WINDPOWER: Blade manufacture begins migration to automation

At WINDPOWER 2009, signs that machinery manufacturers have heard and heeded the cry for greater automation, more consistent quality and faster production in wind blade manufacturing.

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CompositesWorld spent a couple of days at WINDPOWER 2009 (May 4-6, Chicago, Ill.) and filed this report on the the emerging trend, in evidence at the show, toward automation of wind blade manufacture.

For all of the positive attention wind blades have given the composites industry in the last few years, it was immediately apparent at the WINDPOWER show that blade manufacture has become the weak link in the wind turbine supply chain. It seems universally understood that manual placement of glass fiber fabrics, manual management of resin infusion and manual application of adhesives and bonding agents, while acceptable for many boat manufacturing applications, is not acceptable for long-term manufacture of a wind blade that must behave more like an aircraft wing.

Wind blades, it turns out, must meet precise and demanding specifications to provide a well-balanced, well-tuned, efficient turbine that can pass the test of time, weather and wind. Flawed blades are subject to cracking, premature wear, imbalance, and a host of problems that lead, inevitably, to turbine downtime and loss of energy revenue.

This conundrum has not been lost on the composites industry. In the lead-up to the show, MAG Industrial Automation Systems (Hebron, Ky.) announced that it has developed the Rapid Material Placement System (RMPS) for the automated placement of gel coat, fabric (glass or carbon fiber) and adhesive in a wind blade mold. It offers 3m/sec layup speed for blade skin, spar cap and shear web molds and uses laser and vision-based systems to detect fabric wrinkles. The technology is based, in part, on MAG’s automated fiber and tape placement systems used to make aircraft fuselage and wing structures. Roger Cope, president Strategic Business Development Group at MAG, noted that a wind blade is more like a wing, and should be manufactured as such. The goal, he said, is to reduce blade weight and reduce warranty costs for blade manufacturers. Further, such a machine could bring consistent quality at high speed.

For its part, MAG has yet to actually build the RMPS, and to that end it’s pursuing a relationship with a U.S. blade manufacturer with whom to work to develop a functioning RMPS as part of a proof-of-concept program. Randy Kappesser, vice president and general manager Cincinnati Composites Technologies at MAG, said, “This industry is very manual and it’s begging for automation.”

Similarly, automated fiber and tape placement manufacturer Ingersoll Machine Tools (Rockford, Ill.) announced at WINDPOWER that it also has developed an automated system for blade-making. The Wind Blade Composite Deposition system, like MAG’s system, is purely conceptual right now, but the company is said to be working to build a machine and prove the technology. Finally, Danobat Machine Tool Co. Inc. (Elk Grove Village, Ill. and Elgoibar, Spain) announced a gantry-based automated blade manufacturing system that provides fabric layup, gel coat and adhesive application, edge trimming and surface grinding and measuring and inspection capabilities.

When these new machines are built, there is a good chance that they will be tested and proved at the AEWC Advanced Structures and Composites Center at the University of Maine (Orono, Maine). Habib Dagher, director of the center, was at the show and announced the center’s planned expansion of its Advanced Wind Blade Prototyping Facility. Dagher says ground on the expansion will be broken this summer, with completion expected by year’s end. When finished, the facility will allow for prototyping, optimization and testing of wind blades up to 70m/230 ft in length in an ISO-certified lab environment. Manufacturing processes include vacuum-assisted resin transfer molding (VARTM), prepreg, hand layup, injection molding, compression molding, filament winding, tape layup and extrusion. Full-scale structural testing can apply multi-axis loads of up to 300,000 lb/136,363 kg.

Dagher noted that the facility’s ability to help manufacturers evaluate resin, fiber, design, tooling and process should help blade developers reduce the design and engineering for a new blade from two years to one year. He agreed that blade manufacturing is the weak link in turbine production — “We need better automation under controlled conditions” — and thought that proving emerging automation technology would take about two years.

More broadly, Dagher noted that for all of the activity in onshore wind energy development, he thinks there’s greater potential in offshore wind and discussed the need for floating towers and turbines that can be located in water depths greater than 200 ft/61m. “Europe is 10 years ahead of us in offshore projects,” Dagher said, and also noted that the North Sea water in which Europe is placing many of its offshore wind farms tends to be relatively shallow; prime wind locations offshore of the U.S. East Coast, he said, runs deeper and thus requires a fresh look at how turbines can be located and secured.