Liquid Composite Molding: A Widely Used Group of FRPC Processing Techniques, but still a Challenging Topic

Abstract:

Liquid Composite Molding techniques are widely used technologies in order to manufacture fiber reinforced plastic composites using near-net-shaped preforms consisting of single reinforcements, e.g. woven textiles or multiaxial fabrics. All LCM process variants have in common to impregnate and saturate dry reinforcing structures with a liquid thermoset resin system. The challenge during LCM process development and mold designing is the prevention of potential error sources for safe in-spec FRPC production. Race tracking zones and air inclusions are two major issues which need to be avoided in order to ensure an excellent FRPC quality. The knowledge about preform transmissibility, i.e. permeability, of the dry reinforcing structure to the liquid flow during the saturation phase is of major importance. The knowledge about the filling and flow behavior during FRPC processing is responsible for the process efficiency and process success. In-plane and out-of-plane permeability characterization is of great interest. Especially industry is interested in precise permeability values for numerical mold filling simulations in order to support the process development and the mold design. Industrial work is also carried out for filling strategies and textile development as well as textile improvement. The paper presents different LCM processing techniques and discusses the advantages and disadvantages as well as the linked challenges during FRPC processing. Furthermore, the in-plane permeability characterization of reinforcing structures and moreover influencing factors on the filling behavior are presented. Finally the significance of accurate and reliable permeability values according to numerical filling simulations and their validity are discussed.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 1715-1720
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.1715
• Online since: November 2016
• Authors: Ralf Schledjewski*, Harald Grössing
• Keywords: Fiber Reinforcements, Liquid Composite Moulding, Permeability Characterization

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