Vibration-assisted continuous production of composite sheets on double belt presses

Figure 1: Inductive double belt press @ AZL

Natural fibre reinforced plastics (NFRP) combine a promising potential for lightweight applications with a significant carbon footprint reduction, compared to conventional fibre reinforced plastics (FRP). Additionally, the specific material properties of natural fibres can enable further advancements, regarding e.g. low density, low material costs and high damping properties. Especially for applications in mobility, these properties are of great interest. On the other hand, the varying material properties of biobased materials, especially natural fibres, and challenging processing properties have so far prevented a transfer of structural NFRP parts into mass production.

Together with the project partners, AZL was granted a public funded project, “VIBRIO”, by the Federal Ministry for Economic Affairs and Climate Action (BMWK), with the goal to tackle these challenges and substitute FRP parts, which emit high amounts of greenhouse gas emissions during production, with highly functionalised biobased composite parts, produced in a digitised, vibration-assisted production process (see figure 2).

An established process to mass produce composite parts is the double belt press process. In previous joint partner projects, AZL has built up a prototype energy efficient double belt press (DBP) (see figure 1). The DBP uses inductive heating, to reduce energy consumption up to 60 %, compared to conventional heating methods (e.g. oil-bed heating). The high-temperature resistant elastomer coated rollers of AZL’s DBP offer a surface pressure with a smooth gradient. In general, the challenging material properties of natural fibres often lead to insufficient impregnation and reproducibility in the DBP process. Therefore, in the VIBRIO project, AZL will adapt its DBP for NFRP production by adding a vibration module. The approach induces kinetic energy into the plastic and therefore improves the flow properties without increasing the temperature to a point at which the natural fibres are damaged. The goal is to improve impregnation and reproducibility of the produced NFRP parts. After the production of semi-finished products in the DBP, the parts will be functionalised by UD-tape reinforcement, thermoforming and overmoulding. The final demonstrator part will be a bike saddle, which resembles a widely known mobility application with high requirements. Additionally, a holistic digital twin will be build up in the project, based on sensory data collected in the processes, to optimise process parameters.

Figure 2: VIBRIO process chain

An accompanying assessment of life-cycle analyses (LCA) key values and economic feasibility will help the transfer of the project technologies and results into a wide industry application. If you are interested in the technologies of substituting high greenhouse gas FRP products with functionalised biobased composite parts, feel free to contact us

This project is funded in the TTP LB programme of the Federal Ministry for Economic Affairs and Climate Action. We want to thank the Projektträger Jülich and all project partners of the consortium, including A+ Composites GmbH, Ergon International GmbH, FEM-Composites GmbH, Fraunhofer IPT, MITEX GmbH, NetterVibration and SK-Industriemodell GmbH.

The inductively heated double belt press has been developed and refined over several generations of Joint Partner Projects at AZL with industrial partners. Today, the DBP is already available at the AZL Tech Center, currently without the vibration module, to conduct bilateral trials and feasibility studies, including e.g. impregnation, consolidation of tapes and post processing of tapes. If you are interested, please contact us.

Aachen Center for Integrative Lightweight Production (AZL) of RWTH Aachen University
Simon Greive
Research Assistant
Phone: +49 241 8024526

Expertise/ background in:

Production and development of composite parts
Materials: thermoset and thermoplastic resins, continuous fiber composites, metals and plastic-metal hybrids
Process: prepreg, autoclave, resin infusion, RTM, milling, tooling, joining, quality assurance
Design: CAD design and design to process
Networking: Matchmaking with academic and industrial partners

I will support you in:

  • Process selection, evaluation and implementation
  • Evaluation and benchmarking of solutions
  • Identification of applications
  • Benchmarking with market companions state of the art solutions
  • Identification and elimination of pain points
  • Connect with the right partners for industrial implementation