Quasi-isotropic, symmetrical fabric for tooling
This blog comes from my discussions with Steve Savoie, a manufacturing and tooling engineer who spoke at last year’s International Boatbuilders Exhibition (IBEX). Steve has a background in both aerospace and marine composites, and specializes in process development, tooling design and equipment utilization. For example, his session at IBEX discussed temporary oven design and cheap ways to set up aerospace-quality data loggers and temperature control systems (watch for a blog on that coming soon). We were discussing a project using A&P Technology’s (Cincinnati, OH, US) QISO material, and he commented what a great material it is for tooling, but that a lot of people don’t seem aware of it for that end use. Not being an expert on tooling myself, I asked Steve to explain what QISO offers for composite tooling and why.
QISO was introduced by A&P several years ago. Its weave pattern features 0°/±60° carbon fiber tows braided to yield a single layer of fabric that is balanced, symmetrical and quasi-isotropic. This offers real benefits for layup of complex tooling geometry. The bias yarns are two over, two under, alternating over and under the axial yarns with equal amounts of material by weight in each direction. A&P also notes that in testing, QISO has demonstrated reduced interlaminar stresses vs. more traditional laminates (e.g., 0°/±45°/90°) because all QISO plies feature the same architecture — i.e., you don’t have a large stiffness in the 0°, which then drops off in the ±45° directions.