IBT.Thermoprocess supplies infrared oven for tape production to ITA

At ITA TapeCenter, research is conducted across the entire tape-based process chain. In recent years, this research has focused on the development and improvement of machine technology for bar and air spreading processes. In addition, the interactions between the material properties of dry-fiber tapes and their processability in tape-laying processes, as well as their effect on mechanical properties were investigated. Future research at ITA TapeCenter will focus on quality analysis of tapes and further improvements within the spreading process.

The newly acquired infrared oven from IBT.Thermprocess has already been used for the production of dry-fiber tapes with binder fixation within the recently completed IGF research project “Tape2Demand” (20147N). For future research, the oven will also be used for the production of thermoplastic prepreg-tapes. Both powder application and dispersion impregnation are considered. The oven has a heating capacity of 9 kW. It features a non-contact product temperature measurement which enables precise control of the consolidation process. The aim is to produce tapes with a width of up to 150 mm and a production speed of over 20 m/min. All electrical contacts inside the oven are protected against carbon fiber dust and corrosion caused by evaporating water when using water-based dispersions.

IBT.Thermoprocess (Freiberg, Germany) specializes in industrial heating technology, infrared and high temperature furnaces. It provides heating solutions for the plastics, paint ceramics and metal industries. In addition, IBT’s products are already used for composite applications such as heating of tailored blanks and organo sheets. With the newly developed “THT – Tailored Heating Technology”, IBT avoids the formation of hot and cold spots in composite laminates with different thicknesses.

The acquisition of the oven was funded within the research project IGF 20147N “Tape2Demand” from the Forschungskuratorium Textil e.V., Berlin. This project was supported by the Federal Ministry of Economic Affairs and Energy through the German Federation of Industrial Research Associations (AiF) as part of the programme for promoting industrial cooperative research (IGF) on the basis of a decision by the German Bundestag. The project was carried out at Institut für Textiltechnik of RWTH Aachen University.

© ITA of RWTH Aachen University

Contact

Philipp Quenzel

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 23444
Mail: philipp.quenzel@ita.rwth-aachen.de

Dr. Robert Eder

CEO
IBT.Thermprocess
Phone: +49 (0) 3731 1683-24
Mail: r.eder@ibt.de

Smart Composites for automotive interior parts

Fiber-reinforced plastics (FRP) with thermoplastic matrix materials have shown growth in production volume in recent years due to favorable base materials, very short process times for consolidation and the ability to recycle. FRPs also fulfil additional functions which become increasingly important in industry. These materials are referred to as Smart Composites. Due to high melt viscosities, flow paths are too high and cause insufficient fiber impregnation.

One approach of reducing the flow paths and thus also the cycle time when processing these matrix systems is to use hybrid yarns, which are already mixed reinforcing and thermoplastic filaments. This minimizes the flow paths of the thermoplastic matrix and ensures that the preforms can be processed cost-effectively into thermoplastic FRP.

In the project “OptiTFP” at ITA the feasibility of thermoplastic Smart Composites is based on a concept of an FRP with an integrated meander-shaped heating structure. Function integration is achieved by stitching the heating structure using TFP. The hybrid yarns of polyamide 6.6 and glass fiber are supplemented with functional fibers during air texturing.

© ITA of RWTH Aachen University | Figure 1: Thermal image of the temperature distribution of a thermoplastic FRP sample at 10 W power loss

The efficiency of the heating structure and thus also the feasibility of thermoplastic FRP with integrated electrical conductors has been proven (see Figure 1). With the designed functional patterns with heating structures, temperatures of over 210 °C can be achieved with a very homogeneous temperature distribution over the heating structure surface at the same time. The integration of metallic wires significantly reduces the maximum deformability under interlaminar shear stress.

