Saturated out-of-plane permeability and deformation metrology of textiles at high levels of injection pressure

Abstract

Out-of-plane impregnation and high levels of injection pressure are key strategies for cycle time reduction in Liquid Composite Molding processes. The combination of these two strategies provides a promising approach for large volume production of automotive components. In this context, a novel test system is presented, which allows the textile reaction characterization to saturated out-of-plane fluid flow at injection pressure levels of up to 200 bar. For any given engineering textile, the resulting out-of-plane permeability and total hydrodynamic compaction can be measured for different combinations of initial fiber volume content, number of layers and injection pressure. Initial tests on a conventional non-crimp fabric show a compaction-induced out-of-plane permeability decrease for pressure levels up to 95 bar, while for pressure levels between 95 and 170 bar the permeability remains constant. In other words above 95 bar, a further increase in pressure directly pays off in terms of increased flow rate. The identification of such processing windows can be very valuable for process design.

Keywords

• Liquid composite molding
• permeability
• hydrodynamic
• compaction
• textile