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Chemical-stitching process for rapid preform-manufacturing

News International-French

8 Jun 2015

The Fraunhofer Institut introduces a process for automated production of complex dry textile preforms by local adhesive application.

Liquid Composites Moulding (LCM) processes such as RTM require rapid and cost-efficient manufacturing of complex dry textile preforms. In particular, concerning the medium and high volume production required for the automotive and mechanical engineering industry, the preform production is a major issue for manufacturing high-performance composite parts with LCM technologies.

This issue has been addressed using chemical stitching approach and combines the advantages of the existing preform technologies such as binding and stitching, therefore offering a high potential for high-volume production of complexe LCM parts.

Benefits of chemical stitching include:

  • No additional yarn required
  • Permeability of the textiles is maintained by using minimum amount of matrix-compatible adhesives
  • A time consuming bonder application and activation process avoided due to an in-situ curing of the applied adhesive spots enhanced by UV-light, laser, induction microwave
  • In-plane properties of the composites are improved by avoiding ondulation of the fibre-rovings, which is often caused as a result of yarn tension in conventional stitching processes
  • Preform stiffness adjustable by varying the amount of applied binder

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