Streamlining Rotor Blade Manufacturing With Advanced Materials
The wind power sector is growing rapidly, especially with developments in offshore wind farms. The demolding process has traditionally relied on release agents that decrease efficiency and increase costs, but researchers have developed a stretchable film that will streamline the process.
Wind power has lagged behind solar during the worldwide shift to renewable energy, but with recent milestones in offshore wind farm technology, wind energy is making crucial leaps forward. Another important step has just been taken with the development of the PeelPLAS release film, a stretchable film created by researchers from the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM).
The flexible PeelPLAS release film used for improved demolding. Image used courtesy of IFAM
Rotor blade manufacturing for wind turbines has often relied on manual steps during the molding and curing steps of production, and the lack of automation has driven up costs and reduced efficiency. This release film technology will ultimately circumvent manual processes that slow down manufacturing, as once the film has helped demold the blade components in production, there is no need for time-consuming scrubbing and grinding to remove chemical release agent residue.
Challenges of Manual Demolding
The Global Wind Energy Council (GWEC) just released its annual report on the state of wind power, and it is clear that wind power will continue to grow as part of the shift to renewable energy. The GWEC forecasts a yearly growth of electricity produced by wind at a minimum 15% annual increase. Long-term projections are strong as wind power is expected to be critical in reaching net-zero carbon emission goals.
Annual wind power capacity projections. Image used courtesy of GWEC
Given such significant increases in wind power production, the manufacturing process will be strained to meet these goals. Engineers have critical contributions to make in streamlining and improving rotor blade manufacturing, which has often relied on manual operations that raise costs and reduce efficiency.
The challenges of rotor blade manufacturing are significant and have been widely addressed, going as far back as 13 years ago when the Department of Energy, in conjunction with the Wind Energy Technologies Department of Sandia National Laboratories, commissioned the Blade Reliability Collaborative (BRC). The BRC was set up to study these challenges and work toward solutions, and what they found was that blade defects were far too common and often attributable to the manufacturing process. They estimated that 30 of 100 blade failures were due to manufacturing defects.
One step in the blade manufacturing process prone to creating defects is the demolding process when the blade components are separated from the mold they are cured in. This process is delicate, and using chemical release agents has often led to inconsistencies and flaws in the rotor blade surface, which can significantly impact performance.
PeelPLAS Release Film Prevents Surface Defects
IFAM’s PeelPLAS release film helps streamline the demolding process and prevent defects by acting like a second skin on the mold that prevents direct contact between the rotor blade component and the mold itself. Unlike the mold, the release film is made of a special nonstick material that facilitates blade removal after the curing process is complete. Because the film is applied to the mold before any blade production material, the blade components will never come into contact with any surface other than the special PeelPLAS film specifically designed for a seamless release from the mold.
Historically, when release agents have been used, they have increased curing time. Release agent residues cling to both the blade and the mold, necessitating more cleaning and treatments for both, thus slowing down production.
Diagram of release agent residue and PeelPLAS residue prevention. Image used courtesy of IFAM
The PeelPLAS release film prevents this additional curing time and obviates post-production mold cleaning and scrubbing, which is manually intensive labor yet to be automated.
The Future of Rotor Blade Production and Maintenance
IFAM has made a critical contribution to removing costly and time-consuming manual steps to the rotor blade manufacturing process, and they have also just made another contribution to the maintenance of these blades once they are in use.
The Fraunhofer researchers are pioneering a drone technique to apply special protective coatings to blades without shutting down wind turbine operations, which can be costly. Many offshore and onshore wind farms exist in cold, damp environments that catalyze ice formation on rotor blades. Manually removing ice is slow and expensive, and the IFAM team is showing how drones can efficiently apply and reapply protective coatings to blades to prevent ice from forming in the first place.
Both of these innovations, streamlining the manufacturing process and automating parts of the maintenance process, are critical for the wind power sector. As reliance on wind power grows, engineers who can innovate such automation will make essential contributions to maintain the cost efficiency of wind production.
