CompositesWorld
Issue link: https://cw.epubxp.com/i/632301
51 CompositesWorld.com NEWS N E W S N S N E W S E N W S W Spirit AeroSystems Prestwick Longer tool life. Faster speeds and feeds. No delamination. For composites, the AMAMCO Tool Slow Spiral Router, with its custom configurations and CVD diamond coating, can save you both tools and materials. Call to see if we can configure one for your composite application. 800.833.2239 www.amamcotool.com Wayne Taylor –Master Fluter C U T C O S T S. N O T Q U A L I T Y. BOOTH 108 of the part supporting the internal features of a hollow structure after cure. Te ability to warm the structure and soften the SMP tooling, rendering it slightly elastic, helps to facilitate part removal from the tooling. Out-of-autoclave prepreg process development OOA-cured composite materials ofer signifcant afordability and fabrication- fexibility advantages over traditional autoclave-cured materials, but their use on modern rotorcraft structures poses unique challenges. Te need for extremely lightweight structures on rotorcraft fuselages has been met by Spirit through the use of composite skin panels that feature nonmetallic honeycomb core bonded to very thin composite facesheets. For OOA processing of prepreg, vacuum bagging is critical to success, and there are a host of skills that tech- nicians must master to prepare layups well for oven curing. Te autoclave, by comparison, is a more forgiving device. At Prestwick, Watson was able to show some of the development Spirit had done with Cytec's MTM44-1 prepreg on traditional fanged honeycomb panels. An example photomicrograph of a honeycomb ramp fange interface can be seen in Fig. 4, p. 50. Te quality of the interface can be seen to be at least as good, if not better than, that achieved in the autoclave. Spirit reported that when sandwich panels are constructed under atmo- spheric pressure, some flm adhesives exhibit a tendency to foam, creating porosity in the core-to-cell wall fllets that reduces shear strength. Te propen- sity to foam is a function of the adhesive itself and the material and form of the carrier. OOA adhesives are available, and Spirit scientists carefully selected products to match the cure cycle of the facesheet resin system to eliminate strength reductions in sandwich panels caused by adhesive foaming. Also, if not properly bagged and cured, some OOA materials have slightly higher porosity levels that might make OOA materials more susceptible to FIG. 5 OOA target: Rotorcraft landing gear door Out-of-autoclave cured honeycomb sandwich panels could reduce cost on many aircraft programs. An engineer holds a likely OOA prospect: A composite main landing gear door. In the background is the full fuselage of the rotorcraft to which it belongs, a Bell Helicopter V280 rotorcraft.