CNC Onsite and We4Ce carry out first in-field blade root remanufacturing at 50 MW wind park

Press release

CNC Onsite and We4Ce carry out first in-field blade root remanufacturing at 50 MW wind park 

Vejle, Denmark, 5 September 2025 — Danish precision machining company CNC Onsite and Dutch rotor blade specialist We4Ce are applying a new method for remanufacturing loose blade root bushings directly at a 50 MW wind park in South Asia. The project represents the first large-scale use of CNC Onsite’s precision milling equipment combined with We4Ce’s patented infusion technology, allowing operators to restore critical blade components onsite without transporting them to manufacturers.

In spring this year, the companies trained the wind park’s technicians to carry out repairs on more than 20  turbines. The process begins with removing loose bushings using CNC Onsite’s custom mobile machining system, followed by installing replacement bushings with We4Ce’s infusion method.

Precision milling as the enabler

CNC Onsite’s mobile machining system drills out loose or damaged bushings from the blade root composite and re-machines cavities to exact tolerances. Special drills and controlled parameters —RPM and feed rate— maximizes tooling life as well as process time and accuracy across different blade designs and bushing sizes. Micrometer-level precision is critical to both ensuring correct BCD and maintaining structural load paths.

“Drilling in fiberglass composites is extremely demanding. You need to be in control of your process as well as use the correct tools — otherwise your tools wear rapidly and you do not obtain the tolerances needed to ensure the quality of the repair. To ensure a fast and reliable process we have also developed special drills for the process. They have very good durability and tolerance properties    ,” says Søren Kellenberger, partner and sales director, CNC Onsite. “Our role is to bring factory-level machining precision into a field environment, which is what makes We4Ce’s repair method deployable.”

Bushing fastening method

Once the old buhings have been removed, We4Ce applies its patented infusion process. Epoxy resin is introduced under vacuum through the base of each bushing, with glass fiber rovings reinforcing the bond. After insertion, the blade root is checked and flattened as necessary for proper hub mating.

“The progress of this first project shows how a laboratory-developed concept can be applied on a practical scale,” says Arnold Timmer, managing director of We4Ce. “We first tested the idea in 2022 and then spent three years developing and validating the solution.”

Field setup and training

A field workshop consists of three industrial tents: one for drilling, one for bushing replacement, and one for final flattening. This configuration allows multiple blades to be processed in parallel. After some weeks training, the customer’s technicians are able to operate the system independently and transfer the method to other wind parks.

The 50 MW project will restore over 1,000 loose bushings in 2025. The combination of precision milling and resin infusion returns blade roots to near-original stiffness and fatigue resistance, extending component life up to 20 years. Compared with full blade replacement, the method offer up to 60 percent savings reduces downtime, avoids transport risks, and limits material waste..

Blade root bushings are critical load-bearing points connecting the rotor blade to the hub. In older designs, resin shrinkage or uneven distribution during manufacture can create microcracks that loosen bushings over time. Onsite remanufacturing provides a technically and economically viable solution for life extension, reducing costs while maintaining safety.

Future applications and exhibition

CNC Onsite and We4Ce are preparing projects in Brazil and the United States. At the Husum Wind exhibition in September 2025, CNC Onsite will present its onsite precision machining technology and share insights from ongoing blade root repairs, demonstrating how field-deployable equipment can maintain micrometer-level accuracy under challenging conditions.

Über CNC Onsite
CNC Onsite mit Hauptsitz im dänischen Vejle entwirft, baut und liefert hochpräzise mobile Bearbeitungsmaschinen für Windkraftanlagen einschließlich Offshore-Fundamenten. Die von CNC Onsite gebauten Maschinen sind nach dem firmeneigenen „Baustein“-Konzept modular gestaltet, sodass sie für eine Vielzahl von Aufgaben gebaut werden können. CNC Onsite bedient den Onshore- und Offshore-Windenergiesektor und liefert als Standardlösungen: Bearbeitung von Stahlflanschen mit großem Durchmesser und von Blattwurzel-Enden; spezialisierte Reparaturdienste für Gierring, Blattwurzel-Einsätzen, Rotorsperren, Generatorwellen, Lagergehäuse und Gewindebohrungen. Das Entfernen und Ersetzen verschlissener und gebrochener Bolzen rundet das Angebot ab.
www.cnconsite.dk