CompositesWorld
Issue link: https://cw.epubxp.com/i/450689
FEBRUARY 2015 30 CompositesWorld PLANT TOUR From the braiding room, Blair moved us on to Exelis' flament winding operation, where the process is used primarily to manufac- ture potable-water and wastewater storage tanks for aircraft. Here, Exelis operates several winders manufactured by Salt Lake City- based Entec Composite Machines Inc. and one system from McClean Anderson (Schofeld, WI, US). Te tanks, which are about 1m long and 0.25m diameter, are wet wound with carbon fber/epoxy and are outftted with a variety of fxtures and attachments, all of which Exelis assembles in house. Te wastewater tanks feature stainless steel liners; the potable-water tanks have blowmolded plastic liners. Te company manufactures about 700 tanks per year, primarily for Boeing's 737, 747, 757, 767 and 777 aircraft. In addition, Exelis is a certifed FAA repair station for the tanks. CDMC: Seeding the future If the Exelis Billy Mitchell Rd. facility repre- sents the company's legacy processes and applications, then the CDMC site on Amelia Earhart Dr. represents its potential. Tis new (2012) 22,760m 2 purpose-built plant houses the equipment and facilities neces- sary to meet all of the contemporary requirements of aerospace composites manufacturing — high-precision fber and tape place- ment, cleanroom layup, large-format autoclave cure, precision machining, nondestructive inspection (NDI) and assembly. Most Exelis braids preforms in a variety of sizes — the largest for the fuselage of the JASSM, and the most complex, the variable bleed valves (VBV) for GE Aviation's (Evendale, OH, US) GEnx engine. Tis carbon fber/BMI part, also RTM'd, comprises several preforms and features a variety of difcult-to-mold angles and spaces. Exelis makes 11 diferent VBVs per engine and eventu- ally will produce 12 shipsets per month at full rate production. Another notable braided structure is the fow path spacer for the GEnx engine. Te spacer, about 1m in diameter and 60 mm wide, is located aft of the intake fan. Blair notes that, despite its long history in composites manufac- turing, braiding is not usually performed by fabricators. However, braiding is clearly an expertise that Exelis has cultivated carefully and invested in heavily. "Not many compa- nies do their own braiding," Blair points out, but explains, "It gives us more fexibility and makes us more lean." No matter where the Exelis empire expands, it's clear that the company's core strengths are braiding and the products that result. But lessons learned as Exelis devel- oped its braiding expertise are now applied to a variety of processes, including those used to produce its latest product line — struts, tubes and rods (STaR). "We're basically going after galactic domina- tion in struts and rods," Blair quips. High-throughput Winding Hardware Exelis has used flament winding to build a strong competency in the fabrication of struts, tubes and rods for aerospace applica- tions. Most recently, Exelis established a partnership with Italian machinery frm Bodair to develop a manufacturing cell (shown here) for the high-speed manufacture of struts and tubes. The cell will allow Exelis to quickly customize manufacturing to meet material, diameter, hardware, ftting and boss requirements. In-house Braiding for RTM, VARTM An Exelis worker monitors activity on one of the compa- ny's larger braiders. Exelis is rare among composites fabricators in that it performs most of its own braiding operations. All of the braided product is used in RTM and VARTM processes, followed by oven cure. Lessons learned as Exelis developed its braiding expertise are now applied to a variety of processes.