CompositesWorld

FEB 2018

CompositesWorld

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NEWS 45 CompositesWorld.com typically don't want to consolidate the part in the mold, but instead form a pre-heated, pre-consolidated laminate, and then use the tool to cool the pre-heated part." Less common, and still under development, is in-situ consolida- tion (Fig. 3, p. 44), where slit tapes (tows) are placed on a tool via automated fiber placement (AFP) or automated tape laying (ATL). In this system, a high-intensity laser, hot gas or flame at the tape head heats the resin to melt temperature to soften it, while the end-effector applies pressure to consolidate the plies. Ultimately, such a system would perform full consolidation in-situ, but is still being developed for demonstration. For now, further consolida- tion (autoclave or similar) is required to achieve porosity targets. Pierre-Yves Quéfélec, global and defense business unit head at Porcher Industries (Eclose-Badinières, France), which specializes in AFP of thermo- plastic tapes, says the company works with machinery manufacturer Coriolis Composites (Queven, France) and is targeting <0.5% porosity. "An autoclave is still needed for this," he says, "but we are starting to reach this level with oven cure, depending on the quality of the AFP. e high viscosity of thermoplastics is a chal- lenge, as is the homogeneity and consis- tency of the impregnation." Although it is not widely used today, the most promising process in work toward the <0.5% porosity target is possibly continuous compression molding (CCM, see Fig. 4, p. 46 and see Learn More). Here, continuous tapes are passed through forming tools that heat and shape the material and create, effectively, a range of shapes, including T, C, H, hat and Omega profiles and others. is process has particular promise for the manufac- ture of stringers and frames for commer- cial aircraft. As noted, autoclave cure is an option, and for some, a necessity, to ensure minimal porosity. Offringa notes that Fokker prefers the autoclave because it facilitates resin flow through the fiber and helps maintain process control and consistent part quality. e time required to consolidate a thermoplastic compo- nent in an autoclave is usually 3-4 hours — significantly less time than required to cure and consolidate thermoset materials. Solvay's Pratte says achieving porosity targets is not difficult with most of the thermoplastics processes used today. "Time and temperature takes most of Thermoplastic Composites the voids out," he says. e only process that struggles, he says, is in-situ ATL/AFP, because the timescale — the amount of time spent applying pressure at temperature and consolidating the tape — is limited. "e key point here is not so much porosity as wetout of the filaments with polymer in the tape. You might have some porosity in the tape, but you cannot have dry fibers as the in-situ process times- cale and conditions will not compensate for that." Advantages ermoplastics in general, and PEEK and PEKK in particular, are difficult to dislike. As already noted, they offer mechanical Verisurf automates quality inspection and reporting on the shop fl oor, in the quality lab or out in the fi eld. Verisurf Quality Inspection Software combined with expert training and support delivers what you need to increase quality and productivity while lowering costs, now. Simple Align-Inspect-Report workfl ow makes Verisurf easy to learn, easy to use. Built on an open CAD platform with integrated GD&T;, Verisurf supports all brands and models of Coordinate Measuring Machines and Scanners ensuring enterprise compatibility, fl exibility and reduced training costs. Get the power of Verisurf Quality Inspection Suite today, with fl exible purchase options to match your company's needs. Visit https://www.verisurf.com/inspect Quality Inspection Suite Increase Productivity - Reduce Rework - Lower Production Costs www.verisurf.com • 866-340-5551 CAD MEASURE REVERSE BUILD ANALYSIS CMM CMM CMM CMM CMM CMM CMM CMM CMM CMM CMM CMM AUTOMATE VALIDATE PROJECT See the difference at www.verisurf.com

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