Danish precision machining specialist CNC Onsite and Dutch rotor blade expert We4Ce have successfully completed their first joint project, bringing advanced blade repair expertise to a wind park in South Asia. In May, the companies trained the customer s technicians to independently repair loose blade root bushings on 26 turbines, marking the first in-field application of their new remanufacturing method. This innovative approach utilizes a custom machine, designed and built by CNC Onsite, to drill out defective bushings from the rotor blades  composite laminate, creating precisely dimensioned holes for replacements. By leveraging composite materials and on-site repair techniques, the method offers a cost-effective, sustainable alternative to full blade replacement, eliminating the need for offsite transport and significantly reducing blade waste.

CNC Onsite s custom-built precision machine removed the damaged bushings on-site, enabling the park s technicians to apply We4Ce s patented Re-FIT bushing and fastening method. Ahead of the 50MW project, the technicians were trained at We4Ce s laboratory in the Netherlands on the repair technology, and at CNC Onsite in Denmark on operating the precision machine. Delivered under a licensing model, this technology transfer enables wind parks to carry out major blade repairs using their own service teams. Following their training, the South Asian service team set up a field workshop at the wind park and, under the supervision of CNC Onsite and We4Ce, carried out large-scale repairs over several weeks.

Securing and completing this first contract for our bushing and insertion method is the result of fine engineering for practical application, says Arnold Timmer, managing director of We4Ce. We first conceived the idea in early 2022 after an initial job with a client in India and then spent three years developing and testing the solution.

By adopting the remanufacturing technology, the customer will restore more than 1,000 bushings. The process combines precision milling, a specialized fixing method, and the installation of replacement bushings to produce a like-new component engineered for reliable performance over a lifespan of up to 20 years. This approach represents a significant improvement over conventional repair method.

Remanufacturing Technology: A Future Option for O&M

With operation and maintenance (O&M) crucial to long-term turbine performance, remanufacturing, restoring parts to equal of higher quality than original condition, is likely to shape how the wind sector approaches maintenance in the years ahead.

Replacing bushings as an aftersales activity is a complex process, requiring precise removal and re-insertion for a strong mechanical bond.

Three industrial work tents, each measuring 100 m and housing a rotor blade, were set up as clean environments. In the first tent, one blade was drilled; in the second, the bushing replacement was carried out; and in the third, final flattening was completed.

The We4Ce and CNC Onsite method provides significant advantages: up to 60 percent in cost savings, reduced downtime, and environmental benefits from eliminating potential blade waste and blade transportation, which would typically incur high logistical costs and CO2 emissions.

Efficient Drilling in Fiberglass Blades

CNC Onsite designed and built a custom machine to drill out defective bushings from the rotor blades composite laminate, creating accurately dimensioned holes for replacements.

Drilling in fiberglass is typically hard on the tools causing them to wear out quickly. That is why as part of this project, we developed special drills to achieve high precision and efficiency, explains Soren Kellenberger, partner and sales director, CNC Onsite.