© ITA of RWTH Aachen University | Figure 2: TFP preforms are being consolidated for thermoplastic FRP interior parts

Within the project Digel Sticktech GmbH & Co. KG, Pfullingen, developed a spreading and mixing module for the homogeneous, planar TFP of various fiber materials. The TFP preforms can be functionalized with copper wire and were consolidated at ITA of RWTH Aachen University. The company Steinhuder Werkzeug- und Apparatebau Helmut Woelfl GmbH, Wunstorf, developed a tool with several heating and cooling zones to maintain different surface temperatures locally in the tool (see Figure 2). At the ITA of RWTH Aachen University the final embroidered preforms were evaluated by adjusting process pressure, process time and tool temperature for the consolidation process using heat pressing. The best consolidation was determined by a statistical test plan at a temperature of 255 °C, a pressure of 70 bar and a holding time of 8 min. The final consolidated part is a glove compartment cover, shown in Figure 3, which can be used as a heating device in the automotive interior.

The project “OptiTFP” is funded by the Federal Ministry of Economic Affairs and Energy (BMWi) within the framework of the Central Innovation Programme for SMEs (ZIM) and was completed in the end of 2020.

© ITA of RWTH Aachen University | Figure 3: Painted glove compartment cover based on a TFP structure made of glass fiber and polyamide 6.6

Contact

Max Schwab

Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 (0) 241 80 – 23473
Mail: Max.Schwab@ita.rwth-aachen.de

Lars Wollert

Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 (0) 241 80 – 23283
Mail: Lars.Wollert@ita.rwth-aachen.de

Development of an economical concrete moulding system for the production of structural components made of fibre-reinforced composites

Mold making plays a central and important role within the process chain for the production of fiber composite plastics (FRP) parts. With 5.8 thousand tons, the “Molding & Compound” division represents a significant share of 11% of the total volume of the carbon fiber market. Mold making ensures both component quality and process stability in the production of FRP components. The high demand of approx. 11 % of the total market volume of carbon fibers can be explained by a special feature in constructing and handling molds for FRP components: In order to compensate the thermal expansion of the materials (reinforcing fiber and resin) during the autoclave process (curing of the composite component under high pressure and temperature) the molds are made of the same material as the component to be produced. For CFRP components the mold material is also CFRP.

CFRP molds are associated with high manufacturing costs and at the same time have a low durability. The limited durability results from manufacturing defects as well as from very strict specifications regarding the fidelity of the component dimensions.

Due to the growth in the demand for carbon fibers, the demand for tools for the production of fiber-reinforced plastics will also increase. According to the German Engineering Federation (VDMA), the tool industry is dominated by SMEs. Due to the high costs, there is a great need for innovation in tool production.

The aim of the project is the development of a raw mold system based on a low-cost and recyclable material as an alternative to PU, aluminum and CFRP, with which even small batch sizes of components can be produced economically. As an approach, the production of raw molds made of fiber-reinforced concrete is pursued in this project. The advantage of concrete components is the low cost of concrete (0.40 €/kg) compared to aluminum (approx. 4 €/kg) and PU (approx. 6.50 €/kg), a high temperature resistance (refractory) combined with a low coefficient of thermal expansion, increased service life, high compressive strength and the possibility of recycling the concrete components. Compared to molds made of PU or aluminum, concrete molds allow cost savings of 40% to 83%.

Contact

Max Schmidt

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 24749
Mail: max.schmidt@ita.rwth-aachen.de

Machinery expansions at the Center for High Performance Materials (CFM)

The “Center for High Performance Materials” (CFM) was officially opened at the Institute of Textile Technology in Aachen in 2012. In the premises on the Melaten Campus, application-oriented research is conducted into new materials, technologies and processing methods. The entire process chain for manufacturing fiber composite components can be mapped in the laboratory and pilot process for high-performance fibers and semi-finished products. This not only enables basic research, but also the possibility to react quickly and agilely to the development needs of companies.

The CFM is divided into four individual departments. In addition to the solution spinning laboratory and the carbon fiber hall, the CFM is completed by the ITA tape center and the impregnation area.
In the solution spinning laboratory, research is conducted on the process and product development of hollow multifilament and highly porous aerogel fibers. The process can be scaled from small series to industrial scale. The filaments produced range from classic PAN precursor production to new bio-based high-end materials.

