JEC COMPOSITES MAGAZINE - Issue #68 Special JEC Asia - October 2011 - 59

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bi-angle NCF

Pultrusion and Resin Film Infusion (RFI) of bi-angle thin-ply NCF
Pultrusion and RFI processing technologies were developed and employed to produce laminates with mechanical properties superior to conventionally-constructed composites. Despite a few surmountable processing challenges, thin-ply NCF (non-crimp fabric) proved suitable for use with these cost-effective production techniques.
Tab. 1: Materials, processing variables and results RFI - Vacuum Reinforcements Matrix: brand and properties

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(1) VALENTIN NEACSU, PH.D., SENIOR COMPOSITES ENGINEER (2) JERRY FANUCCI, PH.D., CHIEF TECHNICAL OFFICER (3) RICK BALONIS, DIRECTOR OF MANUFACTURING OPERATIONS (4) JOHN STRONCK, SENIOR MANUFACTURING ENGINEER KAZAK COMPOSITES

T

he bi-angle thin-ply NCF development effort conducted by a global team chaired by Professor Stephen Tsai required the generation of a large amount of test data within material and time availability constraints. As a consequence, manufacturing trials made use of different types of materials or substitutes until adequate quantities of fibres and resin could be secured for further stages of the project. The summary presented in the next section shows a combination of manufacturing techniques and raw materials, which concluded in successful pultrusion of a high-quality thinply panel of [0/45/0/-45]8T schedule. Raw materials, processing variables and results are summarized in Table 1.

permeability of the fibres and possibly due to the presence of glass veils supporting the resin film layers, excess resin could not be transferred from the layup out into the breather layer, resulting in a thicker than expected cured panel (Fig. 3, details in

Table 1).

Panel manufacturing via RFI – hot press
Based on the prior finding that transverse resin outflow is minimal, the layup for the

Gurit SA80 film 250 g/m2 epoxy+25g/m2 glass veil support 127μm Two-stage cure at 80-120°C Vacuum level: -686 mm Hg (-27 in Hg)

Processing parameters

Panel manufacturing via RFI – vacuum
The layup of bi-angle carbon fibre plies [60o/85o]16T and epoxy film layers (x22) was bagged and subjected to vacuum, first at 80°C for increased resin flow and tow impregnation and then at 120°C for full cure. Due to the very low transverse

Panel: - dimensions (L-W-H) - fibre volume fraction General assessment

89 x 89 x 3 mm 47%

Non-uniform ply-to-ply resin distribution

Structural properties

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No68 October 2011 / jec composites magazine
RFI - Hot press Pultrusion T700 carbon NCF 160 g/m2, [60o/85o]16T T700 carbon NCF 160 g/m2, [0o/45o/0o/-45o]8T Epon 862 / Lindau LS-81K epoxy, no fillers Hexcel 8552 thin film 160 g/m2 epoxy, no veil 127μm Two-stage cure at 110180°C Pressed at 10 atm Two-zone heated die: entry at 177°C, exit at 166°C Speed: 15 cm/min 610 x 610 x 2.3 mm 61% 2464 x 305 x 2.3 mm 61% Good quality, consistent ply-to-ply resin distribution, high fibre volume fraction Mechanical tests conducted by Dr. Nettles of NASA. Results provided elsewhere in this issue.

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Feature bi-angle NCF
JEC COMPOSITES MAGAZINE - Issue #68 Special JEC Asia - October 2011

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #68 Special JEC Asia - October 2011
