CompositesWorld

MAR 2017

CompositesWorld

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MARCH 2017 40 CompositesWorld PLANT TOUR is building another structure like it. Two more WEG molds and the Acciona molds will eventually be moved to these spaces. Cutting, kitting, resin Next stop is the cutting and kitting building, where glass fabric, peel ply and infusion bagging film are cut and kitted for all non-Vestas wind blade assembly. e room is dominated by a large 10m-long Eastman Machine (Buffalo, NY, US) automatic cutting table for the cutting of glass fiber fabric and, next to it, a 25m long table for manual cutting of peel ply and film (Fig. 5, p. 39). Glass fiber fabric is delivered to this room from the ware- house on large rolls. Glass used here includes fabric from Owens Corning (Toledo, OH, US), SAERTEX (Saerbeck, Germany), CPIC (Chongqing, China) and Gammatensor (Alcoy, Spain). Owens Corning materials are supplied from Rio Claro (São Paulo, Brazil). Saertex materials are supplied from Indaiatuba (São Paulo or Huntersville, NC, US). Cut plies come off the table, are imme- diately re-rolled by workers and then stacked on pallets and prepared for delivery to molds. Lolli says that one of the challenges of molding large blades from large molds is dimensional accuracy. Even the very best molds made to the highest standards are unlikely to match, exactly, the plies in the as-designed layup schedules. us, it is also unlikely that plies cut to design spec will lay up without some gaps or overlaps. Because of this, kit development for each blade SIDE STORY One result of Aeris Energy's close relationship with resin supplier Hexion (Columbus, OH, US) is that the former has embraced much of the latter's strategic and operational thinking. Hexion's wind energy and composites team, led by Johannes Meunier, Hexion's global segment leader, wind/composites, has been a steady, influential presence at Aeris almost from its start. Meunier and his team, based out of Germany, have a long history with composite materials, composites manufacturing and the wind energy industry. Because of this, he has seen good and efficient as well as bad and inefficient composites manufacturing. In short, he has firm opinions about what it takes to maximize efficiency, quality and profitability in the wind blade manufac- turing space. Meunier notes, first, that the wind blade manufacturing industry has matured substantially in the past decade. Product quality standards have tightened, material quality has improved, manufacturing processes have been fine-tuned, blade architecture has evolved, average blade length has increased, and blade lifespan expectations have lengthened — to 25 years. Unchanged, however, is the fact that the blade is the bottleneck in the overall wind turbine manufacturing process. Blademakers, therefore, are under constant pressure to increase the pace of manufacture, without failing to meet quality and cost targets. Compounding this challenge is the famous Square-Cube Law, which says: • Wind turbine power is proportional to the square of rotor diameter, and . . . • Wind blade mass increases in proportion to the rotor diameter cubed. What does this mean? In prractical terms, wind blade mass increases at a greater rate than wind turbine power as rotor diameter increases. Meunier, therefore, has a few simple rules for coping in this environment. First, emphasize quality and value over unit price. Or more simply, you get what you pay for. Second, and conversely, don't choose materials based on low unit price. Very often, Meunier says, the use of a more expensive, higher quality material (glass fiber, resin, bonding paste) can provide long-term savings that more than offset the additional cost of the material. Third, he says, capture data. Good manufacturers value map — that is, they measure every manufacturing activity and know intimately what it costs in money, personnel and time to manufacture a blade. Among the things to measure: In-mold repairs, raw material cost and waste, resin used vs. resin disposed of, blade manufacturing time, man-hours per blade, cycle time and kitting accuracy. Fourth, continuously improve. Use your captured data to feed a continuous effort to increase manufacturing speed and workflow without increasing personnel costs. Look for wasted time, effort, material and money, and then work to get rid of it. "The customers that see that potential are the most successful customers," Meunier contends. "You cannot achieve such savings by pushing down on unit price. You must innovate the cost out." This philosophy is expressed clearly at Aeris in many ways — in how the company manages its workforce, cares for its molds, carries out production, and positions itself in the marketplace. "We do not make the least expensive blades," admits Bruno Lolli, Aeris' planning and process management director. "That is not how we compete. But we make quality blades, and we focus on serving the customer. We feel we are in a very good place." Wind blade economics FIG. 6 Adhesive bonding a top priority Hexion's bright green RIM BP535 bonding paste is ubiquitous throughout the Aeris facility. It's favored because it offers low density, high toughness, low sag, spreadability and long pot life. Source | Wellington Fernandes

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