With the pilot plant, carbon fibre properties can be improved in the “Carbon Fibre Hall” by developing and optimizing conversion profiles. In addition, as part of digitalization (I 4.0), a camera system was installed to monitor the stabilization process, detect fibre damage at an early stage and enable intervention. An innovative plasma module was also retrofitted in the post-treatment of the fibres, so that plasma-based activation of carbon fibres is now also possible.

© ITA of RWTH Aachen University | Figure 1: Plasma module

In addition, a newly developed sizing bath allows targeted flowing of the carbon fibre to achieve a more homogeneous sizing distribution. Furthermore, we meet the increasing demand for low-cost carbon fibers with alternative manufacturing processes and developed profiles for the conversion of polyethylene to carbon fibers at our continuous sulfonation plant.

The research focus of the ITA Tape Center is on product and process development of tapes and tape lay-ups. Rovings can be processed into tapes with different widths on two different laboratory spreaders. Air and rod spreading are part of the portfolio, as is the production of liquid-, binder- and fusion-fixed or impregnated UD tapes. The newly developed automated tape layer enables the generic production of lay-ups from dry tapes. The main focus is on the production of test specimens. The infrared emitter integrated in the tape laying head ensures local melting of the thermoplastic binder material, giving the scrim the necessary dimensional stability for subsequent impregnation processes.

© ITA of RWTH Aachen University | Figure 2: Automated tape layer

The impregnation and consolidation area of the CFM has been redesigned so that it can continue to shape current trends and research priorities in the future. Above all, the impregnation and consolidation of thermoplastic fiber composite materials required an addition to and revision of the machinery. The self-developed multi-material coater enables the coating or impregnation of a wide variety of fiber and matrix materials. In addition, the conversion of the hot press to a new electric tempering unit (up to 400°C) can ensure the precise consolidation of high-performance thermoplastics such as Peek and PPS.

Contact

Lars Wollert

Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 (0) 241 80 – 23283
Mail: Lars.Wollert@ita.rwth-aachen.de

Andreas Bündgens

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49/(0) 241 80-23260
Mail: andreas.buendgens@ita.rwth-aachen.de

ITA acquires new sample weaving machine for carbon fibers

This year, we were able to expand our weaving machine park with a highly flexible and carbon fiber-compatible sample weaving machine from CCI Tech Inc., New Taipei City, Taiwan, type Evergreen II CF 500. On a width of 50 cm and with the help of 24 pneumatically controlled heald frames, a wide range of fabric patterns can be developed, even three-dimensional textiles. The one-sided active weft gripper enables very gentle fiber processing. This is not only beneficial for carbon fibers, but for all sensitive yarns that we want to research and produce in the institute. The warp yarns can be fed from small warp beams as well as from bobbin creels. With the fabric width of 50 cm, we close the gap of our previous weaving machine park, where we could produce either only up to 20 cm width or then directly around 2 m width. The width of 50 cm is sufficient to carry out mechanical tests such as drape tests on the dry textiles, to produce small demonstrator components or hand samples already with a small quantity of available yarn material.

© ITA of RWTH Aachen University |  Figure 1: Sample weaving machine CCI Evergreen II CF 500

© ITA of RWTH Aachen University | Figure 2: Pneumatic heald frame drive (24 heald frames)

The sample weaving machine was procured as part of the FutureTex 2020 funding program, for which we would like to express our sincere thanks to the BMBF. The aim of the investment and research project is to demonstrate the possibilities of digitalization for the textile industry with the help of a demonstrator factory. For this purpose, the sample weaving machine is currently being integrated into a fully connected process chain in which customized products can be manufactured in small batches with a high degree of automation. As a product example, a pair of jeans with protective function will be manufactured at ITA within two locations. At the same time, the process chain provides a basis for further research into the collection of production-relevant data, quality assurance, assistance systems and automation of handling processes.

