How Wind Turbine blades are Manufactured?

The methods of manufacturing influence the lifetime of a wind turbine blade.

Blade manufacturing procedures can introduce conditions in the composite that strongly
influence fatigue life and potential failures. These conditions include local variations in resin
mixture homogeneity, local porosity variations, local fiber curvature and misalignment
of fibers as well as local residual stresses. Such conditions are variables in all composite
manufacturing processes and should be considered in the design.

Wind blades are usually manufactured by a process called vacuum infusion. In this process, the resin is vacuum driven to impregnate the glass fibers. and/or carbon and the structural cores
arranged in a shell-shaped mold, called a shell.

Regardless if the exact same manufacturing process is achieved with the exact same
manufacturing conditions and materials, the composite specimen will never be completely
identical to the previously manufactured composite specimen.

Typically if a blade has a pre-bend, the PS is the blind spot when the mould is closed. This
increases the risk of manufacturing defects on the PS adhesive bond line.

Blade accessories such as balance box, shear webs, spar caps, etc. they are manufactured separately and glued to the shells when the resin is already cured, before closing the blade.

One shell is called the soffit and the other is the upper torso. They look identical but have different aerodynamic profiles. The soffit side is also called the pressure side because it concentrates greater static pressure during the flow of fluids.

The extrados side is called the suction side due to the lower static pressure (and higher dynamic pressure) during the flow of fluids.

After the two shells are fabricated, the paddle is closed and an adhesive is applied to the gluing region. Finally, the blade is finished, with the placement of pins (T-bolts), balancing, and anti-UV painting.

Generic Steps of Composite blade Manufacturing

Prepare Mould

Build up Dry layers

Resin Infusion

Add webs

Join Shells

Demould