of the slivers is used. In the future, an automated process has to be developed.
Tapes with 90 % rCF content from salvage of weaving process and 10 % Co-Polyamide are produced using a dry web formation process. Various basis weight proportions, with the focus on low areal weights are produced. In addition, various processes are being tested to reduce inhomogeneities in the tapes and to produce constant widths. One approach is to integrate several tapes into one overall tape. In the following, the processability of the material is tested on a warp knitting machine. Composite materials are produced from the processable material. The resulting composite panels are tested for tensile strength and stiffness in accordance with DIN EN ISO 527-4.
The main influences on processability are presented. It was found, that areal weights above about 400 gsm with a thermal fixation of the cross-section and inhomogeneous widths are not processable. By lowering the areal weight of the feeding material and by reducing the amount of binder fibres, a processability on standard machines is enabled. The mechanical properties of the tested composites are comparable to commonly used materials. The resulting fibre orientations achieved in the final composite have to investigated.
Depending on the method of recycling, length, quality and surface properties of the fibres differ. Short fibres in different length distributions are available to be processed to various textile products, such as nonwovens, woven fabrics and non-crimp fabrics produced from rCF-slivers or -yarns. In the industry mostly, nonwovens with low degrees of orientation and products from rCF-yarns with high percentages of non-carbon content are used. These textile products are mainly used in non-structural applications, even though the available properties of the single fibres can reach up to 90 % of the virgin material properties of the single filaments [KKG+21]. For proper recycling instead of downcycling, these high residual properties could be utilised specifically for (semi-)structural applications.
To transfer the single fibre properties into part properties, other factors such as fibre orientation in the textile is one crucial factor. Fibre orientation can be achieved using different methods. In the given study, fibre orientation is achieved using a carding machine, followed by a funnel system and a thermal fixation. The produced slivers are processed on a warp knitting machine. The machine setup is constituted for processing fibre rovings with an even width and low thickness. In a first step a manual lay down of the slivers is used. In the future, an automated process has to be developed.
Tapes with 90 % rCF content from salvage of weaving process and 10 % Co-Polyamide are produced using a dry web formation process. Various basis weight proportions, with the focus on low areal weights are produced. In addition, various processes are being tested to reduce inhomogeneities in the tapes and to produce constant widths. One approach is to integrate several tapes into one overall tape. In the following, the processability of the material is tested on a warp knitting machine. Composite materials are produced from the processable material. The resulting composite panels are tested for tensile strength and stiffness in accordance with DIN EN ISO 527-4.
The main influences on processability are presented. It was found, that areal weights above about 400 gsm with a thermal fixation of the cross-section and inhomogeneous widths are not processable. By lowering the areal weight of the feeding material and by reducing the amount of binder fibres, a processability on standard machines is enabled. The mechanical properties of the tested composites are comparable to commonly used materials. The resulting fibre orientations achieved in the final composite have to investigated.