Precision Machining of an 8-Meter Diameter Wind Turbine Flange
1. The Project Challenge
A leading manufacturer of offshore wind turbines required a critical component: a massive 8-meter diameter flange to connect the main tower to the foundation. The immense operational stresses required the flange to be machined from a single, high-strength forged steel billet weighing over 25 tons.
The primary challenges were twofold. First, achieving a stringent flatness tolerance across the entire 8-meter sealing face was essential for a secure connection. Second, hundreds of large-diameter bolt holes needed to be drilled and tapped around the perimeter with extreme positional accuracy. Any deviation would prevent assembly in the field, leading to costly delays.
2. The Openex Solution & Capabilities Engaged
Openex was selected for this project due to our unique combination of ultra-large machining capacity and precision metrology.
- Heavy Turning on 10m VTL: The raw 25-ton forging was loaded onto our 10-meter Vertical Turning Lathe (VTL). This machine allowed us to turn the full diameter of the flange, machine the critical sealing faces to a flatness of less than 0.05 mm, and cut the intricate grooves required for the sealing system.
- Single-Setup CNC Drilling: To ensure the accuracy of the bolt pattern, the turned flange was transferred to a large CNC gantry mill. By machining all holes in a single setup, we eliminated the potential for cumulative error that would arise from repositioning the part, guaranteeing that the bolt pattern was perfect.
- Large-Volume Metrology: Throughout the process, a laser tracker was used for in-process verification. Because the part was too large for a traditional CMM, the laser tracker was essential for mapping the surface flatness and confirming the position of each bolt hole relative to the flange's central datum.
3. Results and Impact
The massive wind turbine flange was completed and delivered ahead of schedule. The final inspection report, generated from the laser tracker data, confirmed that all features were well within the client's tight tolerances. Our ability to perform the turning and drilling operations on equipment properly scaled for the job resulted in a flawless component that enabled a smooth and rapid assembly process for the client's offshore wind farm project.
Execution Floor Documentation
Photographs of the flanges across Openex machining and other large flange projects.