© ITA of RWTH Aachen University | Figure 3: Carbon fabric sample on the machine, 50cm width

© ITA of RWTH Aachen University | Figure 4: Connected process chain for the production of individual Jeans

Contact

Christian Boltersdorf

Research Associare | Flat Composite Reinforcement
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 (0) 241 80 – 22091
Mail: christian.boltersdorf@ita.rwth-aachen.de

Carolin Blaurock

Research Associare | Fabric Production
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49/(0) 241 80 – 23465
Mail: carolin.blaurock@ita.rwth-aachen.de

ITA researches production concepts for small aircraft

As part of the national aviation research program ITA is investigating key technologies for the production of electrohybrid small aircraft

In November 2020, the E-SATstart project was launched as part of the sixth edition of the National Civil Aviation Research Program (LuFo VI-1). The overarching goal of the joint project is to develop key technologies for the electrohybrid Silent Air Taxi. The Silent Air Taxi (SAT) is a particularly quiet small aircraft for up to four passengers with a cruising speed of over 300 km/h and a range of 1000 km, which is currently being developed in Aachen by e.SAT GmbH. It features an innovative boxwing wing and a unique electro-hybrid propulsion system. This enables short take-off distances from almost any asphalt runway. Thanks to its innovative design and powerful powertrain, the Silent Air Taxi can fly to more than 95 % of all German airports and airfields and will thus make a significant contribution to the transformation of mobility. As part of the project, a wide range of key technologies – from propulsion and actuators to structural design – are being developed for future air taxis in close collaboration with other institutes at RWTH Aachen University, Fraunhofer Institut für Produktionstechnologie (IPT) and various industrial partners. The main focus of the Institut für Textiltechnik is the development of manufacturing technologies for the cost- and resource-efficient production of the load-bearing structure. A particular innovation is the hybrid design consisting of a thermoplastic shell, a thermoset spar and the associated joining process. Particular attention is being paid to the automation and digitization of production and quality control, a basic requirement for high-volume series production, especially in the aerospace industry.

Contact

Yanick Schlesinger

Researcher 
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 (0) 241 80 – 23457
Mail: yanick.schlesinger@ita.rwth-aachen.de

Dominik Granich

Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49/(0) 241 80 – 22092
Mail: dominik.granich@ita.rwth-aachen.de

ZIM LiPa successfully concluded – textile reinforced concrete floor slabs developed

Commonly available concrete floor slabs, as used for public and private pavements and places, are limited in their size. For edge lengths above one meter, common slabs need to be very thick to prevent damage during transportation and installation. For even larger slabs, steel reinforcement is usually used, which also requires a high thickness to prevent corrosion of the reinforcement. These thick concrete slabs are very heavy, leading to a difficult and expensive transport and installation.

Within the joint research project “Lightweight Pavement” – LiPa -, the ITA and Basamentwerke Böcke developed an alternative: thin-walled concrete slabs with an edge length of up to two meters using a textile reinforcement. The partners developed a tailored textile reinforcement and concrete mixture, ensuring a high quality surface of the slab and no damage during transportation while remaining economically viable. In addition, the current production process was adapted for the use of textile reinforcements, ensuring quick production with a low reject rate. The slabs were tested continuously during the development to ensure a safe and market ready product.

By reducing the thickness of the concrete slabs whilst increasing their size, the new slabs offer a multitude of advantages. The reduced weight allows for easier handling, with a 2×1 meter slab weighing less than 200 kilograms. The increased size can reduce installation times since fewer slabs need to be installed. In addition, the reduced thickness of four centimeters decreases the necessary storage space, reducing logistics costs. Another important advantage is a reduction in CO2-emissions, since less concrete is used. The production of cement used for concrete produces about 6.5 % of the global CO2-emissions, thrice the amount emitted by the global aviation industry. Therefore, saving on concrete is essential to achieve global emission reduction targets.

The developed slabs are currently being introduced into the market by Basamentwerke Böcke GmbH. The partners are grateful for the support of the BMWI through funding within the ZIM program.

© Basamentwerke Böcke GmbH | Installation example of textile reinforced concrete floor slabs with dimensions of 2×1 metres

Contact

Martin Scheurer

Researcher 
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone:+49 241 80 23471
Mail: martin.scheurer@ita.rwth-aachen.de