Isogrid Composites Canada Inc. (ICCI, Montreal, Quebec, Canada) announced on March 25 that it has produced the first large-surface isogrid panel using its patented automated layup system. The panel, which measures 2 ft by 4 ft (0.61m x 1.2m) is believed to be the first Isogrid panel produced by automated multiple layup heads.
Such structures are normally relegated to hand layup in order to eliminate prepreg build-up at the triangular intersections of the ribs. The ICCI patented process eliminates nodular build-up, which allows composite sheet facing on both sides of the structure, providing strength and stability to the panel comparable to honeycomb, but eliminates the honeycomb moisture and other related disadvantages.
The isogrid design is noted for its extraordinary strength and impact sustainability. The “close-cluster” design of the triangular isogrid ribs is made possible by the miniaturized layup head design which is about the size of a hand. Weighing only 4.7 lb/2.1 kg, the 0.625-inch/16-mm thick panel comprises 86 plies of prepreg faced on a single side with a single layer of carbon composite sheet.
Although the panels are structurally sound with a single side faced, sheathing both sides increases strength approximately 40 percent inch. The panels, which are well suited to aircraft flooring, bulkheads and dozens of alternate aerospace applications, can also be shaped for curved structures as well as cylindrical and cone shapes. Thinner panels are being reviewed for rail and automotive transportation markets where honeycomb isn’t compatible with structural integrity requirements.
The goal of multiple head layup, according to Dr. Bijan Deris, ICCI Composite Products team leader, has always been to reduce the Isogrid-design manufacturing time for large panels and shapes from several days to a matter of hours. ICCI is a company dedicated to designing systems capable of producing isogrid structures in commercially viable production times. “Already we have been able to reduce panel production time to about one-fifth the time of hand layup,” says Deris. “And this is using only two heads.” The company is building a larger, faster multi-head system for panels up to 8 ft by 10 ft (2.4m by 3m).
The development of the system is being conducted with the Canadian National Research Council Canada (CNRC) Aerospace Manufacturing Technology Centre (AMTC). Montreal.