High-pressure turbine blades experience intense stress at the root transition zone, where the blade connects to the dovetail slot. In this region, the corner radius must precisely match the design curve to ensure durability and prevent premature failure.
Challenge
Any deviation-even a few microns-from the design radius may cause stress concentration, compromising the blade's fatigue life. Achieving perfect curvature is tough due to limited tool access and deformation risks during cutting.
Solution
We addressed this with a focused, multi-step precision workflow:
Simultaneous 5-Axis Machining
Employed multi-axis control to maintain exact attitude of the tool through the complex curve.
Specialized Miniature Tooling
Custom small-diameter cutters were used to access tight spaces without deflection.
Controlled Entry/Exit Speeds
Slow, steady feed rates prevented deviations caused by tool impact and sudden loading.
Multi-Point In-Process Probing
During machining, we took multiple radius checks. If deviations appeared, the tool path was compensated immediately.
Outcome
Radius deviation reduced from ±0.03 mm to ±0.005 mm
Surface finish finished at Ra ≤ 0.2 µm
Estimated fatigue life improved by ~15%
This process ensures that even high-stress fillets in turbine blade roots perform reliably under extreme conditions.
