The majority of textiles used to reinforce composites are still woven, even today. Materials such as fibreglass, natural fibres, aramid or carbon fibres are processed here. Of the so-called fibrous materials, carbon fibres possess the greatest potential for lightweight construction due to their property profile. For this reason their application, embedded in plastics - usually epoxy resins (CFK) - has also become increasingly interesting for the automotive industry. With TWINtec healds from Groz-Beckert, customers travel well in any case!
Composites in the automotive sector are of special significance because the structural components here are subjected to high mechanical loads. These so-called structural components are reliant on properties such as high tensile and compressive strength and rigidity at low density, which only carbon fibres can provide.
The processing of carbon filament yarns into fabrics requires especially
gentle thread guidance, to avoid damage to the filaments during the weaving
process. The yarns are in the transverse direction without being embedded in
resin, and are very sensitive.
To optimally apply the mechanical properties of the relatively expensive carbon filament yarns to the textile or subsequent fibre composite material, the yarns have to be guided as flat as possible in a "ribbon-like" manner, without twists. In many cases the carbon fibre filament yarns are spread out, in a process upstream of weaving. In this way especially flat ribbons that are as taut as possible are formed which bear only a faint resemblance to yarn. In other cases, especially rough carbon fibre filament yarns called heavy tow yarns, offering a good price-performance ratio, are used. With these yarns, too, the warp thread has to be processed in as flat and taut a way as possible during weaving.
It was to optimally process yarns like these in warp thread systems that Groz-Beckert developed TWINtec healds. They are ideal for the processing of carbon filament yarns and other ribbon-shaped materials. TWINtec healds move the ribbon-shaped warp threads over two stationary cylinders which, during shaft movement, ensure that the flat and ribbon-like shape of the carbon filament yarns remains intact. The geometry of the healds can be selected independently of the yarn requiring processing, thereby guaranteeing optimal fabric quality.