Textile Technology section
Oerlikon: robust pumps for sophisticated special fibers
New solutions are required to reduce weight and replace heavy metallic parts. Aramid fibers and carbon fibers are processed into special yarns that are frequently deployed as compound materials and as lightweight composites.
Aramid fibers are produced in a highly-chemical process that is aggressive. The acrylic precursor used to manufacture carbon fibers is a different process, but again no less difficult. In these processes the gear metering pumps are not only responsible for the high-precision control of the melt transport. Durability, resistance and cost efficiency also plays decisive roles.
The process, the expected pump lifespan and the maintenance are the decisive factors for choosing the materials from which the pumps and their components are manufactured.
Oerlikon Barmag, Chemnitz/Germany, a subsidiary of the Oerlikon Manmade Fibers segment of Oerlikon Management AG, Pfäffikon/Switzerland, offers solutions that combine the various materials and the latest technologies.
Surfaces with ceramic coatings, gears and shafts featuring DLC coatings, pumps made from cobalt alloys or robust and durable hybrid constructions comprising zirconium oxide ceramic and duplex stainless steel and the high-precision pumps are design-optimized depending on the intended use. Various seal systems and customized drive concepts round off the program. Thus reliable solutions for the high-precision metering of disparate media in complex processes for all applications are made available.
Dilo: new production lines with increasing transparency and efficiency
With an in-person event and a new online sourcing platform, Cinte Techtextil China in Shanghai/China, on September 2-4, 2020 was the first textile show on the Asian continent since the pandemic outbreak. The nonwovens machinery manufacturer DiloGroup, Eberbach/Germany, presented its nonwovens production lines for hygiene products, filters and roofing material. The latest developments of DiloGroup were also widely discussed.
In focus was HyperLayer designed for the highest speeds with hygiene web from fine fibers. This crosslapper is especially suited for very light weight webs with only a few layers. The new card feeder VRS-P combines the principles of a volumetric, precisely charged feeding with the characteristics of a vibration chute feeder and saves a conventional large trunk. The Dilo Compact Line (DCL) meets the requirement for the production of small amounts of high quality felts made from special fibers such as carbon fiber, ceramic or PTFE. Very interesting topics like the recycling of carbon fibers are already researched on these lines in various projects. With a working width of the compact carding machine of 1.1 m and a layering width of 2.2 m, only 60 m² of space is required for the installation.
The Hypertex technology combines a grid of endless yarns and nonwovens as a sandwich using the needlepunch process. An additional weaving process becomes unnecessary. The grid improves the tensile strength of products such as filters or roof sheets and will lower costs and production time. In the field of textile additive manufacturing the 3D-Lofter will provide fiber savings for needlefelts used in automotive and other applications.
diloline 4.0 includes a wide variety of smart manufacturing actions in collaboration with Siemens AG, Munich/Germany, which all aim at further simplifying operation, increasing transparency in web forming and consolidation, thereby increasing efficiency. Production data are stored, documented and compared. An alarm monitor indicates irregular behavior. A production analysis documents the reasons for standstill times. Numerous information modules can be recalled via mobile apps and cloud data (mindSpheres).
Karl Mayer Group: multiaxial non crimp fabrics made with nonwovens polymer
Developments in lightweight construction can lead to significant savings in energy and costs in transportation. Thermoplastic prepregs are becoming increasingly established, especially for the interior lining and thermal insulation of refrigerated containers and truck bodies.
To produce these unidirectional (UD) fiber-reinforced tapes, Karl Mayer Technische Textilien GmbH, Chemnitz/Germany, a subsidiary of the Karl Mayer Group, Obertshausen/Germany, has developed the new Sim.Ply machine. The innovative machine produces thermoplastic fiber-reinforced tapes and uses plastic in the form of films. As part of an inline process, the fibers are spread and impregnated with the plastic film by applying pressure and increasing the temperature.
However, fiber composite structures with multiaxial fiber orientations are in demand for many lightweight construction applications. Therefore a project has been put into place offering manufacturing technologies for thermoplastic prepregs made from multiaxial materials and alternative raw materials for the thermoplastic matrix.
The Cop Max 5 multiaxial warp knitting machine was used in the project work to produce reinforcing structures with flexible fiber orientations for thermoplastic prepregs. Initially, the commercially available glass fibers were homogeneously spread on the UD 700 fiber spreading assembly unit to form 12"-wide (30.5 cm) fiber tapes.
The spread tape was then fed to a Cop Max 5 machine. The multiaxial warp knitting machine is actually designed for using carbon fibers with finite weft insertion. The use of textile glass fiber is now being tested for the first time.
Another innovation was the polymer combination material for the composite solution, using nonwovens rather than a polymer film, in contrast to Sim.Ply. In cooperation with a nonwovens manufacturer, the suitability of these products as a raw material for the plastic component in thermoplastic fiber composites was investigated. The nonwoven polymer consisted of polypropylene (PP) hot-melt nonwovens. The nonwoven fabric is very easy flowing when melted and the individual glass fibers are very well embedded. In general, nonwoven polymers offer advantages over their closed film counterparts thanks to their good air permeability, since the air can escape better from the fiber-plastic composite to be produced.
The PP nonwovens for this project work had an area weight of approx. 45 g/m². The fiber material was fed into the Cop Max 5 as a layer above and below an intermediate layer of spread glass with a fiber orientation of 45° or 60° angles. The individual layers of the sandwich structure were then stitch-bonded. When choosing the right warp knitting yarn, using a classic polyester (PET) variant proved favorable, because PET yarn has a higher melting point than the PP hot-melt nonwovens. This means it can withstand the subsequent impregnation process, thus ensuring the fibers are fixed permanently. The angular positions are not shifted while passing through the impregnation section. Initial investigations completed in the field of nonwovens production yielded positive results.
Hexcel: HiTape dry carbon tapes for racing skis by Madshus
The composites company Hexcel Corp., Stamford, CT/USA, is collaborating with the ski manufacturer Madshus A/S, Biri/Norway, on the engineering of a range of next-generation dry carbon fiber tapes for Madshus’ cross-country racing skies. Hexcel’s new HiTape dry carbon tapes produce less fuzz in production and meet tight tolerances for aerial weight and width. The company is now delivering nearly 500,000 lm of HiTape per year with strong customer demand forecast to increase volumes in the very near future.
HiTape is a dry UD tape, manufactured with industrial grade fiber with aerial weights from 120 - 250 g/m² and widths between 38 - 47mm. Dry fiber tows are sandwiched between lightweight thermoplastic veils on the upper and lower faces. The lack of fiber splices and cut filaments give a clean product, suited for automated production processes.
Hexcel’s new HiTape Dry Carbon Tapes for Madshus Skis will be on display at the Ispo Munich from January 26-29, 2020 in Munich/Germany.